studies on pigeonpea (cajanus cajan (l.) millsp ... · intercropping effects of two maize genotypes...
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STUDIES ON PIGEONPEA (Cajanus cajan (L.) MILLSP.) GENOTYPES IN
INTERCROPPED SYSTEMS WITH MAIZE (Zea mays) IN A DERIVED
SAVANNAH AGRO-ECOLOGY.
BY
MADANG AYUBA DALONG DASBAK
B. AGRIC. (UNIJOS), M.Sc (UAM).
REG. NO: PG/Ph.D/04/35748
DEPARTMENT OF CROP SCIENCE,
UNIVERSITY OF NIGERIA, NSUKKA.
NOVEMBER, 2011.
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STUDIES ON PIGEONPEA (Cajanus cajan (L.) MILLSP.) GENOTYPES IN
INTERCROPPED SYSTEMS WITH MAIZE (Zea mays) IN A DERIVED
SAVANNAH AGRO-ECOLOGY.
BY
MADANG AYUBA DALONG DASBAK
B. AGRIC. (UNIJOS), M. Sc (UAM).
REG. NO: PG/Ph.D/04/35748
A THESIS SUBMITTED TO THE DEPARTMENT OF CROP SCIENCE,
UNIVERSITY OF NIGERIA NSUKKA, IN FULFILMENT OF THE
REQUIREMENTS FOR THE AWARD OF THE DEGREE OF
DOCTOR OF PHILOSOPHY (Ph.D).
NOVEMBER, 2011.
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CERTIFICATION
Dasbak, Madang Ayuba Dalong, a post graduate student in the department of Crop Science
with the registration number, PG/Ph.D/04/35748, has satisfactorily completed the
requirement of research work for the degree of Doctor of Philosophy in Agronomy
(Cropping Systems). The work embodied in this thesis is original and has not been
submitted in part or in full for any other diploma or degree of this or any other university.
------------------------------------ ---------------------------------
Professor J.E. Asiegbu Professor M. I. Uguru
(Supervisor) (Head of Department)
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DEDICATION
This work is dedicated to God Almighty and my parents Mr Samuila Dalong Dasbak and
Mrs Damaris Kaklang Dasbak.
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ACKNOWLEDGEMENT
I am grateful to the Head, Department of Crop Science, University of Nigeria
Nsukka, Prof. M. I. Uguru for making the facilities of the department available to me.
I am highly indebted and grateful to my supervisor, Professor J.E. Asiegbu for his
indebt contributions in making this work a reality. I appreciate his patience and love.
I wish to thank the Provost, Plateau State College of Agriculture, Garkawa, Dr O.N.
Ndam and the Management of the institution for granting me the permission to undertake
this study.
I thank the lecturers and staff of the Department of Crop Science, University Nsukka
for their contributions in diverse ways towards the accomplishment of this work. I highly
appreciate the enormous sacrifices of my wife, Mrs Emmanuella Ayuba, my children, Miss
Charity Fohotnan, Master Victor Nanma, Master Abel Ennan and Master Michael Daksuk. I
thank them for their patience and support. I also wish to thank my sisters, brothers and all
relations for their encouragement and prayers.
My thanks also go to my colleagues Aindigh, F.D, Aruah, B. C. Manggoel, W. and
Oyiga, C. J. with whom I toiled together and other friends too many to mention here. I
appreciate the contributions of all technologists and technicians who in one way or the other
contributed to the success of this work. Thank you and may God bless you all. Amen.
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PUBLISHED ARTICLES FROM THE WORK
1. Dasbak, M.A., Echezona, B.C. and Asiegbu, J.E. (2009). Post-harvest bruchid
richness and residual activity of primiphos-methyl on Callosobruchus
maculabus F. infested pigeonpea (Cajanus cajan L. Millsp.) in Storage.
African Journal of Biotechnology Vol. 8(2), pp 311-315.
2. Dasbak, M.A., B.C. Echezona, and J.E. Asiegbu (2009). Pigeonpea grain physical
characteristics and resistance to attack by the bruchid storage pest.
International Agrophics, 2009, 23, 19-26.
3. Dasbak, M.A. and J.E. Asiegbu (2009). Performance of Pigeonpea genotypes
intercropped with maize under humid tropical ultisol conditions. Journal of
Animal & Plant Sciences, Vol. 4, Issue 2: 329-340.
4. Dasbak, M.A. and J.E. Asiegbu (2011). Intercropping effects of two maize
genotypes on yield and yield attributes of six pigeonpea genotypes under a
pigeonpea/maize intercropping system in a Derived Savanna ecology of
Nigeria. International Journal of Research in Agriculture. Vol. 3, number 6:
67-77.
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ABSTRACT
Four experiments were used for the studies. Experiment 1 studied the performance of six
pigeonpea genotypes namely ICPL 87 and ICP 161 of Short - duration types, ICPL 85063,
ICP 7120 and ICPL 87119 of medium-duration types and Nsukka Local of long-duration
type in intercropped systems with two maize genotypes in 2005 and 2006 cropping seasons
at the Research Farm of the Department of Crop Science, University of Nigeria Nsukka.
The two maize genotypes were hybrid maize and open pollinated maize. There were twenty
treatments consisting of six sole pigeonpea genotypes, six pigeonpea/hybrid maize mixtures,
six pigeonpea/open pollinated maize mixtures and two sole maize treatments comprising of
sole hybrid maize and sole open pollinated maize. The field experiment was a factorial laid
out in a randomized complete block design (RCBD, with three replications. Both intercrop
and sole crop treatments of the crop genotypes were maintained at 40,000 plants ha-1
. The
representative leaf samples of the pigeonpea genotypes were analyzed for N, P, K and Ca
contents at the flowering stage. The intercropping efficiencies of the pigeonpea/Maize
mixtures were analyzed using the land equivalent ratio (LER) technique and benefit/cost
ratio analysis. Correlation analyses on grain yield, growth and yield parameters were carried
out on the pigeonpea data. The 2006 pigeonpea plants were assessed for ratoonability in
2007. Experiment 2 was a two-phased storage experiment on the seeds of the pigeonpea
genotypes to assess the status of field-to-store insect pest infestation. Actellic dust
(Pirimophos-methyl) was applied at zero, half dosage and full dosage levels (0.0g, 0.5g and
1.0g) per treatment in the first phase. Callosobruchus maculatus adults were introduced in
the second phase to assess the residual effect of the actellic dust on the C.maculatus storage
pest. Experiment 3 involved assessment of susceptibility of the seeds of the six pigeonpea
genotypes to C maculatus under storage conditions. Evaluation of the pigeonpea genotypes
seed for hardness was done in a completely randomized design (CRD) with three
replications. Susceptibility index (SI) analysis was carried out to evaluate the resistance of
the genotype seeds to the pest. Proximate analysis was carried out on representative seed
samples of the pigeonpea genotypes. Experiment 4 concerned analysis of antinutritional
factors and enzyme inhibitor contents of tannin, phytate, trypsin and chymortrypsin in the
pigeonpea genotype seeds in a completely randomized design (CRD) with three replications.
Data obtained in all the experiments were analysed using Genstat (3) discovery package of
statistical analysis, and means were separated for significant differences using least
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significant difference (LSD) procedure at 5% level of probability. The result of experiment 1
showed that maize intercropping with pipeonpea significantly (P<0.05) reduced leaf
number, leaf, stem and root dry matter weights, stem girth, nitrogen leaf contents and grain
yield in pigeaonpea. The grain yield of ICRISAT pigeonpea genotypes were superior to that
of Nsukka local genotype. The pigeonpea genotypes differed significantly in their number of
primary branches, pod bearing stem length, leaf and stem dry matter weights, insect pests
damaged seeds, one thousand seed weight and total grain yield. Pigeonpea ratooning in the
second year was significantly higher in the long-duration pigeonpea genotype compared
with the short– and medium–duration ICRISAT genotypes. The yield of pigeonpea ratoon
crops on the average was 60% of the main crop. Land equivalent ratio (LER) values greater
than one (>1.0) were obtained in all pigeonpea/maize mixtures. Mixtures also gave greater
monetary returns than the sole of either pigeonpea or maize. The grain yield in pigeonpea
had significant positive correlation with leaf, pod and seed counts per plant and with the pod
bearing stem length and dry matter yield of leaf, stem and root fractions. The result of
experiment 2 showed that there was no field–to–store infestation in the pigenonpeas. The
residual activity of actellic dust significantly reduced F1 count and final insect mortality
count of C. maculatus under storage. The result of experiment 3 showed that the pigeonpea
genotypes differed significantly in their susceptibility to C maculatus with ICPL 161, ICPL
87 and ICPL 85063 being in resistant category and Nsukka Local, ICP 7120 and ICPL
87119 being in moderately resistant seed category. The pigeonpea genotype seeds also
differed significantly in their physical hardness. The result of experiment 4 showed that the
pigeonpea genotypes had moderate but significantly different anti-nutritional and enzyme
inhibitor contents.
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TABLE OF CONTENTS
Title page … … … … … … … … … … i
Certification … … … … … … … … … … ii
Dedication … … … … … … … … … iii
Acknowledgement … … … … … … … … iv
Published articles from the work ... ... ... … … … … v
Abstract … … … … … … … … … vi
Table of contents … … … … … … … … …
viii
List of Tables … … … … … … … … … x
CHAPTER 1: INTRODUCTION … … … … … … … 1
CHPATER 2: LITERATURE REVIEW
Reasons for intercropping practices … … … … … … 8
Legumes in intercropping systems … … … … … … 10
Cereal/legume intercropping production systems … … … … … 11
Land Equivalent Ratio (LER). .. … … … … … … … 13
Cost/Benefit ratio analysis …. … … … … … … … 15
Crop Genotype … … … … … … … … … 15
Phenology of Pigeonpea … … … … … … … … 17
Maize Production … … … … … … … … 18
Pigeonpea production … … … … … … … … 19
Diseases and pests of pigeonpea … … … … … … … 23
Antinutritional factors in pigeonpea. … … … … … … 25
Plant Tissue analysis … … … … … …. … … … 27
CHAPTER 3: MATERIALS AND METHODS
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Experiment 1: Assessment of six pigeonpea genotypes under two late maize intercropping
systems. … … … … …. …. …. … 28
Assessment of intercropping efficiency … … … … 33
Benefit/Cost ratio analysis. … … … … … … 33
Experiment 2: Assessment of field-to-store insect pests infestation on six pigeonpea
genotype seeds and the residual effect of actellic dust on C. maculatus
insect pests. … …. …. …. … … …. … 33
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Experiment 3: Susceptibility of six pigeonpea genotype seeds to Callosobruchus
maculatus storage pest. … … … … … … 35
- Seed hardness test.. …. …. …. … … … 35
Plant material chemical analyses. … … … … … 37
- Proximate Analysis of pigeonpea seed. … … … … 37
- Mineral element analysis in plant materials. … … … 39
Experiment 4: Antinutritional Factors Assessment in the seeds of six phigeonpea
genotypes. … … … … … … … … 40
CHAPTER 4: RESULTS
Experiment 1: … … … … … … … … … 42
Experiment 2: … … … … … … … … … 95
Experiment 3: … … … … … … … … …
100
Experiment 4: … … … … … … … … …
103
CHAPTER 5: DISCUSSION
Experiment 1: … … … … … … … … …
105
Chemical Analysis … … … … … … … … …
121
Experiment 2: … … … … … … … … …
122
Experiment 3: … … … … … … … … …
124
CHAPTER 6: SUMMARY AND CONCLUSIONS … … …
127
References … … … … … … … … …
131
Appendix I … … … … … … … … …
147
12
Appendix II … … … … … … … … …
151
13
LIST OF TABLES.
Table 1: Meteorological records for 2005, 2006 and 2007 at Nsukka, Nigeria. … 43
Table 2: Physical and chemical characteristics of the experimental sites before planting 44
Table 3: Days to 50% emergence, 50% flowering and 50% maturity of pigeonpea grown in
mixtures with two maize genotypes. … … … … … 45
Table 4: Days to 50% tasselling and 50% maturity in maize genotypes intercropped with six
pigeonpea genotypes. ... ... ... ... ... ... ... 47
Table 5: Pigeonpea genotype plant height (cm) responses at 2-, 4- and 6- WAP under
maize/pigeonpea intercropping systems. … … … … 48
Table 6: Pigeonpea genotype plant height (cm) at 50% anthesis and at 50% maturity under
intercropping with two maize genotypes. … … … … … 49
Table 7: Maize genotypes plant height at 2-, 4- and 6- WAP under intercropping with six
pigeorpea genotypes and sole crop systems. … … … … 50
Table 8: Maize Genotypes plant height (cm) at 50% tasselling and at 50% maturity under
intercropping with six pigeonpea genotypes and sole crop systems. … 51
Table 9: Effects of intercropping on number of primary branches/plant and number of
leaves/plant in six pigeonpea genotypes. … … … … 54
Table 10: Effects of pigeonpea/maize intercropping on pigeonpea inflorescence ( pod
bearing stem) length/plant and stem girth (cm/plant). … … … 55
Table 11: Pigeonpea genotypes leaf, stem and root dry matter fractions (g/plant)
under intercropping with two maize genotypes. … … … … 56
Table 12: Maize leaf, stem, and inflorescence dry matter fractions (g/p) under intercropping
with six pigeonpea genotypes. … … … … … … 58
Table 13 : Field insect pests recorded on pigeonpea at Nsukka in 2005 and 2006. … 59
Table 14: Number of blister beetles and pod borer insect pests/plant at flowering stage and
pod fly, pod sucking bugs and pod borer insect pests at podding stage in
pigeonpea intercropped with maize. … … … … … 60
Table 15: Number of insect pests-damaged pods/plant and insect pests-damaged seeds/plant
in pigeonpea under intercropping with maize. ... ... ... ... 62
Table 16: Number of pigeonpea pods/plant and of seeds/plant under miaze intercropping and
sole crop systems … … … … … … … 63
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Table 17: Pigeonpea genotypes pod length and seed number of pod per plant under maize
intercropping and sole crop systems … … … … 65
Table 18: Pigeonpea grain yield (kg/ha), average 1000 seedweight (g) and threshing
percentage (%) under intercropping with maize. … … … … 66
Table 19: Maize grain yield (kg/ha) and shelling percentage (%) under intercropping with
pigeonpea. … … … … … … … 70
Table 20: Mean relative grain yield of maize and pigeonpea genotypes and land equivalent
ratio (LER) values in the pigeonpea/maize intercropping system. … 71
Table 21: Cost items for production per hectare in pigeonpea/maize mixtures in 2005 .. 72
Table 22: Cost items for production per hectare in pigoenpea/maize mixtures in 2006. .. 73
Table 23: Revenue items and Benefit/cost ratio analysis for 2005 … … …. 74
Table 24: Revenue items and Benefit/cost analysis for 2006 … … …. 75
Table 25: Pigeonpea ratoon crop percentage plant survival. … … … … 77
Table 26; Pigeonpea ratoon crop yield responses in number of pods/plant and number of
seeds/plant at harvest in 2007. … … … … … 78
Table 27: Pigeonpea ratoon crop pod length (cm) and number of seeds/pod. … … 79
Table 28: Number of blister beetles and pod borer insect pests per plant at flowering stage
and pod fly, pod sucking bugs and pod borers at podding stage in pigeonpea
rotoon crops. … … …. … …. … .. …. 81
Table 29: Pigeonpea ratoon crop percentage(%) insect-damaged pods and seeds as
influenced by cropping system and pigeonpea genotype. … … 82
Table 30: Pigeonpea ratoon crop grain yield (kg/ha) and threshing percentage as influenced
by pigeonpea genotype and cropping system …. … … … 83
Table 31: Pigeonpea correlation analysis 2005 … … … … … 86
Table 32: Pigeonpea correlation analysis 2006 … … … … 87
Table 33: Effects of intercropping pigeonpea and maize on the nitrogen (N), phosphorus
(P), potassium (K) and calcium (Ca) leaf contents of pigeonpea at flowering 90
Table 34: Mineral nutrient turnover (kg/ha) in pigeonpea leaf at flowering stage under
intercropping with two maize genotypes. … … … … 92
Table 35: Proximate analysis of pigeonpea genotype seeds. … … … 93
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Table 36: Chemical analysis for nitrogen (N) phosphorus (P), Potassium (K) and Calcium
(Ca) in six pigeonpea genotype seeds ... … … … … 94
Table 37: Residual activity of actellic dust (pirimiphos-methyl) doses on the oviposition and
mean development days (MDD) of Callosobruchus maculatus in pigeonpea 97
Table 38: Residual activity of actellic dust (Pirimophos-methyl) on F1 count and
Percentage adult emergence of C. maculatus in pigeonpea. … … …
… 98
Table 39: Residual activity of actellic dust (pirimiphos-methyl) on percentage seed damage,
seed weight loss and insect mortality count of C. maculatus in pigeonpea 99
Table 40: Seed hardness and infestation by C. maculatus under six months storage of six
pigeonpea genotype seeds. … … … … … …
102
Table 41: Tannin, Phytate, Trypsin inhibitor and Chymortrypsin inhibitor seed contents in
six pigeonpea genotypes. … … … … … … …
104
CHAPTER ONE
INTRODUCTION
Pigeonpea (Cajanus cajan (L.) Millsp) belongs to a group of leguminous crops
called pulses. The pulse legumes, are those species harvested traditionally for their mature
seeds, and are a major source of dietary proteins and feed products throughout the world.
They are especially important as human food in those regions where animal proteins are
scarce (Norton et al., 1985). Their introduction into a feeding regime based on cereals or
tubers balances the latter and combats protein deficiency linked malnutrition, which is
frequent in the developing countries, especially in West Africa (Borget 1992).
According to Reddy et al., (1993), pigeonpea is an important grain legume crop of
rainfed agriculture in the semi-arid tropics. The India sub-continent, eastern Africa, and
central America, in that order, are the worlds three main pigeonpea-producing regions.
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Pigeonpea is cultivated in more than 25 tropical and sub-tropical countries, either as a sole
crop or intermixed with such cereals as sorghum ( Sorghum bicolour (L.) Moench), Pearl
Millet (Pennisetum glaucum (L.) R. Br,), maize (Zea mays L.) or with legumes such as
groundnut (Arachis hypogea L.). It is one of the mandate crops of International Crops
Research Institute for the Semi-Arid Tropics (ICRISAT) which has released improved
genotypes to farmers (Guy et al., 2001), and holds about 13,544 accessions (ICRISAT
Newsletter Oct., 2003).
Consultative Group on International Agricultural Reseach (CGIAR) (2005) report indicated
that in 2005, world production of pigeonpea was about 3.5 million metric tons. Africa
accounted for 317,862 metric tons, and Asia for 3 million tons. It also reported that the area
harvested to pigeonpea in 2005 was 4.5 million hectares globally. India alone accounted for
about 76.5% of this figure. Other producers are Sub-Saharan Africa and Latin America and
the Caribbean. The report further indicated that pigeonpea ranks sixth in area and production
in comparison with other grain legumes such as beans, peas and chickpeas.
Pigeonpea is an erect shrub, a leguminous perennial that is managed in agricultural
systems as an annual or biennial (Snapp et al., 2003). It may reach 4m in height depending
on the genotype, but is usually about 1.5m. It is woody at the base of the plant and the side
branches are generally erect (Morton, 1976). The vertical taproot is deep and extensive,
reaching depths of 1-2m with multiple branches (Anderson et al., 2001; Sheldrake and
Naranyanan, 1979). Maturity ranges from about 90 to 280 days from planting. Genotypes
tend to be extremely sensitive to photoperiod and temperature, which can greatly alter
phenology, height, and productivity (Reddy, 1990). Growth habit ranges from erect with
acutely angled branches (30 degrees or less) to more spreading types with branch angles as
large as 60 degrees (Whiteman et al., 1985). Some cultivars tend to produce long primary
branches with leaves along their entire length and fruits concentrating in the terminal one-
third or one-half of each branch. Some genotypes branch very little and produce flowering
recemes directly on the main axis. Trifoliate leaves are arranged spirally in a 2/5 phyllotaxy
and inflorescences are 4-12 cm long, borne either terminally or at axillary nodes. They
further reported that flowering can be diffuse over the whole plant spreading throughout a
long period, or synchronous, depending upon the genotype and on the photoperiod and
temperature regime. Flowers are about 2.5 cm long with four calyx lobes. The Petal colour
varies from yellow to red or purple, with some tinged, striped or mottled with red purple.
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The stigma is terminal, and the ovary and base of style are hairy. Fruits are flattened pods
with diagonal depressions between each of the two to nine locules, and are up to 10 cm long,
beaked and often hairy. Pod wall colour can be green, brown, dark maroon to dark purple or
blotched, with a greasy or waxy surface when immature, and the pods are straight to sickle
shaped, 5-10 cm wide, glabrous and glandular (Bogdan, 1977). Fruits contain between two
and nine seeds per pod and do not shatter. The seeds are orbicular, oval to flattened,
sometimes speckled. The hilum is small and white. Seed size varies from 6-28g per 100
seeds (Purseglove, 1974).
Pigeonpea has a wide range of products, including the dried seed primarily used as
dahl (a processed, dehulled, split seed). The green pod and immature seed are used as green
vegetables while the leaf and stem are used for fodder and for soil improvement, with the
dry stem used as fuel. It makes an outstanding contribution to home production systems by
enhancing both human nutrition and soil nutrient content (Snapp et al., 2003). Faris et al. ,
(1987) further reported that in addition to protein, pigeonpea provides carbohydrates and
five fold higher levels of vitamin A and C than greenpea (Pisum sativum L.).
According to Whiteman et al., (1985), the crop is most commonly grown for its dry,
split seed (dhal), which has a protein concentration of approximately 20-25%; but the
immature seed is also eaten as green vegetable. Dry seed and the by-products of dhal
manufacture, as well as leaf and pod-wall residues after harvest, can provide suitable feed
for ruminants, which may also graze the standing crop (Whiteman et al., 1985). The
potential for wider consumption and commercialisation of pigeonpea is indicated by an
expanding global market for pigeonpea products (Jones et al., 2002). The export potential of
split pigeonpea (dhal) is high as it is exported to India, the Middle East, Europe and North
America. By promoting processing and widening the scope of utilization of pigeonpea for
local consumption and export, both production and productivity can be substantially
increased (Tuwafe et al., 1994).
In Nigeria, Tabo et al., (1995) reported that the grains are prepared into various
dishes such as yam porridge meal and maize/pigeonpea porridge “ayalaya” for human
consumption. It is also used as a soup thickener. The grains substitute for cowpea in
“akara” balls, can be cooked as “moi moi”, and fermented to produce “Dawadawa” for
food seasoning.
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Snapp et al., (2003) reported that in the Caribbean region, there is persistent demand
for vegetable pods and peas, both canned fresh. Indian and Afro-Caribbean communities
around the globe offer new markets for dahl. In addition to food uses, pigeonpea is reported
to have outstanding soil amelioration and conservation properties. The growth habit
facilitates soil protection, as the canopy continues to expand for 4 months in the dry season
after other crops are harvested when living and senescent pigeonpea leaves may be the only
source of cover in semi –arid agroecosystems. According to Rao et al., (2002), pigeonpea
leaves are reported to have characteristics that promote soil fertility benefits, such as low
lignin levels and high nitrogen content. Pigeonpea nodulates with a wide range of
Rhizobium strains and consistently fixes 20 to 140 kg ha-1
N in infertile soil (Anderson et al.,
2001). The vigorous root system explores a large soil volume and recycles nutrients from
deep in the profile (Johanson, 1990). Further, pigeonpea root exudates have the unusual
ability to solubilize iron-bound phosphorus from some soil types (Ae et al., 1990).
Among pulse crops, pigeonpea is unique, apart from some lupin species, in its
utilization also as an annual crop as well as its use in agroforestry and shifting cultivation
systems and as a source of forage for livestock. Whiteman, et al., (1985) reported that
because of its great diversity of habit and use in quite contrasting production systems,
greater differences exist in growth and development among genotypes adapted to the various
production systems than exists in many other crops.
Maize (Zea mays L.) belongs to the family Poacea and according to IITA (2007), it is
the most important cereal crop in sub-Saharan Africa and, with rice and wheat, is one of the
three most important cereal crops in the world. IITA (2007) further reported that maize is
high yielding, easy to process, readily digested, and cheaper than other cereals.
Maize is an annual monoecious plant with erect cylindrical stem of 0.5-5.0m high
and 2-7cm thick. The leaves are 8-21 in number but usually about 14 are arranged one on
each stem node. They include a leaf sheath which firmly embraces the stem, and a broad
linear leaf blade with a small ligule where it is attached to the stem. It has advantitious roots
developed from the lowest nodes of the stem immediately above the mesocotyl, which are
close together and about 2.5cm below the soil surface. The roots penetrate down to a depth
of 30-40cm and spreading to a diameter of 10-20cm.
In industrialized countries, maize is largely used as livestock feed and as raw
material for industrial products, while in developing countries like in Nigeria, it is mainly
19
used for human consumption. In sub-Saharan Africa, maize is a staple food for an estimated
50% of the population, and important source of carbohydrate, protein, iron, vitamin B, and
minerals. Africans consume maize as a starchy base in a wide variety of porridges, pastes,
grits, and beer. Green maize (fresh on the cob) is eaten parched, baked, roasted or boiled,
playing an important role in filling the hunger gap after the dry season. Maize has been in
the diet of Nigerians for centuries as a subsistence crop but has now risen to a commercial
crop on which many agro-based industries depend on as raw material (Iken and Amusa
2004) . According to Alabi and Esobhawan (2006), most cultivation of maize in Nigeria,
unlike in the temperate countries, is in intercropping. Therefore intercropping research
involving maize will be of immense importance to the traditional farmer who also intercrop
pigeonpea mostly.
Andrew and Kassam (1976), defined intercropping as growing two or more crops
simultaneously on the same field. Crop intensification is in both time and space
dimensions.There is intercrop competition during all or part of crop growth. Farmers
manage more than one crop at a time in the field. Cropping system was also defined as the
cropping patterns used on a farm and interaction with farm resources, other farm enterprises
and available technology which determine their make-up. Andraw and Kassam (1976) also
defined cropping pattern as the yearly sequence and spatial arrangement of crops and fallow
on a given area, and sole cropping as where one crop variety is grown alone in pure stand at
the normal density. Ratoon cropping is the maintenance of crop regrowth from living stumps
after harvest. It is a form of continuous cropping. Intercropping and ratoon cropping
systems are all practised with pigeonpea and have practical benefits.
In intercropping, crops can be mixed in different proportions. In additive series the
component crops are mixed at the recommended sole crop population densities (Baker,
1979). In replacement or substitutive mixture series, the combined densities of the crops
maintain the same population pressure as in sole crops. Improved ground cover achieved by
an additive intercrop contributes to reduced soil erosion and hence better retention of soil
fertility particularly when spreading type cultivars are used as the shorter component (Fukai
and Trenbath 1993). Fukai and Trenbath (1993) suggested that the most productive
intercrops are additive ones involving components differing greatly in growth duration.
Maximum output should be obtained with sequences of “high yielding” crops in compatible
mixtures. In practice, this pattern has evolved in relation to the traditional resources at low
20
and intermediate inputs circumstances where several crops are planted and harvested in
mixtures at different times. Intercropping research involving pigeonpea and maize has not
been common and will be of great importance and benefit considering their economic values
to the farmer. Much of the intercropping work done in ICRISAT, India, had mostly been
with pigeonpea and millet (Penisetum glaucum L.) and sorghum (Sorghum bicolar L). It
would be very desirable to evaluate those newly released pigeonpeas of differing growth
parterns and duration with maize (Zea mays) under Nigerian condition in the humid tropical
lowland conditions of Nsukka where maize is more popular and more widely grown than
millet or sorghum.
Seed yields obtained from pigeonpeas in traditional farming systems are reportedly
low (Whiteman et al., 1985). It is also noted that the major production system of
intercropping of late-maturing pigeonpeas necessarily restricts the yield potential in the
farmers′ fields. Snapp et al., (2003) reported that research attention to pigeonpea remains
limited. Australia and India are two of the few countries to have made significant
investments in pigeonpea research along with the International Crops Research Institute for
the Semi-Arid Tropics (ICRISAT).
Midmore (1993) reported that suitable land areas for food production remain fixed or
are diminishing, yet farmers and agronomists are faced with the task of increasing
production. Successful crop mixtures extend the sharing of available resources over time and
space, exploiting variation between component crops in such characteristics as rate of
canopy development, final canopy width and height, photosynthetic adaptation of canopies
to irradiance conditions and rooting depth.
Much studies involving the ICRISAT short- and medium-duration varieties in
mixture have not been done under the Nigerian conditions. Rao and Willey (1980) had
earlier indicated that the slow establishing and later-maturing pigeonpea combined well with
earlier cereals and legumes to give very large yield advantage as measured by the Land
Equivalent Ratio (LER) under the Indian conditions.
Pigeonpea production is penetrating the Nigerian traditional farming system.
However, not much work has been done across the ecological zones using improved short-
duration and medium-duration varieties to replace poor yielding, tall and long-duration
varieties currently used by the farmers. Tabo, et al., (1995) reported that farmers asked for
21
high yielding, shorter duration varieties with softer, faster cooking grains, and varieties
suitable for alley cropping.
Since there is limited land and other production resources at the disposal of the
traditional farmer, the approach to improve the crop yields per unit area through simple,
adaptable and sustainable technologies such as intercropping with improved genotypes, will
be of great advantage. Giller et al., (1997) had stated that proposed interventions in soil
fertility management must generate cropping systems that are productive, sustainable and
economically attractive for small holder subsistence farmers. Jagtap and Adamu (2003)
reported that farmers may rapidly adopt improved technologies that cost little or nothing or
one within their reach and that can contribute to increasing their productivity. Kimani (1991)
reported that improved long (9 months), medium (6 months) and short (4 months) duration
pigeonpea cultivars have been developed and released by ICRISAT. Although these
varieties showed high yield potential under research environment, their performance under
farmer condition are yet poorly documented.
There is a need to adapt and adopt the newly developed pigeonpea genotypes into the
popular farming systems of the local farmers. The opportunity offered by the compatibility
of legume/cereal intercropping requires a planned study using the newly released ICRISAT
genotypes in a pigeonpea/maize intercropping system research in Nigeria. There is little or
no published literature information of ICRISAT pigeonpea genotypes intercropped with
maize under Nsukka derived savannah agro-ecology condition.
The present study has the following objectives:
i. To assess the growth and yield of five improved and one local pigeonpea genotypes in
mixtures with two maize genotypes under late season cropping.
ii. To assess the intercropping efficiency over sole cropping using LER and cost/benefit
ratio.
iii. To evaluate the general morphological and agronomic attributes of the pigeonpea
genotypes that might have relevance to competitive advantage of each genotype in
mixture with maize.
iv. To study the insect pest problems in the field and to achieve efficient post-harvest
storage.
22
CHAPTER TWO
LITERATURE REVIEW
Reasons for Intercropping Practices
According to Boquet and Breitenbect (2004), much of agriculture in the developed
world had for a time embraced potentially non-sustainable systems
for economic reasons,
over-utilizing monocropping, specialization and mechanization, which were damaging to
soils and the environment. The widespread adoption of cropping systems that are sustainable
and environmentally benign is essential for the long-term survival of civilization. Sullivan
(2003) reported that multiple cropping systems are prevalent in many parts of the world and
farmers in the temperate region have used alternating strip of corn and soybeans. Ghosh
(2004) posits that intercropping offers to the farmer the opportunity to engage nature’s
principle of diversity at their farms. Spatial arrangements of plants, planting rates and
maturity dates must be considered when planning intercrops. According to Keating and
Carberry (1993), efficient use of resources is a major reason given for intercropping and this
objective is achieved by managing the way component crops compete for the available
resources of solar radiation, water and nutrients. Davis and Wolley (1993) reported that
intercropping offers a means for farmers in tropical countries to continue to respond to
changes in their condition, by intensifying their land use in a suitable way, and maximizing
the use of their resources. Planting intercrops that feature staggered maturity dates or
development periods takes advantage of variations in peak resources demands for nutrients,
water, and sunlight. Having one crop mature before its companion crop lessens the
competition between the two crops.
According to Iken and Amusa (2004), intercropping is used by subsistent farmers
primarily to increase diversity of products and stability of annual output at their farms.
However, with rapid increase in farm population and less chance of bringing new lands
under cultivation, intercropping seems to be an attractive way to increase productivity and
intensify land use. Most of the farmers have small holdings and desire to develop
appropriate techniques of growing field crops in association with each other without too
much intercrop interference and competition. Multiple cropping is a solution as the use of
23
multiple crops in a single field also reduces the amount of herbicides or fertilizers applied to
that field at any time.
Mutsaers et al., (1993) described intercropping of two or more crop species with
contrasting growth habits as a time-honoured practice in the humid tropics and identified
three major potential advantages as:
- better use of physical resources (solar radiation, mineral nutrients and water).
- higher labour productivity than sole cropping and
- reduction of risks compared with sole cropping.
Willey (1979) reported that a yield advantage occurs because component crops differ
in their use of growth resources in such a way that when they are grown in combination they
are able to complement each other and to make better overall use of resources than when
grown separately. The component crops are not competing for exactly the same over all
resources and thus intercrop competition is less than intracrop competition. Intercropping
advantages are more likely to occure where the growth patterns of the component crops
differ in time so that the crops make their major demands on resources at different times
giving a better temporal use of resources. Krantz et al., (1976) reported upto 73% yield
advantage with various 80-to-100-day crops/180-day pigeonpea. Crookston and Kent,
(1976) reported that there is the possibility of combining crops which have different inherent
responses to light. The top of the canopy would consist of a component with a high light
requirement like a C4 plant and the bottom a short C3 component with a low light
requirement. A paticular good example of efficient spatial use of light would seem to be
′multi-storey' cropping where crops ranging from tall trees to low growing annuals form
different canopy layers with each crop appearing well adapted to its particular light niche.
According to Willey (1979), component crops may exploit different soil layers, thus in
combination they may exploit a greater volume of soil. Component crops may have their
peak demands for nutrients at different stages of growth which may help to ensure that
demand does not exceed the rate at which nutrients can be supplied. A rather different
temporal effect could occur where nutrient released from one crop as a result of the
senescence of the plant parts are then made more readily available to another crop.
Mead (1979) reported that it is clear that intercropping can give substantial yield
advantage compared with monocropping in the sence of requiring less land to produce same
yields of the component crops and it is also clear that intercropping will continue as a
24
common practice and that there is a need for a substancial experimental programme to
investigate agronomic practice in intercropping. Rao (1980) reported that there is
consisderable scope for increasing pulse production by popularizing improved methods of
intercropping with arable as well as orchard crops, extending to non-traditional areas,
cultivating in off season, or double cropping of hitherto simple cropped areas.
Intercropping is a favoured multiple cropping practice because it provides increased
protection against erosion, insures against crop failure, and helps to spread labour and
harvesting more evenly during the growing season while minimizing storage problems.
Olasantan (1988) attributed increased water infiltration rate in an intercrop to increased
earthworm activity as a result of lower soil temperature which may favour multiplication
and growth of soil micro-organisms. Singh et al., (1986) reported a greater populations of
active soil bacteria under maize/legume intercrops.
Legumes in intercropping systems.
Hall (1995) reported that the ability of legumes to combine symbiotically with the
soil bacterium, genus Rhizobium, to fix atmospheric nitrogen and convert it into forms
available to other organisms is vital to the biosphere, being an important part of the nitrogen
cycle. In mixed cropping this potential is exploited and indeed maximized by growing
legume crop species with non-legumes. From such a mixture one would expect a land
equivalent ratio (LER) well in excess of 1.0 because the two species would be obtaining
their supplies of the major limiting nutrient nitrogen from different sources.
According to Stern (1993), the beneficial effects of legumes (Family Fabaceae) in
farming systems, due to their contribution of nitrogen, have been observed by succeeding
generations of farmers and agronomists. Various species of legumes have been used for
centuries in crop rotations, as green manure crops and in intercropping systems of various
kinds. Their residues and decaying materials contribute to soil organic matter (SOM) and
microbes assist in the break down and mobilizational release of nitrogen. The nitrogen
contained in the SOM is generally stable. A small proportion of the order of 1-3% becomes
available to plants through mineralization to in-organic form and this has the potential to re-
enter the nitrogen cycle (Ladd, 1990). Kanyama-Phiri et al., (1998) and Snapp et al., (1998)
reported that on-farm trials have shown that pigeonpea can produce over 2 t ha-1
of high-
quality residues without any fertilizer inputs on degraded soils and steep mountain slopes of
25
Southern Malawi, providing one of the only cost-effective and sustainable sources of
nutrients for poorer farmers.
In Nigeria, Tabo, et al., (1995) reported that farmers were aware of the benefit of
pigeonpea on soil fertility accrueing from the accumulation of leaf litter on the soil surface
and Nitrogen-fixing root nodules in the soil. It was reported that corn grain yields after a
pigeonpea fallow reflected nitrogen fertilizer equivalence of about 50 kg ha-1
N in Malawi
and Benin studies (MacColl, 1989; Versteeg and Koudokpon, 1993). Yield enhancement of
cereals after a pigeonpea fallow has also been observed in Kenya and Cameroon (Degrande,
2001, Onim et al., 1990). After 2 years of intercrop or rotation with pigeonpea, corn yields
increased from about 3 to 4.6 t ha-1
compared with sole-cropped corn.
Stern (1993) reported that seeds harvested from the component crops is likely to be
the largest source of nitrogen loss from the intercrop system and can range from 50 to
150KgN/ha. He also noted that in an intercrop situation, the amount of nitrogen fixed by the
legume depends on the phenology and morphology of the species or cultivar, legume density
in the intercrop mixture and on general crop management. The amount of nitrogen fixed by
the legume can range between 50 and 300 kgN/ha. In general, it has been found that the
amount of atmospheric nitrogen fixed by the legume declines with increasing native soil
nitrogen.
Cereal/ Legume Intercropping Production Systems.
According to Dahmardeh, et al., (2010); cereal-legume intercropping plays an
important role in subsistence food production in both developed and developing countries
because it helps maintain and improve soil fertility. Fujita et al., (1992) reported that
Cereal/legume intercropping increases dry matter production and grain yield more than their
monocultures. When fertilizer N is limited, biological nitrogen fixation (BNF) is the major
source of N in legume-cereal mixed cropping systems. The soil N use patterns of the
component crops depend on the N source and legume species. Nitrogen transfer from
legume to cereal increases the cropping system's yield and efficiency of N use. The distance
between the cereal and legume root systems is important because N is transferred through
the intermingling of root systems. Consequently, the most effective planting distance varies
with type of legume and cereal. Mutual shading by component crops, especially the taller
cereals, reduces BNF and yield of the associated legume. Light interception by the legume
26
can be improved by selecting a suitable plant type with suitable architecture. Planting
pattern and population at which maximum yield is achieved also vary among component
species and environments. Crops can be mixed in different proportions from additive to
replacement or substitution mixtures.
Davis and Wolley (1993) reported that legumes are normally dominated by cereals
or cassava with the possible exception of pigeonpea, which can be a very competitive crop.
Snapp et al., (2003) reported that in intercrops, commensalisms is occassionaly effected.
Commensalism is loosely defined as one organism gaining benefits from another without
damaging or benefiting it. An exemple is when one crop modifies the microenvironment to
suit another.
Fukai and Trenbath (1993) reported that in an intercrop, when growth is limited by
the availability of a particular resource, the ability of a component crop to gain better access
to the resource determines its competitiveness. Superiority of access to a resource may be
decided by fine details of plant form or physiology. Thus the typically deeper root system of
a legume can give it an advantage over a cereal crop in access to water or nutrients that are
present in the lower soil profile. They also inferred that once a particular component
develops better access to the limiting resource and begins to deny supplies to the other, the
component tends to become progressively more dominant while the growth of the other
component may be suppressed almost completely.
Snapp et al., (2003), reported that long duration pigeonpea cultivars are generally
planted simultaneously as an intercrop with a cereal at the beginning of the rainy season.
Cereals generally are harvested towards the end of the rainy season, and pigeonpea
developes rapidly on residual moisture after harvest of the companion crop. They recognized
that a ratoon system is used in some areas after the stem are cut back to facilitate re-growth,
and a second crop is harvested in the subsequent season.
Generally, long-duration crops (e.g. pigeonpea) usually have slow early growth and
hence photosynthetic active radiation (PAR) interception is low (Fukai et al., 1984).
Therefore solar radiation which would be otherwise wasted during early growth stages can
be utilized by an associated crop growing between the rows of the late maturing crop. Rao
(1980) reported that the prolonged slow growth of pigeonpea and its adjustability to wide
row spacing provide an excellent opportunity for growing early maturing intercrops so that
early season resources can be used efficiently. The commonly grown intercrops are the
27
competitive cereals (sorghum, maize, millets, rice) or cash crops with growth pattern similar
to pigeonpea (cotton, castor). According to Cenpukdee and Fukai (1992), a large time gap
with favourable conditions between the harvesting of the component crops ensures that the
late-maturing crop has sufficient time to develop a complete canopy and root system to
capture as much of the remaining resources as possible. The greater the fraction of the
growing season available before its own harvest, the closer its yield in the intercrop to that in
sole crop (Rao and Willey, 1983b). The late-maturing crop also utilizes resources (e.g.
residual water) which might otherwise be wasted. According to Fukai and Trenbath (1993),
the removal of the early maturing crop releases the plants from suppression. They also
reported that flowering and grain production were better in intercropped plants that had
smaller vegetative structure than in their corresponding sole crops. The plants are often able
to produce a moderate grain yield on a relatively small body. Studies by Enyi (1973) showed
that maize intercropped with either beans or cowpeas had lower yields than maize
intercropped with pigeonpea, probably because the high rates of nutrient absorption by the
two legumes coincided with uptake by the maize harvested.
Sivakumar and Virmani (1980) reported intercropped and sole maize yields of 3,500
kg/ha and 3,518 kg/ha, respectively, while the yields of intercropped and sole pigeonpea
were 1,520kg/ha and 1,833 kg/ha, respectively. The bulk of dry matter accumulation in sole
pigeonpea was in its stems mostly between 100 and 150 days after planting, after which
pods and seeds accumulated a fair amount of dry matter at the period coinciding with rapid
leaf senescence. Even after the maize was harvested, pigeonpea did not show an appreciable
accumulation of dry matter up to 120 days after planting. Its total dry matter reached only
63% of the maximum at harvest when stem fraction was the dominant dry matter
component. The habit of pigeonpea in pure stands resulted in a very low utilization of PAR
in the first 80 days after planting and it is logical to modify this situation by growing a short
duration cereal crop with the expectation of a substantial reduction in the legume yield.
Land Equivalent Ratio (LER).
According to Fukai and Trenbath (1993), intercropping productivity depends on the
genetic constitution of the component crops, the growth environment (atmospheric and soil)
and agronomic manipulations of the microenvironment. The interactions of these factors
should be optimized so that the limiting resource is utilized by the intercrop. An
28
understanding of the sharing of resources among component crops will help identify the
most appropriate agronomic manipulations and cultivars for intercrops. Davis and Wolley
(1993) reported that an important aspect of intercropping system is the extent of competition
between the crops. Where this is large, there is likely to be a significant genotype x cropping
systems interaction.
Because competition in intercropping usually results in a different proportion of final
yields than from sole cropping, Willey (1979) concluded that the most generally useful
single index for expressing the yield advantage is probably the Land Equivalenr Ratio
(LER), defined as the relative land area required as sole crops to produce the same yield as
intercropping:
LER = SB
YB
SA
YA , where
YA and YB are the individual crop yields in intercropping and SA and SB are their yields
as sole crops. According to Mead and Willey (1980), the advantages of the LER are that it
provides a standardized basis so that crops can be added to form “combined” yields and
comparison between individual LERs (LA and LB) can indicate competitive effects. Of
primary importance, the total LER can be taken as a measure of the relative yield advantage,
e.g. the LER of 1.2 indicates a yield advantage of 20% or, strictly speaking, that 20% more
land would be required for sole crops to produce the same yields as intercropping.
In a pigeonpea intercrop studies with millet genotypes and sorghum genotypes, Rao
and Willey (1980a) reported that early maturing millet gave a total Land Equivalent Ratio
(LER) value of 1.78 and also more monetary returns. Early maturing and/or short stature
sorghum produced large LERs of 1.51-1.59, while a tall sorghum gave LER of 1.30 and less
returns. Intercropping any of the cereals with pigeonpea gave a large increase in net
monetary return compared with sole cropping, emphasizing the widespread usefulness of the
intercropping systems. Tom (1995) reported LER values greater than 1.0 when three
pigeonpea short- duration genotypes were intercropped with an open pollinated maize
(FARZ-7) in Nsukka. LER values of 1.33, 1.38 and 1.78 were reported for pigeonpea
genotypes ICPL 84023, ICPL 151 and ICPL 87, respectively. This showed that the
pigeonpea genotypes yielded differently in the intercropping system.
29
Benefit/cost ratio analysis
Cost-benefit analysis according to John-Rey (1997), identifies, quantifies and
subtracts all the negatives -the costs from the benefits. The real trick to doing a cost-benefit
analysis well is making sure you include all the costs and all the benefits and properly
quatify them.
- Profit is declared when total revenue is greater than total cost.
- Loss is incurred when total revenue is less than total cost.
- Benefit/cost ratio = cost Total
realised Revenue
- Gross margin (%) = 1
100
Revenue Total
cost Total - ueTotalReven
Mburu et al., (2007) reported that measuring the cost of production is important if a
farmer wants to know whether or not he is making profit. Cost-benefit analysis states
that if a project is to proceed on a successful basis then total benefits should outweigh
total costs. Nwosu (1981) reported that resource use efficiency on the average is higher
for crop mixtures than for sole crops and that gross return per hectare is generally higher
under mixtures than in sole crops.
Crop Genotype.
According to El-Titi (1995), the genotype of a plant species has many different
implications for the crop production. It determines the yield potential under a given
environment, the quality of the product and its resistance to pests and pathogens. The
characteristics of the crop cultivar can have profound effects on the levels of nutrient
exploitation, on residual nutrients in soil and on soil microflora through root exudates. A
deliberate diversification of the crop genome in a given environment offers a potential tool
to counter these problems.
Davis and Wolley (1993) reported that plant varieties may respond differently to
their environment, climate, soil and crop management. The most important aspects to
consider are the extent of competition between the crops and the variation in competition
ability among cultivars. Where the variation in competition among cultivars is large, there is
likely to be highly significant genotype x cropping system interaction. According to Willey
(1979), crop genotypes should be selected to minimize intercrop competition and maximize
30
complementary effects. Achieving earlier maturity of the early component is likely to be a
valid and acceptable effect.
According to Fukai and Trenbath (1993), crop yield is an end product of many plant
growth processes which interact with the environment. The yield of the crop is based on its
genetic constitution. And for a given cultivar, it is commonly determined by the availability
of environmental resources (e.g solar radiation, Co2, nutrients and water). High crop yields
are obtained when particular cultivars are grown in such a way that they utilize limiting
resources efficiently and mature before the resource limitation or environmental factor
becomes too severe. Choice of the correct cultivars and agronomic manipultions to ensure
the most efficient use of limiting resources is a key element for high crop yield.
Van der Maesen et al., (1981) reported that collection (approximately 5000
accessions) of pigeonpea now forms the basis of the world collection of some 8900
accessions maintained at ICRISAT. Approximately 90% of accessions have been collected
in India which is the principal centre of diversity of pigeonpea. Only limited collections
have been made so far from other countries in Asia, Africa, Central and South America and
Australia. Systematic descriptions of the germplasm on the basis of standard descriptors
(Anon 1981) and the results of screening for specific characteristics such as resistance to
insects, pests, diseases, waterlogging, photoperiod response, annuality and plant habit are
now stored on computer for rapid retrieval and use (van der Maesen et al., 1981). The
collection is maintained by ICRISAT using controlled self-pollination of plants within each
accession.
Upadhyaya, et al., (2006), reported that inspite of its multiple uses, pigeonpea
germplasm has been used at ICRISAT primarily for developing high grain yielding varieties
of different maturity groups, as sources of resistance to major diseases and insect pests and
for other simply inherited traits. Pigeonpea genotypes are generally grouped into four
categories based on growth/maturity duration of extra short-duration (<105 days), short-
duration (105-145days), medium-duration (146-199days), and late-maturing (above
200days) cultivars (van der Maesen, 1989). It has been reported that several cultivar types
or evolutionary forms can be recognized in pigeonpea based on plant type, crop duration,
photoperiod sensitivity, flower number and inflorescence size, pod and seed dormancy,
seedling vigour, habitat preferences, and biochemical constitution. These cultivar types are
of immense agronomic significance to their suitability to different agroecologies, time of
31
planting, types and levels of cultivation, consumer preferences, and the use for which the
crop is grown.
Pigeonpea production traditionally in India involves photoperiod sensitive medium
and late-maturing cultivars (Sharma et al., 1981) intercropped with cereals (maize,
sorghums and millets) and with various other short-duration legumes and vegetables (Ali,
1990). Tabo et al., (1995) reported that in Nigeria, perennial types with white or brown
seeds and 3-4 seed per pod types were most commonly grown, and remain in the field for
two years. Plants mature in 7-8 months and grow to a height of 2-3m. Farmers retain seeds
or purchase from the market for sowing in the following season.
The developed early-maturing pigeonpea cultivars are relatively photoperiod
insensitive; they flower and mature in less than 80 to 150 days (Singh et al., 1990).
Development of these cultivars permits the use of pigeonpea in double or multiple cropping
systems distinct from the traditional use as a two-season crop (Chauhan et al.,. 1993;
Troedson et al., 1990). According to Willey (1979) using modern cultivars in combination
with improved crop management techniques and improved intercropping systems have the
potential to use the moisture supplied by the rains and the nutrients available more
efficiently. According to Whiteman et al., (1985) the outstanding ability of pigeonpeas to
survive in marginal environments, their drought tolerance and ability to recover after severe
environmental or biotic stress are the major reasons for the crop′s success in subsistence
agricultural systems in the semi-arid tropics
Phenology of Pigeonpea
Whiteman et al., (1985) defined phenology as the sequence of developmental events
involving times to germination, emergence to flowering, flowering to fruit fill to harvest and
to ratoon crop development. They reported that germination of pigeonpea seeds is not
normally limited by hardseededness although some genotypes have well-developed hard
seeds. Pigeonpea germinates most rapidly at 20-30 oC and only poorly at temperatures
below 19oC (de Jabrun et al., 1981). Whiteman et al., (1985) further reported that the
duration of vegetative phase is extremely variable, depending upon genotype, photoperiod,
temperature and, moisture status, all of which interact to determine time of flowering.
Depending on the genotype, days to flowering can range from about 60 to more than 200
days for sowing made prior to the longest day at 17 oN (Green et al., 1979). Growth rates of
32
pigeonpea from emergence to canopy closure are relatively small. The duration of fruit
filling and ripening depends on the synchrony of flowering and on climatic conditions.
Whiteman et al., (1985) reported that because of their perennial habit, pigeonpea plants
remain vegetative even at fruit maturity. This enables ratoon growth after harvest of the
plant crop, and two or more subsequent harvests are possible. Rao (1980) reported that
cropping can be extended in the post rainy season by allowing the pigeonpea stuble to ratoon
which can be maintained for grain or forage. Borget (1992) reported that pigeonpea could
fruit for 3-5 years or more in favourable conditions.
Sharma et al., (1978) compared the ratooning ability of early- , medium- and late-
maturing cultivars. Early cultivars produced ratoon yields equal to the plant crop, but the
plant-crop yields were relatively small. Medium cultivars produced seed yields in the ratoon
crop equal to about 50% of the plant crop, while late cultivars (238 days to first harvest)
grew vegetatively after plant crop harvest but did not produce seeds in the ratoon. In the
medium and late cultivars, there were marked differences among genotypes in ability to
ratoon.
Maize Production: Maize requires a temperature range of 18-30oC. It can be grown on a
wide range of soils, but it performs best on well drained; well aerated deep, warm loams and
silt loams containing adequate organic matter and a good supply of nutrients. It can grow
successfully on soils with a pH of 5.0 to 8.0, but 6 to 7 is optimum. In the tropics, maize
does best within 600-900mm of rain during the growing season (Purseglove 1972). Land for
maize should be ploughed, harrowed and rigded, though it could be planted on the flat after
harrowing. Sowing is done in rows with a spacing of 75-100cm between rows to obtain a
population of 50000-66000 plants per hactare. According to Gibbon and Pain (1985), plant
population can vary between 15000 and 90000 plants per hectare. In farmers fields maize
plant density varies greatly between 15000-51000 plants per hectare (Mutsaers et al., 1995),
but can be below the optimum density of 66000 plants per hectare recommended for high
yields (Kang and Wilson 1981).
In Nigeria. Iken and Amusa (2004) recommended a plant population of 53000 plants
per hectare at a spacing of 75cm x 50cm with 2 plants per hill or 75cm x 25cm spacing at 1
plant per hill. Farmers grow maize at very irregular and wide spacing, due to the fact that
most farmers intercrop maize with other crops.
33
In the rain forest zones of Southern Nigeria, two crops of maize are possible per
year. Mid March to first week of April for early and August-September for late planting(
Obi, 1991). Weed Control could be manual or chemical using herbicides. Atrazine could be
applied pre-emergence at the rate of 3.0kg a i /ha. Where grass weed predominate, primextra
at 2 5 kg a i/ha could be applied or Lasso/Atrazine at 2 5 kg a i per hectare.
Maize requires a lot of nitrogen for its growth. Thus it does not perform well in poor
soils. On poor soils, 150 kg N, 60 kg P205 and 60 kg k20/ha can be applied in a split dose.
Harvest: The period between planting and harvesting varies considerably between
90-200days depending on the varieties used. Yields of maize vary tremendously according
to the country and the condition under which the crop was grown. In Nigeria, expected yield
range is 2000-3000kg/ha for open pollinated maize and 3000-4000 kg/ha for hybrid maize in
the southern zone (Iken and Amusa 2004).
Pigeonpea Production.
Pigeonpea requires an optimum temperature range of 18 to 38oC, a rainfall range of
between 600 to 1000 mm/yr and does best at a pH between 5-7. It can grow on a wide range
of soils from coarse to fine texture soils but does not tolerate waterlogged condition (van der
Maesen 1989) It is usually adaptable, flourishing in the dry as well as the wet tropics and
sub-tropics. Tuwafe et al., (1994) reported that the crop is grown in several countries in
Africa and the major producers are Kenya, Malawi, Mozambique, Tanzania and Uganda.
Pigeonpeas are grown in a wide range of cropping systems including sole crops,
intercrops with cereals, often with sorghum, maize or pearl millet, or with other legumes
such as groundnuts, cowpea, mung beans and soyabeans, or with long-season annuals such
as castor, cotton or cassava (Willey et al.,1981). Tuwafe et al., (1994) reprted that in Eastern
and Southern Africa, pigeonpea is grown as an intercrop or mixed-cropped with cereals,
short-duration legumes, or other long-duration annuals. Tabo et al., (1995) reported that in
Nigeria, little seems to be known about production level and there has not been a systematic
attempt to evaluate production practices, constraints, and utilization of the crop. Local
pigeonpea was observed growing in a variety of cropping systems in all of the states visited.
All of the following were found as pigeonpea intercrops: cassava, yams, cocoyams, maize,
sorghum, rice, cowpea, bambaranuts, melons and castor. Pigeonpea was seen being tested in
maize-based cropping systems by Taraba Agricultural Development Programme (ADP). It
34
was seen in mixed cropping systems with sorghum where rainfall is limiting, while maize
and cassava predominate in areas with better rainfall. Rachie and Silvertre (1977) classed
pigeonpea as a crop that can be cultivated in semi-arid to very humid regions of West
Africa. This crop can therefore be cultivated in most ecological regions of Nigeria although
the level of adaptation to ecological regions may depend on genotypes.
Tuwafe, et al., (1994) reported that concerted research efforts have resulted in the
development of short-duration varieties that can escape drought and provide higher yields.
This allows farmers more flexibility and has facilitates the use of pigeonpea in different
cropping systems. In addition, short-duration pigeonpea can be introduced in areas where
intensive management is feasible option to maximize production. Before commercial
cultivation can be initiated, more research is required on the agronomy of this new crop and
on insect pest and disease management, both in the field and in storage. Despite the
importance of pigeonpea in Africa, research efforts in the region have been limited.
Information is lacking on pigeonpea cultivars suitable for intercropping in drought-prone
areas, and on the role of pigeonpea and other short-duration legumes in maintaining
sustainability as it provides long-term benefits in terms of nitrogen-fixation, increased
phosphorus availability and improved soil structure.
Land preparation: The production of pigeonpea starts with land clearing and cultivation to
obtain a fine tilt. The land should be ploughed, harrowed and ridged to required spacing with
tractor or hand moulded with hoes. It can also be planted on flat bed after ploughing and
harrowing on well drained soils. Tabo, et al., (1995) reported that in Nigeria, land is usually
prepared manually, sowing is done on the flat from May to July, depending on the locality,
and ridges are formed later at the time of the second weeding. Row to row spacing varies
from 1-1.5m and within row spacings from 0.3-1m. Plant stand is highly variable, even on
the same field, with an average of about 2-3 plants per stand. Santos, et al., (1995) used a
spacing of 1.0 0.5m which gave a population density of 40000 plants ha-1
in a preliminary
evaluation of pigeonpea genotypes in Brazil.
Seed rate and planting: A seed rate of 45-67 kg ha-1
and seeding depth of 2.5cm-10cm is
recommended (van der Maesen, 1989). Pigeonpea can be planted at 2 plants/stand and to be
thinned to one plant/stand depending on the spacing adopted. Pigeonpea seedlings emerge 2-
3 weeks after sowing. Vegetative growth begins slowly but accelerates at 2-3 months (van
der Maesen, 1989).
35
Nutrient requirement: Pigeonpea can grow on infertile as well as fertile soils. Bogdan
(1977), reported that pigeonpea responded well to P and modestly to K while high N
applications usually reduced yields.
Weed control: Pigeonpea does not compete well with weed during its early growth stage
when growth is slow such that weed control is needed during establishment. Weeds will be
suppressed when crop canopy is well developed.
Harvesting: Pigeonpeas are harvested as green pods or as dry pods, depending on whether
harvested as vegetable or for dry seeds. Rachie and Silvestre (1977) reported that the fresh
seeds of pigeonpea comprised 45% of the weight of the whole fresh pod. In this form they
contain two-thirds water, 20% carbohydrates, 7% protein, 3.5% fibre, 1.5% fat, and 1 3%
mineral materials. Dry, ripe seeds contain about 10% water. 23% protein, 56%
carbohydrate, 8.1% fibre and 3.8% mineral matter. The protein is of resonably good quality
but, like most grain legumes, it is deficient in sulphur amino acids and tryptophan in
comparison with animal protein. Analysis of ′dhal' (without husk) gave the following values:
moisture, 15.2; protein, 22.3; fat (ether extract), 1.7; mineral matter, 3.6; carbohydrate, 57.2;
Ca, 9.1; and P, 0.26%; carotene evaluated as vitamin A, 220 IU and vitamin B1, 150 IU per
100 g. The oil of the seed contains 5.7% linolenic acid, 51.4% linoleic acid, 6.3% oleic acid,
and 36.6% saturated fatty acids. The seed is reported to contain trypsin inhibitors and
chymotrypsin inhibitors. Fresh green forage contains 70.4% moisture, 7.1 crude protein,
10.7 crude fiber, 7.9 N-free extract, 1.6 fat, 2.3 ash. The whole plant, dried and ground,
contains 11.2% moisture, 14.8 crude protein, 28.9 crude fiber, 39.9 N-free extract, 1.7 fat,
and 3.5 ash. (Duke, 1981).
Pigeonpea can produce a moderate yield level of 0.2 to 2.5 t ha-1
across an
impressively broad range of environments (Degrande, 2001; Versteeg and Koudokpon,
1993). According to van der Maesen (1989), pigeonpea is hand harvested in the Tropics.
Ripe pods can be harvested with combine harvesters for cultivars which mature uniformly
with pods at a uniform level above the ground. Tabo, et al., (1995) reported that pigeonpea
is harvested from January to March in Nigeria. Farmers in many places harvested pigeonpea
by picking the pods. In some places, stems were cut at 25-30cm from base and pods were
picked later at home. Most farmers begin to harvest when 90% or more of the pods became
dry to minimize losses due to shattering and dry season bush fires. Pods may be harvested 2-
36
3 times, especially on large farms. Pigeonpeas are cut for forage at the pre flowering stage or
when first pods ripen (Bogdan 1977).
Willey et al., (1981) reported intercropping systems involving pigeonpea in which
the yield of the companion crop is not significantly reduced compared with the situation for
sole crop and in which intercropped pigeonpea yielded up to 70% of a sole pigeonpea crop.
Rao and Willey (1983) reported that in traditional systems, pigeonpea studies have shown
that yields can be increased substantially with little or no reduction in yield of the cereal
component of the mixture if the proportion of pigeonpea sown is increased and both crops
are sown at their full sole crop production. Pigeonpea grown on-farm in poor soils and
without inputs produces highly variable yields; from 0.2-2.5 t ha-1
grain and 1.0 to 3.8 t ha-1
l
of the leaf and stems and where a complementary short-duration legume is grown as an
intercrop, it produces an additional 0 to 1.6 t ha-1
(El-Awad et al., 1993. Natarajan and
Mafongoya, 1992, Ritchie et al., 2000, Sakala, 1994, and Snapp, 2000).
According to Whiteman et al., (1985), seed yield per hectare in grain legume crops
has traditionally been divided into the following broad components of number of fruits plant-
1 , number of seeds fruit
-1; mean dry weight seed
-1, and number of plants ha
-1. In general,
the number of seeds fruit-1
and mean seed weight are characteristic of a genotype and are
influenced relatively little by environmental conditions. Artificial shading treatments
reduced the number of fruits plant-1
but had little effect on the number of seeds fruit-1
or on
mean seed weight (Sheldrake, et al., 1979). In most situations, economic yield is determined
largely by fruit number plant-1
which is related to plant size and duration of the crop
(Whiteman et al., (1985). In particular Akinola and Whiteman (1975), reported that the
number of fruit-bearing branches and the length of the stem over which inflorescences are
produced are clearly related to fruit number plant-1
and are affected by crop density, the time
of sowing (in photo-sensitive genotypes) and climatic factors. According to Singh, et al.,
(1995) it is now known that pods per plant is the most important yield-contributing trait in
pigeonpea. In any selection scheme to increase the yield levels in pigeonpea, the maximum
weight should be given to the two traits of pods per plant, and number of primary branches.
As in other grain legumes, a large proportion of pigeonpea flowers abort. Wallis, et al.,
(1983) reported that with appropriate agronomic practices, yields in replicated small plots of
early maturing genotypes have often exceeded 8 t ha-1
fresh pods.
37
Diseases and Pests of pigeonpea
Diseases: Reddy et al., (1993) reported that diseases are major biological constraints to
production and that more than 60 pathogens including fungi, bacteria, viruses, mycoplasma,
and nematodes can infect pigeonpeas. Fortunately, only a few of them cause economic
losses. Of these, sterility, mosaic and witches broom are region specific; whereas, others
such as fusarium wilt, are widespread across regions.
Phytophthora Blight.-Caused by Phytophthora drechsleri Tuker f. sp. Cajani is a soil borne
fungal disease. It causes seedlings to die suddenly. Infected plants develop water-soaked
leisions on their leaves. The leaves lose turgidity and become desiccated.
Fusarium wilt (Fusarium udum). It is a seed and soil borne fungal disease. The fungus can
survive on infected plant debris in the soil for about 3 years. Wilt symptoms usually appear
when plants are flowering and podding or earlier when plants are 1-2 months old. A purple
band extending upwards from the base of the main stem is normally seen.
Field pests: According to Shanower and Romeis (1999), insect pests feeding on flowers,
pods, and seeds are the most important biotic constraint affecting pigeonpea yields.
Reed and Lateef (1990) reported that the pod borer (Helicoverpa armigera), pod-sucking
bugs (Clavigralla spp), and the pod fly (Melanogromyza obtusa) are the major pests of
pigeonpea. Ajayi et al., (1995) reported that though more than 200 species of insects are
recorded as pests of pigeonpea, there are relatively few published accounts of insect damage
to this crop in Africa. In their observations on insect damage to pigeonpea in Nigeria, they
reported that the observed insects were thrips, leaf hoppers, leaf feeding caterpillars
(Spodoptera exempta), pod sucking bugs (Clavigralla tomentoscicollis), flower beetles, pod
borers (Maracu testulalis), ants, and spittle bugs. Some hymenopterous natural enemies
were reared from the pod borers and were identified as Habrobracon hebetor. In general,
damage by C. Tomentoscicollis was most prominent. Minja et al., (1999) reported that in
humid regions insect pests cause considerable seed damage from 14% to 69% in the farmers′
fields. Pod suckers and borers are the primary pests. The major insect pests include the moth
Heliothis armigera (a larval pod borer) and Melanagromyza obtuse (the pod fly).
Davis and Wolley (1993) reported that intercropping tends to reduce the incidence
and spread of diseases and pests. According to Trenbath (1993), components of intercrops
are often less damaged by pests and disease organisms than when grown as sole crops; but
38
the effectiveness of this escape from attack often varies unpredictably. They further reported
that combining genetic resistance with the benefits of intercropping should result in a more
sustainable control of diseases and pests, reducing significantly the need to apply pesticides
in the field.
Whiteman et al., (1985) reported that two major limitations to yield that can be
manipulated genetically are disease and pest susceptibility. Host plant resistance to insect
attack is an exciting possibility in the search for resistance to pest attacks. Hill and Waller
(1999) reported that Callobruchus maculatus can effectively be controlled culturally in the
field by growing vulnerable crops at least 0.8km distant from farm crop stores which are the
primary source of infestation. Prompt harvest in areas at risk will also reduce attack. He
further recommended that when insecticidal treatment is required, for the control of
Clavigralla spp. in the field, a spray of endosulfan (0.35kg a.i./ha), or fenitrothion (1kg
a.i./ha), permethrin (0.2 kg) or pirimiphosmethyl (0.5kg a.i./ha) can be used.
Storage pests: Dongre et al.,(1993) reported that the cowpea weevil, Callosobruchus
maculatus, is a major pest of pigeonpea and other pulse crops. Generally infestation of
legumes by Callosobruchus occurs in the field and during storage. In the field eggs are
usually glued onto the maturing or drying pods from where young instar larvae will bore
into the seeds. Subsequently at threshing, seeds either show slight or no apparent external
damage (Booker, 1976, Caswell 1968, Southgate, 1978). Although infestation and damage
in the field are generally low, such infestation has serious implications because the insects
multiply very rapidly with very high consequent damage, once the infested seeds are stored
(Taylor, 1981).
According to Ali et al., (2004), the family Bruchidae to which C. maculatus belongs
, exists in every continent especially in tropical regions of Asia, Afrca and central and south
America, except Antarctica. Among storage bruchids, the pulse beetle, C. chinensis and the
cowpea beetle, C. Maculatus, are considered serious pests, causing immense damage every
year to many varieties of the pulse seeds. They are able to generate exceedingly high levels
of infestation even when they passed only one or two generations on the host. The larvae of
both bruchids feed on the pulse seed contents reducing their degree of usefulness to become
unfit to become either for planting or for human consumption. There has been a move
between plant breeders and entomologists to improve grain legume crops by breeding
39
varieties that give higher yields and are resistant to the pests that devastate the current
varieties. Halawa (2004) reported that stored product pests do a great deal of damage to
many grains in storage defeating the purpose of grain storage which according to Gharib
(2004) is to increase the net value by holding grain until prices are more favourable.
Several storage studies have been carried out on the effects of C. maculatus on
different pulses. Ali et al., (2004) reported variations in susceptibility of sixteen varieties of
broadbean to C. chinensis and C. maculatus infestation. Dongre et al., (1993) assessed the
resistance of four pigeonpea species to C. maculatus and reported that none of the pigeonpea
accessions tested was found resistant to C. maculatus but they did show different responses
to infestation. Hill and Waller (1999) reported that fumigation with methyl bromide in the
store is very effective.
Anti-Nutritional Factors in Pigeonpea: Ahmed et al., (2006), reported that food grain
legumes represent the main supplementary protein source in cereal and starchy food–based
diets consumed by large sectors of the population living in developing countries. According
to Bressani, (1993) nutritional considerations of grain legumes are divided into two large
groups: positive and negetive factors.The positive factors include high protein and lysine
content, which allow legumes to serve as excellent protein supplements to cereal grains.
The negative factors acording to Bressanni, (1993) fall into two sub-groups of Antintritional
factors such as enzyme inhibitors, flatulence factors, polyphenols, tannin and phytic acid.
The other negative nutritional factors include protein, carbohydrates digestibility and sulfur
amino acid deficiencies. Champ (2002) also reported that the main benefits of the minor
biotic substances of pulses are:
- the anticarcinogenic properties of protease inhibitors, phytic acid, phyto-oestrogens
and lignans, saponins and phenolic compounds.
- the decrease of blood glucose associated with pulses as well as the role of the starch
and dietary fibre present in large amounts in pulses.
Binita and Khetarpaul (1997) reported that the antinutritional factors interfer with metabolic
process so that growth and bioavailability of nutrients are negetively influenced. Tannins are
capable of lowering of lowering available protein by antagonistic competition and can
therefore elicit protein deficiency syndrome, ′Kwashiorkor' (Maynard 1997). It imposes an
40
astringent taste that affect palatability, reduce food intake and consequently body growth. It
also binds to both exogenous and endogenous proteins including enzymes of the digestive
tract, thereby affecting the utilization of protein (Bagepallis et al., 1993, Aleto, 1993, Sotelu
et al., 1995). Phytic acid can bind to mineral elements such as calcium, zinc, manganese,
iron and magnesium to form complexes that are undigestable, thereby decreasing the
bioavailability of these elements for absorption. Maynard (1997) reported that phytic acid
has complicated effect in human system including indigestion of food and flatulence.
According to Mulimani and Paramjyothi (1995) pigeonpea, an important pulse crop of India,
is a valuable source of protein, minerals, and vitamins for human nutrition. However, it is
known to contain anti-nutritional factors. Trypsin inhibitory activity (TIA) and
Chymotrypsin inhibitory activity (CIA) are observed only in the seed coat (238 .0 +- 0.50
trypsin inhibitory units g-1
flour and 191.3+- 1.80 chymotrypsin inhibitory units g-1
flour).
The levels of these factors and the role of polyphenolic compounds (tannins) in the bio-
availability of nutrients assume importance in pigeonpea in areas where it is consumed
without cooking when whole and mature or as a developing green seed (Jambunathan and
Singh 1980). Umaru (2007) reported that the low levels of these antinutritional factors both
in pigeonpea and chickpea, which would be further reduced or destroyed on cooking,
suggest no great need for concern. They reported Trypsin inhibitor and chymotrypsin
inhibitor mean values of 9.6 and 3.0 units/mg meal respectively in pigeonpea. Champ (2002)
reported that antinutrients have adverse effects on animals when ingested regularly in large
amounts over a long period of time.
Legumes have to be processed prior to consumption due to their content of
antinutritional compounds, such as trypsin inhibitors, phytic acid, galactosides (Vidal-
Valverde et al. 2002, Ahmed, et al., 2006). Processing techniques such as soaking, cooking,
germination and fermentation have been found to reduce significantly the levels of phytates
and tannins by exogenous and endogenous enzymes found during processing (Mosha and
Svanberg 1990; Iorri and Svanberg 1995). Removal of seedcoat helps in reducing the levels
of these antinutritional factors-a process possible at the home level prior to cooking and
consumption, since it is easy, simple and inexpensive (Mulimani and Paramjyothi 1995)
41
Plant Tissue analysis.
Evenhuis and de-Waard (1980) reported that for growth, development and
production, crop plants require a continous, well adjusted supply of essential mineral
nutrients to the roots for uptake and transport to the aerial parts. These nutrients, according
to Mengel and Kirkby (1987) are Nitrogen (N), Phosphorus (P), Potassium (K), Calcium
(Ca), Sulphur (S), Magnesium (Mg), Iron (Fe), Manganese (Mn), Copper (Cu), zinc (Zn),
Molybdenum (Mo), Boron (B), Chlorine (Cl), sodium (Na), Silicon (Si), and Cobolt (Co). In
addition to these are Carbon (C), Hydrogen (H) and Oxygen (O) which are supplied by the
atmosphere. If any of the elements is limited in supply, crop performance decreases and
ultimately results in nutritional disorder. The main factor controlling the mineral content of
plant material is the specific genetically fixed nutrient uptake potential for the different
mineral nutrients. Within plant species, however, considerable differences in the mineral
content occur, which are also partly genetically determined. The second factor controlling
the mineral content of plant material is the availability of plant nutrients in the nutrient
medium. Borget, (1992) reported that the removal of phosphate by pigeonpea from the soil
is always low, but its response to phosphate application is practically always positive.
Generally pigeonpea′s response to potassium is generally positive. The mineral content of
plant is generally expressed on a dry weight basis where fresh plant material has been oven
dried to constant weight.
According to Hinga (1980), the ground plant material can be dissolved either by wet
oxidation or dry ashing for the determination of the mineral content to follow.
Different methods for the analysis of plant tissue mineral content have been developed and
are being used in diferent laboratories. Viets (1980) reported that soil testing and plant
analysis are important means of increasing crop production by the rational use of fertilizers
in combination with the application of other up-to-date management practices.
42
CHAPTER THREE
MATERIALS AND METHODS
Experiment 1 investigated the performance of six pigeonpea genotypes which
comprised of five improved International Crops Research Institute for the Semi-Arid
Tropics (ICRISAT) pigeonpea genotypes and a local (Nsukka) pigeonpea genotype in
mixtures with two maize genotypes under the low-land humid tropical agro-ecology of
Nsukka, Nigeria. The five improved pigeonpea genotypes comprised of two short-duration
genotypes (ICPL 87 and ICPL 161) and three medium-duration genotypes (ICPL 85063,
ICP 7120 and ICPL 87119) obtained from ICRISAT/IAR Zaria station Kano while the Local
pigeonpea genotype was a large seeded long-duration genotype obtained from Nsukka
market. The two maize genotypes used were a hybrid maize (Oba super II) genotype
popularly grown in Nigeria and an open pollinated maize genotype (New Kaduna) both
obtained from Molon Agro Services Enugu.
Experiment 1: Assessment of six pigeonpea genotypes under two late maize intercropping
systems.
Experimental site: A pigeonpea/maize intercropping field experiment was conducted under
late season condition in 2005 and repeated in 2006. The 2006 season pigeonpea experiment
crops were also maintained for ratoon crop assessment in the 2007 cropping season. The
experiments were both conducted in the Teaching and Research Farm of the Department of
Crop Science, University of Nigeria Nsukka. Nsukka is located at latitude 6o52
N and
longitude 7o24
E and altitude 447m above sea level. It is within the Low-land humid
tropical agro-ecology of Nigeria. The test crops for the experiment comprised the six
pigeonpea genotypes and two maize genotypes. The six pigeonpea genotypes were
combined with the two maize genotypes to obtain pigeonpea/maize mixture treatments for
two intercrop systems and were equally maintained as sole crop treatments for the sole crop
system for the pigeonpea. Two sole treatments for the two maize genotypes were also
included to give a total of twenty treaments as follows:
43
ICPL 87 Pigeonpea sole crop
ICPL 161 Pigeonpea sole crop
ICPL 85063 Pigeonpea sole crop
ICP 7120 Pigeonpea sole crop
ICPL 87119 Pigeonpea sole crop
Nsukka Local Pigeonpea sole crop
ICPL 87 Pigeonpea /Open pollinated maize (OPM) intercrop
ICPL 161 Pigeonpea /Open pollinated maize (OPM) intercrop
ICPL 85063 Pigeonpea /Open pollinated maize (OPM) intercrop
ICP 7120 Pigeonpea /Open pollinated maize (OPM) intercrop
ICPL 87119 Pigeonpea /Open pollinated maize (OPM) intercrop
Nsukka Local Pigeonpea /Open pollinated maize (OPM) intercrop
ICPL 87 Pigeonpea /Hybrid maize (HM) intercrop
ICPL 161 Pigeonpea /Hybrid maize (HM) intercrop
ICPL 85063 Pigeonpea /Hybrid maize (HM) intercrop
ICP 7120 Pigeonpea /Hybrid maize (HM) intercrop
ICPL 87119 Pigeonpea /hybrid maize (HM) intercrop
Nsukka Local Pigeonpea /Hybrid maize (HM) intercrop
Sole Hybrid Maize (HM)
Sole Open Pollinated Maize (OPM)
The treatments were randomly allocated to treatment plots and laid out in
randomized complete block design (RCBD) with three replications.
Soil samples to a depth of 0-30 cm were taken with soil auger at random over the
experimental land area at the beginning of the experiment. The samples were bulked and
mixed thoroughly. A sub-sample was taken and used for physical and chemical analyses for
characterization of the site.
In 2005 and 2006 cropping, the land was ploughed, harrowed and ridged at 1.0m
apart. The land was marked out into three blocks with a spacind of 1.0m between blocks and
1.0m between plots. Each block had 20 plots each measuring 5.0m 3.0m = 15m2. Cross
bars were erected across furrows to check erosion from running water. The treatments were
randomly assigned to the treatment plots in each block by use of Table of Random Numbers.
44
Pigeonpea was planted on the two sides of the ridge to give a spacing of 0.5m 0.5m
giving 6 plants on either side of a ridge and 12 plants/ridge. This gave 60 plants per plot,
equivalent to 40,000 plants per hectare. Maize was planted at the crest of the ridges at a
spacing of 1m x 0.25m giving 12 plants/ridge and 60 plants/plot representing 40,000
plants/ha. The same plant population was used under both intercrop and sole crop systems
in additive series. Planting was done in July, 2005 and 2006 respectively. Two seeds were
planted per hole and later thinned to one plant per stand to give the appropriate plant
population at three weeks after planting.
Weed control was manually done by hoeing at 21 and 45 days after planting (DAP).
In the pigeonpea ratoon crops of 2007 cropping season, weeding was done manually in the
months of May and August. Fertilizer application was done manually by banding at 3 weeks
after planting and at the rate of 120 kg N, 60 kg P205 and 80 kg K2O per hectare. Insect pests
were controlled on the pigeonpea by spraying plants with “BEST Action” (Cypermethrin
plus Dimathoate) at the rate of 1.5 litres/ha using knapsack sprayer. Spraying was done at
50% flowering and at podding stages of the pigeonpea when the maize crop had been
harvested in the intercrop systems.
Data Collection.
Pigeonpea parameters: Parameters on growth, pest and yield were taken and
recorded in pigeonpea. They included daily record of seedling emergence which was used
to obtain days to 50% emergence in the treatments. Plant height (cm) was measured from
the base of the plant to the tip of the terminal leaf bud by use of a metre rule. Measurements
were made at two weeks interval up to the flowering stage and then at harvest. Five plants at
the central three ridges of each plot were tagged for this measurement with the average
obtained for each plot. The number of primary branches at flowering stage were taken on
tagged plants and averaged to get mean value per plant. The primary branches were those
that emerged from the main stem of the plant.
Daily count of plants with at least a flower was made on plants of the three central
ridges (i.e.36 plants per plot) in each plot and used for the calculation of days to 50%
flowering. Two representative plants were destructively sampled in each treatment plot at
anthesis and carefully separated into stem, leaf and root fractions. The leaves were counted
to get the average number of leaves per plant and thereafter the fractions were oven dried at
45
700C to get the dry matter weight (g) of each per plant. The fifth leaf that was fully
expanded from the apex was obtained from the branches, oven dried and used for N P K and
Ca nutrient content analyses.
Measurement of plant girth (cm) was made at 5cm above ground level on tagged
plants using a venier calipers and averaged to obtain mean value per plant per plot. Pod
dispersion/distribution on the branches from the first to the last pod was measured with a
metre rule and the length (cm) of the pod bearing stem portion on each tagged plant was
taken at harvest. This was averaged to get mean value per plant. Plants were observed
weekly against insect pests incidences/conspicuous damage. Observed insect pests were
carefully counted, the damage to plants recorded, the number of plants affected recorded and
the insect samples taken for identification.
Daily inspection of plants to record pod maturity was conducted. Brown colouration
of pod indicated maturity and time to pod maturity was taken. This record was used to
obtain number of days to 50% maturity. Dry pods were harvested by hand picking from the
tagged plants for yield and yield parameter assessments. The records taken included:
a. The mean number of pods per plant.
b. Average pod length (cm) was based on ten pods taken at random. Usually length of
pod was measured with a meter rule.
c. The mean number of damaged (shrivelled) pods per plant was recorded. Shrievelling
of pod was essentially by insect pest. The pods were carefully separated into good
and damaged ones and recorded. The average number of the damaged pods per plant
was kept. The percentage of damaged pods was also obtained in relation to the total
number of pods per plant.
d. The mean grain yield (g) per plant and threshing percentage (%) were obtained from
properly sun dried pods that were threshed and separated into shell and seed and
weighed separately. The grain yield was later expressed as grain yield in kg/ha.
e. The mean number of seeds per plant was obtained by averaging counted seeds from
the number of sampled plants per plot after threshing and cleaning.
f. The number of shrivelled seeds/plant was obtained after separating shrivelled seeds
from good seeds and dividing total number of shrivelled seeds by the number of
sampled plants per plot.
46
g. The average number of seeds per pod was obtained by dividing the total number of
seeds per plant by the total number of pods per plant.
h. 1000 seed weight (g). One thousand seeds were counted from each treatment plot,
weighed and recorded.
i. Percentage of survived ratooned plants: The number of plants that survived as
ratoons from the 2006 crop in the 2007 ratoon year was obtained. The percentage
survival in the 2007 ratoon year was then obtained in relation to the plant population
in 2006.
Maize parameters: The following growth and yield parameters of maize were measured and
recorded.
Plant height.
Five maize plants in the middle of three ridges of each plot were tagged and
measured from the base to the tip of the apical leaf with a metre rule for plant height (cm).
Measurements were taken at two weeks interval. The average for the five plants were
obtained. Daily inspection for tasselling was made on maize in the three central ridges for
the calculation of days to 50% tasselling.
Two plants from the three central ridges per plot were randomly selected and
destructively sampled at tasselling. The maize plants were separated into leaf, stem and
inflorescence. The fractions were then oven dried at 700C to constant weight. The dry
weights were recorded.
The number of maize plants on the three central ridges that had brown cobs were
recorded on daily inspection to obtain the number of days to 50% maturity. Maize cobs
were hand harvested at maturity, dehusked and sun dried. The cobs from the five tagged
plants were shelled, cleaned and the weights of the grains and cobs recorded separately.
They were averaged to obtain grain yield (g) per plant. The grain yield (g) /plant were
thereafter expressed in kg/ha.
Statistical Analysis
Growth and yield data in experiment 1 were analysed for a Randomized Complete
Block Design as outlined by Gomez and Gomez (1984) and Obi (2002). Genstat (3)
Discovery Edition package was used to implement the analyses. Detection of differences
47
among treatment means for significant effect was by least significant difference (LSD) at
5% level of probability as obtained from Genstat implementation.
Assessment of intercropping efficiency
From the yield data obtained, the land equivalent ratio (LER) according to Mead and
Willey (1980) was used to assess the intercropping efficiency. The formular is:
LER= SB
YB
SA
YA
Where, YA and YB are the individual crop yields in intercropping, and SA and SB, their
yields as sole crops. LER>1 indicates intercrop land use advantage.
Benefit/cost ratio analysis
According to John-Rey (1997), cost-benefit analysis identifies, quantifies and
subtracts all the costs from the benefits. According to Flannery et al., (2004), the analysis
should be based on the cost of producing the crop and the returns thereof in crop production.
Profit is obtained when total revenue is greater than total cost, and loss is incurred when
total revenue is less than total cost..
- Benefit/cost ratio = cost Total
realised Revenue
- Gross margin (%) = 1
100
Revenue Total
cost Total - ueTotalReven
Benefit-cost ratio value greater than 1.0 implies higher revenue than cost and vice versa.
This also implies gross margin (%) value greater than 50% or less when total cost is
greater than the total revenue realised.
Experiment 2: Assessment of field-to-store insect pests infestation on six pigeonpea
genotype seeds and the residual effect of actellic dust on C. maculatus insect pests.
This was a two-phased storage experiment using the pigeonpea genotypes seeds from the
2005 season cropping. The first phase investigated the phenomenon of field–to-store insect
pests infestation which is very common in pulses affecting their storability. The seeds of the
six pigeonpea genotypes were subjected to zero and two levels of actellic dust (2%) storage
pesticide at half and full dosages to assess emergence and control of any field-to-store insect
pests infestation on the seeds from the field. This was monitored for a period of six months.
48
Thereafter the second phase assessed the residual effect of the actellic dust on introduced C.
maculatus insect pest development on the seeds of the pigeonpea genotypes for another six
months.
Phase 1
Treatments consisted of the six pigeonpea genotype seeds and three dosages- 0.0, 0.5
and 1.0g of Actellic dust (2%). The 0.0g dosage was used as the control to allow for the
emergence of any field-to-store insect pests while the 0.5g was half of the normal dosage
and 1.0g was full dosage of the actellic dust for the assessment of the control of infestation
(if any existed) of the field-to-store insect pests infestation on the test seeds. Thirty (30) gm
each of the six pigeonpea genotypes was used per treatment. The Actellic dust rates were
thoroughly mixed with the seeds in each treatments.
Plastic containers of about 6.5cm x 11.5cm with covers were used to simulate
storage containers. Three ventilation holes of about 1.5cm in diameter were made on all the
plastic containers towards the top and covered with fine wire mesh. Evostick gum was used
to hold the mesh firmly on the plastic containers to prevent entrance or escape of any insect
pests. The experiment was arranged in a 6 x 3 factorial and laid out in a completely
randomized design (CRD) with three replications. The pigeonpea seeds and the appropriate
dosage levels of the insecticide were weighed into the plastic containers according to the
treatment schedule and properly mixed to ensure proper dusting of the seeds with actellic
dust. This was monitored for six months from April, 2006 to Sept. 2006 as the first phase of
the experiment.
Phase 2
When there was no emergence of insect pests, five (5) males and 5 females of C. maculatus
were introduced in all the treatments six month later (September 2006) and monitored for
six months (to March, 2007) as the second phase to assess the residual effect of Actellic
Dust on the introduced C. maculatus development based on the treatment schedules.
Data for phase 2
The following parameters were taken after the introduction of C. maculatus storage pest:
1. Daily count of oviposition on 20 sampled seeds from the fourth day to the 14th
day
being oviposition period. This was to get the number of oviposition per treatment
2. Days to first instar emergence.
49
3. Daily count and removal of emerged adult insects up to the 45th
day were carried out
to know the number of emerged F1 adult insects. This was used for calculating
susceptibility index (S1) as outlined by Howe (1971) and later modified by Dobie
(1977) as follows. Susceptibility index (S1) = 100 D
LogF ,
where F = Total number of F1 progeny emerged
D = mean developmental period (days), estimated as the time from the middle of the
oviposition period to the emergence of 50% of the F1 progeny.
4. Seed weight loss (g) at the end of the study was taken.
5. Number of insects/treatment at the end of the experiment. The number of insects
(dead and alive) within each treatment were counted and recorded.
Statistical Analysis
The data collected were analysed using Genstat (3) Discovery edition package for statistical
analysis. Detection of differences among treatment means for significant effects was by the
use of least significant difference (LSD) at 5% level of probability.
Experiments 3: Susceptibility of six Pigeonpea genotype seeds to Callosobruchus
maculatus storage pest and evaluation of their seed hardness.
This experiment investigated the susceptibility of the pigeonpea genotype seeds to C.
maculatus introduced on freshly harvested pigeonpea seeds. The storage experiments were
conducted in the Teaching Laboratory of Crop Science Department, University of Nigeria
Nsukka.
Plastic containers as in experiment 2 were used to simulate storage containers. Test
seeds were prefumigated with phostoxin in air-tight polythene bags for 48 hours to disinfect
the seeds of any field-to-store insects and eggs. The seeds were then ventilated in plastic
containers with tops covered with fine wire mesh for ten days to eliminate the effect of
phostoxin.
Thirty grams (30g) seed of each of the six pigeonpea genotypes were weighed into
the plastic storage containers and ten adult C. maculatus insects comprising 5 males and 5
females were introduced to each treatment container and covered. The treatments were laid
out in a Completely Randomized Design (CRD) with three replications. Male and female
50
insects were identified with the aid of Helix magnifier hand lense. The adult insects were
left to oviposit for two weeks and then removed. The experiment was monitored for six
months from April 2006 October, 2006. At the onset of the experiment, 20 seeds from each
of the pigeonpea genotypes were subjected to pre-experiment germination test in Petri
dishes lined with moistened filter paper and left under open laboratory condition as a vitality
test of the seeds. At the end of the experiment, a similar post-experiment germination test
was carried out on 20 sampled seeds from the treatments to assess the damage to seeds
caused by the insect pest. Germination count records were kept from which percentage
germination values were obtained.
Data Collected.
Daily record of oviposition on 20 sample seeds was taken from the fourth day to the
14th
day being the oviposition period. The number of oviposition was obtained based on the
number of seeds per treatment. Treatments were monitored and recorded for number of days
to first adult insect emergence. This was followed by the daily record of emerged adult
insects up to the 45th
day to know the number of emerged F1 adult insects. Emerged adult
insects were counted daily and removed. This was used in calculating susceptibility index
(S1) according to the procedure outlined by Howe (1971) and later modified by Dobie
(1977) as earlier described in experiment 2. The values of susceptibility indices were
categorized into five ranks according to the procedure outlined by Mensah (1986) as
follows:
A. The values between 0.0 – 2.5 are considered resistant variety (R)
B. Those between 2.6 – 5.0 are considered moderately resistant variety (MR)
C. The values between 5.1 – 7.5 are considered moderately susceptible variety (MS)
D. The values between 7.6 – 10.0 are considered susceptible variety (S).
E. Those above10.0 are considered highly susceptible variety (HS).
The total number of dead and alive insects per treatment was recorded at the end of
the experiment. Damaged seeds (those with hole(s)) were separated from good or
undamaged seeds and the number recorded per treatment. From the values, percentage
damaged seeds were determined.
In furtherance to getting more information on the attributes of the pigeonpea
genotypes seeds, a replicated Seed hardness test was carried out on the seeds of the six
51
pigeonpea genotypes using 30 sample seeds (i.e 10 per replicate) each for the six genotypes.
This was done using Grain Hardness Tester 30 kg F. (km-model No 174886) machine at the
Department of Agricultural and Bioresources Engineering of the University of Nigeria,
Nsukka. Each grain was placed in position in the machine and when started, the machine
exerted pressure or force on the seed while its arm deflected showing the force (kgf) being
exerted until when the grain cracked with a pop sound and automatically stopping the
deflecting arm and the reading recorded.
Data Analysis
The data collected were statistically analysed using Genstat (3) Discovery edition package
employing the procedure for a CRD experiment. Detection of differences among treatment
means for significant effects was by the use of least significant difference (LSD) at 5% level
of probability as suggested by Riley (2001). The coefficient of variability (CV) was also
calculated using Genstat Discovery package.
Chemical Analyses
The following chemical analyses were carried out on plant materials:
1. Samples of the pigeonpea seeds harvested in the 2005 cropping season were
subjected to proximate analysis, mineral analysis for N, P. K and Ca, and for anti-
nutritional factors of Tannins, Phytate, Trypsin-inhibitor and Chymortrypsin-
inhibitor.
2. Pigeopea leaf samples were taken from five randomly selected plants per plot at the
flowering stage in 2005 and analysed for N, P, K and Ca. The leaves were obtained
from the fifth young fully developed leaves from the apex.
Plant Material Chemical Analyses
The plant sample materials (leaf and seed) were oven dried at 70oC to constant weight and
ground with the hammer to pass through a 0.5mm sieve for the chemical analyses.
A. Proximate Analysis of Pigeonpea Seed
1. Determination of Ash.
Silica dishes were heated at 600oC, cooled and weighed. 2.0g of each sample was
weighed and transferred into the silica dish. The weight of each dish was weighed before
52
introducing the sample. Each dish with sample content was placed into muffle furnace,
ashed at 600oC for 3 hours and allowed to cool, and weighed.
% Ash was calculated as:
Ash % = 1
100
sample ofwt
ash ofwt
2. Determination of Crude Protein
Each sample weighing 0.5g was used and the total nitrogen was determined by
micro-Kjeldahl method as outlined by AOAC (1984). The results were multiplied by 6.25 to
give crude protein.
3. Determination of Crude Fibre
Each sample weighing 1.5g was used and the protein, starch and other digestable
carbohydrates and fat were hydrolysed out of the sample according to method outlined by
AOAC (1984). The residue (crude fibre) was calculated as:
% Fibre = 1
100
w
w- w
1
32
Where: W1 = initial weight of sample
W2 = weight of dried extricated sample before ashing.
W3 = weight of ash.
4. Determination of Soluble Carbohydrate
Soluble carbohydrate was determined spectrophotometrically. Anthrone reagent,
glucose stock solution (0.8 mg ml of glucose) and glucose working standard solutions (0-0.2
mg ml of glucose were made). 2ml of each glucose working standard solution was pipetted
into the glass test tube. 10ml of anthrone reagent was rapidly added and mixed by shaking.
The tube was loosely covered with a glass bulb stopper and immediately placed in a boiling
water bath for 20 minutes to cool. The absorbance was measured in a 10 min. optical cell at
620 nm. A graph relating absorbance to mg of glucose present was constructed. The
absorbance corresponding to 0 and 0.4mg of glucose were approximately 0.03 and 1.0,
respectively. A standard graph with each batch of extract was examined. 2 ml of extract was
pipetted into a test tube and same process as in preparation of standard graph was carried out
ending with measurement of absorbance in a 10 min. optical cell at 620 nm.
53
Calculation of results from the standard graph. The number of mg of glucose
equivalent to the absorbance of the sample and the blank determinations were read. The
differences were multiplied by 50. The result gave the percentage soluble carbohydrate.
5. Determination of Moisture
Sample of 20g seeds from each of the pigeonpea genotypes was weighted and
recorded as initial weights. The sample grains were then oven dried at 70oC to constant
weight and recorded as dry weight of sample.
Moisture content (%) was calculated as:
Moisture content (%) = 1
100
wtsample Initial
wt sampledry - wt sample Initial
6. Determination of Crude Fat Content
Soxhlet extractor was used. 2g of minced sample was accurately weighed and
transferred into rolled ashless filter papers and placed inside the extractor thimble. The
thimble was placed into soxhlet extractor. The flask was three quarter filled with petroleum
ether and placed inside the extraction flask. The soxhlet was connected in the flask and in
turn to the condenser. The heater was switched on not to heat beyond the boiling point of the
petroleum ether used and allowed to run for 3-6 hours. When the extraction ended, the ether
was recovered before the thimble was removed. The oil was collected in the flask and dried
at 100oC in the oven. The differences in the weight of empty flask and the flask with the oil
gave the oil content of the sample.
The % fat content was calculated as follows:
% Fat = 1
100
B
A - C
Where A = weight of empty flask
B = weight of the sample.
C = weight of flask and oil after drying.
Mineral element analysis in plant materials
1. Total Nitrogen Determination in seed and leaf material
A sample of 0.5g of ground seed or leaf material was weighed out into a 500ml
Kjeldahl flask. 1.0g of the catalyst mixture and 20ml of conc. H2SO4 was then added and
54
subjected to the micro-Kjeldahl steam distillation method as outlined by AOAC (1984). The
% total Nitrogen was calculated as:
% total N = T × N × )Distillate thefrom taken (aliquote 10
100%
wt
)distillate (Toal 1000
1000
14
2. Determination of Phosphorus in 0.5g seed and plant materials
Total phosphorus was determined by the perchloric acid digestion combined with
Colorimetric assessment according to AOAC (1990). 0.5g of plant material was used and the
calculation of P in ppm (or mg/ml) was read from the graph and used to calculate the
number of P equivalent to the absorbance of the sample and blank determination.
3. Determination of Potassium (K) and Calcium (Ca) in seed and leaf materials using
Flame Photometry method
The standard solution of potassium and calcium were first prepared and each used in
the flame-photometry method according to Pearson (1976). Concentration of the element in
sample solution was read from the standard curve and % K or % Ca was calculated as:
% K = ppm x 100 x DF
1 million
Where ppm = parts per million (1ml of solution was diluted to 50ml water giving = 2.ppmk).
Nutrient dry matter turnover in pigeanpea leaf.
The nutrient element contents of the sampled pigeonpea leaf was used to calculate
the nutrient turnover per hecture using the leaf fraction dry matter content of the sampled
plants as follows:
Nutrient turn over = hectareper matter wt dry leaf 100
nutrient ofcontent %
Experiment 4: Antinutritional Factors Assessment in the seeds of six phigeonpea
genotypes.
The following antinutritional factors were determined in the seed of the six pigeopea
genotypes.
i. Determination of Tannins. 1.0g of ground sample was weighed into 5mls flask and
the concentration of tannin was determined according to the procedure outlined by
55
Pearson (1976). The formula for calculating the concentration of tannins from the
standard was: % Tannin = An/As C va
vf
w
100
Where:
An = absorbance of test sample.
As = absorbance of standard solution.
C = conc. Of standard solution.
W = weight of sample used.
Vf = total volume of extract.
Va = volume of extract analysed.
ii. Determination of Phytate. A sample of 0.5g of the seed of each pigeonpea genotype
was weighed into a 500ml flat bottomed flask and used for the determination of
phytate according to the procedure of Oberleas D. (1973). The concentration of
phytate was calculated form the prepared standard curve and blank using the
formular:
Conc. of phytate in sample (mg/100g) =
sample of Absorbance standard of Absorbance
std of conc.
iii. Determination of Trypsin
A sample of 1.0g each of pigeonpea genotype seeds was used in the procedure of
Rick (1974) to determine the concentration of trypsin spectrophotometrically. The extinction
of the experimental tube after subtraction of the blank extinction was used to calculate the
enzyme activity.
iv. Determination of Chymortrypsin
A sample of 1.0g of each seed sample was used to determine the concentration of
chymortrypsin spectrophotometrically at 280nm after the precipitation of the residual
substrate according to the procedure of Rick (1974). A standard curve was used to determine
the chymortrypsin concentration of the blank and subsequently in the sample solution.
56
CHAPTER FOUR
RESULTS
The total monthly rainfalls (mm) for 2005 and 2006 followed the characteristic
bimodal pattern peaking first in the months of June or July and second in October (Table 1).
Rainfall was highest in June compared with little or no rainfall in December for 2005 and
2006. Rain always fell more frequently between June and October. During the periods of
January, February, November and December rainfall was very low at 0 - 70.6mm. The
minimum air temperature was always rather high all through the period of the experiments.
Similarly, the maximum air temperature ranged from 28.3oC in July to 22.4
oC in December
in 2005 and from 28.6oC in July to 32
oC in December in 2006.
The highest maximum and minimum temperatures within the year were in the
months of February to April in both 2005 and 2006 seasons. The Relative Humidity (%)
followed closely from the rainfall pattern, rising with high rainfalls and decreasing with
decreased rainfalls, being lowest in the months of November, December January and
February. The Relative Humidity was always comparatively low in the months of
December and January.
The soils of the experimental sites were texturally sand clay loam and essentially
acidic in reaction (Table 2). Phosphorus content was moderate in the 2005 site but low in the
2006 site, while potassium, calcium and sodium were considered moderate in those sites.
Experiment 1:
Assessment of six pigeonpea genotypes under late maize intercropping production
systems with two maize genotypes.
Phenological development in pigeonpea and maize genotypes in mixtures.
Days to seedling emergence, and to anthesis in pigeonpea were not significantly (
P<0.05) affected by cropping system. Days to pod maturity were however significantly
delayed under intercropping with hybrid maize compared with sole pigeonpea cropping
(Table 3). The seedlings of Nsukka Local genotype emerged faster than the other genotypes
in both 2005 and 2006. Seedling emergence appeared generally faster in 2006 than in 2005.
Period to anthesis took long in Nsukka Local compared with others by over 39 days in both
2005 and 2006.
57
Table 1: Metereological records for 2005, 2006 and 2007 at Nsukka, Nigeria.
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
2005 weather records
Total rainfall (mm)
Rain days (No.)
Max. air temp (oC)
Min. air temp (oC)
Relative Hum (%)
0
0
31.6
25.2
57.5
70.6
2
35.2
22.8
64.3
14.9
2
34.4
23.3
67.1
14.0
10
33.6
23.1
69.2
142.5
11
30.6
22.2
73.9
323.8
18
29.4
21.8
74.8
246.2
20
28.3
20.9
76.9
125.4
17
27.3
20.3
76.9
208.0
19
28.7
21.5
76.9
304.2
16
30.1
21.1
73.8
10.1
1
32.4
21.3
66.2
1.2
1
22.4
20.7
63.1
2006 weather records
Total rainfall (mm)
Rain days (No.)
Max. air temp (oC)
Min. air temp (oC)
Relative Hum (%)
36.3
1
33.1
23.0
66.5
4.0
2
33.6
23.2
67.8
103.1
4
33.1
22.8
67.6
51.0
5
35.5
23.3
68.2
243.8
16
30.5
21.3
74.4
259.6
16
29.9
21.2
74.9
213.8
21
28.6
21.5
76.8
195.5
19
27.8
20.8
77.4
190.5
25
28.1
21.3
76.7
313.9
19
29.9
21.2
74.8
1.5
1
31.7
18.9
60.8
0
0
32.6
17.9
50.0
2007 Weather records
Total rainfall (mm)
Rain days (No.)
Max. air temp (oC)
Min. air temp (oC)
Relative Hum (%)
0
0
33.2
20.8
57.5
9.9
1
35.0
22.6
64.3
39.1
4
35.1
23.1
67.1
121.6
8
32.6
22.9
69.2
193.5
11
31.1
21.8
73.9
327.6
16
29.3
21.8
74.8
62.9
14
28.5
21.2
76.9
323.6
17
27.6
21.8
76.9
169.6
19
28.2
21.3
76.9
267.2
18
29.5
20.7
73.8
55.1
4
30.4
21.3
66.2
0
0
31.6
20.0
63.1
58
Table 2: Physical and chemical characteristics of the experimental sites before
planting
Mechanical properties: 2005 2006
Clay (%( 19.76 21.04
Silt (%) 9.28 10.56
Fine sand (%) 24.40 18.36
Coarse sand (%) 46.56 50.04
Textural class Sandy clay loam Sandy clay loam
Chemical Properties
pH in H2O 5.2 5.1
pH in KCl 4.5 4.9
Organic matter:
Carbon (%) 0.93 0.63
Nitrogen (%) 0.070 0.068
Exchangeable bases
(meq/100g)
Na 0.57 0.66
K 0.23 0.37
Ca 1.60 0.80
Mg 1.20 0.96
CEC 2.24 1.12
P (ppm) 44.78 26.87
59
Table 3: Days to 50% emergence, 50% flowering and 50% maturity of pigeonpea
grown in mixtures with two maize genotypes.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
Days to 50% seedling emergence
ICPL87 7.3 6.6 7.3 7.1 6.3 6.6 6.0 6.3
ICPL161 8.0 7.3 7.6 7.6 6.0 6.0 6.0 6.0
ICPL85063 7.3 7.6 7.6 7.5 6.0 6.0 6.0 6.0
ICP7120 7.6 7.3 7.6 7.5 6.0 6.0 6.0 6.0
ICPL87119 7.6 7.6 8.0 7.7 6.6 6.6 6.6 6.6
Nsukka Local 6.3 6.6 6.6 8.5 6.0 6.0 6.0 6.0
Mean 7.3 7.2 7.6 7.3 6.1 6.2 6.1 6.1
Days to 50% flowering
ICPL87 94.6 94.0 93.3 94.0 87.0 84.3 84.3 85.2
ICPL161 92.3 93.3 93.0 92.8 86.6 85.3 88.0 86.6
ICPL85063 93.0 91.0 94.0 92.6 88.6 84.0 84.0 85.5
ICP7120 92.6 90.3 91.0 91.3 80.3 84.3 83.6 82.7
ICPL87119 91.6 90.0 92.6 91.4 83.0 85.3 82.6 83.6
Nsukka Local 129.3 129.3 127.6 128.7 123.3 122.0 122.6 122.6
Mean 98.9 98.0 98.6 98.5 91.5 90.8 90.8 91.0
Days to 50% maturity
ICPL87 173.0 175.0 164.7 170.9 162.0 169.3 162.0 164.4
ICPL161 181.7 177.0 164.7 174.4 161.3 152.7 162.0 158.7
ICPL8563 181.3 178.3 169.3 176.3 171.0 171.0 170.3 170.8
ICP7120 179.3 171.0 166.0 172.1 162.0 162.3 162.0 161.8
ICPL87119 171.0 169.7 156.3 165.7 170.7 171.0 170.0 170.6
Nsukka Local 208.0 208.0 207.7 208.1 204.1 202.7 203.7 203.6
Mean 182.5 179.8 171.4 177.9 171.9 171.3 171.7 171.6
50%Emergence
50% Flowering
50% Maturing
2005 2006 2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means Ns Ns Ns Ns 7.81 Ns
LSD0.05 for 2 p/pea geno. means 0.15 0.28 2.01 2.28 11.04 10.11
LSD0.05 for 2 crop sys p/pea gen Ns Ns Ns Ns Ns Ns
CV (%) 7.30 4.80 0.30 2.60 6.50 6.20
Hm = Hybrid maize P/pea = Pigeonpea Opm= Open pollinated maize
60
Days to pod maturity mostly followed from days to anthesis in both years. Pod maturity was
significantly delayed by over 42 days in Nsukka Local compared with ICPL 87119 in 2005
and by at least 31 days compared with all the other ICRISAT genotypes. ICPL 85063 and
ICPL87119 had significantly higher number of days to pod maturity compared with ICPL
161.There were no interaction effects between cropping system and pigeonpea genotypes.
Days to tasselling and to maturity in maize were not significantly affected by
cropping system in either of the two years (Table 4). Days to tasselling and maturity were
always significantly shorter with the hybrid maize compared with the open-pollinated maize.
There were no interaction effects between maize genotype and cropping system on days to
tasselling and days to maturity.
Plant height of component crops.
Pigeonpea plant height (cm) measured at 2-, 4- or 6- weeks after planting (WAP), at
50% anthesis and at 50% maturity were not ststistically different for those grown in
mixtures with maize and those grown as sole pigeonpea crops (Table 5). However, the
pigeonpea genotypes differed among themselves. Nsukka Local genotype maintained
significantly (P<0.05) taller plants compared with some of the ICRISAT genotypes in both
2005 and 2006. ICRISAT genotypes levelled up in height amongst themselves as from 4
WAP in both 2005 and 2006.
Pigeonpea height at pod maturity showed that Nsukka Loca, except for ICPL87, was
significantly taller than the other genotypes in 2005 (Table 6). A similar trend was obtained
in 2006 but with no statistical difference among the pigeonpea genotypes. Remarkably after
anthesis the pigeonpea plants still increased in height by an average of over 48cm.
Interaction effects of pigeonpea genotype and cropping system were not obvious.
Maize plant height measured at 2, 4 and 6 WAP did not differ significantly (P<0.05)
for those grown either as sole crops or in mixtures with pigeonpea in both 2005 and 2006
(Table 7). However, hybrid maize genotype attained greater height at these stages compared
with open pollinated maize in 2005; but were of similar heights statistically in 2006. Maize
plants did not differ in height at tasselling and maturity periods regardless of genotype or
cropping system under which they were grown (Table 8). Combining cropping system with
pigeonpea genotypes did not produce significant effect.
61
Table 4: Days to 50% tasselling and 50% maturity in maize genotypes intercropped
with six pigeonpea genotypes.
Maize Cropping system
Genotypes Maize Maize Maize Maize Maize Maize Sole Mean +
ICPL87
+
ICPL161
+
ICPL85063
+
ICP7120
+
ICPL87119
+
NSK
Local
Maize
Days to 50% tasselling
2005
Hybrid maize 67.0 71.3 71.3 72.6 68.3 68.3 69.3 69.7
Open P-maize 75.6 74.6 75.6 74.6 74.3 76.3 76.0 75.2
Mean 71.3 73.0 73.5 73.3 71.3 72.3 72.6 72.5
2006
Hybrid maize 69.3 70.0 70.0 69.3 68.3 70.0 69.0 69.4
Open P-maize 70.0 71.3 70.6 70.0 70.0 69.3 70.0 70.1
Mean 69.6 70.6 70.3 69.6 69.1 69.6 69.5 69.8
Days to 50% maturity
2005
Hybrid maize 115.6 116.6 116.3 116.3 115.3 116.0 116.3 116.1
Open P-maize 118.0 118.6 119.0 118.3 118.0 119.3 117.0 118.3
Mean 116.8 117.6 117.6 117.3 116.6 117.6 116.6 117.2
2006
Hybrid maize 111.3 11.6 112.0 110.3 111.3 111.6 111.3 111.3
Open P-maize 115.0 114.3 115.0 115.0 115.0 114.6 114.6 114.8
Mean 113.1 113.0 113.5 112.6 113.1 113.1 113.0 113.0
50% tasselling
50% Maturing
2005 2006 2005 2006
LSD0.05 for 2 crop. systems Ns Ns Ns Ns
LSD0.05 for 2 maize gen. means 1.487 0.689 0.816 0.550
LSD0.05 for 2 crop-sys maize gen. Ns Ns Ns Ns
CV(%) 3.2 1.6 1.1 0.8
Hm = Hybrid maize P/pea = Pigeonpea Opm= Open pollinated maize
62
Table 5: Pigeonpea genotype plant height (cm) responses at 2-, 4- and 6- WAP under
maize/pigeonpea intercropping systems.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
2 WAP
ICPL87 11.0 10.7 10.2 10.6 9.1 8.5 8.8 8.8
ICPL161 9.1 9.5 9.5 9.4 9.2 9.5 8.4 9.0
ICPL85063 9.1 10.1 9.6 9.6 7.9 9.8 8.6 8.8
ICP7120 9.7 10.3 10.8 103 8.3 9.1 8.4 8.6
ICPL87119 10.5 9.3 8.8 9.5 8.4 7.7 7.9 8.0
Nsukka Local 11.6 10.6 12.7 11.6 9.3 10.2 10.1 9.9
Mean 10.2 10.1 10.2 10.2 8.7 9.1 8.7 8.8
4WAP
ICPL87 16.7 16.2 15.4 16.1 14.7 15.1 15.4 15.1
ICPL161 14.3 14.5 14.6 14.4 14.6 16.5 14.8 15.3
ICPL85063 14.7 15.4 14.9 15.0 15.6 16.2 17.2 16.4
ICP7120 14.8 15.5 16.2 15.5 16.8 15.9 15.2 15.9
ICPL87119 15.0 14.5 13.9 14.4 14.8 13.5 15.1 14.4
Nsukka Local 17.4 16.0 19.0 17.5 16.8 19.2 16.2 17.4
Mean 15.5 15.3 15.6 15.5 15.5 16.0 15.6 15.7
6WAP
ICPL87 31.1 29.5 26.3 29.0 24.8 27.7 25.7 26.1
ICPL161 25.0 26.1 25.0 25.4 23.4 26.2 25.1 24.9
ICPL8563 20.3 26.0 23.6 23.3 22.8 23.0 28.9 24.9
ICP7120 27.0 28.0 28.5 27.8 25.2 26.9 22.0 24.7
ICPL87119 28.6 24.5 20.7 24.6 23.9 23.0 25.6 24.1
Nsukka Local 33.3 30.0 36.6 33.3 24.8 29.4 25.0 26.4
Mean 27.5 27.0 26.8 27.2 24.1 26.0 25.4 25.2
2 WAP
4 WAP
6 WAP
2005 2006 2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means Ns Ns Ns Ns Ns Ns
LSD0.05 for 2 p/pea geno. means 1.031 0.808 1.075 1.595 3.411 Ns
LSD0.05 for 2 crop. sys. p/pea Ns Ns Ns Ns Ns Ns
CV (%) 10.5 9.5 7.2 10.5 5.1 13.7
Hm = Hybrid maize Opm = open pollinated maize
P/pea = Pigeonpea WAP = weeks after planting.
63
Table 6: Pigeonpea genotype plant height (cm) at 50% flowering and at 50% maturity
under intercropping with two maize genotypes.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
50% flowering
ICPL87 141.1 154.8 134.5 143.5 117.9 123.8 118.7 120.1
ICPL161 122.1 123.0 128.8 124.7 113.8 124.3 117.3 118.5
ICPL85063 128.9 134.0 118.4 127.1 118.2 121.7 125.8 121.9
ICP7120 126.3 137.8 134.2 132.8 121.4 116.3 108.7 115.5
ICPL87119 107.0 117.0 131.7 118.6 123.3 107.8 118.7 116.6
Nsukka Local 153.4 144.5 144.2 147.4 118.8 115.5 108.5 114.2
Mean 129.8 135.0 132.0 132.3 118.9 118.2 116.3 117.8
50% maturity
ICPL87 191.5 190.8 190.7 191.0 163.9 171.4 171.3 168.9
ICPL161 182.4 160.2 184.4 175.6 161.8 173.1 168.6 167.8
ICPL85063 175.6 182.6 176.4 178.2 156.3 166.6 190.9 171.2
ICP7120 175.3 172.3 182.0 176.6 173.6 153.6 150.7 159.3
ICPL87119 154.9 168.0 176.7 166.5 157.5 164.1 160.1 160.5
Nsukka Local 190.3 194.5 197.3 194.0 171.9 170.2 164.6 168.9
Mean 178.3 178.1 184.6 180.3 164.1 166.5 167.7 166.1
50% flowering
50% maturity
2005 2006 2005 2006
LSD0.05 2 crop. sys. means Ns Ns Ns Ns
LSD0.05 2 p/pea geno. means 15.79 Ns 11.01 Ns
LSD0.05 for 2 crop.sys. p/pea gen
CV(%)
Ns
12.5
Ns
10.4
Ns
6.4
Ns
8.1
Hm = Hybrid maize Opm = open pollinated maize
P/pea = Pigeonpea WAP = weeks after planting.
64
Table 7: Maize genotypes height at 2-, 4- and 6- WAP under intercropping with six
pigeorpea genotypes and sole crop systems.
Maize Cropping system
Genotypes Maize Maize Maize Maize Maize Maize Sole Mean +
ICPL87
+
ICPL161
ICPL85063
ICP7120
+
ICPL87119
+
NSK
Local
Maize
At 2 WAP
2005
Hybrid maize 11.0 12.1 11.8 11.4 12.1 11.9 11.6 11.7
Open P-maize 10.1 10.0 10.9 10.4 11.4 10.3 10.6 10.5
Mean 10.5 11.0 11.3 10.9 11.7 11.1 11.1 11.1
2006
Hybrid maize 7.4 7.3 8.0 8.8 7.6 7.9 7.8 7.8
Open P-maize 8.7 8.0 8.4 8.5 8.5 8.9 8.6 8.5
Mean 8.0 7.7 8.2 8.7 8.0 8.4 8.2 8.2
At 4 WAP
2005
Hybrid maize 14.8 15.4 15.1 14.9 15.3 15.1 15.0 15.1
Open P-maize 13.8 13.5 14.6 13.8 14.8 14.1 14.6 14.2
Mean 14.3 14.5 14.8 14.3 15.0 14.6 14.8 14.6
2006
Hybrid maize 12.6 12.2 14.0 14.2 14.0 12.7 12.0 13.1
Open P-maize 14.5 12.2 13.8 12.8 12.1 14.2 12.4 13.1
Mean 13.5 12.2 13.9 13.5 13.1 13.5 12.2 13.1
At 6 WAP
2005
Hybrid maize 26.2 28.2 25.4 23.9 29.5 26.8 28.5 26.9
Open P-maize 24.3 23.7 26.9 22.1 23.4 24.4 26.8 24.5
Mean 25.2 25.9 26.1 23.0 26.5 25.6 27.6 25.7
2006
Hybrid maize 24.6 24.8 24.0 25.3 26.8 25.4 23.3 24.9
Open P-maize 25.9 26.4 25.4 25.4 23.1 25.6 24.0 25.1
Mean 25.2 25.6 24.7 25.3 24.9 25.5 23.7 25.0
At 2WAP At 4 WAP At 6 WAP
2005 2006 2005 2006 2005 2006
LSD0.05 for 2 crop. systems means Ns Ns Ns Ns Ns Ns
LSD0.05 for 2 maize gen. means 0.532 Ns 0.553 Ns 1.815 Ns
LSD0.05 for 2 crop.sys. maize gen
CV (%)
Ns
7.5
Ns
15.2
Ns
5.9
Ns
14.4
Ns
11.1
Ns
10.2
65
Table 8: Maize Genotypes plant height (cm) at 50% tasselling and at 50% maturity
under intercropping with six pigeonpea genotypes and sole crop systems.
Maize Cropping system
Genotypes Maize Maize Maize Maize Maize Maize Sole Mean +
ICPL87
+
ICPL161
+
ICPL85063
+
ICP7120
+
ICPL87119
+
NSK
Local
Maize
50% tasselling
2005
Hybrid maize 56.4 57.8 54.7 55.7 57.7 59.0 58.7 57.2
Open P-maize 57.4 55.7 60.4 57.4 58.2 48.2 59.9 56.7
Mean 56.9 56.7 57.5 56.5 57.9 53.7 59.3 56.9
2006
Hybrid maize 53.5 55.5 52.9 59.9 58.2 58.2 55.6 56.3
Open P-maize 59.3 55.5 52.5 55.8 50.8 54.1 52.2 54.2
Mean 56.4 55.3 52.7 57.8 54.5 56.5 53.9 55.3
50% maturity
2005
Hybrid maize 132.2 138.9 131.2 129.4 133.5 136.2 138.6 134.3
Open P-maize 139.5 132.1 135.9 133.8 140.0 134.0 145.8 137.3
Mean 135.8 135.5 133.5 131.6 136.7 135.1 142.2 135.8
2006
Hybrid maize 148.3 133.1 132.6 146.8 145.2 133.5 147.4 141.0
Open P-maize 137.1 140.5 151.9 130.5 134.4 153.5 133.3 140.0
Mean 142.7 136.8 142.3 138.6 139.8 143.5 140.3 140.6
50% tasselling 50% Maturing
2005 2006 2005 2006
LSD0.05 for 2 crop. systems means Ns Ns Ns Ns
LSD0.05 for 2 maize gen. means Ns Ns Ns Ns
LSD0.05 for 2 crop. sys maize gen
CV (%)
Ns
9.2
Ns
10.4
Ns
6.0
Ns
14.4
66
The number of primary branches and and number of leaves of pigeonpea were
significantly (P<0.05) reduced under intercropping with maize compared with sole
pigeonpea (Table 9). Hybrid maize depressed those values more in pigeonpea compared
with open pollinated maize. The pigeonpea genotypes differed in their number of primary
branches and leaves either with sole cropping or in intercropping system. Nsukka Local
genotype had significantly (P<0.05) higher number of primary branches than the ICRISAT
pigeonpea genotypes in both 2005 and 2006. The variation in number of leaves among the
pigeonpea genotypes did not show a definite pattern in the two years. In 2005, ICPL 87 had
significantly higher number of leaves compared with all other genotypes with Nsukka Local
having the least. In 2006 however, ICPL 85063 had the highest and significantly different
number of leaves compared with other ICRISAT genotypes and it was follwed by Nsukka
Local. Interaction of cropping system with pigeonpea genotypes did not produce significant
effect. However, the number of primary branches and leaves were always higher under sole
cropping for all the pigeonpea genotypes.
Intercropping of pigeonpea with maize significantly (P<0.05) depressed pigeonpea
pod bearing stem length in 2005, and stem girth in both 2005 and 2006 in the pigeonpea
(Table 10). Intercropping hybrid maize with pigeonpea had a greater depressant effect on
pigeonpea inflorescence distribution, stem length and on stem girth than pigeonpea was
intercropped with open pollinated maize. Nsukka Local pigeonpea genotype had less than
half the pod distribution length in the ICRISAT genotypes in both 2005 and 2006. However
Nsukka Local had significantly (P<0.05) higher stem girth compared with the ICRISAT
genotypes in 2006. Although there was no significant cropping system × pigeonpea
genotypes interaction for pigeonpea pod distribution (pod bearing stem length) and stem
girth, they were slightly higher under sole cropping than with all the mixtures except for
ICPL 87 and Nsukka Local mixtures with open pollinated maize in 2006 where they had
higher pod distribution stem length compared with their sole crops.
Dry mater distribution in crop fractions under the cropping systems
Pigeonpea dry matter in plant fractions of leaf, stem and root were depressed by the
maize intercrop by about 30.6%, 26.8% and 23.8%, respectively in 2005, and by 33.2%,
34.6% and 37.7%, respectively in 2006 (Table 11). The leaf dry matter yield depression by
67
maize was higher with hybrid maize intercropping than with open pollinated maize
intercropping in both 2005 and 2006. Pigeonpea genotypes differed significantly (P<0.05)
in their leaf dry matter yields in 2005 and 2006 but there was no significant (P<0.05)
difference in their root dry matter weights. Leaf dry matter was always higher with sole
cropping than with mixtures. In 2006, all the sole crops of the genotypes had significantly
higher leaf dry matter compared to those in mixtures except for ICPL 7120 where there was
no significant difference. Stem dry matter was higher in the sole crop of ICRISAT
genotypes and more so with ICPL 87, ICPL 85063 and ICPL 87119 than those where they
were mixed with maize. In Nsukka Local, stem dry matter was similar in the sole crop and
its mixture with open pollinated maize and were significantly higher than that in mixture
with hybrid maize.
68
Table 9: Effects of intercropping on number of primary branches/plant and number
of leaves/plant in six pigeonpea genotypes.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
No. of primary branches
ICPL87 12.4 14.9 21.0 16.1 12.5 13.4 15.6 12.8
ICPL161 12.9 14.2 16.3 14.5 10.8 12.9 16.0 13.2
ICPL85063 10.3 13.6 18.0 14.0 11.8 14.0 20.0 10.5
ICP7120 12.2 13.0 13.8 13.0 10.8 10.4 10.4 10.5
ICPL87119 12.4 11.4 14.2 12.7 11.9 11.4 13.0 12.1
Nsukka Local 14.7 19.6 24.2 19.5 16.9 18.6 16.5 17.3
Mean 12.4 14.4 17.9 14.9 12.4 13.4 15.2 13.7
No of leaves
ICPL87 268.3 266.0 330.3 288.2 157.8 194.5 218.3 190.2
ICPL161 264.3 245.3 300.0 269.9 193.1 168.2 253.4 204.9
ICPL85063 156.3 260.3 303.0 239.9 184.9 208.5 409.5 267.6
ICP7120 205.3 248.3 319.0 257.8 161.7 153.0 226.9 180.5
ICPL87119 185.0 209.3 289.7 228.0 158.9 172.1 224.1 185.4
Nsukka Local 169.0 233.3 206.7 203.0 207.6 203.6 258.9 223.4
Mean 208.1 243.8 291.6 247.8 177.6 183.3 265.2 208.7
No. of pri. branches
No. of Leaves.
2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means 1.723 1.789 32.83 36.07
LSD0.05 for 2 p/pea geno. means 2.436 2.530 46.43 51.01
LSD0.05 for 2 crop sys.x p/pea gen Ns Ns Ns Ns
CV (%) 17.0 19.2 19.6 25.5
69
Table 10: Effects of pigeonpea/maize intercropping on pigeonpea inflorescence ( pod
bearing stem) length(cm)/plant and stem girth (cm)/plant.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
PBSL (cm)
ICPL87 34.9 34.2 38.2 35.8 27.2 39.3 38.9 35.1
ICPL161 33.9 31.8 40.1 35.3 35.7 29.4 33.0 32.7
ICPL85063 29.0 31.4 39.2 33.2 31.4 31.1 36.3 32.9
ICP7120 35.4 38.1 38.9 37.4 36.1 33.0 35.8 35.0
ICPL87119 31.3 29.9 34.7 32.0 35.9 31.6 38.4 35.3
Nsukka Local 14.0 15.0 17.4 15.4 14.4 16.4 15.3 15.4
Mean 29.8 30.0 34.7 31.5 30.1 30.2 32.9 31.1
Stem girth (cm)
ICPL87 0.94 1.13 1.44 1.17 1.00 1.09 1.27 1.12
ICPL161 1.17 1.14 1.34 1.18 1.23 1.05 1.29 1.19
ICPL85063 0.96 1.25 1.47 1.22 1.09 1.16 1.39 1.21
ICP7120 0.91 1.27 1.43 1.20 1.05 1.09 1.20 1.11
ICPL87119 0.98 0.98 1.17 1.04 1.05 1.09 1.20 1.10
Nsukka Local 1.06 1.29 1.45 1.27 1.27 1.30 1.50 1.36
Mean 0.98 1.17 1.38 1.18 1.11 1.12 1.31 1.18
PBSL (cm)
Stem Girth (cm)
2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means 2.434 Ns 0.1293 0.0624
LSD0.05 for 2 p/pea geno. means 3.443 6.233 Ns 0.0883
LSD0.05 for 2 crop.sys x p/pea gen. Ns Ns Ns Ns
CV (%) 11.4 20.9 16.1 7.8
PBSL= Pod bearing stem length
70
Table 11: Pigeonpea genotypes leaf, stem and root dry matter fractions (kg/ha) under
intercropping with two maize genotypes.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005
2006
Leaf (kg/ha)
ICPL87 1140.0 1176.0 1628.0 1315.0 814.0 926.0 1492.0 1077.0
ICPL161 1044.0 950.0 1237.0 1077.0 1056.0 919.0 1368.0 1114.0
ICPL85063 762.0 908.0 1413.0 1028.0 848.0 1142. 1853.0 1281.0
ICP7120 1089.0 1213.0 1777.0 1360.0 861.0 1011. 1011.0 961.0
ICPL87119 753.0 897.0 1180.0 944.0 743.0 859.0 1354.0 985.0
Nsukka Local 922.0 1277.0 1492.0 1230.0 1125.0 1290. 1606.0 1340.0
Mean 952.0 1070.0 1455.0 1159.0 908.0 1024. 1447.0 1126.0
Stem (kg/ha)
ICPL87 1435.0 1444.0 1831.0 1570.0 1234.0 1271. 1963.0 1489.0
ICPL161 1317.0 1207.0 1603.0 1375.0 1518.0 988.0 1587.0 1364.0
ICPL85063 1081.0 1193.0 1672.0 1315.0 953.0 1316. 2623.0 1631.0
ICP7120 1365.0 1370.0 2036.0 1590.0 1349.0 1018. 1381.0 1249.0
ICPL87119 1030.0 1108.0 1511.0 1217.0 947.0 1090. 2039.0 1359.0
Nsukka Local 1090.0 1513.0 1755.0 1452.0 1360.0 1995. 1960.0 1772.0
Mean 1219.0 1306.0 1735.0 1420.0 1227.0 1280. 1925.0 1477.0
Root (g/p)
ICPL87 469.0 4290 6850 528.0 327.0 325.0 560.0 404.0
ICPL161 468.0 440.0 549.0 486.0 347.0 345.0 519.0 434.0
ICPL85063 393.0 406.0 461.0 420.0 252.0 331.0 675.0 420.0
ICP7120 455.0 400.0 583.0 480.0 286.0 319 .0 408.0 338.0
ICPL87119 404.0 370.0 521.0 431.0 287.0 285.0 501.0 358.0
Nsukka Local 437.0 483.0 581.0 500.0 330.0 445.0 527.0 434.0
Mean 438.0 421.0 563.0 474.0 305.0 357.0 532.0 398.0
Leaf
Stem
Root
2005 2006 2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means 173.0 126.8 154.0 188.4 61.5 76.4
LSD0.05 for 2 p/pea geno. means 244.5 179.3 217.0 266.4 Ns Ns
LSD0.05 for crop. sys p/pea gen. Ns 310.5 Ns 461.5 Ns Ns
CV (%) 22.0 16.6 16.0 18.8 19.2 28.3
71
Leaf, stem and inflorescence dry matter fractions in maize were not significantly
(P<0.05) affected by Pigeonpea intercropping in 2005 (Table 12). However in 2006,
pigeonpea intercropping significantly (P<0.05) depressed leaf, stem and inflorescence dry
matter yields in the maize by 11.8%, 32.2% and 22.2% respectively. Maize genotypes did
not differ significantly in their dry matter fractions in 2005, but open pollinated maize
genotype had significantly (P<0.05) higher leaf dry matter compared to hybrid maize in
2006. Interaction between cropping system and the maize genotype dry matter fractions
were not significant (P<0.05).
Field insect pests attack on pigeonpea
A few pigeonpea plants were attacked sporadically at the seedling and early vegetative
stages by variegated grasshopper (Zonocerus variegatus), crickets (Brachytrupes
membranaceus) and termites (Odontotermes badius) (Table 13). Some affected seedlings
were lost while some where only the leaves were destroyed or the stems cut developed new
shoots and continued to grow. A large number of white flies were observed at the vegetative
stage when plants were shaken but there was no associated observable damage on crop
plants. Pod flies (Melanogromyza spp.), Pod sucking bugs (Clavigralla spp.) and pod borer
(Helicoverpa armigera) seem endemic with pigeonpea plants at the reproductive stage,
causing damages on flowers, pods and developing seeds of the pigeonpea.
Intercropping did not significantly affect the number of insect pests plant-1
in
pigeonpea both at flowering and at podding stage of plant development in 2005 or 2006
although the number was always lower in intercropped conditions (Table 14). The
pigeonpea genotypes did not also differ significantly in this parameter in 2005 but ICPL
87119 had significantly (P<0.05) higher number of insect pests plant-1
at the podding stage
compared with the other genotypes in 2006. Nsukka Local had the least number of insect
pests plant-1
compared with the ICRISAT genotypes in both 2005 and 2006. Interactions
between cropping system and
72
Table 12: Maize leaf, stem, and inflorescence dry matter fractions (kg/ha) under
intercropping with six pigeonpea genotypes.
Maize Cropping system
Genotypes Maize Maize Maize Maize Maize Maize Sole Mean +
ICPL87
+
ICPL161
ICPL85063
ICP7120
+
ICPL87119
+
NSK
Local
Maize
Leaf
2005
Hybrid maize 947.0 958.0 836.0 758.0 1060.0 987.0 1070.0 945.0
Open P-
maize
840.0 700.0 765.0 704.0 682.0 1006.0 840.0 814.4
Mean 974.0 829.0 800.0 731.0 872.0 996.0 955.0 879.0
2006
Hybrid maize 746.0 735.0 759.0 825.0 757.0 736.0 790.0 764.0
Open P-
maize
753.0 796.0 908.0 855.0 847.0 764.0 1023.0 849.0
Mean 749.0 765.0 834.0 840.0 802.0 750.0 907.0 807.0
Stem
2005
Hybrid maize 3261. 3199. 2661. 2483. 3904. 3201. 2962. 3096.
Open P-maize 3185. 2188. 2514. 2379. 2109. 2824. 3213. 2630.
Mean 3223. 2694. 2587. 2431. 3006. 3013. 3087. 2863.
2006
Hybrid maize 1695. 1801. 1815. 2107. 1909. 1788. 2724. 1977.
Open P-maize 1789. 1745. 1720. 2175. 1782. 1681. 2737. 1947.
Mean 1742. 1773. 1767. 2141. 1846. 1735. 2730. 1962.
Inflorescence
2005
Hybrid maize 105.7 104.1 97.6 88.3 90.3 110.3 119.0 102.2
Open P-maize 126.1 85.8 98.9 92.4 90.8 140.8 100.9 105.1
Mean 115.9 94.8 98.3 90.3 90.5 125.6 110.1 103.6
2006
Hybrid maize 105.6 90.8 93.6 96.0 92.5 84.7 116.3 97.1
Open P-maize 96.1 94.1 100.9 100.0 100.5 91.3 129.2 101.8
Mean 100.9 92.5 97.3 98.0 96.5 88.0 122.7 99.4
Leaf
Stem
Inflorescence
2005 2006 2005 2006 2005 2006
LSD0.05 for 2 crop. systems means Ns 105.7 Ns 326.0 Ns 13.63
LSD0.05 for 2 maize gen. means Ns 56.5 Ns Ns Ns Ns
LSD0.05 for crop.sys x p\pea gen. Ns Ns Ns Ns Ns Ns
CV (%) 25.4 11.0 28.6 14.0 21.2 11.6
73
Table 13: Field insect pests recorded on pigeonpea at Nsukka in 2005 and 2006.
Insect Pest Characteristic/discription of insect Nature of damage
and period
Variegated Grasshopper
(Zonocerus variegatus)
Adults are dark green with patterned
black, yellow and orange body about 3 –
5cm long. Adults and nymphs have
biting and chewing mouth parts.
Sporadic defoliation
and cutting off of
seedlings.
Crikets
(Brachytrupes membranaceus)
Large fat-bodied insects about 5cm long
with biting and chewing mouth parts.
Sporadic cutting of
seedlings stems.
Termites
(Odonototermes badius)
Social insects that net underground with
biting and chewing mouth parts.
Cut the stems of
seedlings and young
plants at ground level
at random.
White Flies (Bemisia Spp). Minute white four winged insects about
1mm long with piercing and sucking
mouth parts.
No obvious damage
was observed on
plants.
Pod Fly
(Melanogromyza spp.)
Small black flies that affect plants
through the larvae which are white in
colour about 3 – 5mm long that mines
into pods and feed on developing seeds.
Larvae ate
developing seeds
within pods.
Blister Beetles
(Mylabris spp.)
Medium to large beetles (2-5cm) in
length, black and yellow or black and
red in colour with biting and chewing
mouth parts.
Destroyed flowers
and anthers.
Pod sucking bugs
(Clavigralla spp.)
Adults are dark brown bugs 7 – 10 mm
in length according to species – with
piercing and sucking mouth parts.
Sucked developing
seeds giving
shrivelled (bad
seeds). Affected
pods are wrinkled.
Pod borer
(Helicoverpa armigera)
A bollworm that feeds on flowers and
pods. The caterpillars are 1.5 – 4cm
long and bore holes on pods and feed on
seeds.
Destroyed buds,
flowers and pods.
74
Table 14: Number of blister beetles and pod borer insect pests/plant at flowering stage
and pod fly, pod sucking bugs and pod borer insect pests at podding stage in pigeonpea
intercropped with maize.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005
2006
Insect pests no./plt at flowering
ICPL87 2.4 2.1 2.5 2.3 1.7 1.7 2.1 1.9
5ICPL161 2.1 2.1 2.5 2.2 1.8 1.7 1.9 1.8
ICPL85063 2.3 2.5 2.5 2.4 2.1 1.1 2.2 2.1
ICP7120 2.3 2.3 2.5 2.4 1.8 1.9 1.9 1.9
ICPL87119 2.3 2.1 2.6 2.3 2.1 1.7 2.0 1.9
Nsukka Local 2.4 2.6 2.3 2.4 2.0 2.0 1.6 1.9
Mean 2.3 2.3 2.5 2.3 1.9 1.9 2.0 1.9
Insect pests no./plt at podding
ICPL87 2.0 1.9 2.4 2.1 1.5 1.3 2.0 1.6
ICPL161 2.0 2.4 1.8 2.1 1.9 2.7 1.5 2.0
ICPL85063 2.4 2.1 2.5 2.3 2.5 1.9 2.8 2.4
ICP7120 2.1 2.3 2.6 2.3 1.5 1.8 2.6 2.0
ICPL87119 2.4 2.7 2.7 2.6 2.5 2.5 2.7 2.6
Nsukka Local 1.9 1.9 2.0 1.9 1.2 1.4 1.1 1.3
Mean 2.1 2.2 2.3 2.2 1.9 1.9 2.1 2.0
No. at flowering
No. at podding
2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means Ns Ns Ns Ns
LSD0.05 for 2 p/pea geno. means Ns Ns 0.288 0.599
LSD0.05 for crop. sys. p/pea gen Ns Ns Ns Ns
CV (%) 12.1 16.8 13.3 30.7
75
pigeonpea genotypes were not significant (P<0.05) for the number of insect pests at both
flowering and pod formation stages. However, intercropping of pigeonpea tended to reduce
the number of insect pests, while Nsukka local genotype had slightly lower number of pests
under both intercropping and sole crop conditions at podding stage.
Damage to pods and seeds in pigeonpea caused by insect pests.
Intercropping significantly (P<0.05) reduced the number of insect damaged pods and
seeds in the pigeonpea compared with the situation for sole cropping system in both 2005
and 2006 (Table 15). Hybrid maize intercropping reduced the number of damaged pods in
the pigeonpea compared to open pollinated maize intercropping in both 2005 and 2006 but
not at a significant level. In 2005, ICPL 87 had the highest number of damaged pods
compared with the other genotypes. Nsukka Local had significantly (P<0.05) the least
number of damaged pods and seeds in both 2005 and 2006 compared with the ICRISAT
genotypes which did not differ among themselves. Cropping system interaction with the
pigeonpea genotypes was not significant for these parameters. However, damaged pods and
seeds were higher in sole crop than with intercropping with maize in both 2005 and 2006.
Effects of intercropping on pod and seed numbers in pigeonpea.
Intercropping of pigeonpea with maize on average significantly (P<0.05) reduced the
number of pods plant-1
by 32.9% in 2005 and by 34.2% in 2006 (Table16). It also
significantly reduced the number of seeds plant-1
by 35.2% in 2005 and by 24.6% in 2006.
The lower number of pods plant-1
and number of seeds plant-1
under hybrid maize compared
with open pollinated maize intercropping in both 2005 and 2006 did not attain statistical
significance. Among the pigeonpea geotypes, Nsukka local had significantly (P<0.05) lower
number of pods plant-1
and lower number of seeds plant-1
in both 2005 and 2006. ICPL 87
and ICPL 85063 genotypes had significantly higher number of pods plant-1
and number of
seeds plant-1
when compared with all the other genotypes in 2005 and 2006. There was no
significant (P<0.05) cropping system x pigeonpea genotypes interaction on both the
76
Table 15: Number of insect pests-damaged pods/plant and insect pests-damaged
seeds/plant in pigeonpea under intercropping with maize.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
No. of damaged pods/plant
ICPL87 14.0 22.3 32.7 23.0 5.9 5.5 13.4 8.3
ICPL161 7.7 13.0 15.0 11.9 8.6 6.13 20.1 11.6
ICPL85063 43. 13.3 20.0 12.6 5.8 12.2 18.0 12.0
ICP7120 11.0 10.0 13.0 11.3 8.5 10.9 6.8 8.7
ICPL87119 12.7 8.7 21.7 14.3 13.3 8.2 8.2 9.9
Nsukka Local 3.0 3.3 6.3 4.2 2.7 2.5 2.6 2.6
Mean 8.8 11.8 18.1 12.9 7.5 7.5 11.5 8.8
No. of damaged seeds/plants
ICPL87 80.7 95.3 129.3 101.8 59.0 62.7 101.3 74.3
ICPL161 65.3 55.7 98.0 73.0 50.7 61.3 58.7 56.9
ICPL85063 50.0 76.7 139.0 88.6 52.3 82.3 88.0 74.2
ICP7120 41.0 60.0 111.7 70.9 50.7 44.7 82.7 59.3
ICPL87119 66.3 65.7 124.0 85.3 67.0 64.0 57.3 62.8
Nsukka Local 25.7 27.3 32.0 28.3 24.0 21.9 17.8 21.2
Mean 54.8 63.4 105.7 74.6 50.6 56.2 67.6 58.1
No. of damaged
pods
No. of damaged
seeds.
2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means 5.33 3.635 13.30 12.88
LSD0.05 for 2 p/pea geno. means 7.54 5.141 18.81 18.22
LSD0.05 for 2 crop. sys x p/pea gen. Ns Ns Ns Ns
CV (%) 61.0 60.4 26.3 32.7
77
Table 16: Number of pigeonpea pods/plant and of seeds/plant under miaze
intercropping and sole crop systems
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
Number of Pods/Plant
ICPL87 183.3 187.0 225.7 198.7 92.9 92.1 165.0 166.7
ICPL161 146.0 144.7 213.3 168.1 102.3 89.9 166.4 119.5
ICPL85063 86.7 144.0 227.0 152.6 108.0 129.9 215.2 151.0
ICP7120 132.3 130.3 200.0 154.2 98.2 125.9 131.4 118.5
ICPL87119 108.7 118.7 163.7 130.3 119.5 96.1 140.7 118.7
Nsukka Local 49.0 51.0 76.0 58.0 44.1 56.0 59.6 53.2
Mean 117.7 129.3 184.3 143.8 94.2 98.3 146.4 112.9
Number of seeds/plant
ICPL87 503.0 543.0 673.0 573.6 351.0 297.0 515.0 388.0
ICPL161 486.0 439.0 600.0 508.0 360.0 404.0 342.0 369.0
ICPL85063 268.0 459.0 686.0 471.0 286.0 379.0 587.0 417.0
ICP7120 278.0 358.0 571.0 403.0 283.0 367.0 402.0 251.0
ICPL87119 320.0 314.0 531.0 389.0 352.0 292.0 409.0 351.0
Nsukka Local 153.0 192.0 272.0 208.0 152.0 195.0 209.0 185.0
Mean 335.0 385.0 556.0 425.0 297.0 322.0 411.0 343.0
No of pods/plant
No. of seeds/
plant
2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means 28.40 17.96 58.5 62.8
LSD0.05 for 2 p/pea geno. means 40.17 25.40 82.8 88.7
LSD0.05 for 2 crop. sys. x p/pea Ns Ns Ns Ns
CV (%) 29.2 23.5 20.32 27.0
78
number of pods plant-1
and number of seeds plant-1
in 2005 and 2006. However, sole
cropping had higher number of pods and seeds in both 2005 and 2006.
The pigeonpea pod length was approximately 5cm on the average while the number
of seeds per pod was approximately 4 (Table 17). Pod length (cm) and number of seeds pod-
1 in pigeonpea were not significantly (P<0.05) affected by maize intercropping in both 2005
and 2006. Pigeonpea genotypes did not differ significantly in these parameters in 2005 but
Nsukka Local had significantly longer pods compared with the ICRISAT genotypes, while
ICP 7120 genotype had the lowest number of seeds pod-1
compared with any of the other
genotypes in 2006. Nsukka Local and ICPL 85063 genotypes also had significantly lower
number of seeds pod-1
compared with ICPL 161 in 2006. Interactions between cropping
system and pigeonpea genotypes on pod length and number of seeds pod-1
in both 2005 and
2006 were not significant (P<0.05).
Crop yields as influenced by intercropping
Intercropping of pigeonpea with maize on average significantly (P<0.05) depressed
pigeonpea grain yield (kg/ha) by 40% in 2005 and by 32% in 2006 (Table 18). There was a
greater yield depression under hybrid maize intercropping compared with the situation for
open pollinated maize intercropping in both 2005 and 2006. The pigeonpea genotypes
differed significantly (P<0.05) in grain yield (kg/ha) in both 2005 and 2006 with Nsukka
Local genotype yielding significantly lower than the ICRISAT genotypes in 2005. ICPL 87
yielded significantly (P<0.05) higher than the other ICRISAT genotypes. However, ICPL
85063 yielded highest compared with all the other genotypes in 2006. Intercropping with
maize did not significantly (P<0.05) affect 1000 seed weight (g) and threshing percentage
(%) in pigeonpea in both 2005 and 2006. Nsukka Local had significantly (P<0.05) the
highest 1000 seed weight (g) compared with the ICRISAT genotypes in both 2005 and 2006.
Threshing percentage (%) in the pigeonpea was not significantly affected by neither
cropping system nor pigeonpea genotype. Interaction between cropping system and
pigeonpea genotypes for grain yield, 1000 seed weight and threshing percentage were not
significant (P<0.05). However, sole cropping gave higher grain yield but it did not affect
1000 seed weight and threshing percentage. Intercropping with hybrid maize tended to
depress yield
79
Table 17: Pigeonpea genotypes pod length and seed number pod-1
under maize
intercropping and sole crop systems
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
Pod length (cm)
ICPL87 3.96 4.53 4.60 4.36 4.35 4.63 5.08 4.68
ICPL161 4.00 4.16 4.33 4.16 4.69 4.70 4.33 4.57
ICPL85063 3.83 4.60 4.40 4.27 4.48 4.73 4.40 4.54
ICP7120 4.20 4.00 4.50 4.23 4.50 4.52 4.38 4.46
ICPL87119 4.23 4.26 3.76 4.08 4.60 4.71 4.65 4.65
Nsukka Local 4.63 4.83 4.66 4.71 4.84 4.80 5.08 4.90
Mean 4.14 4.40 4.37 4.30 4.48 4.68 4.65 4.60
Number of seeds/pod
ICPL87 3.66 4.00 4.00 3.88 3.53 3.53 4.00 3.68
ICPL161 3.50 3.53 3.93 3.65 3.73 3.73 3.73 3.73
ICPL85063 3.50 3.83 3.66 3.66 3.40 3.66 3.40 3.48
ICP7120 4.06 3.60 3.93 3.86 3.46 3.40 3.26 3.37
ICPL87119 3.83 3.66 3.60 3.70 3.46 3.60 3.86 3.64
Nsukka Local 3.50 3.66 3.50 3.55 3.46 3.46 3.66 3.53
Mean 3.67 3.71 3.77 3.72 3.51 3.56 3.65 3.57
Pod length (cm)
No. of seeds/
pod
2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means Ns Ns Ns Ns
LSD0.05 for 2 p/pea geno. means Ns 0.269 Ns 0.220
LSD0.05 for 2 crop. sys. x p/pea Ns Ns Ns Ns
CV (%) 9.7 6.1 10.2 6.4
80
Table 18: Pigeonpea grain yield (kg/ha), average 1000 seedweight (g) and threshing
percentage (%) under intercropping with maize.
Pigeonpea Cropping system Cropping system
Genotypes P/pea P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
+
Hm
+
Opm
P/pea
2005 2006
Grain yield (kg/ha)
ICPL87 1429.0 1459.0 1792.0 1560.0 904.0 840.0 1415.0 1053.0
ICPL161 1219.0 1168.0 1617.0 1335.0 850.0 871.0 1283.0 1001.0
ICPL85063 749.0 1050.0 1680.0 1160.0 1035.0 1149.0 1694.0 1293.0
ICP7120 1011.0 1142.0 1521.0 1225.0 895.0 1154.0 1405.0 1151.0
ICPL87119 791.0 847.0 1334.0 990.0 974.0 847.0 1315.0 1045.0
Nsukka Local 701.0 809.0 1016.0 842.0 714.0 754.0 957.0 808.0
Mean 983.0 1079.0 1493.0 1185.0 895.0 936.0 1345.0 1059.0
1000 seed wt (g)
ICPL87 83.0 80.2 80.6 81.3 88.3 91.4 89.2 89.6
ICPL161 74.9 79.2 79.2 77.9 80.7 80.3 83.7 81.5
ICPL85063 75.6 82.0 80.2 79.3 88.1 29.9 90.5 89.5
ICP7120 78.8 82.8 80.1 80.6 86.1 92.8 89.4 89.4
ICPL87119 73.6 78.9 80.0 77.5 77.9 77.2 81.5 78.9
Nsukka Local 114.2 107.0 118.0 113.1 117.2 111.7 110.4 113.1
Mean 83.3 85.1 86.3 84.9 89.7 90.6 90.8 90.4
Threshing (%)
ICPL87 54.7 52.8 54.8 54.1 54.6 54.3 51.6 53.5
ICPL161 52.8 51.0 53.2 52.3 54.1 54.3 53.4 54.0
ICPL85063 50.8 52.3 54.4 52.5 54.6 52.9 53.8 53.7
ICP7120 51.8 52.6 52.2 52.2 50.8 54.4 53.4 52.8
ICPL87119 50.2 52.6 53.8 52.2 51.1 52.8 54.7 52.9
Nsukka Local 52.7 52.6 51.8 53.4 53.5 55.4 53.9 54.3
Mean 52.2 52.3 53.4 52.6 53.1 54.0 53.4 53.5
Grain yield
1000 seed wt
Threshing %
2005 2006 2005 2006 2005 2006
LSD0.05 for 2 crop. sys. means 132.7 165.0 Ns Ns Ns Ns
LSD0.05 for 2 p/pea geno. means 92.3 233.4 7.61 8.23 Ns Ns
LSD0.05 for crop.sys. x p/pea
CV (%)
Ns
16.5
Ns
23.0
Ns
9.4
Ns
9.5
Ns
3.7
Ns
3.7
81
slightly more than open pollinated maize in ICPL 85063, ICP 7120, ICPL 87119 and
Nsukka Local mixtures in both 2005 and 2006.
Maize grain yield (kg/ha) was significantly (P<0.5) reduced when intercropped with
pigeonpea by 23.7% and 22.2% on the average in 2005 and 2006 respectively (Table 19).
Intercropped maize yields with the pigeonpea genotypes for both hybrid and open pollinated
maize did not differ among themselves but were least in their mixtures with Nsukka Local
pigeonpea in 2005. In 2006 however, hybrid maize yields in mixture with ICPL 7120 and
ICPL 87119 were significantly higher compared with its yields in mixtures with the other
pigeonpea genotypes. In open pollinated maize genotype, its mixture yield with ICPL 87119
was significantly higher compared with its mixture yield with other genotypes and least for
its mixture yield with Nsukka Local. The maize genotypes did not differ significantly in
grain yield in 2005 but hybrid maize yielded significantly (P<0.05) higher than the open
pollinated maize in 2006. Interaction of cropping system and maize genotypes was not
obvious but maize grain yield tended to be reduced in mixture with Nsukka Local than with
the ICRISAT genotypes in 2005. Intercropping maize with pigeonpea did not significantly
(P<0.05) affect maize shelling percentage in both 2005 and 2006, but the open pollinated
maize had significantly (P<0.05) higher shelling percentage in 2005 and there was no clear
effect in 2006. Interactions between cropping system and maize genotypes was not
significant for maize shelling percentage in both 2005 and 2006.
Land Equivalent Ratio (LER) assessment of the mixtures.
The mixture yields of most of the crop genotypes grown in the pigeonpea/maize
mixtures were close to or above half of their corresponding sole crop yields (relative grain
yields) (Table 20). Combining the relative grain yield values for the component crops in
mixtures gave land equivalent ratio (LER) values greater than 1.0 in all cases. Under hybrid
maize, relative yield of pigeonpea was lowest with ICPL 85063 but highest with ICPL 87 in
2005. The LER value was lowest (1.12) with ICPL 85063 and highest (1.54) with ICPL 87
and closely followed by ICPL 161 with (1.52). In 2006, the relative yield was lowest with
ICP 7120 and highest with Nsukka Local. The LER was lowest (1.29) with ICPL 161 and
highest (1.49) with ICP 7120.
82
Under open pollinated maize, relative yield of pigeonpea was lowest with ICPL 85063 and
highest with ICPL 87 in 2005 and lowest with ICPL87119 and ICPL 87 and highest with
ICPL 7120. The LER values were lowest (1.39) with Nsukka Local and highest with ICP
7120 and ICPL 87 in 2005 and lowest with ICPL 87119 and highest with ICP 7120 in 2006.
Benefit/Cost Analysis.
Cost of production was higher in intercropping systems of pigeonpea/maize mixtures than in
sole cropping systems of either pigeonpea or maize in 2005 (Table 21). Cost of production
of ICRISAT pigeonpea genotypes mixtures with hybrid maize was higher than cost of
production of their mixtures with open pollinated maize by two hundred and twenty five
naira (₦225) due to higher cost of hybrid maize seed. The cost of production was higher in
ICRISAT pigeonpea/maize mixtures than with Nsukka Local/maize mixtures by 1810 due to
higher cost of the ICRISAT pigeonpea seeds and the higher cost of its transportation
compared with that of Nsukka Local genotype seed. This also resulted in higher cost of
production in sole ICRISAT pigeonpea genotypes compared with the Nsukka Local
genotype counterpart. The higher cost of hybrid maize seed compared with open pollinated
maize seed resulted in higher cost of production in hybrid maize compared with open
pollinated maize. Cost of sole crop production was higher in pigeonpea than in maize.
Cost of production was again higher with intercropping of pigeonpea and maize
mixtures than in the sole cropping of either pigeonpea or maize in 2006 (Table 22). The cost
of production of pigeonpea genotypes in mixture with hybrid maize was slightly higher than
the cost of production of their mixtures with open pollinated maize counterpart due to the
higher cost price of hybrid maize compared with open pollinated maize. This also resulted in
higher cost of production for sole hybrid maize compared with sole open pollinated maize.
In like manner, the cost of production of ICRISAT pigeonpea genotypes was slightly higher
than the cost of production for Nsukka Local genotype both under intercrop and sole crop
production systems due to the higher cost price for the ICRISAT pigeonpea genotypes seeds
compared with the Nsukka Local genotype. The cost of fertilizer and its transportation was
slightly higher in 2006 but the cost of transportation for ICRISAT pigeonpea seeds dropped
compared to that in 2005. Cost of production was slightly lower in 2006 compared with
2005.
83
The revenue analysis showed that intercropping systems gave higher revenue than
sole cropping systems (Table 23). Greater yield (kg/ha) and revenue (naira) accrued from
the maize crop in both intercrop and sole crop systems than from its pigeonpea counterpart.
The ICRISAT pigeonpea genotypes gave greater yield, revenue and profits under both
intercrop and sole crop systems compared with Nsukka Local genotype where a loss and
negative gross margin (-18%) was obtained in the sole crop. All the ICRISAT
pigeonpea/maize mixtures had above 2.0 benefit/cost ratio while their sole crops had above
1.0 benefit/cost ratio. The Nsukka Local genotype had a lower performance with a
benefit/cost ratio above 2.0 in mixture with hybrid maize, below 2.0 with open pollinated
maize and below 1.0 in its sole crop. All the ICRISAT pigeonpea/maize mixtures gave
greater gross margin values than the Nsukka Local/maize mixtures. Sole maize crops gave
higher profits compared to their sole pigeonpea counterparts.
The revenue analysis in 2006 (Table 24) showed a similar trend to that in 2005
(Table 23) with higher total crop yields, revenue and profits under intercropping systems
compared with sole crop systems for both the pigeonpea and maize crops. The ICRISAT
pigeonpea genotypes again performed better in crop yield, revenue and profit under both
intercrop and sole crop systems compared to its Nsukka Local pigeonpea counterpart. Crop
yields, revenue and profits were higher in sole maize crops compared with the crops of both
the ICRISAT and Nsukka Local pigeonpea genotypes.
84
Table 19: Maize grain yield (kg/ha) and shelling percentage (%) under intercropping
with pigeonpea.
Maize Cropping system
Genotypes Maize Maize Maize Maize Maize Maize Sole Mean
+
ICPL87
+
ICPL161
+
ICPL85063
+
ICP7120
+
ICPL87119
+
Nsk-Lo
Maize
Grain yield (kg/ha)
2005
Hybrid maize 2915 2896 2653 2965 3083 2550 3826 2984
Open P-maize 2957 2568 2845 2990 2907 2194 3510 2853
Mean 2936 2732 2749 2977 2995 2372 3668 2918
2006
Hybrid maize 2890 2753 3120 3621 3156 3033 4281 3265
Open P-maize 2845 2752 2707 3305 2859 2699 3902 3010
Mean 2867 2752 2913 3463 3007 2866 4091 3137
Shelling (%)
2005
Hybrid maize 62.3 63.4 63.3 59.8 59.5 61.0 59.1 61.3
Open P-maize 62.2 64.8 68.3 61.9 62.3 63.0 64.0 63.8
Mean 62.3 64.3 65.8 60.9 60.9 62.0 61.6 62.5
2006
Hybrid maize 62.9 63.1 62.2 64.4 61.9 63.3 64.1 63.2
Open P-maize 61.5 61.7 61.3 64.4 62.8 62.2 61.7 62.2
Mean 62.2 62.4 61.8 64.4 62.4 62.8 63.0 62.7
Grain yield
Shelling (%)
2005 2006 2005 2006
LSD0.05 for 2 crop. systems means 499.9 399.0 Ns Ns
LSD0.05 for 2 maize geno. means Ns 213.3 2.155 Ns
LSD0.05 for 2 crop. sys. x maize Ns Ns Ns Ns
CV (%) 14.4 10.7 5.4 2 .9
85
Table 20: Mean relative grain yield of maize and pigeonpea genotypes and land
equivalent ratio (LER) values in the pigeonpea/maize intercropping system
Hybrid maize + Pigeonpea mixtures
2005 2006
Maize P/pea LER Maize Pigeonpea LER
Sole maize 1.00 - 1.00 1.00 - 1.00
Sole Pigeonpea - 1.00 1.00 - 1.00 1.00
HM/ICPL 87 0.75 0.79 1.54 0.67 0.66 1.33
HM/ICPL 85063 0.68 0.44 1.12 0.72 0.66 1.38
HM/ICP 7120 0.77 0.68 1.45 0.86 0.63 1.49
HM/ICPL 161 0.76 0.76 1.52 0.63 0.66 1.29
HM/ICPL 87119 0.80 0.59 1.39 0.73 0.74 1.47
HM/Nsukka local 0.65 0.68 1.33 0.70 0.75 1.45
Open pollinated maize + Pigeonpea mixtures
Sole maize 1.00 - 1.00 1.00 - 1.00
Sole Pigeonpea - 1.00 1.00 - 1.00 1.00
OM/ICPL 87 0.83 0.81 1.64 0.74 0.64 1.38
OM/ICPL 85063 0.82 0.61 1.43 0.69 0.72 1.41
OM/ICP 7120 0.85 0.76 1.64 0.83 0.82 1.66
OM/ICPL 161 0.75 0.74 1.49 0.71 0.68 1.39
OM/ICPL 87119 0.81 0.65 1.46 0.73 0.64 1.37
OM/Nsukka local 0.61 0.78 1.39 0.69 0.80 1.49
86
Table 21: Cost items for production per hectare in pigeonpea/maize mixtures in 2005
Item
Mixtures Sole crops
ICRISAT
P/pea
+
HM
ICRISAT
P/Pea
+
OPM
NSK
Local
P/Pea
+
HM
NSK
Local
P/Pea
+
OPM
ICRISAT
P/Pea
NSK
Local
HM
OPM
Cost of prelim. soil analysis (N) 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500
Cost of land preparation (N) 15,000 15,000 15,000 15,000 15,000 15,000 15,000 15,000
Cost of seeds –ICRISAT P/Pea @ N100/kg and Nsukka
Local P/Pea @ N60/kg for 4 kg each.
400
400
240
240
400
240
-
-
Hybrid maize @ N150/kg and OPM at N100/kg for 4.5kg
each.
675
450
675
450
-
-
675
450
Seed transportation cost - Pigeonpea
- Maize
1,800 1,800 150 150 1,800 150 - -
500 500 500 500 - - 500 500
Cost of planting - Pigeonpea
- Maize
3,000 3,000 3,000 3,000 3,000 3,000 - -
2,000 2,000 2,000 2,000 - - 2,000 2,000
Cost of fert. (4 bags @ N500/bag) 10,000 10,000 10,000 10,000 10,000 10,000 10,000 10,000
Cost of transportation of fertilizer 600 600 600 600 600 600 600 600
Cost of application of fertilizer @ N500/bag
2,000
2,000
2,000
2,000
2,000
2,000
2,000
2,000
Purchase of insecticide (1.5L) @ N1800/L 2,700 2,700 2,700 2,700 2,700 2,700 - -
Cost of spraying insecticide 1,500 1,500 1,500 1,500 1,500 1,500 - -
Cost of weeding - 1st
- 2nd
12,000 12,000 12,000 12,000 12,000 12,000 12,000 12,000
12,000 12,000 12,000 12,000 12,000 12,000 12,000 12,000
Cost of Harvest - Pigeonpea
- Maize
3,000 3,000 3,000 3,000 3,000 3,000 - -
2,000 2,000 2,000 2,000 - - 2,000 2,000
Cost of threshing pigeonpea 2,500 2,500 2,500 2,500 2,500 2,500 - -
Cost of shelling maize 2,000 2,000 2,000 2,000 - - 2,000 2,000
Total 75,175 74,950 73,365 73,140 68,000 66,190 60,275 61,050
87
Table 22: Cost items for production per hectare in pigoenpea/maize mixtures in 2006.
Item
Mixtures Sole crops
ICRISAT
P/pea
+ HM
ICRISAT P/Pea
+
OPM
NSK Local P/Pea
+
HM
NSK Local P/Pea
+
OPM
ICRISAT
P/Pea
NSK Local
HM
OPM
Cost of prelim. Soil analysis (N) 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500
Cost of land preparation (N) 15,000 15,000 15,000 15,000 15,000 15,000 15,000 15,000
Cost of seeds –ICRISAT P/Pea @ N100/kg and
Nsukka Local P/Pea @ N60/kg for 4 kg each.
400
400
240
240
400
240
-
-
Hybrid maize @ N150/kg and OPM at N100/kg
for 4.5kg each.
675
450
675
450
-
-
675
450
Seed transportation cost - Pigeonpea
- Maize
100 100 100 100 100 100 - -
500 500 500 500 - - 500 500
Cost of Planting - Pigeonpea
- Maize
3,000 3,000 3,000 3,000 3,000 3,000 - -
2,000 2,000 2,000 2,000 - - 2,000 2,000
Cost of fert. (4 bags @ N500/bag) 10,800 10,800 10,800 10,800 10,800 10,800 10,800 10,800
Cost of transportation of fertilizer 800 800 800 800 800 800 800 800
Cost of application of fertilizer @ N500/bag
2,000
2,000
2,000
2,000
2,000
2,000
2,000
2,000
Purchase of insecticide (1.5L) @ N1800/L 2,700 2,700 2,700 2,700 2,700 2,700 - -
Cost of spraying insecticide 1,500 1,500 1,500 1,500 1,500 1,500 - -
Cost of weeding - 1st
- 2nd
12,000 12,000 12,000 12,000 12,000 12,000 12,000 12,000
12,000 12,000 12,000 12,000 12,000 12,000 12,000 12,000
Cost of Harvest - Pigeonpea
- Maize
3,000 3,000 3,000 3,000 3,000 3,000 - -
2,000 2,000 2,000 2,000 - - 2,000 2,000
Cost of threshing pigeonpea 2,500 2,500 2,500 2,500 2,500 2,500 - -
Cost of shelling maize 2,000 2,000 2,000 2,000 - - 2,000 2,000
Total 74,475 74,250 74,315 69,640 67,800 67,140 61,275 61,050
88
TABLE 23: Revenue items and Benefit/cost ratio analysis for 2005
Cropping System Yield (kg/ha)
Pigeonpea maize
Revenue
Pigeonpea Maize
Total
Revnue
Realized (N)
Profit
(Revenue –
Cost prod.)
Benefit/cost
Ratio
Gross
margin
(%)
ICPL 87 + HM 1,429 2,915 78,595 131,175 209,770 134,595 2.79 64
ICPL 87 + OPM 1,459 2,957 80,245 133,065 213,310 138,360 2.84 65
ICPL 87 SOLE 1,792 - 98,560 - 98,560 30,560 1.45 31
ICPL 161 + HM 1,219 2,896 67,045 130,320 197,365 122,190 2.63 62
ICPL 161 + OPM 1,168 2,568 64,240 115,560 179,800 104,850 2.40 58
ICPL 161 SOLE 1,617 - 88,935 - 88,935 20,935 1.31 24
ICPL 85063 + HM 749 2,653 41,195 119,385 160,580 85,405 2.14 53
ICPL 85063 + OPM 1,050 2,845 57,750 128,025 185,775 110,825 2.48 60
ICPL 85063 SOLE 1,680 - 92,400 - 92,400 24,400 1.36 26
ICP 7120 + HM 1,011 2,965 55,605 133,425 189,030 113,855 2.51 60
ICP 7120 + OPM 1,142 2,990 62,810 134,550 197,360 122,410 2.63 62
ICP 7120 SOLE 1,521 - 83,655 - 83,655 15,655 1.23 19
ICPL 87119 + HM 791 3,085 43,505 138,825 182,330 107,155 2.42 59
ICPL 87119 + OPM 847 2,907 46,585 130,815 177,400 102,450 2.37 58
ICPL 87119 SOLE 1,334 - 73,370 - 73,370 5,370 1.08 07
Nsukka Local + HM 701 2,550 38,555 114,750 153,305 79,940 2.09 52
Nsukka Local + OPM 809 2,194 44,495 98,730 143,225 70,085 1.96 49
Nsukka Local SOLE 1,016 - 55,880 - 55,880 -10,310 0.76 -18
SOLE HM - 3,824 - 172,170 172,170 111,895 2.86 65
SOLE OPM - 3,510 - 157,950 157,950 97,900 2.63 62
* Profit = Total Revenue realized - Total cost of production.
* Benefit/Cost Ratio = Revenue Realized
Total Cost
* Gross Margin (%) = Total Revenue – Total Cost
Total Revenue.
89
TABLE 24: Revenue Items and Benefit/cost analysis for 2006
Cropping
combination
Yield (kg/ha)
Pigeonpea maize
Revenue
Pigeonpea Maize
Total Revnue
Realized (N)
Profit
(Revenue –
Cost prod.)
Benefit/cos
t Ratio
Gross
margin
(%)
ICPL 87 + HM 904 2,890 49,720 130,050 179,770 105,295 2.41 59
ICPL 87 + OPM 840 2,845 46,200 128,025 174,225 99,975 2.35 59
ICPL 87 SOLE 1,415 - 77,825 - 77,825 10,025 1.15 13
ICPL 161 + HM 850 2,753 46,750 123,885 170,635 96,160 2.29 56
ICPL 161 + OPM 871 2,752 47,905 123,840 171,745 97,495 2.31 57
ICPL 161 + SOLE 1,283 - 70,565 - 70,565 2,765 1.04 04
ICPL 85063 + HM 1,035 3,120 56,925 140,400 197,325 122,850 2.65 62
ICPL 85063 +
OPM
1,149 2,707 63,196 121,815 185,011 110,761 2.49 60
ICPL 85063
+SOLE
1,694 - 93,170 - 93,170 25,370 1.37 27
ICP 7120 + HM 895 3,621 49,225 162,945 212,170 137,695 2.85 65
ICP 7120 + OPM 1,154 3,305 63,470 148,725 212,195 137,945 2.86 65
ICP 7120 + SOLE 1,405 - 77,275 - 77,275 9,475 1.14 12
ICPL 87119 + HM 974 3,156 53,570 142,020 195,590 121,115 2.63 62
ICPL 87119 +
OPM
847 2,859 46,585 128,655 175,240 100,990 2.36 58
ICPL 87119 +
SOLE
1,315 - 72,325 - 72,325 4,525 1.07 06
Nsukka Local +
HM
714 3,033 39,270 136,485 175,755 101,440 2.37 58
Nsukka Local +
OPM
754 2,699 41,470 121,455 162,925 93,285 2.34 57
Nsukka Local +
SOLE
957 - 52,635 - 52,635 -15,005 0.78 -29
SOLE HM - 4,281 - 192,645 192,645 131,370 3.14 68
SOLE OPM - 3,902 - 175,590 175,590 114,540 2.88 65
* Profit = Total Revenue realized - Total cost of production.
* Benefit/Cost Ratio = Revenue Realized
Total Cost
* Gross Margin (%) = Total Revenue – Total Cost
Total Revenue.
90
Evaluation of pigeonpea ratoon crops.
Percentage plant survival in pigeonpea ratoon crops
Some pigeonpea plants dried up in the dry season prior to the rains in the second season of
production for the ratoon crops. Ratoon plants percentage survival was significantly
(P<0.05) higher in plants that were grown in mixture with open pollinated maize compared
with those that were grown in mixture with hybrid maize and as sole crops as shown by the
records made in March and May 2007 (Table 25). Percentage survival was significantly
higher in the long-duration Nsukka Local genotype compared with the ICRISAT short- and
medium-duration genotypes in both the months of March and May 2007. There was no clear
differences between the ICRISAT short- and medium-duration genotypes as ICPL 85063 (
medium-duration) and ICPL 87 (short-duration) genotypes had significantly higher
percentage survival compared with ICPL 87119 and ICP 7120 which are of medium
duration type. Similarly in May 2007, ICPL 85063 (medium-duration), ICPL 87 (short-
duration) and ICPL 161 (short-duratio) had significantly higher survival compared with
ICPL 87119 and ICP 7120 which are of medium-duration types. Effects of cropping system
interaction with pigeonpea genotypes was not significant (P<0.05) but ratoon plants survival
tended to be lower in those that were grown as sole crops.
Yield parameters and yield assessment in pigeonpea ratoon crops.
The number of pods plant-1
and seeds plant-1
were on average significantly (P<0.05)
higher in sole cropped pigeonpea ratoon crops compared with those intercropped with
hybrid maize (Table 26). The number of pods plant-1
and seeds plant-1
were significantly
higher in sole cropped ratoon plants than those previously intercropped with hybrid maize.
The number of pods plant-1
and seeds plant-1
were lower in those previously intercropped in
hybrid maize than those with open pollinated maize. The ICRISAT genotypes had
significantly (P<0.05) higher number of pods plant-1
and seeds plant-1
compared with
Nsukka Local genotypes. The effect of cropping system interaction with pigeonpea
genotypes on the number of pods or seeds plant-1
was not significant.
Cropping system did not affect pigeonpea pod length and number of seeds per pod
(Table 27). Nsukka Local had significantly longer pods on average but had similar number
of seed with the other varieties. There were no clear significant interaction effects between
cropping system and pigeonpea genotypes on pod length and number of seed per pod.
91
Table 25: Pigeonpea ratoon crop percentage plant survival.
Pigeonpea Previous Cropping system
Genotypes P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
March (2007) % plant survival
SD types
ICPL87 60.0 73.4 62.7 65.3
ICPL161
MD types
60.7 64.9 56.7 60.8
ICPL85063 69.6 65.8 66.9 67.5
ICP7120 58.4 56.2 53.3 56.0
ICPL87119
LD type
62.4 66.5 49.9 59.3
Nsukka Local 81.4 86.9 90.0 86.1
Mean 65.3 69.0 63.2 65.8
May 2007 % plant survival.
SD types
ICPL87 54.5 66.8 52.9 58.1
ICPL161
MD types
56.0 58.8 51.0 55.2
ICPL85063 63.0 63.9 57.1 61.3
ICP7120 46.4 47.5 45.1 46.4
ICPL87119
LD type
46.2 55.9 42.8 48.3
Nsukka Local 74.1 76.3 73.6 74.7
Mean 56.7 61.5 53.7 57.3
March %plt. Surv
May % plt. surv.
LSD0.05 for 2 crop. sys. means 4.12 4.69
LSD0.05 for 2 p/pea geno. means 5.83 6.64
LSD0.05 for 2 crop. sys. x p/pea Ns Ns
CV( %) 9.2 12.1
92
Table 26; Pigeonpea ratoon crop yield responses in number of pods/plant and number
of seeds/plant at harvest in 2007.
Pigeonpea Previous Cropping system
Genotypes P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
Number of pods/plant
ICPL87 70.1 82.0 87.0 79.7
ICPL161 79.1 122.0 122.0 107.7
ICPL85063 78.9 97.9 110.6 95.8
ICP7120 82.7 113.3 100.7 98.9
ICPL87119 95.2 74.1 93.8 87.7
Nsukka Local 61.6 55.0 59.3 58.6
Mean 77.9 90.7 95.5 88.1
Number of seeds/plant
ICPL87 207.7 230.9 255.0 231.2
ICPL161 195.4 207.0 308.3 236.9
ICPL85063 225.6 271.3 254.5 250.5
ICP7120 216.3 300.0 279.3 265.2
ICPL87119 261.7 213.9 271.5 249.0
Nsukka Local 170.7 157.4 171.8 166.6
Mean 212.9 230.1 256.8 233.2
No. of pods/plant
No of seeds/plant
LSD0.05 for 2 crop. sys. means 13.98 32.46
LSD0.05 for 2 p/pea geno. means 19.77 45.91
LSD0.05 for 2 crop. sys. x p/pea Ns Ns
CV (%) 23.4 20.5
93
Table 27: Pigeonpea ratoon crop pod length (cm) and number of seeds/pod.
Pigeonpea Previous Cropping system
Genotypes P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
Pod length (cm)
ICPL87 4.6 4.5 4.3 4.5
ICPL161 4.4 4.5 4.9 4.6
ICPL85063 4.9 4.6 4.4 4.4
ICP7120 4.3 4.4 4.4 4.4
ICPL87119 4.9 4.4 4.6 4.6
Nsukka Local 5.1 4.9 5.1 5.0
Mean 4.6 4.5 4.6 4.6
No. of seed/pod
ICPL87 2.9 2.8 2.8 2.8
ICPL161 2.5 2.5 2.5 2.5
ICPL85063 2.9 2.9 2.3 2.7
ICP7120 2.7 2.7 2.7 2.7
ICPL87119 2.7 2.9 2.8 2.8
Nsukka Local 2.8 2.8 2.8 2.8
Mean 2.7 2.7 2.6 2.7
Pod length (cm)
No of seeds/pod
LSD0.05 for 2 crop. sys. means Ns Ns
LSD0.05 for 2 p/pea Geno. means 0.27 Ns
LSD0.05 for 2 crop. sys x p/pea Ns Ns
CV (%0 6.3 12.4
94
Insect pests on pigeonpea ratoon crops at the reproductive stage.
The number of insect pests plant-1
at flowering and podding stages in pigeonpea
ratoon crops were not affected by cropping system while the pigeonpea genotypes differed
significantly (P<0.05) in this parameters at both stages (Table 28). ICPL 87119 and ICPL
85063 had significantly (P<0.05) higher number of insect pests per plant at the flowering
stage while ICPL 85063 had significantly higher number of insect pests plant-1
at the
podding stage. ICPL 7120, ICPL 161 and Nsukka Local maintained relatively lower number
of insect pests plant-1
at both flowering and podding stages compared with ICPL 87119,
ICPL 85063 and ICPL 87. Cropping system interaction with pigeonpea genotypes had no
significant effect on the number of insect pests per plant at both flowering and podding
stages in pigeonpea ratoon crops.
The percentage insect damage of pods or and seeds in pigeonpea ratoon crop was
not significantly (p<0.05) affected by maize intercropping (Table 29). On average, over 29%
of the seeds and about 23% of the pods were damaged by insect pests. Damages of
pigeonpea pods and seeds by pests in the pigeonpea genotypes did not vary with the same or
varying cropping systems.
Grain yield (kg/ha) and threshing percentage (%) in pigeonpea ratoon crops.
The sole cropped pigeonpea ratoon crop yielded higher than cases of intercropping
by 10.2% to 13% although no clear statistical significance was established (Table 30). The
pigeonpea genotypes did not differ significantly (P<0.05) in their grain yield but the
ICRISAT genotypes yielded higher with 693.8kg/ha on the average against the 574.0kg/ha
in the Nsukka Local. The medium-duration genotypes yielded higher than the short-duration
and the long-duration genotypes. It was medium-duration>short-duration>long-duration.
ICP 7120 genotype yielded significantly higher than Nsukka Local, ICPL 161 and ICPL 87
genotypes, but not more than ICPL 85063 and ICPL 87119.
Threshing percentage was on average about 44%. Cropping system had no effect on
threshing percentage for the same or varying pigeonpea genotypes. Cropping system
interaction with the pigeonpea genotypes had no significant effect on grain yield and
threshing percentage in the pigeonpea ratoon crops.
95
Table 28: Number of blister beetles and pod borer insect pests plant-1
at flowering
stage and pod fly, pod sucking bugs and pod borers at podding stage in pigeonpea
ratoon crops.
Pigeonpea Previous Cropping system
Genotypes P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
No. of insect pests at flowering
ICPL87 2.896 2.926 2.890 2.904
ICPL161 2.883 2.730 2.806 2.806
ICPL85063 2.980 2.936 3.003 2.973
ICP7120 2.873 2.890 2.853 2.872
ICPL87119 3.020 3.030 3.006 3.018
Nsukka Local 2.866 2.843 2.860 2.856
Mean 2.920 2.892 2.903 2.905
No. of insect pests at podding
ICPL87 2.440 2.443 2.437 2.440
ICPL161 2.240 2.390 2.443 2.358
ICPL85063 2.697 2.577 2.420 2.564
ICP7120 2.487 2.370 2.460 2.439
ICPL87119 2.497 2.460 2.390 2.449
Nsukka Local 2.197 2.330 2.213 2.247
Mean 2.426 2.428 2.394 2.416
At flowering
At podding
LSD0.05 for 2 crop. sys. means Ns Ns
LSD0.05 for 2 p/pea geno. means 0.0623 0.114
LSD0.05 for 2 crop.sys. x p/pea Ns Ns
CV (%) 2.2 4.9
96
Table 29: Pigeonpea ratoon percentage(%) crop insect-damaged pods and seeds as
influenced by cropping system and pigeonpea genotype.
Pigeonpea Previous Cropping system
Genotypes P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
Seed damaged /plant(%)
ICPL87 32.3 29.8 31.2 31.1
ICPL161 31.9 29.8 28.8 30.1
ICPL85063 32.0 27.8 27.8 29.2
ICP7120 30.1 28.4 30.2 29.6
ICPL87119 29.9 30.8 25.7 28.8
Nsukka Local 28.2 28.3 26.1 27.5
Mean 30.7 29.2 28.3 29.4
Pod damaged /plant(%)
ICPL87 19.8 24.0 22.1 22.0
ICPL161 24.0 23.2 24.1 23.8
ICPL85063 25.6 21.9 21.7 23.1
ICP7120 23.1 21.3 24.8 23.1
ICPL87119 21.2 25.5 26.1 24.3
Nsukka Local 23.0 19.7 19.8 20.8
Mean 22.8 22.6 23.1 22.8
% Damaged pods
% Damaged seeds
LSD0.05 for 2 crop. sys. means Ns Ns
LSD0.05 for 2 p/pea geno. means Ns Ns
LSD0.05 for crop. sys. x p/pea Ns Ns
97
Table 30: Pigeonpea ratoon crop grain yield (kg/ha) and threshing percentage as
influenced by pigeonpea genotype and cropping system.
Pigeonpea Cropping system
Genotypes P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pea
Grain yield (kg/ha)
ICPL87 592.0 676.0 652.0 640.0
ICPL161 526.0 60.9.0 732.0 623.0
ICPL85063 601.0 830.0 745.0 726.0
ICP7120 769.0 791.0 861.0 807.0
ICPL87119 743.0 566.0 710.0 673.0
Nsukka Local 608.0 476.0 637.0 574.0
Mean 640.0 658.0 723.0 674.0
Threshing percentage (%)
ICPL87 44.9 45.4 45.5 45.3
ICPL161 40.1 41.9 43.0 41.7
ICPL85063 40.8 51.0 47.4 46.4
ICP7120 44.0 42.6 44.7 43.8
ICPL87119 47.7 46.0 43.1 45.6
Nsukka Local 41.6 43.5 42.7 42.6
Mean 43.2 45.1 44.4 44.2
Grain yield
Threshing %
LSD0.05 for 2 crop. sys. means Ns Ns
LSD0.05 for 2 p/pea geno. means Ns Ns
LSD0.05 for 2 crop. sys. x p/pea Ns Ns
CV (%) 23.9 8.8
98
Pigeonpea Correlation Matrix of pigeonpea grain yield with growth and yield
component parameters.
The pigeonpea genotypes grain yield (g/plant) in 2005 had a highly significant
(P<0.01) positive correlation with the number of leaves/plant, number of primary
branches/plant, plant girth, number of pods per plant, number of seeds per plant and dry
matter weight of leaf, stem and root plant fractions (Table 31). It also had a significant
(P<0.05) positive correlation with pod bearing stem length (inflorescence distribution
length) and number of seeds per pod. Grain yield had no statistically significant correlation
with pod length and plant height although there were positive trends. Seed grain yield
related very negatively to days to 50% maturity and negatively with days to 50% anthesis.
The number of seeds had a highly significant (P<0.01) correlation with grain yield, number
of pods, number of leaves, plant girth and dry matter weight of stem, leaves, plant girth and
dry matter weight of correlation with inflorescence distribution length and had no significant
correlation with the number of primary branches. It however correlated very negatively with
number of days to 50% flowering. The number of days to maturity in the pigeonpea also had
highly significant negative correlation with pod bearing stem length, number of pods,
number of seeds and negatively but not significant correlation with the number of leaves,
root dry matter weight, plant girth and number of seeds per pod. However, it had highly
significant positive correlation with days to 50% flowering and number of primary branches.
The pigeonpea genotypes grain yield in 2006 had a highly significant (P<0.01)
positive correlation with the number of leaves per plant, number of pods per plant, number
of seeds per plant, dry matter weight of leaves, stems and roots plant fractions (Table 32).
The pigeonpea genotypes grain yield also had a significant (P<0.05) positive correlation
with plant girth, pod bearing stem length (inflorescence distribution length) and plant height
at harvest. There was no statistically significant correlation between grain yield and the
number of primary branches, number of seeds per pod and one thousand seed weight
although there were positive trends. The pigeonpea genotypes′ seed grain yield correlated
negatively with the number of days to 50% flowering. It also showed a negative correlation
trend with pod length and days to 50% maturity. The number of seeds had a highly
significant (P<0.01) positive correlation with seed grain yield, number of pods,
inflorescence distribution length and dry matter weights of stem and root fractions. It had a
99
significant (P<0.05) positive correlation with number of leaves and leaf dry matter weight. It
had a positive but not significant correlation with number of primary branches and plant
girth. It however had a significantly negative (P<0.01) correlation with days to 50%
flowering. The number of days to maturity also had a highly significant negative correlation
with pod bearing stem length and number of pods and a negative but not significant
correlation with grain yield, number of seeds and number of seeds pod-1
. It however had
highly significant positive correlation with days to 50% flowering and plant girth and a
significant correlation with pod length.
100
Table 31: Pigeonpea Correlation Analysis 2005
Yield
(g)
50%
(flow.
(Days)
Leaves
(No)
DM
Leaves
(g)
DM
Stem
(g)
DM
Root (g)
Pri.
Branch
(No)
Girth
(cm)
Pod.
Bear. SL
(cm)
Pods
(No)
Seeds
(No)
Pod
Length
(cm)
Seeds/
pod (No)
50%
mat
(days)
Height
Harvest
(cm)
Thousand
seed wt
(g)
Yield (g) - -.388* .824** .581** .608** .508*** .659*** .449** .293* .908** .910** .093 .320* -.563** .196 -.291*
50% Flow (day) - -.312* .109 .053 .127 .212 .172 -.836** -.563** -.542** .345* -.221 .739** .425** .845**
Leaves (No) - .622* .619** .454** .235 .421** .520** .725** .744** .099 .379** -.229 -.527** .824**
DM-Leaves (g) - .953** .560** .530** .634** .143 .430** .413** .336* .336* .109 .335* .158
DM stein (g) - .568** .517** .653** .190 .460** .475** .323* .351** .153 .308* .102
DM Root (g) - .441** .385** .130 .316* .432** .201 .196 -.151 .331* .164
Pri. Branch (No) - .633** -.315 .152 .173 .438** .097 .509** .389** .510**
Girth (cm) - .073 .366* .350** .413** .179 -.076 .206 .133
Pod Bear. SL(cm) - .732** .722* -.291* .167 -.755** -.246 -.716**
Pods (No) - .902** .049 .331* -.664** .011 -.468**
Seeds (No) - .030 .270* -.644** .014 -.431**
Pod Length (cm) - .534** .200 .229 .307*
Seeds/ Pod (No) - -.232 .122 -.209
50% Mat. (days) - .269* -.563**
Height Harvest (cm) - .269*
Thousand seed wt
(g)
-
** Correlation is significant at the 0.01 level
* Correlation is significant at the 0.05 level
101
Table 32: Pigeonpea Correlation Analysis 2006
Yield
(g)
50%
(flow.
(Days)
Leaves
(No)
DM
Leaves
(g)
DM
Stem
(g)
DM
Root
(g)
Pri.
Branch
(No)
Girth
(cm)
Pod.
Bear. SL
(cm)
Pods
(No)
Seeds
(No)
Pod
Length
(cm)
Seeds/
pod (No)
50%
mat
(days)
Height
Harvest
(cm)
Thousand
seed wt (g)
Yield (g) - -.329* .580** .452** .459** .471** .260 .314* *343* .833** .730** -.060 .222 -.188 .299* .106
50% Flow (day) - .0.75 .275* .216 .125 .456** .521** -.778** -.555** -.557** .367** -.053 .407** .050 -.329*
Leaves (No) - .688** .665** .577** .567** .573** .110 .549** .348* -.119 -.050 .142 .438** .204
DM-Leaves (g) - .848** .821* .632** .715* -.119 .351* .309* .183 .186 .264 .426** .249
DM stein (g) .730** .618** .649** -.028 .370** .396** .123 .138 .243 .506** .218
DM Root (g) - .572** .580** -.023 .353** .387** .122 .253 .065 .434** .064
Pri. Branch (No) - .629** -.358** .164 .097 .260 .075 .407* .558** .466**
Girth (cm) - -.273* .150 .075 .331* .185 .538** .311* .478**
Pod. Bear. SL (cm) - .540** .405** -.208 .122 -.574** .071 -.564**
Pods (No) .794** -.277* .156 -.373** .238 -.383**
Seeds (No) - -.051 .239 -.435 .264 -.433**
Pod Length (cm) - .424** .294* .102 .351**
Seeds/ Pod (No) - -.003 .247 -.174
50% Mat. (days) - .221 .622**
Height Harvest (cm) - .106
Thousand seed wt (g) -
** Correlation is significant at the 0.01 level
* Correlation is significant at the 0.05 level
102
Chemical analysis.
Leaf mineral contents of six pigeonpea genotypes at flowering stage under mixed and
sole cropping systems.
Intercropping pigeonpea with maize resulted in significant (P<0.05) variations in the
nitrogen (N) and calcium (Ca) contents of the pigeonpea leaf taken at flowering stage
(Table 33). Nitrogen content was significantly highest in the leaf of the pigeonpea plants
intercropped with open pollinated maize followed by the leaf of pigeonpea in sole cropping
system which had a significantly higher leaf N content than pigeonpea plants intercropped
with hybrid maize. Calcium content was, however, highest in pigeonpea plants intercropped
with hybrid maize followed by those intercropped with open pollinated maize and least in
sole cropped pigeonpea. No cropping system effect was apparent with respect to the P and K
contents in pigeonpea leaf.
Pigeonpea genotypes differed significantly (P<0.05) in their leaf nitrogen,
phosphorus, potassium and calcium mineral contents. Leaf nitrogen was significantly higher
in ICP 7120 and ICPL 161 compared with the other genotypes. ICPL 85063 had a
significantly higher value compared with ICPL 87119, Nsukka Local and ICPL 87
genotypes which had statistically similar values. Phosphorus and potassium leaf contents
were significantly lower in Nsukka Local genotype compared with the ICRISAT genotypes.
Among the ICRISAT genotypes however, potassium leaf content differed significantly with
a higher value in ICPL 161, followed by ICPL 87 and ICPL 87119 which also had
significantly higher value compared with ICP 7120 and Nsukka Local. Calcium leaf content
was significantly higher in ICPL 87 compared with the other genotypes. This was followed
by ICPL 85063 and Nsukka Local with statistically similar values but significantly higher
than the values for ICPL 87119, ICPL 161 and ICP 7120 which were also statistically
different.
Combining cropping system with pigeonpea genotype showed that irrespective of the
cropping system, ICP 7120 had greater leaf N content than the other genotypes except ICPL
161. Hybrid maize intercropping of pigeonpea depressed leaf N-content in all the pigeonpea
genotypes compared with the situation for open pollinated maize. Open pollinated maize
intercropping with pigeonpea enhanced N-content in ICPL 161, ICP 7120, ICPL 87119 and
Nsukka Local compared with sole cropping. Pigeonpea intercropping with hybrid maize
103
depressed K-content in most of the pigeonpeas compared with open pollinated maize and
sole cropping. Maize intercropping of pigeonpea enhanced the Ca leaf content of most of the
pigeonpea genotypes.
104
Table 33: Effects of intercropping pigeonpea and maize on the nitrogen (N),
phosphorus (P), potassium (k) and calcium (Ca) leaf contents of pigeonpea at
flowering.
Pigeonpea Cropping system Cropping system
Genotypes P/pe
a
P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pe
a
+
Hm
+
Opm
P/pea
Nitrogen (N) Phospho
ICPL87 3.20 3.31 3.34 3.27 0.21 2.26 0.22 0.22
ICPL161 3.28 3.73 3.58 3.53 0.21 0.25 0.21 0.22
ICPL85063 3.17 3.42 3.60 3.40 0.24 0.24 0.22 0.24
ICP7120 3.43 3.69 3.56 3.56 0.22 0.20 0.24 0.22
ICPL87119 2.37 3.62 3.06 3.30 0.26 0.18 0.24 0.23
Nsukka Local 3.22 3.60 3.06 3.29 0.15 0.15 0.18 0.16
Mean 3.25 3.56 3.36 3.39 0.22 0.21 0.22 0.22
Potassium (k)
Calcium (Ca)
ICPL87 0.11 0.10 0.10 0.10 0.26 0.28 0.05 0.19
ICPL161 0.12 0.11 0.10 0.11 0.09 0.08 0.06 0.08
ICPL85063 0.08 0.11 0.08 0.09 0.12 0.08 0.17 0.12
ICP7120 0.09 0.10 0.09 0.09 0.07 0.05 0.08 0.06
ICPL87119 0.10 0.10 0.12 0.10 0.15 0.09 0.08 0.10
Nsukka Local 0.07 0.08 0.11 0.08 0.24 0.09 0.05 0.12
Mean 0.09 0.10 0.10 0.09 0.15 0.11 0.08 0.11
N
P
K
Ca
LSD0.05 for 2 crop.sys means 0.067 Ns Ns 0.020
LSD0.05 for 2 p/pea geno. 0.095 0.031 0.009 0.029
LSD0.05 for 2 crop sys. p/pea 0.165 Ns 0.015 0.051
2.9 14.9 9.7 26.1
105
Nutrient turnover in the leaves of six pigeonpea genotypes at the flowering stage under
maize intercropping systems.
The nitrogen turnover in pigeonpea leaf was significantly (p<0.05) depressed with
maize intercropping by about 13-19% on the average compared with sole cropped pigeonpea
(Table 34). The nitrogen turnover was least in the pigeonpea that was intercropped with
hybrid maize and followed by that intercropped with open pollinated maize and highest in
sole cropped pigeonpea leaf. ICP 7120 yielded significantly (P<0.05) higher nitrogen
turnover compared with ICPL 85063 and ICPL 87119 genotypes. ICPL 87119 had the least
value compared with those of other genotypes. Phosphorus leaf turnover was significantly
(P<0.05) higher in pigeonpea intercropped with open pollinated maize compared with those
intercropped with hybrid maize and those grown as sole crops. ICP 7120 and ICPL 87 gave
significantly (p<0.05) higher values compared with those of Nsukka Local and ICPL 87119
genotypes. ICPL 85063 and ICPL 161 genotypes followed with statistically similar values
which were also significantly higher than those of Nsukka Local and ICPL 87119
genotypes. Potassium turnover in the pigeonpea leaf was significantly (P<0.05) depressed by
maize intercropping. K- turnover was lowest with hybrid maize intercropped pigeonpea. The
pigeonpea genotypes did not differ in their leaf potassium turnover. Calcium turnover in
pigeonpea leaf was significantly higher in hybrid maize intercropped pigeonpea leaf
compared with those grown as sole crop and least in the leaves of those intercropped with
open pollinated maize. ICPL 87 had a significantly higher calcium turnover compared with
all the other genotypes. ICPL 85063 and Nsukka Local genotypes had statistically similar
values which were significantly higher than those for ICP 7120, ICPL 87119 and ICPL 161
genotypes. Interaction of cropping systems with pigeonpea genotypes did not significantly
affect nitrogen, phosphorus and potassium turnover in pigeonpea leaf. However, calcium
turnover increased with intercropped pigeonpea in ICPL 87 and Nsukka Local genotypes but
decreased with ICPL 87119 and ICP 7120.
106
Table 34: Mineral nutrient turnover (kg/ha) in pigeonpea leaf at flowering stage under
intercropping with two maize genotypes.
Pigeonpea Cropping system Cropping system
Genotypes P/pe
a
P/pea Sole Mean P/pea P/pea Sole Mean
+
Hm
+
Opm
P/pe
a
+
Hm
+
Opm
P/pea
Nitrogen (N) Phosph
ICPL87 33.0 38.7 53.6 41.8 2.23 3.28 3.60 3.04
ICPL161 39.9 37.4 44.3 40.6 2.44 2.61 2.65 2.57
ICPL85063 24.4 31.0 51.1 35.5 2.04 2.49 3.20 2.58
ICP7120 37.4 46.2 63.7 49.1 2.45 2.40 4.35 3.07
ICPL87119 24.5 27.3 33.8 28.5 2.03 2.50 2.76 2.10
Nsukka Local 25.6 48.2 52.1 42.0 1.25 2.09 3.23 2.19
Mean 30.8 37.1 49.8 39.6 2.07 2.40 3.30 2.59
Potassium (k)
Calcium (Ca)
ICPL87 1.12 1.17 1.65 1.32 3.07 3.27 0.80 2.38
ICPL161 1.28 1.13 1.23 1.21 1.21 0.74 0.79 0.91
ICPL85063 0.63 0.99 1.21 0.94 1.23 0.44 2.41 1.36
ICP7120 1.02 1.23 1.66 1.30 0.98 0.54 1.43 0.98
ICPL87119 0.75 0.79 1.33 0.96 0.98 0.69 1.23 0.96
Nsukka Local 0.60 1.16 1.84 1.20 1.89 1.20 0.92 1.34
Mean 0.90 1.08 1.49 1.16 1.55 1.15 1.27 1.32
Nitrogen
Phosphor
Potas.
Calc.
LSD0.05 for 2 crop. sys. means 6.85 0.52 0.24 0.18
LSD0.05 for 2 p/pea gen. means 9.69 0.73 Ns 0.26
LSD0.05 for 2 crop. sys. x p/pea Ns Ns Ns 0.45
CV (%) 25.5 29.6 30.9 20.9
107
Proximate analysis of the seed of six pigeonpea genotypes
The pigeonpea genotypes were closely related in their seed nutrient contents (Table
35). The ICRISAT genotypes had similar but relatively higher fibre and protein contents
compared with Nsukka Local genotype. Among the ICRISAT genotypes however, ICP 7120
had lower fibre and protein contents. Nsukka Local had relatively higher carbohydrate and
moisture contents compared with the ICRISAT genotypes. ICPL 87119 had the least
moisture and carbohydrate contents and highest ash, fat and fibre contents compared to the
other genotypes. ICPL 161 had low fat, ash and moisture contents compared to the other
genotypes.
All the pigeonpea genotypes were similar in their seed contents of nitrogen (N),
Phosphorus (P), Potassium (K) and Calcium (Ca) (Table 36). However, the Nsukka Local
(Long-duration) genotype had relatively higher content of phosphorus (P) and Potassium (K)
but a lower content of Calcium compared to those of the ICRISAT genotypes. Among the
ICRISAT genotypes, ICPL 85063 and ICPL 87119 had relatively lower contents of P and K
while ICPL 87119 had the least contents of N and K. The ICRISAT genotypes showed little
variation in K content among themselves.
Table 35: Proximate analysis of pigeonpea genotype seeds.
Pigeonpea Genotypes Moisture Ash Fat Fibre Protein Carbohydrate
(%) (%) (%) (%) (%) (%)
ICPL 87 5.3 4.4 2.1 9.3 19.8 59.2
ICPL 161 5.2 3.0 1.9 9.2 19.8 61.1
ICPL 85063 6.1 4.6 2.1 9.7 19.6 58.1
ICP 7120 6.2 3.8 2.7 8.8 18.1 60.5
ICPL 87119 5.1 4.8 2.6 9.9 19.7 58.0
Nsukka Local
Average
Standard deviation
6.9
5.8
0.71
4.2
4.1
0.65
2.1
2.2
0.32
7.9
9.1
0.71
17.9
19.1
0.89
61.2
59.6
1.45
108
Table 36: Chemical analysis for nitrogen (N), phosphorus (P), Potassium (K) and
Calcium (Ca) in six pigeonpea genotype seeds.
Pigeonpea Genotypes Nitrogen (N) Phosphorus (P) Potassium (k) Calcium (ca)
% (mg/100g) (mg/100g) (%)
ICPL 87 2.80 29.43 10.15 0.15
ICPL 161 3.08 27.67 10.73 0.11
ICPL 85063 3.08 26.48 10.73 0.11
ICP 7120 3.15 27.67 10.44 0.15
ICPL 87119 2.70 26.93 9.86 0.13
Nsukka Local
Average
Standard dev.
3.01
2.97
0.17
32.61
28.46
2.26
11.59
10.58
0.29
0.09
0.12
0.02
109
Experiment 2:
Study of field-to-store insect pest infestation of six pigeonpea seeds and evaluation of
the residual activity of actellic dust on C. maculatus.
Field- to- store insect pests study showed that insects did not emerge in the stored
seed, irrespective of the pigeonpea genotype in six months of storage. The subsequent
introduction of adult Callosobruchus maculatus to seeds where different dosages of actellic
dust (pirimophos–methyl) were earlier applied revealed that oviposition count and insect
mean development days (MDD) of the oviposited eggs of C. maculatus were not
significantly (P<0.05) affected by the residual effect of the actellic dust dosages (Table 37).
The pigeonpea genotypes seeds did not differ significantly in the oviposition counts.
However, the mean development days (MDD) for C. maculatus on the seeds differed
significantly (P<0.05) with pigeonpea genotypes. C. maculatus mean development days was
quickest with ICPL 85063 followed by ICPL 161 while Nsukka Local and ICP 7120 had the
greatest number of days to C. maculatus development. C. maculatus on average took about
32 days to develop. Interaction between actellic dust doses and pigeonpea genotype did not
give significant effect on oviposition count and on the mean development days for deposited
eggs. However, the residual activity of actellic dust slightly depressed oviposition count.
The first filial (F1) generation count of emerged C. maculatus was significantly higher
where no actellic dust was applied compared with where 0.5g or 1.0g of the actellic dust was
applied (Table 38). The pigeonpea genotypes did not differ in their F1 count. Percentage adult
emergence was significantly (P<0.05) higher where no actellic dust was applied and where 0.5g
was applied compared to where 1.0g was applied. On average, 40.8% of the F1 counts taken
developed into adult C. maculatus. Percentage emergence was significantly higher in Nsukka
Local, ICPL 87119 and ICP 7120 compared with ICPL 85063 and ICPL 161 where it was low.
Combining actellic dust doses with pigeonpea genotypes seeds did not give significant effect.
However, F1 count and percentage (%) adult emergence reduced with increase in actellic dust
dosage.
There was a significant (P<0.05) residual activity by 0.5g and 1.0g treatment dosages of
actellic dust on percentage seed damage and total insect mortality count in the pigeonpea
genotype seeds at the end of six months (Table 39). Seed damage was about 64% where actellic
dust was not applied and ranged between 41% and 46% where it was applied. Similarly seed
110
weight loss(g) was significantly (P<0.05) lower in 1.0g treatment dosage compared with 0.5g
treatment. The pigeonpea genotypes differed significantly in their seed weight lost. ICPL 87119
had significantly higher seed weight loss compared with ICP 7120 and ICPL 161. Insect
mortality count was significantly higher where no actellic dust was applied compared to where it
was applied. Insect mortality count also differed among the pigeonpea genotype seeds. ICPL
87119 genotype had significantly higher insect mortality count at the end of the experiment
compared with Nsukka Local and ICPL 161 genotypes but with statistically similar values with
ICPL 85063, ICPL 87 and ICP 7120 genotypes. The residual activity of actellic dust dosage
interaction with pigeonpea genotypes seeds for percentage seed damage, seed weight loss (g)
and total insect mortality count did not give significant effect.
111
Table 37: Residual activity of actellic dust (pirimiphos-methyl) dosages on the
oviposition and mean development days (MDD) of Callosobruchus maculatus in
pigeonpea
Pigeonpea genotypes Actellic dust dosages (g)
0.0g 0.5g 1.0g Mean
Oviposition Count.
ICPL 87 6.3 5.2 5.1 5.5
ICPL 161 4.9 5.0 4.3 4.7
ICPL 85063 7.1 5.5 5.2 5.9
ICP 7120 6.1 4.3 4.9 5.1
ICPL 87119 6.0 5.8 5.4 5.7
Nsukka Local 5.6 4.6 4.5 4.9
Mean 6.0 5.1 4.9 5.3
Mean Development Days
(MDD)
ICPL 87 31.0 31.6 31.3 31.3
ICPL 161 28.3 28.0 29.0 28.4
ICPL 85063 26.0 26.0 26.3 26.1
ICP 7120 35.0 35.0 35.3 35.1
ICPL 87119 33.0 32.0 33.0 32.6
Nsukka Local 37.0 37.6 36.0 36.8
Mean 31.7 31.7 31.8 31.7
Oviposition
Mean Dev. Days
LSD0.05 for 2 oviposition count means Ns Ns
LSD0.05 for 2 mean dev. days means Ns 1.12
LSD0.05 for 2 doses x p/pea gen. means Ns Ns
CV (%) 27.9 3.7
112
Table 38: Residual activity of actellic dust (Pirimophos-methyl) on F1 count and
percentage adult emergence of C. maculatus in pigeonpea.
Pigeonpea Genotypes Actellic dust Dosages (g)
0.0g 0.5g 1.0g Mean
F1 count
ICPL 87 3.5 3.8 2.7 3.3
ICPL 161 3.4 2.6 2.1 2.7
ICPL 85063 4.9 2.9 2.3 3.4
ICP 7120 4.8 3.0 3.3 3.7
ICPL 87119 4.8 4.4 2.7 4.0
Nsukka Local 4.5 3.2 2.7 3.5
Mean 4.3 3.3 2.6 3.4
% Adult emergence
ICPL 87 39.4 47.0 30.4 39.0
ICPL 161 44.6 30.5 28.8 34.6
ICPL 85063 44.1 35.0 29.5 36.2
ICP 7120 49.7 48.4 34.9 44.3
ICPL 87119 54.9 47.9 30.6 44.5
Nsukka Local 54.2 47.2 36.8 46.1
Mean 47.8 42.7 31.9 40.8
F1 Count % Adult Emergence
LSD0.05 for 2 dosages means 0.81 4.83
LSD0.05 for 2 pigeonpea genotype means Ns 6.84
LSD0.05 for 2 doses x genotypes interaction Ns Ns
CV (%) 34.7 17.5
113
Table 39: Residual activity of actellic dust (pirimophos-methyl) on percentage seed
damage, seed weight loss and insect mortality count of C. maculatus in pigeonpea
Pigeonpea Actellic dust dosages (g)
Genotypes 0.0g 0.5g 1.0g Mean
Percentage seed damage
ICPL 87 63.9 52.5 58.1 58.2
ICPL 161 56.8 43.8 37.6 46.1
ICPL 85063 72.0 61.0 61.4 65.1
ICP 7120 63.8 32.4 40.7 45.6
ICPL 87119 69.0 58.2 34.5 53.9
Nsukka Local 55.6 43.8 42.6 47.3
Mean 63.5 48.8 45.8 52.7
Seed weight loss (g)
ICPL 87 12.98 11.71 12.72 12.47
ICPL 161 11.42 8.09 9.78 9.76
ICPL 85063 13.67 11.82 12.62 12.70
ICP 7120 12.44 9.15 10.56 10.71
ICPL 87119 14.41 13.25 10.95 12.87
Nsukka Local 10.76 10.85 10.88 10.83
Mean 11.25 12.61 10.81 11.56
Insect mortality count
ICPL 87 15.85 13.63 14.04 14.51
ICPL 161 14.65 9.46 10.38 11.50
ICPL 85063 18.56 16.01 15.02 16.53
ICP 7120 16.10 9.06 12.50 12.55
ICPL 87119 18.96 19.00 12.73 16.90
Nsukka Local 16.62 9.58 10.09 12.10
Mean 16.79 12.79 12.46 14.01
% seed
damage
Seed weight
loss
Mortality
LSD0.05 for 2 dosages means 10.98 1.49 2.52
LSD0.05 for 2 genotype means Ns 2.11 3.56
LSD0.05 doses x genotype interaction Ns Ns Ns
CV (%) 30.8 19.1 26.6
114
Experiment 3:
Susceptibilty of pigeonpea genotype seeds to C. maculatus infestation under storage
and evaluation of their seed hardness.
Oviposition was significantly higher on ICP 7120 and ICPL 87119 compared with
the other genotypes but least on Nsukka Local and ICPL 87 (Table 40). Insect development
took the shortest number of days in ICP 7120 and significantly the greatest number of days
in Nsukka Local. F1 count was significantly higher in ICP 7120 and Nsukka Local
compared to the other genotypes except Nsukka local. This was followed by ICPL 87119
with significantly higher F1 count compared with ICPL 85063, ICPL 161 and ICPL 87
which had statistically similar values. Percentage seed damage was 36% on the average and
was greatest in ICPL 87119, ICP 7120 and ICPL 85063 and Nsukka local with statistically
similar values and least in ICPL 87 and ICPL 161.
ICPL 87119 had significantly higher seed weight loss compared to the other
genotypes except ICPL 85063 which had statistically similar value. ICPL 85063 also had
significantly higher value compared with ICPL 161 which had the least value. Percentage
seed weight loss due to the insect pest damage was about 32% on average. There was
however no significant difference among the pigeonpea genotypes in this parameter. Total
insect mortality count was significantly higher in ICPL 87119 compared with ICP 7120,
Nsukka Local, and ICPL 87 which had statistically similar values, while ICPL 161 had the
least and significantly different value compared with all the other pigeonpea genotypes.
Susceptibility index values for the pigeonpea genotype seeds ranged from 1.6 in ICPL 161
to 4.2 in ICPL 7120 which was a significantly higher value compared with all the other
genotypes. It was followed by ICPL 87119 and Nsukka Local which were statistically
similar but with significantly higher values compared with ICPL 85063, ICPL 87 and ICPL
161 pigeonpea genotypes. A careful consideration of both field insect pests infestation
resistance attributes in the pigeonpea genotypes to their seed resistance attributes to storage
insect pests infestation showed that ICPL 161 genotype exhibited more consistent resistance
characteristics compared with the other genotypes. Although Nsukka local genotype had a
low level of field insect pests infestation, the same resistance was not exhibited under
storage condition. Placing the pigeonpea genotype seeds according to their susceptibility
index (SI) values as suggested by Mensah (1986) showed that ICPL 161, ICPL 87 and ICPL
115
85063 were in resistant (R) group, where SI values are between 0.0– 2.5; and Nsukka Local,
ICPL 87119 and ICP 7120 were in moderately resistant (MR) group where the SI values fell
between 2.6-5.0. None of the pigeonpea genotypes fell into the susceptible group, of SI
values between 7.6 and 10.0.
There were no significant (P<0.05) difference among the pigeonpea genotypes in
percentage seed germination values at the beginning of the experiment although Nsukka
Local and ICP 7120 had high values of 90%. Germination percentage of the test seeds at the
end of the experiment showed great losses in germination percentage. Nsukka Local had the
highest and significantly different germination value of 43% compared with all the
ICRISAT genotypes. It was followed by ICPL 161, ICPL 87 and ICP 7120 with between 39
– 40% and whose values were significantly higher compared with ICPL 85063 and ICPL
87119 which had between 34% to 35%.
The Pigeonpea genotypes differed significantly (P<0.01) in the physical hardness of
their seeds. ICPL 85063 and Nsukka Local had significantly harder seeds compared with
ICPL 87119, ICPL 161 and ICP 7120 but statistically same with ICPL 87. Nsukka Local had
significantly harder seeds compared with ICPL 87119, ICPL 161 and ICP 7120.
116
Table 40: Seed hardness and infestation by C. maculatus under storage for six months
of six pigeonpea genotype seeds.
Pigeonpea
Genotypes
Ovipo-
sition
count
Mean
dev.
days
F1
Insect
count
Percent
seed
damage
(%)
Seed
weight
loss
(g)
Percent
seed wt
loss
(%)
Total
insect
count
Suscept.
Index
(SI)
values
Germination
percentage
(%)
Before After
storage
Seed
hardness
(kgf)
ICPL 87 4.7 31.0 2.0 31.5 7.3 29.6 13.4 1.8 87.2 15.5 39.6
ICPL 161 6.3 32.0 2.1 26.9 5.3 28.1 10.4 1.6 87.2 14.5 40.0
ICPL
85063
6.8 31.3 2.1 39.1 9.7 34.5 15.8 1.9 85.2 17.8 35.2
ICP 7120 8.3 28.3 3.9 39.2 8.0 31.8 14.0 4.2 90.0 13.6 39.2
ICPL
87119
8.0 31.3 3.1 41.4 11.6 38.5 15.9 3.1 83.4 14.7 34.8
Nsukka
Local
5.2 36.0 3.6 35.3 6.3 27.1 14.0 3.0 90.0 17.5 43.0
Mean 6.5
31.6
2.8
35.6
8.0
31.6
13.8 2.6
87.2
15.6
38.6
LSD0.05
CV(%)
1.55
13.3
ns
8.5
0.73
14.4
7.68
12.1
3.36
23.4
ns
14.9
1.24
5.1
0.93
19.9
ns
5.7
2.15
7.7
2.78
4.1
117
Experiment 4: Antinutritional Factors Assessment in the seeds of six pigeonpea
genoptype.
The major pigeonpea anti-nutritional factors contained in the seed consisted of
tannin, phytate, trypsin inhibitor and chymortrypsin inhibitor (Table 41). Nsukka Local had
statistically similar contents of tannin with ICPL 87119, ICPL 85063, and ICPL 87 but had
significantly (P<0.05) higher value compared with ICPL 161 and ICP 7120. ICP 7120, ICPL
87119 and Nsukka Local had high and significantly different contents of phytate from each
other. They were followed by ICPL 85063 and ICPL 87 which had significantly higher
values compared with ICPL 161 with the least value. Nsukka Local and ICPL 87 had
significantly higher content of trypsin inhibitor compared with the other genotypes which
differed significantly among themselves. Trypsin inhibitor contents were very low in ICP
7120 and ICPL 161 compared to the other genotypes. The pigeonpea genotype seeds
differed significantly (P<0.05) among themselves in chymortrypsin inhibitor content except
for ICPL 161 and Nsukka Local that had statistically similar and moderate contents. ICPL
87119 had the highest value compared with the other genotypes while ICPL 87 had the
lowest value. Comparatively ICPL 161 was characterized by relatively lower contents of
phytate, trypsin inhibitor and chymortrypsin inhibitor. ICP 7120 and ICPL 87119 had
remarkedly high contents of phytate while trypsin inhibitor and chymortrypsin inhibitor
were low in ICPL 85063 and ICPL 87119.
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Table 41: Tannin, Phytate, Trypsin inhibitor and Chymortrypsin inhibitor seed
contents in six pigeonpea genotypes.
Pigeonpea genotypes Antinutritional Factors
Tannin Phytate Trypsin Chymortrypsin
ICPL87 3.25 2.84 3.41 0.19
ICPL161 3.24 1.55 1.84 1.33
ICPL85063 3.28 3.03 2.48 0.48
ICP7120 3.14 8.71 0.65 1.84
ICPL87119 3.33 5.62 3.17 3.09
Nsukka Local 3.83 3.97 3.46 0.57
Mean 3.50 4.12 2.50 0.50
LSD0.05
CV(%)
0.59
9.5
0.44
6.1
0.17
3.9
0.24
14.9
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CHAPTER FIVE
DISCUSSION
Pigeonpea is usually adaptable, flourishing across broad ranges of environment
(Versteeg and Koudokpon, 1993, Degrande, 2001). Maize can grow across a broad range of
agroecological zones (IITA, 2007). Improvement in the production systems of these crops
could have a wide range of adaptability. The high rainfall in the months of July to October
and the minimum and maximum temperature ranges from 20.3 – 21.5oC and 27.4 – 30.1
oC
in this study were within the requirements for both the maize and pigeonpea crops as
reported by Purseglove (1972) and van der Maesen (1989). The drop in rainfall and relative
humidity in the months of November and December coincided with flowering and maturity
periods for pigeonpea and was good for the pod harvest. The slightly acidic sandy clay loam
nature of the soil was within the tolerable limits for both the maize (IITA, 2007) and
pigeonpea crops (Bogdan, 1977, and van der Maesen 1989). The soil has been classified as
an ultisol (Asiegbu, 1989).
Experiment 1: Assessment of six pigeonpea genotypes under late maize intercropping
production system with two maize genotypes.
Both pigeonpea and maize crops were planted at the same time on freshly prepared
ridgesin this study. The non significant effect of cropping system on days to seedling
emergence was therefore expected since the crops were not yet established to create any
system effects. It is competition for scarce resources among crops that result in their
differential responses. The long days to anthesis (128 days) and pod maturity (208 days) in
Nsukka Local pigeonpea seem to suggest a short day response attribute compared with the
day neutral ICRISAT short- and medium-duration genotypes. The pigeonpea genotypes
matured according to their duration types as van der Maesen (1980) reported maturity days
of 105-145 days for short-duration genotypes, 146-199 days for medium-duration genotypes
and above 200 days for long-duration genotypes. Although there was no day response to
maturity in maize, the shorter days to tasselling and maturity in hybrid maize compared with
the open pollinated maize was attributed to the uniform growth feature expected of a hybrid
genotype.
120
The non significant influence of cropping system on the height of the pigeonpea
plants in this study was expected as the maize intercropping could not have influenced the
environment enough to surpress the growth of the pigeonpea crop. Smith et al., (2001)
reported that plant height is a genetic character in crop plants that could not be affected
easily by environmental factors. The taller plants in Nsukka Local genotype was however
attributed to the characteristic tall plant attributes of the Local pigeonpea genotypes as
reported by Kimani (2000) and Snapp et al., (2003). The improvement in pigeonpea is both
for high yield and agronomic characters which could involve reduction in plant height. The
lower plant height in the ICRISAT pigeonpea genotypes was an exhibition of their genetic
attributes.
The similarity in height among the maize genotypes at the early growth stages (4 and
6 WAP) and at tasselling and maturity stages under intercrop and sole crop conditions was
attributed to the non effect of the pigeonpea counterpart on the maize crop under
intercropped situations. This agreed with report by Egbe and Adeyemo (2006) that
intercropping maize with pigeonpea in Benue State, Nigeria resulted in near or equally tall
plants for maize in both sole and intercrop systems. The slow growth in pigeonpea at the
early vegetative stage too was such that it could not have affected the height in the maize
crop. The significant reduction in the number of primary branches, number of leaves, pod
bearing stem length (pod distribution) and plant girth in pigeonpea due to maize
intercropping was attributed to the domineering effect of maize in the intercropping system
over the slow establishing pigeonpea in their early vegetative stage and it agreed with report
by Snapp et al; (2003). The fast development in the maize crop should have led to fast leaf
development and expansion culminating in shading the pigeonpea crop thereby affecting
these parameters. Similarly, Akinola and Whiteman (1975) reported that the number of fruit-
bearing branches and the length of the stem over which inflorescences are produced are
affected by crop density and climatic factors. Therefore the higher plant density under the
pigeonpea/maize mixtures reduced the number of fruit-bearing branches and length of the
stem over which inflorescences are produced in the intercropped pigeonpea plants compared
with their sole cropped counterparts. The greater effect of hybrid maize compared with open
pollinated maize on these parameters on intercropped pigeonpea plants implied its greater
competitiveness over open pollinated maize in the intercropping system. The uniform
121
growth and upright leaf orientation characteristics of the hybrid maize could have aided in
shading the pigeonpea thereby creating greater intercropping effect compared with open
pollinated maize. The higher number of leaves and pod distribution length (pod bearing
stem length) in the ICRISAT pigeonpea genotypes under both intercrop and sole crop
conditions over the Nsukka Local genotype could have been the agronomic and yield
attributes achieved in their improvement at ICRISAT.
Dry matter distribution in the Pigeonpea and maize plant factions.
The high depression of between 23–37% in dry matter fraction weights of
intercropped pigeonpea unlike in intercropped maize which had comparable fraction weights
with sole maize crops was indicative of the advantaged position of maize in the
intercropping system. The fast development in maize and its shorter duration compared to
pigeonpea placed the maize crop in an advantaged position in competing for scarce
resources with the pigeonpea. It consequently had greater shading effect on the pigeonpea t
hereby depressing its dry matter fraction yield. The slow growth of the pigeonpea at the
early growth stages (Snapp et al., 2003) resulted in less competitive effect of the pigeonpea
on the maize counterpart resulting in non significant reduction in intercropped maize dry
matter fraction yields compared with its sole maize counterpart in this study. Lingaraju et al;
(2008) reported similar findings in a maize/pigeonpea intercropping study in Karnataka,
India.
The greater depressing effect of hybrid maize compared with open pollinated maize
on the dry matter fractions of pigeonpea butresses the hybrid maize′s greater intercropping
effect on the pigeonpea. The differences among the pigeonpea genotypes in dry matter
fractions of leaf, stem and root was attributed to their genotypic and duration differences
since the pigeonpea genotypes comprised of short-, medium- and long-duration types.
Ibeawchi et al., (2005) reported variation among soybean varieties in dry matter
accumulation and attributed it to genotypic differences
Field Insect pests incidence in pigeonpea as affected by maize intercropping
The sporadic and low level field insect pest damage on the pigeonpea plants by
variegated grasshopper (Zonocerus variegates), crickets (Brachytrupes membranaceus) and
122
termites(Odontotemes badius) at the early vegetative stage was attributed to the low
population of these pests in the experimental site. Mitchell (2002) reported that seedlings in
the nurseries and newly planted trees are particularly susceptible to attack by termites.
Although the damage incidences by these insect pests were quite low in this study, the
damage on affected plants were however obvious such that where the population of these
insect pests are high, the level of damage could be significant requiring some level of
control. According to Mitchell (2002), termites attack a wide range of crops at all stages of
growth cycle and reported that crop losses at between 3 -100% had been recorded. The high
population of white flies (Bemisia Spp) on pigeonpea plants at the mid vegetative stage
without observed damage to crop plants was attributed to the non incidences of viral
diseases in the pigeonpea plants for which the whiteflies are known to be vectors. The
observed high populations of pod fly (Melanogromyza Spp), Blister beetles (Mylabris Spp),
pod sucking buds (Clarigralla Spp.) and pod borer (Helicoverpa armigera) at the
reproductive stage of pigeonpea in this study confirms earlier report by Snapp et al; (2003).
Kooner and Cheema (2006) also reported that the pigeonpea is attacked by several insect
pests from seedling stage till harvesting.
The slightly lower reproductive stage pests incidences on intercropped pigeonpea at
both flowering and podding stages compared with sole cropped pigeonpea confirms earlier
reports by Trenbath (1993) and Davis and Wolley (1993) that intercropping tends to reduce
the incidence and spread of diseases and pests. The slight difference in pest incidence
among the pigeonpea genotypes with ICPL 161 genotype having the least number of pests at
the flowering stage was suggestive of differences among the pigeonpea genotypes.
Similarly, the significant difference among the pigeonpea genotypes with Nsukka Local
genotype having the least number of insect pests at the podding stage further buttresses the
inffered differential resistance to insect pests among the pigeonpea genotypes. The least
number of insect pests on Nsukka Local at the podding stage could as well be attributed to
its being out of phase with the ICRISAT genotypes as it fruited much later when the
temperatures and relative humidity were lower. Lower temperatures and relative humidity
are always associated with lower pests and diseases situations. Mergeai et al; (2001)
reported higher pests incidence on improved varieties than on local cultivers in Kenya such
that the higher pests population on some of the ICRISAT genotypes could be attributed to
123
genotypic characteristics. The difference among the ICRISAT genotypes still buttresses the
fact that there was genetypic difference in resistance to field insect pests among them.
The high number of damage to Pigeonpea pods and seeds in this study was attributed
to the presence of pod sucking bugs (Clavigralla spp) and pod borers (Helicoverpa
armigera) at the reproductive stage of the crop. Flower and pod field pests are a common
phenomenon among pulse crops. Shonawer and Romeis (1999) reported that insect pests
feeding on flowers, pods and seeds are the most important biotic constraints affecting
pigeonpea yields. The significant reduction in the number of insect pests damaged pods and
seeds due to maize intercropping of pigeonpea followed after the reduction in the number of
insect pests under the intercropping systems in this study. This is a pointer to the advantage
of intercropping system over sole cropping. The lower number of damaged pods and seeds
under hybrid maize intercropping was attributed to its greater intercropping effect compared
with open pollinated maize. Their shading of the pigeonpea plants could have prevented
access of the pigeonpea plants to insect pests. The lower damaged pods and seeds in
Nsukka local was attributed to its late fruiting compared to those of the ICRISAT genotypes
and possible inherent resistance attribute. The result in this study agreed with that by Smith
et al., (2001) where significant difference was obtained among pigeonpea cultivars in seed
and pod damage by insect pests.
Yield parameters as affected by maize intercropping in pigeonpea
The reduction in the number of pods per plant by 32-34% and in number of seeds per
plant by 24-35% in intercropped pigeonpea compared with sole cropped pigeonpea followed
after the reduction in dry matter fractions which were attributed to the intercropping effect
of maize on the pigeonpea. The maize crop was advantaged in the intercropping system
through its fast growth and early maturity compared to the pigeonpea which fruited after the
maize harvest. The maize crop could have exploited both the soil resources better than the
pigeonpea and equally utilized the air and sunlight at the detriment of the pigeonpea under
intercropped situation. Sheldrake et al., (1979) reported that shading reduced the number of
fruits per plant in pigeonpea. The maize crop in the intercropping system in this study could
have shaded the pigeonpea crop at their active vegetative growth stages leading to the
reduction in the number of pods plant-1
. The lower number of both pods plant-1
and number
124
of seeds plant-1
under hybrid maize intercropped pigeonpea compared with open pollinated
maize intercropped pigeonpea corroborates the greater intercropping effect of the hybrid
maize compared with open pollinated maize earlier reported in this study. The lower
number of pods per plant and seeds per plant in the Nsukka local genotype compared to
those of the ICRISAT genotypes was attributed to the poor yielding attribute typical of local
pigeonpea genotypes as reported by Obuo, et al., (1996). The low number of seeds plant-1
in
the Nsukka Local genotype could be attributed to its genotypic characteristic as it was a
large seeded genotype compared to the ICRISAT genotypes. However, the differences
among the ICRISAT genotypes in the number of pods and seeds could be suggestive of
differential yield attributes among them.
The non significant effect of maize intercropping on pod length and number of seeds
per pod in the pigeonpea in this study agreed with the findings of Sheldrake et al., (1979)
who reported that artificial shading of pigeonpea had little effect on the number of seeds
fruit-1
. The differences in the pod length and number of seeds per pod among the pigeonpea
genotypes were attributed to genotypic diferences.
Pigeonpea grain yield.
The 40% and 32% depression in Pigeonpea grain yield due to maize intercropping in
2005 and 2006 respectively were attributed to the dorminant effect of the maize crop in the
intercropping system. This was similar to the reduction in dry matter fractions of leaves,
stems and roots obtained in this study agreeing with report by Lingaraju et al., (2008). This
was also of the same pattern with the reduction in the number of pods plant-1
and number of
seeds plant-1
in this study. The greater depression in grain yield under hybrid maize
intercropping further buttresses the greater competitive effect of hybrid maize compared
with open pollinated maize on the pigeonpea as earlier pointed out in this study. The lower
grain yield in Nsukka local genotype compared with the ICRISAT genotypes was attributed
to the low yielding attribute typical of the local pigeonpea genotypes commonly used by
traditional farmers. The lower number of pods plant-1
and seeds plant-1
in Nsukka Local
compared to the ICRISAT genotypes in this study are also attributes of low yield. Obuo et
al., (1996) reported that pigeonpea land races give yields on farmers fields of 300 – 600
kg/ha compared to over 2.5 t/ha achievable on-station with new high yielding cultivars.
125
The high yields in the ICRISAT genotypes are attributed to their high yielding attributes for
which they were bred for as reported by Upadhyaya et al., (2006). The ICRISAT genotypes
also had higher number of primary branches and pod bearing stem length which would
obviously contribute to their having higher yields compared with Nsukka Local genotype
where the numbers were low. The highest yield obtained in ICPL 87 (Short-duration)
genotype under both intercrop and sole crop conditions in 2005 compared to the other
genotypes agreed with similar higher yield compared to others obtained by Reed (1987)
when he evaluated some short-duration pigeonpea cultivars in intercropping systems with
maize in Eastern and Central Africa. Similarly, Maingu and Mligo (1991) reported best
performers lines as ICPL 87 and ICPL IL6 under different production systems in Tanzania.
The variation in grain yield among the pigeonpea genotypes was attributed to genotypic
differences. The differences in yield among the pigeonpea genotypes was not unexpected
considering the variation in genotypes among the pigeonpea genotypes where ICPL 87 and
ICPL 161 were of short-duration types, ICPL 85063, ICP 7120 and ICPL 87119 were of
medium-duration types and Nsukka Local being of long-duration type. It is expected that
they would differ in their interaction with the maize genotype under intercropped condition
and with the environment too resulting in different yields.
The non significant effect of maize intercropping on 1000 seed weight and threshing
percentage in the pigeonpea in this study were attributed to being inherent genetypic
attributes as rightly observed by Sheldrake et al., (1979) that mean seed weight are
characterisitic of a genotype and influenced relatively little by environmental conditions.
The higher 1000 seed weight in Nsukka local genotype compared with the ICRISAT
genotypes was attributed to its large seeded feature.
The comparative fetures, yield and yield attributes of Nsukka Local long-duration
genotype with the day neutral short- and medium-duration pigeonpea genotypes could be
tabulated as shown below.
126
Agronomic and yield attributes of ICRISAT short- and medium-duration pigeonpea
genotypes compared with Nsukka long-duration pigeonpea genotype.
ICRISAT Genotypes Nsukka Local Genotype
Shorter days to anthesis and maturity
(day neutral)
Longer days to anthesis and maturity
(short day).
Fewer but longer primary branches Large number but shorter primary
branches
High number of leaves at anthesis Low number of leaves at anthesis
Higher Pod bearing (pod distribution)
stem length
Shorter (less than half) pod bearing (Pod
distribution) stem length.
Higher number of pods and seeds per
plant
Lower number of pods and seeds per
plant
Higher grain yield (kg/ha). Lower grain yield (kg/ha)
The shorter days to anthesis and maturity in the ICRISAT genotypes were due to
their photoperiod insensitivity. This attribute could effectively be used in intercropping
systems to time of planting such that high competition between the crops in mixtures could
be avoided to give greater intercropping advantage. This could be also be used in double or
multiple cropping systems as reported by Chauchan et al; (1993); and Troedson et al; (1990)
to enhance crop production per unit land.
The fewer but longer primary branches in the ICRISAT genotypes could be a
mechanism to effectively reach out for sunlight for photosynthesis and under intercropping
system, it could be an advantage leading to greater productivity. This might have stimulated
greater leaf development and hence the higher number of leaves at anthesis in the ICRISAT
genotypes compared to Nsukka local pigeonpea genotype.
The longer pod bearing (pod distribution) stem length in the ICRISAT genotypes is
an attribute for high yield (Akinola and Whiteman 1975) and could be responsible for their
higher number of pods and seeds per plant and consequently higher grain yield obtained in
this study. The advantageous yield and yield attributes of the ICRISAT genotypes makes
them more suitable for adoption under different intercropping systems that could be
exploited for greater yields and profitable farming by traditional farmers.
127
Maize grain yield.
The 14.5% and 22.3% yield reduction in maize grain yield in 2005 and 2006
respectively due to pigeonpea intercropping implied that pigeonpea did not affect maize as
much as the effect of maize on the pigeonpea where grain yield reduction was by 40% in
2005 and 32% in 2006 in the intercropped system. This agreed with earlier report by Egbe
and Adeyemo (2006). The higher effect of maize on the pigeonpea in the intercropped
system was attributed to the fast growth in maize which made it to dominate the slow
growing pigeonpea in their early vegetative stage. The fast growth in maize was such that it
matured before the pigeonpea attained anthesis. This low reduction in maize grain yield
under intercropped system compared to sole maize system was highly responsible for the
high productivity of pigeonpea/maize intercropping system considering the additional yield
from the pigeonpea crop. This was evident in the greater than one land equivalent ratio
values (LER >1.0) obtained in the intercropped systems in this study. The less dependence
of the pigeonpea crop on the soil Nitrogen (N) as a legume gave the maize crop the leverage
to utilize this limited nutrient to enhance its productivity in the intercropping system. The
higher hybrid maize yield compared with open pollinated maize was attributed to the hybrid
vigour in the hybrid maize.
The non significant effect of pigeonpea intercropping on maize shelling percentage
was attributed to its being a gene controlled attribute not easily influenced by environmental
conditions. The dominance of maize in the intercropping system could also had been
responsible.
Land Equivalent Ratio (LER).
The greater than 1.0 land equivalent ratio values (LER>1.0) obtained in each of the
pigeonpea/maize mixtures implied intercropping advantage of all the crop combinations in
the pigeonpea/maize mixtures. Similar greater than 1.0 LER values have been reported in
maize/Pigeonpea mixtures by Tom (1995) in a maize/pigeonpea intercropping systems in
Nsukka, Nigeria, and by Lingaraju (2008) in pigeonpea/maize intercropping systems in
Karnataka, India. Similarly, Rao and Willey (1980a) obtained LER values greater than one
in millet/pigeonpea mixtures in India. An LER value greater than one (LER > 1.0) indicates
greater returns on land in terms of total yield (Mead and Willey 1980). Hall (1995) posits
128
that due to the nitrogen fixing ability in legumes, growing with non-legumes would give
land equivalent ratio (LER) well in excess of 1.0 because the two species would be
obtaining their supplies of the major limiting nutrient nitrogen from different sources. This
is an advantage that is exploited in cereal/legume intercropping. Willey (1979) reported that
the main reason for higher yields in intercropping is that component crops are able to use
growth resources than grown separately.
The superior LER values of 1.54 in 2005 and 1.64 in 2006 in ICPL 87 pigeonpea
genotype mixture with hybrid maize and 1.64 and 1.66 in 2006 by ICPL 7120 mixture with
open pollinated maize are indications of their compatibility for high returns in the
intercropping systems. The advantage in land productivity offered by this pigeonpea/maize
intercropping systems could best be exploited under the increasing reduction in land
availability for agricultural production and the increase in human population.
Cost and Revenue analysis in the pigeonpea/maize mixtures.
Crops have their management requirents for optimum output with their cost
implications. The combined cost of managing two crops in the intercropping system
compared to managing one crop only in the sole cropping system made the cost of
production in the intercrop system to be higher in this study. The higher cost of hybrid
maize seeds compared with its open pollinated maize counterpart made the cost of
production higher in the hybrid maize systems compared with those of the open pollinated
maize. Similarly, the higher cost of ICRISAT pigeonpea seeds and its initial high
transportation cost from Kano/Zaria in 2005 made their intercrop and sole crop production
costs to be higher than those of Nsukka Local pigeonpea where the seed was obtained
locally within Nsukka. The higher cost of sole production in pigeonpea system compared to
that in maize system was due to the higher cost of seed transportation of the pigeonpea in
2005, the higher cost of planting in pigeonpea compared to that in maize, the cost of
insecticide and its spraying in pigeonpea which is not applicable in maize and the higher
cost of threshing in pigeonpea compared to that in maize. The slight differences in the cost
of production in 2005 and 2006 were due to the higher cost of transporting ICRISAT
pigeonpea genotype seeds in 2005 and the higher cost of fertilizer and its transportation in
2006 only.
129
The cost – benefit analysis estimated and added up the equivalent money value of the
benefit and costs to the production of the crops in the production systems in this study.to
establish their worthiness. The higher revenue in the intercropping systems over the sole
cropping systems in this study was attributed to the several advantages in the use of time,
space, labour and yields from two crops on the same piece of land within a cropping season.
The land was under production for a longer period because when the early maturing crop
(maize) was harvested, the later maturing crop (pigeonpea) in the intercropping system
continued to grow further utilizing both the soil and edaphic resources until its harvest. The
labour for most operations in the intercropping system such as land preparation and weed
control measures among others served the two crops at the same time thereby distributing
the cost among the two crops and saved time. Although greater time was saved in the sole
cropping of the maize crop in this study, such time was not a productive one in the benefit
analysis. The combined yields from the two crops in the intercropping system were in most
cases greater than those from their counterparts sole cropping system yields. This was
evident in the greater than one land equivalent ratio values (LER >1.0) recorded in the
intercropping systems. This translated into greater revenue coming from the intercropping
systems compared with sole cropping sytem of the crops
The greater revenue accruing from the maize crop compared with pigeonpea crop in
both intercrop and sole crop systems in this study despite the higher unit price of N55/kg in
pigeonpea compared with the N45/kg in maize was due to greater yield (output) (kg/ha)
obtained in maize compared with pigeonpea under both intercrop and sole crop systems.
Velayutham et al; (2003) reported that growing pigeonpea as a pure crop is not
economically viable due to its low productivity and longer duration. Snapp et al (2003)
reported a marginal returns of >450% in pigeonpea/corn intercrops compared with
monoculture corn. The higher revenue and profit obtained from ICRISAT pigeonpea
genotypes as sole crops and in intercrops compared with Nsukka local genotype were
attributed to their higher yields under both intercrop and sole crop systems.
The greater than 2.0 Benefit/cost ratio and above 50% gross margin (%) obtained
under all the ICRISAT pigeonpea/maize mixtures further buttresses their higher
performances in the intercropping system compared with Nsukka local genotype. This was
attributed to their high yields compared to Nsukka Local genotype. Lingaraju et al (2008)
130
reported that intercropping of legumes with cereals is a recognized practice for increasing
the productivity and profitability per unit area and time. The only loss incurred in this study
was in Nsukka local genotype sole crop system which had a benefit/cost ratio of 0.76 and a
grosss margin of -18%. This was attributed to its low yield. However under its interdropping
system with the maize genotypes, losses were not recorded. This was attributed to the
complimentary yields from the maize crop in the intercropping systems. This informs that
for a profitable production with the Nsukka Local genotype, it should be intercropped with
high yielding compartible crops like maize. However, for a productive production under
either sole or intercrop systems, the Nsukka Local genotype needs to be replaced with high
yielding genotypes such as the ICRISAT pigeonpea genotypes as revealed by this study.
Pigeonpea ratoon crop performance.
Snapp et al; (2003) reported that a ratoon system is used in some areas whereby after
harvest, the pigeonpea stems are cut back to facilitate re-growth and a second crop is
harvested in the subsequent seasons. Since the pigeonpea genotypes in this study were of
different duration types and grown under different systems, the survival of the ratoon crops
would differ. The higher percentage plant survival in the pigeonpea ratoon crops previously
intercropped with hybrid maize compared to those that were grown as sole crops suggests
that some intercropping situations could enhance ratoon crops survival. Where the effect of
intercropping was relatively higher on the ratoon crops as was the case with hybrid maize,
intercropping on pigeonpea compared with open pollinated maize in this study, it led to
greater pigeonpea ratoon crop losses. The high variability in ratoon crops percentage plant
survival among the pigeonpea genotypes was attributed to differential duration types of
short-, medium-, and long-duration genotypes used in this study. The high level of plant
survival in Nsukka local genotype was attributed to its long-duration type maturing late into
the dry season with little time left to the next cropping season. This enhanced its chances to
survive into the next cropping season compared with the short- and medium-duration
genotypes which matured early with longer periods to the next cropping season such that if
it were not for the perenniality of the crop, they could have dried up before the next
cropping season.. Wallis et al; (1987) reported that the perenniality of pigeonpea allows the
possibility of ratoon crops. The low percentage plant survival in ICP 7120, ICPL 87119
131
(medium-duration) and ICPL 161 (short-duration) compared with lower percentage plant
losses in ICPL 87 (short-duration) and ICPL 85063 (medium-duration) of the ICRISAT
genotypes implied that there was no marked difference between the short-duration and
medium-duration genotypes in ratoon crops survival under the humid tropical condition of
this study.
The lower number of pods per plant and seeds per plant in previously intercropped
pigeonpea ratoon crops was attributed to intercropping effect. The greater effect in ratoon
crops previously intercropped with hybrid maize further reflected the greater negative effect
of hybrid maize on pigeonpea plants in the intercropping system compared with open
pollinated maize. The low number of pods per plant and seeds per plant in Nsukka
pigeonpea genotype compared with those of the ICRISAT genotypes was attributed to its
poor yielding characteristics. The variability in pod length among the pigeonpea genotypes
was attributed to genotypic effect.
The slightly lower number of percentage damaged seeds and pods in Nsukka local
genotype compared with the ICRISAT genotypes was attributed to genotypic difference
since it was from the local environment and likely to be more adaptive to the environment
than the ICRISAT genotypes.
The slightly higher yields of about 10.2% to 13% in sole cropped pigeonpea ratoon
crops compared with those that had been intercropped with the two maize genotypes implied
intercropping effect on the ratoon crops. The slightly higher grain yield in the ICRISAT
medium-duration genotypes (ICPL 85063, ICP 7120 and ICPL 87119) compared with their
short-duration genotypes (ICPL 87 and ICPL 161) counterparts implied greater ratoon
productivity. The lowest yield in Nsukka local genotypes was attributed to its poor yielding
characteristics as exhibited by the regular crop in this study. Cheema et al; (1996) reported
differences in total ratoon yields among some short-duration pigeonpea genotypes. The lack
of influence of the previous cropping system on threshing percentage followed similar
pattern with that under regular production implying that cropping system did not have any
significant effect on this parameter in pigeonpea. The slightly higher threshing percentage
of the medium-duration genotypes compared with short-duration genotypes among the
ICRISAT genotypes implied genotypic differences among duration types. The low
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threshing percentage of Nsukka local genotype was attributed to being its genotypic poor
quality.
Correlation matrix.
The very high positive correlation between grain yield in pigeonpea and its number
of leaves, number of primary branches, number of pods, number of seeds and dry matter
weight of leaves, stems and root fractions per plant portrayed their high contribution to grain
yield in the crop. The high contribution of leaves to grain yield is obvious being the main
photosynthetic organ for the manufacture of stored products in plants. The higher the
number of primary branches, the better the positioning of the plant′s leaves for the capture of
photosynthetic radiation thus its high positive correlation with grain yield. It is an important
yield attribute in crops particularly when grown under very competitive situation like in
intercropping systems. The number of pods and number of seeds directly relate to grain
yield thus their high positive correlation with grain yield. Vange and Egbe (2009) also
reported a significant positive correlation between grain yield and dry pod weiht in
pigeonpea. Dry matter weight of leaf, stem and root fractions would obviously relate
positively to grain yield as they determine plant size.
The high positive correlation of number of seeds in pigeonpea to grain yield, number
of pods, number of leaves and dry matter fraction weights of leaves, stems and roots
corroborates the importance of these attributes to seed grain yield in the crop. Smith et al;
(2001) reported a positive correlation between pigeonpea absolute yields with the number of
pods (P<0.01) and number of seeds (non significant) and Singh et al; (1995) reported that in
any selection scheme to increase yield levels in pigeonpea, maximum weight should be
given to two traits, pods per plant and number of primary branches. The high positive
correlation of the grain yield in pigeonpea to pod bearing stem length, number of seeds per
pod and plant girth show their relevance to the final yield of the crop.It is obvious that the
length the pod bearing stem, the greater the chances to have many pods which will
ultimately result in high yield. Similarly, the greater the plant girth, the higher the plant size
which will also contribute to crop yield. It is reported that in most situations, economic yield
is determined largely by fruit number per plant, which is related to plant size and duration of
the crop (Whiteman et al., 1985). Pod length, 1000 seed weight and plant height contributed
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only little to the grain yield in the crop in view of their low positive correlation with grain
yield. The high negative correlation between grain yield and number of days to attainment
of anthesis and maturity signified their non contribution to grain yield in pigeonpea and this
agreed with report by Vange and Egbe (2009).
The negative correlation of the number of days to attainment of maturity in
pigeonpea to grain yield agreed with earlier reports by Vange and Egbe (2009) and, Thanki
and Sawargaonker (2010). Crops of shorter duration are more desirable for greater utility of
time and space in agriculture such that longer days to attainment of anthesis and maturity
would not correlate positively with grain yield.
Effects of maize intercropping on N, P, K and Ca leaf contents of six pigeonpea
genotypes.
The high nitrogen content of the pigeonpea leaves in this study agreed with the
findings of Rao et al., (2002). This was characteristic of leguminous crop plants due to their
nitrogen fixing ability through symbiotic association with the Rhizobium spp. This makes
pulse crops suitable as bruise plants for feeding livestock and for reploughing into the soil to
improve soil fertility. The lowest nitrogen, and potassium contents of pigeonpea leaves
intercropped with hybrid maize was attributed to greater competition from hybrid maize
affecting the pigeonpea negatively in this study. Egbe et al; (2007) reported that
intercropping lowered the total nitrogen yield of most pigeonpea compared to sole cropping
in a pigeonpea/maize intercropping system. Katayama et al; (1996) observed at final
harvest that sole pigeonpea accumulated more N than intercropped pigeonpea, though the
differences were often not statistically significant. This was attributed to shading and
competition for N in intercropped pigeonpea.
The Phosphorus content was similar to that reported by Snapp et al; (2003) in
pigeonpea residues surveyed in Malawi. The potassium contents in this study were within
the requirement range of 0.01-1.0% recommended for ruminants by McDowell (1992). The
high calcium leaf contents in intercropped pigeonpeas was attributed to maize intercropping
effect on its absorption. The difference in nitrogen, phosphorus, potassium and calcium
mineral contents of the pigeonpea leaves was attributed to genotypic differences. Evenhuis
and de-waard (1980) reported that the main factor controlling the mineral content of plant
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material is the specific genetically fixed nutrient uptake potential for the different mineral
nutrient. The second factor controlling the mineral content of plant material is availability
of plant nutrients in the nutrient medium.
Nutrient turn over in Pigeonpea leaves.
The higher nitrogen turn over in sole cropped pigeonpea was attributed to lack of
competition from maize which is obtainable in intercrops. A 3 years study at 40 farm sides
in Malawi found pigeonpea residues providing 30 – 70kg/ha N and were particularly suited
to the resource base of small holders (Kanyama – Phiri et al; (1998). Snapp et al., (1998)
reported that N contribution from leaf abscission over the growing season has been
estimated to be 10 – 40 kgNha-1
. They reported tha high quality residues of perennial
legumes were most effective at supplying N in farmers farms. Ladd (1990) reported that on
farm trials have shown that pigeonpea can produce over 2 tha-1
of high quality residues
without any fertilizer input on degraded soils. Pigeonpea has roots that penetrate deep into
the soil which in most cases remain in the soil and along with the leaves and some stems that
drop on the siol form the residue that would decompse in the soil. This makes the
contribution of soil organic matter of pigeonpea to be high and thus significant for
sustainable agricultural production.
Trumbore (1997) reported that the ultimate source of organic matter in soils is Co2
fixed by plants, including leaf litter, roots, and root exudates. The high phosphorus turn over
in open pollinated maize intercropped pigeonpea leaves was attributed to greater
compatibility between the mixtures creating a conducive environment for the microbial
activity leading to greater phosphorus turn over. Trumbore (1997) reported that the activity
of soil fauna (especially fungi and microbial communities) metabolizes some of these
substrates. The differences among the pigeonpea genotypes in their Nitrogen and calcium
leaf nutrient turn over were attributed to genotypic differences. The higher turn over of
calcium in pigeonpea leaves where intercropping was high was attributed to reduce leaching
of the nutrient due to greater leaf cover thereby making the nutrient more available for
absorption thus available in the pigeonpea leaves. The turnover of nutrients into the soil
through the decomposition of plant residues is important as it determines the balance of
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nutrients that need to be added through fertilizers as a proportion of nutrients lost to
harvested portions of crops which are normally taken out ofbthe fields.
Proximate analysis of six pigeonpea genotype seeds.
The carbohydrate content of between 58% - 61.2% in the pigeonpea genotype seeds
in this study was similar to that repor ted by Singha (1977). Borget (1992) also reported a
figure of 60-66% carbohydrate. The relatively high carbohydrate content is important as
energy source, besides its crucial importance as a protein source ( ). According to Alli-Smith
(2009) carbohydrate content in food is necessary in the digestion and assimilation of other
foods. The 17.9% protein in Nsukka Local compared with the 19.8% in ICPL 87 and ICPL
161 agreed with report by Mergeai et al., (2001) grains are rich in protein (17 – 28%), while
Borget (1992) also reported figures of between 15-29% protein. Nsukka Local was therefore
shown to have lower protein than the ICRISAT genotypes. Protein plays a vital role in
human and livestock nutrition. It can contribute to the formation of hormones which controls
a variety of body functions such as growth, repair and maintenance of body tissue (Mau et
al., 1999). The moisture, ash, fibre and fat contents of the pigeonpea genotypes were similar
to those in guar gum seeds as reported by Majed et al., (2006) and considered adequate for
livestock feed formulation. The low fibre content in the pigeonpea genotypes seeds makes
them suitable for both human and livestock nutrition. Hassan et al., (2007) reported that low
fibre content of feeds could stimulate increased feed intake as well as enhance the quality
and digestibility of the feed.The mineral and fat contents of the pigeonpea genotypes give an
idea of their contents in the respective pigeonpea genotypes.The fat content can be used for
storage and transport form of metabolic fuel (Alli-Smith 2009). The slightly higher fibre (%)
and protein (%) contents of the ICRISAT pigeonpea genotypes compared with the Nsukka
local genotypes was attributed to their genotypic improvement over the Nsukka local
genotype which had slightly higher carbohydrate and moisture contents.
Chemical Analysis of Nitrogen (N), Phosphorus (P), Potassium (K) and calcium (Ca)
contents in pigeonpea seeds.
The Nitrogen content of the pigeonpea genotype seeds were high as similarly
observed in the leaves. This was typical of pulse crops due to their Nitrogen fixing ability
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through their symbiotic association with the bacteria of the genus Rhizobium (Hall, 1995).
The high contents of P, K and Ca were attributed to their being macronutrients usually
absorped in large quantities from the soil by crop plants. Their high contents in the
pigeonpea genotype seeds make the seeds valuable for human and livestock nutrition as they
are required in large quantities for proper growth and good health. According to Ekanayoke
and Nair (1993), the deficiency of minerals such as potassium, phosphorus, sodium, calcium
and magnesium also influences the capacity of the body to utilze amino acids and proteins.
The relatively higher phosphorus (P) and Potessium (K) contents in the ICRISAT genotypes
compared to Nsukka Local was attributed to genotypic differences. The improvement in the
ICRISAT short- and medium-duration genotypes could have enhanced their absorption
capacity for these nutrients compared with the long-duration unimproved Nsukka Local
genotype. The high calcium ontent of ICPL 87 compared to all the other pigeonpea
genotypes was could be its genetic affinity for the element.
Experiment 2: Study of field-to-store insect pest infestation on pigeonpea genotype
seeds and evaluation of the residual activities of actellic dust on C. maculatus.
This study revealed that there was no transfer of field pests infestation on the
harvested pigeonpea seed overulling any field-to-store infestation with post harvest stored
pigeonpea unlike in cowpea (vigna unguiculata L. Walp) as reported by Caswell (1984) in
Nigeria reported that cowpea pods stored for 8 months in Nigeria had 50% of the grain
damaged by bruchids, but when stored as grain, 82% of the grain had one or more holes.
The lack of field-to-store infestation on pigeonpea grains stored for 6 months in this study
was primarily attributed to the thick and tougher pod-wall that is always associated with this
crop compared with those of cowpea. Generally, pigeonpea has tougher and thicker pod
walls than cowpea which in most cases do not dehisce. Akingbohungbe (1976) had ealier
attributed pod-wall thickness to be responsible for reduced bruchid adult emergence from
resistence cowpea with this trait. Similarly Silim Nahdy et al., (1998) reported that the pods
in pigeonpea prevents many adults from emerging. The dry pods prevent infestation of seeds
inside the pods by bruchids which are outside. Consequently, the post harvest storage losses
to bruchids usually encountered in pigeonpea should not be attributed to field-to-store
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infestation but could be re-infested in the store. In Uganda, pigeonpea samples obtained
from markets showed only low infestation by C. maculatus, which was attributed to cross
infestation from cowpea (Silim Nahdy et al., 1998). The reductions in emerging number of
F1 generation, adult emergence, mortality count, damaged grains and grain weight loss on
the infested stored pigeonpea grains implied residual effectiveness of actellic dust on
bruchid development and damage six months after treatment. The high bruchid population
in the untreated seeds at the termination of the experiment was expected due to rapid insect
multiplication and lack of actellic dust. This also implied having higher damaged grain
number due to insects that would have developed and left the seed, mated and laid additional
eggs for further development culminating in greater seed damage and seed weight loss. This
agrees with the report by Ali et al., (2004) that the pest generates exceedingly high levels of
infestation even when they pass only one or two generations on the host plant. The less
effectiveness of half-dose of actellic as a residual treatment in this study compared with full
dose was expected because the half-life of the active ingredient (a.i.) in the half-dose would
normally be shorter and would wane down faster than the half-life of the a.i. in the full dose.
Jackai and Adalla (1997) demonstrated that with a susceptible vita 7 cowpea variety, where
half dose of freshly applied Apron plus (2.5g/kg seed) did not reduce aphid infestation after
2 weeks. But on aphid resistant cultivar, IT8455-2246, they showed a marked reduction in
the number of aphids even with a half dose. Relative susceptibility/resistance of the different
variaties under prolonged storage to bruchid attack was evident in this study. This agrees
with earlier report by Dongre et al., (1993). The evident trend of lower oviposition count, F1
count, damaged grain, grain weight loss in ICPL 161 compared to others having the least
susceptibility index value implied having higher resistance trait although they fell within
moderate resistant classificiation according to Mensah (1986).
Combination of chemical treatment and variety generally did not produce any
significant effect. However, ICPL 7120 admixed with half actellic dose appeared to produce
less oriposition count, F1 count, MDD, mortality count, damaged grains (percentage) and
loss in grain weight. Adesuyi (1979) reported that factors kown to be responsible for the
resistance of stored products to attack by insects included presence of toxic alkaloids or
amino acids in some stored products, digestive enzymes inhibitors and kernel hardness.
These are absent or their levels are very low in susceptible varieties.
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Experiment 3: Susceptibility of pigeonpea seeds to C. maculatus infestation under
storage and evaluation of their seed hardness.
The high variability among the pigeonpea genotype seeds in their responses to C.
maculatus infestation in terms of oviposition count, F1 count, percentage seed damage, seed
weight loss, total insect mortality count, susceptibility index (SI) values, and percentage
seed germination at the end of the experiment implied that the pigeonpea genotype seeds
differed in their inherent resistance attributes to the pest. Mahgoub and Khalifa (1993)
reported significant variations too among 16 varieties of faba bean in oviposition rate, mean
development days (MDD), and percentage adult emergence which were not consistant
indicating that resistance was most likely lying within the seed testa. Bamaiyi et al., (2000)
also reported wide variability between 36 sorghum varieties with respect to the number of F1
adult emergence, median development period, index of susceptibility, percentage damage
and weight loss and grain hardness. More eggs were deposited on susceptible seeds in this
study agreeing with earlier report by Khokhar and Gupta (1974). Similarly, the insect
development in the pigeonpea genotype seeds followed the same pattern with higher
percentage seed damage, seed weight loss and total insect mortality count being more in the
susceptible genotype seeds. The low values of oviposition count, mean development days
and percentage germination at the end of the experiment and the least values of F1 count,
percentage seed damage and seed weight loss, total insect mortality and susceptibility index
value exhibited by ICPL 161was suggestive of its being a resistant genotype.
The similar trend in the number of emerged adults (F1) and the susceptibility index
values of the genotypes in this study was expected. Susceptibility of the seeds would have
allowed for development and emergence of the adult insects. The higher the number of
emerged adults, the greater the chance of further development of the insects on the seeds and
a correspong damage on the crop. F1 count could then be used to predict the susceptibility of
the pigeonpea genotypes. Bamaiyi et al., (2000) similarly found that sorghum vatrieties with
high index of susceptibility had shorter periods for completion of the development of S.
oryzae and those with low index of susceptibility had longer periods within which
development of S. oryzae was completed. This also agreed with report by Dobie (1984) that
resistant maize varieties extended the development period of Zea mays.
Based on Mensah (1986) categorization, ICPL 161, ICPL 87 and ICPL 85063 were
classified as resistant accessions with S.I. values between 0.0 - 2.5. These accessions did
139
not allow high egg deposition and seed damage. Nsukka local, ICPL 87119 and ICPL 7120
were classified as moderately Resistant (MR) accessions with S.I. values between 2.6 – 5.0.
These accesssions allowed higher oviposition and insect development compared with those
of resistant accessions. On the bases of obtained S.I. values too, Ali et al., (2004) reported
that broad bean varieties were moderately resistant (MR) to C. maculatus and moderately
susceptible (MS) to C. chinensis
The high variability in physical hardness amongst the pigeonpea genotypes was
irrespective of their maturity grouping and was attributed to differences in their genetic
make-up. To relate physical characteristics of host in the development of resistance to insect
pests, Semple (1992) reported that the rate of insect population increase could be adversely
affected when a resistant variety is used which causes a reduction in oviposition rate through
physical or mechanical barrier. The barrier is said to either deter access into the grain or
make it unsuitable for oviposition was suggestive to be caused either by barriers that are too
hard for species that perfer smooth substrates to adhere their eggs or to the difficulty in
penetrating such barriers by larvae after hatching from eggs. The difficulty in host tissue
penetration is what Murdock et al., (1997) described as pre stabishment larval mortality
(preM) as against death after penetration which was called post establishment larval
mortality (postM). Bamaiyi et al., (2000) reported differences in hardness among 36
sorghum varieties agreeing with earlier report by Dobie (1974) for maize. While grains
differ in their hardness, it is considered an important attribute for their storability. Bamaiyi
et al., (2000) report showed that all the sorghum varieties having hard grains in their study
were also found to be resistant to S. oryzae. A similar trend was exhibited by most of the
pigeonpea genotypes in this study. The lowest value of seed hardness (13.6kgf) and highest
susceptibility index value (4.2) in ICP 7120 implied that seedhardness played a significant
role in its resistance to C. maculatus pest infestation. Similarly ICPL 87119 had low seed
hardness value and relatively high S.I. value implying low resistance to the pest. The same
situation held for ICPL 85063 and ICPL 87 with high seed hardness values and low S.I.
values. Although the mean development days did not differ significantly in this study, the
longer days in harder seeds agreed with the pre- and post-establishment larval mortality
according to Murdock et al., (1997).
The influence of seed hardness as a resistance attribute in the pigeonpea genotype
seeds to C. maculatus however did not hold for ICPL 161 and Nsukka Local genotypes in
this study. The seed hardness value was low for ICPL 161 but it had the least S.I. value of
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1.6 and Nsukka Local had high seed hardness value and moderately high (3.0) S.I. value.
This implied that other factors could have been responsible for their resistance to C.
maculatus infestation in this study. Adesuyi (1979) reported that other factors other than
seed hardness such as presence of toxic alkaloids or amino acids in some stored products,
insect feeding deterrants, seed coat characteristics that discourage oviposition, and digestive
enzymes inhibitors are known to be responsible for the resistance of stored products by
insects.
Antinutritional Factors in the seeds of pigeonpea genotypes.
The presence of antinutritional factors in the pigeonpea genotype seeds was typical
of the seeds of pulse crops as reported by Mulimani and Paramjyothi (1995). Binital and
Khetarpaul (1997) reported that the antinutritional factors interfer with metabolic process so
that growth and bioavailability of nutrients are negatively influenced. Champ (2002)
reported that antinutrients have adverse effects on animals when ingested regularly in large
amount over a long period of time. The levels of these antinutritional factors in the
pigeonpea genotypes seeds in this study are considerd low as Umaru (2007) reported that
antinutritional factor levels in pigeonpea and chickpea are low and would be further reduced
or destroyed on cooking suggesting no great need for concern. Similarly, Odeng (2007)
reported that antinutritional factors such as protease (trypsin and chymortryipsin) inhibitors,
amylase inhibitors and polyphenols, which are a known problem in most legumes are less
problematic in pigeonpea than soybean, peas (Pisum sativum) and field beans. Processing
techniques such as soaking, cooking, germination and fermentation have been found to
reduce significantly the levels of Phytates and tannins by exogenous and endogenous
enzymes found during processing (Iorri and Svanberg 1995, Ekpo et al., 2004, Ekpo and
Eddy, 2005). Removal of seed coat helps in reducing the levels of these antinutritional
factors, a process possible at the home level prior to cooking and consumption since it is
easy, simple and inexpensive (Mulimani and Paramjyothi 1995). This suggests that
pigeonpea could easily be processed/cooked by the traditional farmer making it safe for
consumpyion to derive the benefit of its high nutritional value and to equally benefit from
the positive anticarcinogenic properties of phytic acid as reported by Champ (2002). They
could as well be slightly processed and used in feed formulation for livestock feed to further
increase its utility. The difference in the antinutritional factor contents of the pigeonpea
genotypes seeds in this study were attributed to genotypic differences.
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CHAPTER SIX
SUMMARY AND CONCLUSIONS
Experiment 1: Assessment of six pigeonpea genotypes under late maize intercropping
production systems with two maize genotypes.
The work is a build up on the importance of intercropping system of crop production
being in common practice among the traditional farmers. It also reveals the advantages of
using improved genotypes over using low yielding traditional varieties.
The five improved ICRISAT pigeonpea genotypes differed in yield among
themselves but they all outyielded the Nsukka Local pigeonpea genotype under both
intercrop and sole crop conditions. Similarly, they gave greater monetary returns under both
intercrop and sole crop conditions compared with the Nsukka local genotype. The pigeonpea
genotypes were highly compartible with the two maize genotypes in the intercropping
systems. All the six pigeonpea genotypes mixtures with the two maize genotypes outyielded
their respective sole crops by having greater than one land equivalent ratio values (LER>
1.0) and higher economic returns as measured by the benefit/cost ratio analysis. This was
more so with the improved ICRISAT pigeonpea mixtures and their sole crops. The
benefit/cost ratio analysis indicated a loss under sole cropping of only the Nsukka Local
pigeonpea genotype due to its low yield. This implied that the ICRISAT pigeonpea
genotypes are ideal for intercropping with maize to replace the long-duration pigeonpea
genotypes in the traditional farming system. This implied too that the additive series
pigeonpea/maize intercropping adoption is considered worthwhile.
Maturity period in pigeonpea was significantly delayed in the Nsukka Local
genotypes being of long-duration type compared with the ICRISAT genotypes which were
of short- and medium-duration types. The improvrd ICRISAT pigeonpea genotypes had
fewer but longer primary branches with longer pod distribution length and higher number of
pods resulting in higher grain yield compared with the Nsukka Local genotype. These are
good agronomic attributes in the ICRISAT genotypes that made them comparatively more
effective under intercropping systems compared with the local pigeonpea genotype with
longer duration period, shorter primary branches and lower number of leaves at anthesis.
142
The ICRISAT pigeonpea genotypes are therefore suitable for adoption in intercropping
systems.
The maize crop had comparatively greater intercropping effect on all the pigeonpea
genotypes in the intercropping systems reducing both their vegetative and grain yields.
Hybrid maize genotype gave greater negative intercropping effect on the pigeonpea
geotypes than its open pollinated maize counterpart. This clearly shows the effect of
genotypic difference among crop species because they differ in competition for growth
resources affecting their competitiveness under intercropping systems. Maize intercropping
also reduced nitrogen and potassium leaf contents in the pigeonpea crops at the flowering
stage with greater effect from the hybrid maize. The need to assess the productivity of crop
genotypes under different intercropping systems cannot be over emphasized. The
significantly different leaf contents of N, P, K. and Ca in the pigeonpea genotypes leaves
was attributed to genotypic differences.
Minor insect pests affected the pigeonpea crop at the early vegetative stage without
much effect on the crop but at the reproductive stage, the insect pest infestation was high
affecting the grain yield in the pigeonpea. Maize intercropping also slightly reduced the
insect pests count in the pigeonpea compared with sole cropping at the reproductive stage.
This implied that combining pests resistance attributes in crop species with intercropping
practices may reduce the effects of pests on crops.
Ratoon crop production was possible for all the pigeonpea genotypes under the
humid tropical condition of this production with higher plant losses in the ICRISAT
genotypes due to their short- and medium-duration nature compared to the long-duration
Nsukka Local genotype. Effects of intercropping reflected on the pigeonpea ratoon crops as
grain yield was lower in those plants that were previously intercropped compared with those
that were cropped as sole crops. Insect pest infestation at the reproductive stage was higher
in the ratoon crops compared with the regular crops and attributed to pest build-up in the
ratoon crops.
Experiment 2: Field-to-store insect pest infestation of six pigeonpea seeds and
evaluation of the residual activity of actellic dust on C. maculatus.
Post-harvest storage studies on the pigeonpea genotypes revealed that there was no
field-to-store insect pest infestation on the pigeonpea. This was attributed to the thick pod
143
wall and the non-shattering pods of the pigeonpea genotypes at maturity which could have
protected the seeds from oviposition by adult insect pests in the field. This implied that a
good storage condition with no pre-storage pest infestation would guarantee for a long-
storage period for the pigeonpea grains considering the high resistance rating of the seeds.
Disinfected stores would ensure for long period storage of the crop which will attract good
prices and better returns to the farmer and a prolonged food supply.
Residual activity of actellic dust (Pirimophos-methyl) six months post storage
reduced C. maculatus storage pest development and multiplication on the seeds of the
pigeonpea genotypes. The effect was greater under half and full dosage treatments compared
to where actellic dust was not applied. This implied that storage chemicals have tendency to
reduce insect pests build up where they are applied after some period but not effective for a
complete control.
Experiment 3: Susceptibility of the seed of six pigeonpea genotypes to Callosobruchus
maculatus in storage.
The pigeonpea genotypes seeds differed significantly in their physical hardness and
susceptibility to C. maculatus infestation under storage condition. Seed hardness contributed
greatly to pest resistance attributes in most of the pigeonpea genotypes seeds but not
absolutely based on the susceptibility index values of the seeds obtained in this study.
The susceptibility index (SI) analysis on the stored pigeonpea genotype seeds and
their resistance classification according to Mensah (1986), placed ICPL 161, ICPL 87 and
ICPL 85063 in resistant (R) genotypes category and Nsukka Local, ICP 7120 and ICPL
87119 genotypes in moderately resistant (MR) seed category. This implied that the
ICRISAT pigeonpea genotypes combined both high yield and good seed storage qualities
that would greatly be useful to the traditional farmer under local production systems.
Experiment 4: Antinutritional factors assessment in the seeds of six pigenotypes.
The antinutritional factor contents of the pigeonpea genotype seeds were low but
varied significantly among the genotypes. This was attributed to genotypic differences
among the pigeonpea genotypes. Such contents do not pose much threat to human and
livestock consumption as the antinutritional factors could easily be destroyed or removed
through simple processes like cooking and soaking.
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Conclusion.
It can be concluded that the high grain yields of the ICRISAT pigeonpea genotypes
under intercropping systems and as sole crops compared with the Nsukka Local genotype
makes them suitable for adoption by the traditional farmers to replace their poor yielding
cultivars. It can be concluded too that the higher land productivity and economic returns of
the pigeonpea/maize intercropping systems over sole cropping systems was a manifestation
of the intercropping advantage associated with the intercropping systems over sole cropping
of the component crops which could be exploited to the advantage of the farmer. The longer
primary branches with lengthy pod distribution of the ICRISAT pigeonpea genotype plants
and their higher number of pods and seeds when compared with the Nsukka Local genotype
were observed to be agronomic attributes that enhanced their productivity.
It can be concluded too that the non transfer of field-to-store insect pests in the
pigeonpea genotype grains was a manifestation of their resistance to such pests. The low
level of susceptibility of the pigeonpea genotype seeds to Callosobruchus maculatus pest
under storage condition for being in resistant (R) and moderately resistant (MR) categories
only further revealed their resistance attributes. With ICPL 161, ICPL 87 and ICPL 85063
ICRISAT pigeonpea genotypes in resistant (R) seed category, it can be concluded that they
combined both high yield and good storage qualities which are desired agronomic attributes.
The ICRISAT pigeonpea genotypes are suitable for adoption to boost the production of the
crop under the traditional cropping system both as main and ratoon crops.
145
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pigeonpea and its role in cropping systems of the Indian subcontinenet. Science
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APPENDIX I
WORKED EXAMPLE ANALYSIS FOR 2006 PIGEONPEA YIELD (KG/HA) DATA.
Treatments Rep I Rep II Rep III Total
V1SO 1293.2 970.0 1984.0 4248.0
V2SO 1735.6 1168.4 2177.2 5081.2
V3SO 1350.8 1327.2 1536.0 4214.0
V4SO 1059.2 1414.4 1374.0 3847.6
V5SO 1327.2 1303.2 1313.6 3944.0
V6SO 954.0 2800.8 1114.8 2869.6
V1OM 1274.0 603.2 642.8 2520.0
V2OM 1323.6 1121.6 1002.8 3448.0
V3OM 1181.6 1299.2 980.4 3461.2
V4OM 858.8 820.4 933.6 2612.8
V5OM 959.6 826.4 756.4 2542.4
V6OM 813.2 751.2 698.8 2263.2
V1HM 1133.6 636.4 940.8 2710.8
V2HM 1238.4 1067.6 797.6 3103.6
V3HM 1290.0 601.2 794.0 2685.2
V4HM 825.2 916.4 807.2 2548.8
V5HM 1022.8 1213.6 686.4 2922.8
V6HM 756.4 616.8 769.6 2142.8
Total 20397.2 17458.0 19310.8 57166.0
Note: V1 – V6 = Pigeonpea genotypes
SO = Sole cropped pigeonpea
OM = Open pollinated maize intercropped pigeonpea
HM = Hybrid maize intercropped pigeonpea.
Xijk = + i + j + k + ()ij + ijk
1. Correction factor (CF) =
162
2. Block SS =
= 60763029.36 – 60517621.4 = 245407.96
3. Total SS =
= 66486519.8 – 60517621.4 = 596898.44
4. Error SS = TSS Treat. comb. SS – block SS
= 5968898.44 – 3705400.73 – 245407.96
= 2018089.75
Two-way totals of factors A and B.
Pigeonpea
Genotypes
Factors A.
V1 V2 V3 V4 V5 V6 Total
Factors B SO 4248.0 5081.2 4214.0 3847.6 3944.0 2869.6 24204.4
OM 2520.0 3448.0 3461.2 2612.8 2542.4 2263.2 16847.6
Crop. sys. HM 2710.8 3103.6 2685.2 2548.8 2922.8 2142.8 16114.0
Total 9475.8 11632.8 10360.4 9009.2 9409.2 7275.6 57166.0
Two-way table of means of factors A and B.
Pigeonpea
Genotypes
Factors A.
V1 V2 V3 V4 V5 V6 Mean
Factors B SO 1416.0 1693.7 1404.6 1282.5 1314.6 956.5 1344.68
OM 840.0 1149.3 1153.7 870.9 847.4 754.4 935.97
Crop. sys. HM 903.6 1034.5 895.0 849.6 974.2 714.2 895.22
Total 1053.2 1292.5 1151.0 1001.0 1045.4 808.4 1058.63
To decompose treatment SS to SS for factor A, factor B and SS for AB interaction, we use
two-way totals of factor A and B.
1. SS of factor A (SSA) =
163
= 61682295.34 – 60617621.4 = 1164673.94
2. SSB = =
3. SS. AB =
4. Final Analysis of Variance (ANOVA) Table.
Sources of
variation
df ss mss F.cal Table
5%
1%
Block (r-1) 2 245407.96 122703.93 2.067 8.32 5.39
Treat. combs.
(ab-1)
17 3705400.73 217964.74 3.672** 1.89 2.47
Factor A (a-1) 5 1164673.94 232934.78 3.924** 2.53 3.70
Factor B (b-1) 2 2224356.44 1112178.22 18.737** 3.22 5.39
Interaction AB
(a-1) (b-1)
10 316370.35 31637.03 0.533 2.27 2.84
Error (r-1) (ab-1) 34 2018089.75 59355.58
Least significant difference (lsd) t(error df) Sd.
164
1. Lsd0.05 = t/34(2.0337) 2 59355.58 =233.56
9
2. Lsd0.05 = 2.0337 2 59355.58 = 165.15
18
3. Lsd0.05 for pigeonpea cropping system interaction = 2.03372 59355.85
3
=404.63
165
APPENDIX II
Summary of Analysis of Variance Table
1. Experiment I: Assessment of six pigeonpea genotypes under two late maize genotypes in
intercropping systems (Pigeonpea data)
Source of Variation Degree of Freedom
Block (r-1) 2
Treatment Combinations (ab-1) 17
Factor A (a-1) 5
Factor B (b-1) 2
Interaction AB (a-1) (b-1) 10
Error (r-1) (ab-1) 34
Total (rab-1) 53
2. Experiment I; Assessment of six pigeonpea genotypes under two late maize genotypes in
intercropping systems (maize data)
Source of Variation Degree of Freedom
Block (r-1) 2
Treatment Combinations (ab-1) 13
Factor A (a-1) 6
Factor B (b-1) 1
Interaction AB (a-1) (b-1) 6
Error (r-1) (ab-1) 26
Total (rab-1) 41
3. Experiment I: Assessment of intercropping efficiency (LER).
LER =SB
YB
SA
YA ; YA and YB are individual crop yields in intercropping SA and SB the
crop yields as sole crops.
LER> I indicates intercrop land use advantage.
166
Analysis of some antinutritional factors in pigeonpea.
Source of Variation Degree of Freedom
Treatment Combinations (t-1) 5
Error t (r-1) 12
Total (tr-1) 17
Experiment 2: Assessment of field-to-store insect pests infestation on seeds of six
pigeonpea genotypes and the residual effect of actellic dust on introduced C.
maculatus insect pest six months after storage.
Source of Variation Degree of Freedom
Treatment Combinations (ab-1) 17
Factor A (a-1) 5
Factor B (b-1) 2
Interaction AB (a-1) (b-1) 10
Error ab (r-1) 36
Total (rab-1) 53
Experiment 3: Susceptibility of the seed of six pigeonpea genotypes to Callosobruchus
maculatus storage Rest.
Source of Variation Degree of Freedom
Treatment Combinations (t-1) 5
Error t (r-1) 12
Total (tr-1) 17
Experiment 3: Seed hardness test on seeds of six pigeonpea genotypes
Source of Variation Degree of Freedom
Treatment Combinations (t-1) 5
Error t (r-1) 12
Total (tr-1) 17