mutagenic effects of ultraviolet radiation on growth and agronomic characters in maize cultivars

Molecular Plant Breeding 2016 Vol7 No01 1ndash10

httpmpbbiopublisherca

1

Research Article Open Access

Mutagenic Effects of Ultraviolet Radiation on Growth and Agronomic Characters in Maize Cultivars Olawuyi OJ

1 Bello OB

2 Abioye AO

1

1Department of Botany University of Ibadan Ibadan Nigeria

2Department of Biological Sciences Fountain University Osogbo Nigeria

Corresponding authors email obbello2002yahoocom

Molecular Plant Breeding 2016 Vol7 No01 doi 105376mpb2016070001

Received 15 Sep 2015

Accepted 26 Oct 2015

Published 01 Jan 2016

Copyright copy 2016 Olawuyi et al This is an open access article published under the terms of the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Preferred citation for this article

Olawuyi OJ Bello OB and Abioye AO 2016 Mutagenic effects of ultraviolet radiation on growth and agronomic characters in maize cultivars Molecular Plant Breeding 7(01) 1ndash10 (doi 105376mpb2016070001)

Abstract Ultraviolet (UV) light has strong genotoxic effect to induce mutations for developing high genetic variability in yields

early maturity and other characters in crops The study investigated the mutagenic effects of UV radiation on growth yield

agronomic and mutation tolerance of six maize cultivars Maize seeds were exposed to UV radiation and planted in 7 kg soils in the

polythene bags while unexposed served as control The effect of UV radiation on the first order interaction between weeks after

planting (WAP) and treatments was only significant (plt005) on plant height The interaction between treatments and cultivars also

produced significant effect on all growth characters except leaf width There was reduction in growth characters at 8 and 10 WAP for

number of leaves and at 10 WAP for plant height leaf length and leaf width All the growth and agronomic characters at 100 minutes

of UV radiation were significantly higher (plt005) than other exposure periods The exposure period of stover weight at 100 minutes

were significantly higher (plt005) than other periods while grain weight and total number of grains at 20 minutes exposure

significantly higher but not different from control The height of ARTOB98SW1 was significantly higher than other cultivars

ARTOB98SW6 10ndash1ndashY and ARTOB98SW1 were the most tolerant cultivars to the mutagenic effect of the UV radiation OBA

98 had the most significant genotypic effect for yield characters while the genotypic influence on plant stand plant aspect mutation

tolerance and plant harvest was highly significant The grain weight per stand for OBA 98 and ARTOB98SW1 were significantly

(plt005) higher than other cultivars while the total number of grains for ART0B98SW1 and ARTOB98SW6 were significantly

higher and different from other cultivars ARTOB98SW6 had the least values of days to plant emergence mutation tolerance and

other agronomic characters compared to other cultivars The plant height was positive and strongly correlated (plt001) with leaf

length leaf width and number of leaves with r = 095 096 089 respectively Only the periods of exposure of the UV radiation was

positive and strongly correlated with leaf width (r = 079) The association between the stover weight and periods of exposure was

positive and insignificant while the correlation between total numbers of grains and grain weight per stand was positive and strong (r

= 099) Therefore quality protein maize cultivars should be improved by introgression of favourable genes of drought tolerance

grain yield and related characters through induced mutation of UV radiation

Keywords Maize tolerance mutation ultraviolet radiation yield

1 Introduction

Maize (Zea mays L) is a tall monoecious and annual

nutritious plant of the family Poaceae which shares a

classification with other important agricultural crops

including wheat rice oats sorghum barley and

sugarcane (EllneskogndashStaam et al 2007 Bello and

Olaoye 2009 Olawuyi et al 2010 Fapohunda et al

2013 Bello et al 2014abc) There are five species in

the genus of Zea with chromosome number of 2n=20

except Zea perennis (Perennial teosinte with 2n=40)

(Rierandashlizarazu et al 1996 CIMMYT 2003

Singletary et al 2003 Rabinowicz and Bennetzen

2006) Maize is characterized by a wider genetic base

and adapt to wide range of changes in the environment

Maize possesses diverse morphological and

physiological characters resulting from a wide genetic

base available for selection (Paliwal 2000 White et

al 2000 Srinivasan et al 2004 Mano et al 2005

Bello et al 2011 2012 Olawuyi et al 2015)

Mutation is a heritable sudden change in gene

structure which opposes the wild characteristics The

abnormal changes in genetic materials alter the DNA

sequence of purine and pyrimidine base pairs

Mutation could result in death of cells ranges in size

from a single DNA building block to a large segment of a chromosome (Beadle and Tatum 1959 Mertz et

al 1964 Misra et al 1972 Mochida et al 2004

Messing and Dooner 2006) Mutation plant breeding



2

methods had been used in many fields as

Biotechnology Cytogenetics and Molecular Biology

(Javed et al 2016) Mutation breeding in maize

encompasses a number of approaches including

spontaneous mutation tissuendashculture induced

mutation (somaclonal variation) chemical

mutagenesis transposon mutagenesis and irradiation

mutagenesis (Anderson and Georgeson 1989

Newhouse et al 1991 Tan et al 2005) Induced

mutation including gammandashrays physical and

chemical mutagens are prime methods for developing

high genetic variability in yields early maturity and

other characters in crops such as cereals and fruits

(Acharya et al 2007 Javed et al 2016) The

mutagenic effect can lead to chromosomal instability

breakages and rearrangement such as substitution

deletion and insertion of the bases which occur

through the modification of DNA sequence and could

enhance production of yield and other related

characters for selective breeding in crops (Boyer and

Hannah 1994 Ahloowalia et al 2004 Shah et al

2008)

Ultraviolet (UV) light is a physical mutagen and

electromagnetic radiation that causes adverse effect to

genetic makendashup of organisms of which plants are

included It has a shorter wavelength than visible light

but longer than Xndashray UV lights had been classified

into three bands based on their wavelengths as

absorption maximum for nucleic acid and protein viz

i UV light A (320 nm to 400 nm) ii UV light B (290

nm to 320 nm) and iii UV light C (200 nm to 280 nm)

UV light A is subdivided into UV A1 (340nm to 400

nm) and UV A2 (320 nm to 340 nm) (Caldwell et al

2011 Tanigawa et al 2011)

UV light has strong genotoxic effect to induce

mutations of which Sun ray is the major natural source

UV rays induced mutation by causing inactivation of

plant genome as UVndashsignature and triplet mutations

The diversity of soil environments and climatic

conditions as well as biotic stresses had created the

basis for the development of mutant varieties of maize

Based on the foregoing assessment of gene expression

of individual response genes to UV radiation in maize

is very imperative This study therefore investigated

the mutagenic response of maize to exposure periods

of UV radiation on growth yield mutation tolerance

and agronomic characters

2 Materials and Methods

21 Germplasm

Six maize cultivars were used for the experiment

Three quality protein maize (ARTOB98SW6 OBA

98 ARTOB98SW1) were collected from the

Institute of Agricultural Research and Training (IAR

amp T) Ibadan Nigeria Cultivar 10ndash5ndashW was sourced

from the National Centre for Genetic Resource and

Biotechnology (NACGRAB) Ibadan Nigeria

Cultivar 3ndash1ndash4 was obtained at Ado Ekiti Nigeria

while Cultivar 10ndash1ndashY was acquired at Ago Iwoye

Nigeria (Table 1)

22 Source of ultraviolet radiation

The ultraviolet (UV) light source used was an UV

lamp B (320 nm to 290 nm) at the Department of

Physiotherapy University College Hospital Ibadan

Nigeria The seeds were spread in the Petri dishes and

exposed to UV lamp at a distance of 22 m The time of

exposure was varied at intervals of 20 minutes The

treatments were 0 20 40 60 80 100 minutes while

0 minute served as control

Table 1 Sources and collection of maize cultivars

Maize cultivars Sources

ARTOB98SW6 Quality protein maize IAR

amp T Ibadan Nigeria

OBA 98 Quality protein maize IAR




10ndash5ndashW NACGRAB Ibadan

Nigeria

3ndash1ndash4 Ado Ekiti Nigeria

10ndash1ndashY Ago Iwoye Nigeria

23 Soil preparation

The polythene pots were filled with loam soil of 7 kg

and holes were punched at the bottom to allow

aeration and drainage of excess water from the pot

24 Experimental site and design

The experiment was conducted in screen house of the

Department of Botany Nursery Farm University of

Ibadan The site is situated within the tropical rain

forest region of Nigeria (Latitude 70o 30rsquoN Longitude

30o 54rsquoE) The polythene pots were arranged in a



3

complete randomized design with three replications

25 Planting and cultural practices

Two maize seeds per cultivar were planted per hole at

the depth of 15cm After two weeks thinning of one

plant per stand was applied Weeding was conducted

at weekly intervals while watering was done at

intervals of 3 days to field capacity

26 Data collection

Data were collected on days to plant emergence

growth yield agronomic and mutation tolerance

characters Growth characters evaluated were plant

height leaf length leaf width number of leaves

tasseling length and stem girth Yield characters

assessed were stover weight and grain weight per

stand Stover weight was determined using weighing

balance while total number of grains was estimated

by visual counting of the grains Agronomic

characters include plant stand plant aspect mutation

tolerance ear aspect plant husk cover ear harvest

plant harvest Mutation tolerance scores ranges

between 1 and 9 Highly tolerance to mutation scores

from 1ndash3 moderately tolerant 4ndash6 while highly

susceptible to mutation was scored 9 Other

agronomic and drought tolerance characters ranged

between 1 and 5 in which one is excellent 2 is good

3 is fairly good 4 is fair while 5 is poor

27 Data analysis

The data were statistically analyzed using the SAS

software program version 92 (SAS Institute 2009

Version 5) Analysis of variance (ANOVA) was

computed while the means were separated by

Duncanrsquos Multiple Range Test (DMRT) The

relationship among the growth characters stages of

growth agronomic characters mutagenic tolerance

exposure periods and yield of maize cultivars were

also determined using Pearson correlation coefficient

Table 2 Mean square effect of ultraviolet radiation (UV) on growth characters of maize

Source of variation df Plant height Leaf length Leaf width Number of

leaves

Intercept 1 253690942 104711879 317115 1540261

Replicate 2 188320ns 52680ns 183ns 902ns

WAP 4 5390389 1912166 4729 15831

Treatment 5 875818 328804 905 5187

Cultivars 5 1444233 665155 1487 4249

ReplicateWAP 8 61044ns 24083ns 062ns 312ns

ReplicateTreatment 10 411753 135736ns 584 2123

ReplicateCultivars 10 210000ns 77119ns 173ns 730ns

WAPTreatment 20 292112 70901ns 298ns 1127ns

WAPCultivars 20 559066 214595 595 2025

TreatmentCultivars 25 299207 135855 351ns 1421

WAPTreatmentCultivars 100 140140ns 50245ns 152ns 742ns

ReplicateWAPTreatmentCultivars 325 155489ns 56836ns 165ns 647ns

Error 10 96097 48327 177 490

Total 545

plt 001 highly significant plt005 significant ns= non significant

3 Results

Table 2 shows that the mean square effect of

ultraviolet (UV) radiation on growth stages exposure

periods and cultivars produced highly significant

(plt001) effects on the growth characters The first

order interaction of replicates and treatments had

significant effect on growth characters except leaf

length Again the effect of UV radiation on first order

interaction between weeks after planting (WAP) and

treatments was only significant (plt005) on plant

height but not significant on other growth characters

The interaction between treatments and cultivars also

produced significant effects on all the growth

characters except leaf width The effect of UV

radiation on WAP and cultivars was significant

(plt001 and plt005) on plant height leaf length leaf



4

width and number of leaves (Table 2)

Table 3 shows that the exposure periods of UV

radiation was significantly (plt001) higher on plant

husk but significantly (plt005) affected ear aspect

ear harvest and plant harvest while days to plant

emergence plant stand plant aspect and mutation

tolerance did not differ The genotypic influence on

plant stand plant aspect mutation tolerance and plant

harvest however was highly significant (Table 3)

Table 4 shows that the cultivars produced significant

effect on stover weight but not differed significantly

for grain weight per stand and total number of grains

The effect of the treated maize cultivars at varied

exposure periods was unaffected by differences in

yield characters Table 5 shows that there are

variations in performance of growth characters in

maize under varied exposure periods of UV radiation

All the growth and agronomic characters at 100

minutes were significantly higher (plt005) than other

exposure periods On the other hand the periods at 20

40 and 60 minutes as well as control did not differ

significantly for plant height and leaf length Also the

mean number of leaves at 60 and 80 minutes were not

significantly different

Table 3 Mean square effect of UV radiation on agronomic characters of maize

Source of variation

df Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Corrected model 12 879 507 400ns 1513 708 820 736 1157

Intercept 12 202800 35934 30334 80033 18934 24001 24300 36300

Replicate 2 075ns 123ns 140ns 286ns 207ns 112ns 536ns 411ns

Periods of exposure 5 349ns 079ns 103ns 267ns 783 1161 600 1256

Cultivars 5 1731 1088 777 3251 834 763 951 1358

Error 95 289 252 239 646 268 249 300 337

Total 108

Corrected total 107

plt001 highly significant plt 005 significant ns= nonndashsignificant

Table 4 Mean square effect of UV radiation on yield characters of maize

Source of variation df Stover weight (g) Grain weight per stand (g) Total number of grains

Corrected Model 12 958 148ns 3272ns

Intercept 1 17777 606 12675

Replicates 2 548ns 067ns 1769ns

Periods of exposure to UV

radiation

5 780ns 119ns 2657ns

Cultivars 5 12995 209ns 4488ns

Error 95 470 097 2160

Total 108

Corrected Total 107


Table 5 Growth performance of maize under varied exposure periods of UV radiation

Exposure periods of UV radiation (minutes) Plant height (cm) Leaf length (cm) Leaf width Number of

leaves

0 (control) 5622c 3672c 202d 437d

20 7259ab 4617ab 253abc 542bc

40 7571ab 4655ab 274ab 599ab

60 5812c 3696c 210cd 473cd

80 6524bc 4429bc 229bcd 502cd

100 8086a 5218a 279a 642a

Means with the same letter in the same column are not significantly different at pgt 005 using Duncanrsquos multiple range test



5

Table 6 shows that there were significant effect

(plt005) of different exposure periods of UV radiation

on days to plant emergence ear aspect plant husk ear

harvest and plant harvest while plant stand plant

aspect and mutation tolerance produced similar effect

The period of exposure at 100 minutes was higher and

highly tolerant than other exposures for days to plant

emergence mutation tolerance and other agronomic

characters The ear aspect at 40 and 80 minutes as

well as control and 60 minutes were not significantly

different Table 7 shows that the exposure period of

stover weight at 100 minutes is significantly higher

(plt005) than other periods while grain weight and

total number of grains at 20 minutes are significantly

higher but not different from the control The periods

of exposure at 40 and 60 minutes as well as 80 and

100 minutes did not differ from each other for grain

weight and total number of grains Table 8 shows that

all the growth characters in Cultivar ARTOB98SW1

are significantly higher than other cultivars The leaf

length leaf width and number of leaves of

ARTOB98SW1 were not significantly different from

10ndash5ndashW The number of leaves for 3ndash1ndash4 was not

significantly different from 10ndash5ndashW and

ARTndashOBndash98ndashSW1 OBA 98 had significant reduction

in mean values for all the growth characters but not

different from the plant height of 10ndash1ndashY The height

status for OBA 98 and 10ndash1ndashY as well as the leaf

length and leaf width for 10ndash1ndashY and

ARTOB98SW6 were not significantly different

from one another On the other hand

ARTOB98SW6 was outstanding for days to

emergence and other agronomic characters compared

to other cultivars while 10ndash5ndashW was the worst

ARTOB98SW6 10ndash1ndashY and ARTOB98SW1

were the most tolerant cultivars to mutagenic effect of

UV radiation while 3ndash1ndash4 was most susceptible

There was an excellent contribution of genotypic

effect on ear aspect plant husk ear harvest and plant

harvest for all the cultivars though

Table 6 Different exposure periods of UV radiation on mutation tolerance and agronomic character of maize

Exposure

periods of UV

radiation

( minutes)

Days to

plant

emergence

Plant stand Plant

aspect

Mutation

tolerance

Ear aspect Plant husk Ear harvest Plant

harvest

0 439ab 156ab 144ab 222ab 033c 106ab 100ab 100b

20 433ab 172ab 139ab 239ab 078b 111ab 167ab 194b

40 411ab 106ab 159ab 211ab 167ab 167ab 211a 283ab

60 428ab 167ab 156ab 256ab 033c 056b 061b 067c

80 378b 189ab 189ab 294ab 172ab 167ab 167ab 217ab

100 511a 361a 249a 411a 211a 289a 294a 339a

Means with the same letter in the same column are not significantly different at plt 005 using Duncanrsquos multiple range test

Mutational tolerance Highly tolerant 1ndash3 moderately tolerant 4ndash6 moderately susceptible 7ndash8 highly susceptible 9 Drought

tolerant rating 1 is excellent 2 is good 3 is fairly good 4 is fair 5 is poor

Table 7 Effect of different exposure periods of UV radiation on the yield characters of maize

Periods of exposure of UV radiation

(minutes)

Stover weight(g) Grain weight per stand (g) Total number of grains

0 121ab 049a 239a

20 147ab 063a 283a

40 123ab 003c 006c

60 023c 002c 006c

80 127ab 011b 061b

100 229a 015b 056b

Means with the same letters in the same column are not significantly different at pgt005 using Duncanrsquos multiple range test



6

Table 8 Genotypic effect on growth characters of maize

Cultivars Plant height(cm) Leaf length(cm) Leaf width Number of leaves

Oba 98 5312d 3316c 182c 421c

10ndash1ndashY 5835d 3761bc 220bc 479bc

ARTOB98SW6 6122cd 3943bc 221bc 531ab

3ndash1ndash4 6991bc 4471b 256ab 574a

10ndash5ndashW 7944ab 5255a 271a 580a

ARTOB98SW1 8658a 5536a 297a 606a

Means with the same letter in the same column are not significantly different at pgt005 using Duncanrsquos multiple range tests (DMRT)

better than OBA 98 (Table 9) Table 10 shows

significant differences (plt005) in genotypic effect on

the yield characters of maize The mean values of

stover weight for ARTOB98SW1 and


from each other The grain weight per stand for OBA

98 and ARTOB98SW1 were not significantly

different but higher and different from other maize

cultivars The cultivars 10ndash5ndashW and 10ndash1ndashY for grain

weight per stand were not different from each other

but higher and significantly different from cultivar

3ndash1ndash4 The total number of grains for

ART0B98SW1 and ARTOB98SW6 were

significantly (plt005) higher but different from other

cultivars The plant height was positive and strongly

correlated (plt001) with leaf length leaf width and

number of leaves with r = 095 096 089 respectively

The associations among plant height treatments and

cultivars were positively insignificant (Table 11) The

leaf width was positive and strongly related with plant

height and leaf length with r = 095 and 094

respectively There were strong positive associations

between number of leaves and plant height leaf length

and leaf width with r = 089 089 and 095

respectively Only the periods of exposure was

positive and strongly correlated with leaf width (r =

079) (Table 11)

Table 9 Genotypic effect on agronomic characters and mutation tolerance of maize

Cultivars

Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

Tolerance

Ear

aspect

Plant

husk Ear harvest

Plant

harvest

ARTOB98SW6 244b 100c 083c 133c 050c 089c 067c 078c

OBA98 444a 211b 194abc 306b 250a 261a 278a 333a

ARTOB98SW1 422a 144c 139bc 194c 156ab 189ab 178ab 222ab

(10ndash5ndashW) 506a 194c 200ab 311b 089c 139b 106b 144bc

(3ndash1ndash4) 500a 317a 267a 506a 122b 106b 133b 156bc

(10ndash1ndashY) 483a 128c 122bc 183c 128b 111b 139b 167bc

Means with different letters in the same column are not significantly different at plt005

Table 10 Effect of cultivars on the yield characters of maize

Cultivars Stover weight(g) Grain weight

per stand(g)

Total number

of grains

ART OB98SW6 178ab 075a 300a

OBA98 255a 071a 289ab

ARTOB98SW1 190ab 064ab 333a

10ndash5ndashW 060bc 006b 022b

3ndash1ndash4 024c 000c 000c

10ndash1ndashY 103b 001b 006bc

Means with the same letter in the same column are not significantly different at plt005 using Duncanrsquos multiple range test



7

Table 11 Correlation matrix of growth characters of maize

Plant

height

Leaf

length

Leaf

width

Number of

leaves Replicates WAP Treatment

Plant height

Leaf length 095

Leaf width 096 094

Number of leaves 089 089 093

Replicate 003 ndash002 ndash004 ndash004

WAP 035 022 027 017 003

Treatment 009 011 079 013 003 002

Cultivars 002 003ns 006 011 007 002 004

plt001 plt005 Treatment = Periods of exposure

Table 12 shows that there was positive and strong

associations between plant stand with plant aspect and

mutation tolerance at r = 096 and 097 respectively

while negative and strong relationship existed between

plant stand and replicates with r = ndash075 Also plant

stand was positive and strongly related with periods of

exposure and plant aspect at r = 076 and 096

respectively There were significant and positive

correlations between ear harvest and ear aspect (r =

059) plant husk (r = 061) as well between plant

husk and ear aspect (r = 082) while the associations

between plant harvest and ear aspect (r = 057) plant

husk (r = 064) and ear harvest (r = 090) were strong

and positive (Table 12) The association between the

stover weight and periods of exposure is positive and

insignificant while the correlation between total

number of grains and grain weight per stand was

positive and strong (r = 099) The association

between the periods of exposure and grain weight per

stand total number of grain was negative and

significant with r = ndash046 and ndash048 respectively The

cultivars are positive and strongly related with the

periods of exposure at r = 070 (Table 12) The

correlation between total number of grains and grain

weight per stand however was positive and significant

with r = 099 (Table 13)



8

Table 12 Correlation matrix of the agronomic characters of maize

Replicates Day to plant

emergence

Cultivars Periods of

exposure

Plant

stand

Plant aspect Mutation

tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038

Periods of exposure 000 006 000

Plant stand ndash075 039 015 076

Plant aspect ndash036 036 015 010 096

Mutation tolerance ndash003 037 017 010 097 096

Ear aspect ndash011 016 ndash002 015 026 024 020

Plant husk ndash007 023 ndash011 027 024 022 018 082

Ear harvest ndash014 022 ndash009 009 021 015 017 059 061

Plant harvest ndash012 022 ndash039 013 025 018 017 057 064 090

Highly significant at plt001 Significant at plt005



9

Table 13 Correlation matrix of yield characters of six cultivars of maize

Stover weight Grain weight per stand Total number of

grains

Replicate Periods of exposure

Stover weight

Grain weight per stand 014

Total number of grains 015 099

Replicates 006 ndash01 ndash011

Periods of exposure 008 ndash016 ndash016 000

Cultivars ndash021 ndash013 ndash012 000 000

4 Discussion

The reduction in the growth characters at 8 and 10

WAP for number of leaves and 10 WAP for plant

height leaf length and leaf width could be due to

mutagenic effect of UV radiation on maize as

similarly reported by Teramura (1983) There were

variations in the contribution of the genotypic effect

on growth performance of maize ARTOB98SW1

showed greater tolerance to the mutagenic effect of

the UV radiation while OBA 98 could not tolerate the

varied exposure periods This could be due to the

differences in the genetic makendashup of the maize

cultivars The performance of ARTOB98SW1 and

ART0B98SW6 could also be attributed to the high

quality protein contents in maize (Olakojo 2004

Olaoye et al 2009 Bello et al 2014a) The least

mean values of days to plant emergence for

ARTOB98SW1 compared to 10ndash5ndashW and other

cultivars showed that they have early maturity traits as

similarly reported by Olawuyi et al (2010 2013)

This could be due to presence of early and maturing

genes present in the quality protein maize

ARTOB98SW6 10ndash1ndashY and ARTOB98 SW1 had

higher tolerance to mutagenic effect of UV radiation

This could be due to the presence of tolerant genes

present in the maize cultivars Olakojo and Kogbe

(2003) Olawuyi et al (2011) and Bello et al (2014b)

had earlier reported tolerance of quality protein maize

cultivars to Stiga lutea and resistance to drought

Maize grain weight and total number of grains at 20

minutes and control showed the best tolerance to UV

radiation compared to other periods Though the

performance of stover weight at 100 minutes as well

as at 80 and 100 minutes for grain weight and total

number of grains could be due to the contribution of

the mutation tolerant gene present in some of the

cultivars particularly the quality protein maize OBA

98 and ARTOB98SW1 performed appreciably in all

the yield characters compared to other cultivars The

superior performance of these cultivars revealed their

tolerant potential to the mutagenic effect of the UV

radiation

5 Conclusion and recommendations

The quality protein maize cultivars not only showed

greater tolerance to mutagenic effect of the UV

radiation but were outstanding in grain yield

compared to other cultivars It appears that the effect

on exposure to UV radiation did not have deleterious

effect on the growth and agronomic characters of

maize but cause reduction in grain yield on exposure

to UV radiation at longer periods Therefore quality

protein maize cultivars should be improved by

introgression of favourable genes of drought tolerance

grain yield and related characters through induced

mutation of UV radiation The characters evaluated

from correlation analysis should further be

encouraged and explored in the breeding programmes

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Advances in medicinal plant researchResearch Signpost

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Ahloowalia BS Maluszynski M and Nichterlein K 2004 Global

impact of mutation derived varieties Euphytica 135 187ndash204

Anderson PC and Georgeson M 1989 Herbicidendashtolerant mutants of

corn Genome 31 994ndash999

Beadle GW and Tatum EL 1941 Genetic control of biochemical

reactions in Neurospora PNAS 27 (11) 499ndash506

Bello OB and Olaoye G (2009) Combining ability for maize grain yield

and other agronomic characters in a typical southern Guinea savanna

ecology of Nigeria African Journal of Biotechnology 8(11) 2518 ndash

2522

httpwwwacademicjournalsorgjpbcsPDFpdf2009 JuneOlaoye 20and20Bellopdf

Bello OB Afolabi MS Ige SA Abdulmaliq SY Azeez M A and



10

Mahamud J 2011 Yield Response of diallelic crossed maize (Zea

mays L) cultivars to varying nitrogen regimes in Nigeria Journal

of BiondashSciences 19 43ndash52

httpwwwBanglajolInfoIndexPhpJbsIndex

Bello OB Abdulmaliq SY Ige SA Mahamood J Oluleye F Azeez

MA and Afolabi MS 2012 Evaluation of early and

late intermediate maize varieties for grain yield potential and

adaptation to a southern Guinea savanna agrondashecology of Nigeria

Scholarly Journal of Agricultural Science 2(3) 42ndash51 http

wwwscholarlyndashjournalscomSJAS

Bello OB Olawuyi OJ Ige SA Mahamood J Afolabi MS Azeez

MA and Abdulmaliq SY 2014a Agrondashnutritional variations of

quality protein maize (Zea mays L) in Nigeria Journal of

Agricultural Sciences 59(2) 101ndash116

httpwwwdoiserbianbrsftaspxid=1450ndash81091

402101B 11

Bello OB Olawuyi OJ Abdulmaliq SY Ige S A Mahamood J

Azeez M A and Afolabi MS 2014b Yield performance and

adaptation of early and intermediate droughtndashtolerant maize

cultivars in Guinea savanna of Nigeria Sarhad Journal of

Agriculture 30(1) 53ndash66

httpwwwbanglajolinfoindexphpJBSindex

Bello OB Olawuyi OJ Lawal M Ige SA Mahamood J Afolabi

MS Azeez M A and Abdulmaliq SY 2014c Genetic gains in

three breeding eras of maize hybrids under low and optimum

nitrogen fertilization Journal of Agricultural Sciences 59(3)

227ndash242

httpwwwjoasagrifbgacrssitesjoasagrifbgacrsfilesarticlepdf

379ndash02ndash690_bello_et_alpdf 6

Boyer CD Hannah LC 1994 Kernel mutants of corn Chapter 1 In

AR Hallauer ed Specialty corns CRC Press Inc Boca Raton

USA pp 1ndash28

Caldwell K Henshaw L and Taylor G 2011 Developing a framework

for Critiquing health research Nursing Fires 103(17) 32ndash33

CIMMYT 2003 The development and promotion quality protein

maize in subndashSaharan Africa Progress report submitted to Nippon

Foundation Harare Zimbabawe

EllneskogndashStaam P Henry Loaisiga C Merker A 2007 Chromosome

Cndashbanding of the teosinte Zea nicaraguensis and comparison to other

Zea species Hereditas 144 96ndash101

Fapohunda SO Olawuyi OJ Bello OB and Lawal T 2013

Comparative shoot responses of two Nigerian crops to Glomus

clarum and other fertilizers Greener Journal of Agricultural

Sciences 3(4) 280ndash285

httpwwwgjournalsorgGJASGJAS20Pdf

Fapohunda20et20alpdf

Javed I Ahsan M Ahmad HM and Ali Q 2016 Role of mutation

breeding to improve Mungbean (Vigna radiata L Wilczek) yield An

overview Nature Science 14(1) 63ndash77

httpwwwsciencepubnetnature 9 doi107537marsnsj14011609

Mano Y Omori F Muraki M and Takamizo T 2005 QTL mapping of

adventitious root formation under flooding conditions in tropical maize

(Zea mays L) seedlings Breeding Science 55 343ndash347

httpdxdoiorg101270jsbbs55343

Mertz ET Bates LS and Nelson OE 1964 Mutant gene that changes

protein composition and increases lysine content of maize endosperm

Science 145 279ndash280

httpdxdoiorg101126science1453629279

Messing J and Dooner HK 2006 Organization and variability of the

maize genome Current Opinion in Plant Biology 9(2) 157ndash163

httpdxdoiorg101016jpbi200601009

Misra PS Jambunathan R Mertz ET Glover DV Barbosa HM and

McWhirter KS 1972 Endosperm protein synthesis in maize mutants

with increased lysine content Science 176(4042) 1425ndash1427


Mochida K Tsujimoto H and Sasakuma T 2004 Confocal analysis of

chromosome behavior in wheat x maize zygotes Genome 47(1)

199ndash205 httpdxdoiorg101139g03ndash123

Newhouse K Singh B Shaner D Stidham M 1991 Mutations in corn

(Zea mays L) conferring resistance to imidazolinone herbicides

Theoretical and Applied Genetics 83 65ndash70

Olakojo SA and Kogbe JOS 2003 Reaction of maize to infestation

with the witch weed (Striga lutea) Moor Journal of Agricultural

research 4210ndash217

Olakojo SA 2004 Evaluation of maize inbred lines for tolerance to

Striga lutea in southern guinea savanna ecology Food agriculture

and Environment 2 256ndash259

Olaoye G Bello OB Ajani AK Ademuwagun T K 2009 Breeding

for improved organoleptic and nutritionally acceptable green maize

varieties by crossing sweet corn (Zea mays saccharata) Changes in

quantitative and qualitative characteristics in F1 hybrids and F2

population Journal of plant breeding and Crop science 1(9)

298ndash305

httpwwwacademicjournalsorgjpbcsPDFpdf2009

NovemberOlaoye20et20alpdf

Olawuyi OJ Odebode AC AlfarndashAbdullahi A Olakojo SA and

Adesoye AI 2010 Performance of maize cultivars and

arbuscularmycorrhizal fungi in Samara district of South west region of

DohandashQatar Nigeria journal of mycology 3(1) 86ndash100

Olawuyi OJ Odebode AC Olakojo SA and Adesoye AI 2011 Host

parasite relationship of maize (Zea mays L) and Strigalutea(Lour) as

influenced by Arbuscular mycorrhizal fungi Journal of Science

research 10(2)186ndash198

Olawuyi OJ Odebode AC and Olakojo SA 2013 Cultivar treatments

concentration interaction and characters association in maize (Zea

mays L) under Arbuscular mycorrhizal fungi and Striga lutea (Lour)

In KnowndashNdung EH Ogah DM Yakubu A editors proceedings of

the 37th

Annual Conference of Genetics Society of Nigeria Oct 21ndash24

Lafia Federal University pp 210ndash223

Olawuyi OJ Bello OB Ntube CV and Akanmu AO 2015 Progress

from selection of some maize cultivarsrsquo response to drought in the

derived savanna of Nigeria AGRIVITA Journal of Agricultural

Science 37(1) 8ndash17

httpwwwagrivitaubacidindexphpagrivita

articleview485

Paliwal RL Granados G Lafitte HR Violic AD Maratheacutee JP 2000

Tropical Maize Improvement and Production Food and Agriculture

Organization of the United Nations Rome pp 1ndash3

Rabinowicz PD Bennetzen JL 2006 The maize genome as a model for

efficient sequence analysis of large plant genomes Current Opinion in

Plant Biology 9(2) 149ndash 156




11

RierandashLizarazu O Rines HW and Phillips RL 1996 Cytological and

molecular characterization of oat x maize partial hybrids Theoretical

and Applied Genetics 93(1ndash2) 123ndash135

httpdxdoiorg101007BF00225737

Singletary GW 2003 Genetic modification of corn Chapter 21 In White

PJ Johnson LA eds Corn chemistry and technology Edition 2nd

American Association of Cereal Chemists Inc St Paul Minesota

USA pp 751ndash782

Srinivasan G Zaidi PH Singh NN and Sanchez C 2004 Increasing

productivity through genetic improvement for tolerance to drought and

excessndashmoisture stress in maize (Zea mays L) Seng V Craswell E

Fukai S and Fischer K eds Australian Centre for International

Agricultural Research Canberra pp 227ndash239

Shah TM Mirza JI Haq MA and Atta BM2008 Induced genetic

Tan S Evans RR Dahmer ML Singh BK Shaner DL 2005

Imidazolinonendashtolerant crops history current status and future Pest

Management Science 61 246ndash257

Tanigawa H Katsumi S Shunsuke F Norikazu O Tetsuhiro S Eji K

variability in chickpea (Cicer arietinum L) II Comparative

mutagenic effectiveness and efficiency of physical and chemical

mutagens Pakistan Journal of Botany 40 605ndash613

Teramura AH 1983 Effects of ultravioletndashB radiation on the growth and

yield of crop plants Physiologia Plantarum 58(3) 415ndash427

Statistical Application Software Institute (2009) Statistical Application

Software (SAS) system for windows version 92 Vol 5 SAS Institute

Cary NC USA

White CN Proebsting WM Hedden P Rivin CJ 2000 Gibberellins and

seeddevelopment in maize I Evidence that gibberellin abscisic acid

balance governs germination versus maturation pathways Plant

Physiology 122(4) 1081ndash1088

httpdxdoiorg101104pp12241081



2

methods had been used in many fields as

Biotechnology Cytogenetics and Molecular Biology

(Javed et al 2016) Mutation breeding in maize

encompasses a number of approaches including

spontaneous mutation tissuendashculture induced

mutation (somaclonal variation) chemical

mutagenesis transposon mutagenesis and irradiation

mutagenesis (Anderson and Georgeson 1989

Newhouse et al 1991 Tan et al 2005) Induced

mutation including gammandashrays physical and

chemical mutagens are prime methods for developing

high genetic variability in yields early maturity and

other characters in crops such as cereals and fruits

(Acharya et al 2007 Javed et al 2016) The

mutagenic effect can lead to chromosomal instability

breakages and rearrangement such as substitution

deletion and insertion of the bases which occur

through the modification of DNA sequence and could

enhance production of yield and other related

characters for selective breeding in crops (Boyer and

Hannah 1994 Ahloowalia et al 2004 Shah et al

2008)

Ultraviolet (UV) light is a physical mutagen and

electromagnetic radiation that causes adverse effect to

genetic makendashup of organisms of which plants are

included It has a shorter wavelength than visible light

but longer than Xndashray UV lights had been classified

into three bands based on their wavelengths as

absorption maximum for nucleic acid and protein viz

i UV light A (320 nm to 400 nm) ii UV light B (290

nm to 320 nm) and iii UV light C (200 nm to 280 nm)

UV light A is subdivided into UV A1 (340nm to 400

nm) and UV A2 (320 nm to 340 nm) (Caldwell et al

2011 Tanigawa et al 2011)

UV light has strong genotoxic effect to induce

mutations of which Sun ray is the major natural source

UV rays induced mutation by causing inactivation of

plant genome as UVndashsignature and triplet mutations

The diversity of soil environments and climatic

conditions as well as biotic stresses had created the

basis for the development of mutant varieties of maize

Based on the foregoing assessment of gene expression

of individual response genes to UV radiation in maize

is very imperative This study therefore investigated

the mutagenic response of maize to exposure periods

of UV radiation on growth yield mutation tolerance

and agronomic characters

2 Materials and Methods

21 Germplasm

Six maize cultivars were used for the experiment

Three quality protein maize (ARTOB98SW6 OBA

98 ARTOB98SW1) were collected from the

Institute of Agricultural Research and Training (IAR

amp T) Ibadan Nigeria Cultivar 10ndash5ndashW was sourced

from the National Centre for Genetic Resource and

Biotechnology (NACGRAB) Ibadan Nigeria

Cultivar 3ndash1ndash4 was obtained at Ado Ekiti Nigeria

while Cultivar 10ndash1ndashY was acquired at Ago Iwoye

Nigeria (Table 1)

22 Source of ultraviolet radiation

The ultraviolet (UV) light source used was an UV

lamp B (320 nm to 290 nm) at the Department of

Physiotherapy University College Hospital Ibadan

Nigeria The seeds were spread in the Petri dishes and

exposed to UV lamp at a distance of 22 m The time of

exposure was varied at intervals of 20 minutes The

treatments were 0 20 40 60 80 100 minutes while

0 minute served as control

Table 1 Sources and collection of maize cultivars

Maize cultivars Sources



OBA 98 Quality protein maize IAR




10ndash5ndashW NACGRAB Ibadan

Nigeria

3ndash1ndash4 Ado Ekiti Nigeria

10ndash1ndashY Ago Iwoye Nigeria

23 Soil preparation

The polythene pots were filled with loam soil of 7 kg

and holes were punched at the bottom to allow

aeration and drainage of excess water from the pot

24 Experimental site and design

The experiment was conducted in screen house of the

Department of Botany Nursery Farm University of

Ibadan The site is situated within the tropical rain

forest region of Nigeria (Latitude 70o 30rsquoN Longitude

30o 54rsquoE) The polythene pots were arranged in a



3








26 Data collection



















27 Data analysis












leaves

Intercept 1 253690942 104711879 317115 1540261


WAP 4 5390389 1912166 4729 15831

Treatment 5 875818 328804 905 5187

Cultivars 5 1444233 665155 1487 4249





WAPCultivars 20 559066 214595 595 2025




Error 10 96097 48327 177 490

Total 545


3 Results


















4


























Source of variation

df Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest


Intercept 12 202800 35934 30334 80033 18934 24001 24300 36300



Cultivars 5 1731 1088 777 3251 834 763 951 1358

Error 95 289 252 239 646 268 249 300 337

Total 108

Corrected total 107





Intercept 1 17777 606 12675



radiation

5 780ns 119ns 2657ns


Error 95 470 097 2160

Total 108

Corrected Total 107




leaves

0 (control) 5622c 3672c 202d 437d

20 7259ab 4617ab 253abc 542bc

40 7571ab 4655ab 274ab 599ab

60 5812c 3696c 210cd 473cd

80 6524bc 4429bc 229bcd 502cd

100 8086a 5218a 279a 642a




5










































Exposure

periods of UV

radiation

( minutes)

Days to

plant

emergence

Plant stand Plant

aspect

Mutation

tolerance


harvest

0 439ab 156ab 144ab 222ab 033c 106ab 100ab 100b

20 433ab 172ab 139ab 239ab 078b 111ab 167ab 194b


60 428ab 167ab 156ab 256ab 033c 056b 061b 067c


100 511a 361a 249a 411a 211a 289a 294a 339a






(minutes)


0 121ab 049a 239a

20 147ab 063a 283a

40 123ab 003c 006c

60 023c 002c 006c

80 127ab 011b 061b

100 229a 015b 056b




6



Oba 98 5312d 3316c 182c 421c





ARTOB98SW1 8658a 5536a 297a 606a




























079) (Table 11)


Cultivars

Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

Tolerance

Ear

aspect

Plant

husk Ear harvest

Plant

harvest


OBA98 444a 211b 194abc 306b 250a 261a 278a 333a








per stand(g)

Total number

of grains


OBA98 255a 071a 289ab








7


Plant

height

Leaf

length

Leaf

width

Number of


Plant height

Leaf length 095

Leaf width 096 094



WAP 035 022 027 017 003

Treatment 009 011 079 013 003 002

Cultivars 002 003ns 006 011 007 002 004






























8



emergence


exposure

Plant

stand


tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038












9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








3








26 Data collection



















27 Data analysis












leaves

Intercept 1 253690942 104711879 317115 1540261


WAP 4 5390389 1912166 4729 15831

Treatment 5 875818 328804 905 5187

Cultivars 5 1444233 665155 1487 4249





WAPCultivars 20 559066 214595 595 2025




Error 10 96097 48327 177 490

Total 545


3 Results


















4


























Source of variation

df Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest


Intercept 12 202800 35934 30334 80033 18934 24001 24300 36300



Cultivars 5 1731 1088 777 3251 834 763 951 1358

Error 95 289 252 239 646 268 249 300 337

Total 108

Corrected total 107





Intercept 1 17777 606 12675



radiation

5 780ns 119ns 2657ns


Error 95 470 097 2160

Total 108

Corrected Total 107




leaves

0 (control) 5622c 3672c 202d 437d

20 7259ab 4617ab 253abc 542bc

40 7571ab 4655ab 274ab 599ab

60 5812c 3696c 210cd 473cd

80 6524bc 4429bc 229bcd 502cd

100 8086a 5218a 279a 642a




5










































Exposure

periods of UV

radiation

( minutes)

Days to

plant

emergence

Plant stand Plant

aspect

Mutation

tolerance


harvest

0 439ab 156ab 144ab 222ab 033c 106ab 100ab 100b

20 433ab 172ab 139ab 239ab 078b 111ab 167ab 194b


60 428ab 167ab 156ab 256ab 033c 056b 061b 067c


100 511a 361a 249a 411a 211a 289a 294a 339a






(minutes)


0 121ab 049a 239a

20 147ab 063a 283a

40 123ab 003c 006c

60 023c 002c 006c

80 127ab 011b 061b

100 229a 015b 056b




6



Oba 98 5312d 3316c 182c 421c





ARTOB98SW1 8658a 5536a 297a 606a




























079) (Table 11)


Cultivars

Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

Tolerance

Ear

aspect

Plant

husk Ear harvest

Plant

harvest


OBA98 444a 211b 194abc 306b 250a 261a 278a 333a








per stand(g)

Total number

of grains


OBA98 255a 071a 289ab








7


Plant

height

Leaf

length

Leaf

width

Number of


Plant height

Leaf length 095

Leaf width 096 094



WAP 035 022 027 017 003

Treatment 009 011 079 013 003 002

Cultivars 002 003ns 006 011 007 002 004






























8



emergence


exposure

Plant

stand


tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038












9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








4


























Source of variation

df Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest


Intercept 12 202800 35934 30334 80033 18934 24001 24300 36300



Cultivars 5 1731 1088 777 3251 834 763 951 1358

Error 95 289 252 239 646 268 249 300 337

Total 108

Corrected total 107





Intercept 1 17777 606 12675



radiation

5 780ns 119ns 2657ns


Error 95 470 097 2160

Total 108

Corrected Total 107




leaves

0 (control) 5622c 3672c 202d 437d

20 7259ab 4617ab 253abc 542bc

40 7571ab 4655ab 274ab 599ab

60 5812c 3696c 210cd 473cd

80 6524bc 4429bc 229bcd 502cd

100 8086a 5218a 279a 642a




5










































Exposure

periods of UV

radiation

( minutes)

Days to

plant

emergence

Plant stand Plant

aspect

Mutation

tolerance


harvest

0 439ab 156ab 144ab 222ab 033c 106ab 100ab 100b

20 433ab 172ab 139ab 239ab 078b 111ab 167ab 194b


60 428ab 167ab 156ab 256ab 033c 056b 061b 067c


100 511a 361a 249a 411a 211a 289a 294a 339a






(minutes)


0 121ab 049a 239a

20 147ab 063a 283a

40 123ab 003c 006c

60 023c 002c 006c

80 127ab 011b 061b

100 229a 015b 056b




6



Oba 98 5312d 3316c 182c 421c





ARTOB98SW1 8658a 5536a 297a 606a




























079) (Table 11)


Cultivars

Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

Tolerance

Ear

aspect

Plant

husk Ear harvest

Plant

harvest


OBA98 444a 211b 194abc 306b 250a 261a 278a 333a








per stand(g)

Total number

of grains


OBA98 255a 071a 289ab








7


Plant

height

Leaf

length

Leaf

width

Number of


Plant height

Leaf length 095

Leaf width 096 094



WAP 035 022 027 017 003

Treatment 009 011 079 013 003 002

Cultivars 002 003ns 006 011 007 002 004






























8



emergence


exposure

Plant

stand


tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038












9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








5










































Exposure

periods of UV

radiation

( minutes)

Days to

plant

emergence

Plant stand Plant

aspect

Mutation

tolerance


harvest

0 439ab 156ab 144ab 222ab 033c 106ab 100ab 100b

20 433ab 172ab 139ab 239ab 078b 111ab 167ab 194b


60 428ab 167ab 156ab 256ab 033c 056b 061b 067c


100 511a 361a 249a 411a 211a 289a 294a 339a






(minutes)


0 121ab 049a 239a

20 147ab 063a 283a

40 123ab 003c 006c

60 023c 002c 006c

80 127ab 011b 061b

100 229a 015b 056b




6



Oba 98 5312d 3316c 182c 421c





ARTOB98SW1 8658a 5536a 297a 606a




























079) (Table 11)


Cultivars

Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

Tolerance

Ear

aspect

Plant

husk Ear harvest

Plant

harvest


OBA98 444a 211b 194abc 306b 250a 261a 278a 333a








per stand(g)

Total number

of grains


OBA98 255a 071a 289ab








7


Plant

height

Leaf

length

Leaf

width

Number of


Plant height

Leaf length 095

Leaf width 096 094



WAP 035 022 027 017 003

Treatment 009 011 079 013 003 002

Cultivars 002 003ns 006 011 007 002 004






























8



emergence


exposure

Plant

stand


tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038












9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








6



Oba 98 5312d 3316c 182c 421c





ARTOB98SW1 8658a 5536a 297a 606a




























079) (Table 11)


Cultivars

Days to

plant

emergence

Plant

stand

Plant

aspect

Mutation

Tolerance

Ear

aspect

Plant

husk Ear harvest

Plant

harvest


OBA98 444a 211b 194abc 306b 250a 261a 278a 333a








per stand(g)

Total number

of grains


OBA98 255a 071a 289ab








7


Plant

height

Leaf

length

Leaf

width

Number of


Plant height

Leaf length 095

Leaf width 096 094



WAP 035 022 027 017 003

Treatment 009 011 079 013 003 002

Cultivars 002 003ns 006 011 007 002 004






























8



emergence


exposure

Plant

stand


tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038












9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








7


Plant

height

Leaf

length

Leaf

width

Number of


Plant height

Leaf length 095

Leaf width 096 094



WAP 035 022 027 017 003

Treatment 009 011 079 013 003 002

Cultivars 002 003ns 006 011 007 002 004






























8



emergence


exposure

Plant

stand


tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038












9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








8



emergence


exposure

Plant

stand


tolerance

Ear

aspect

Plant

husk

Ear

harvest

Plant

harvest

Replicates

Days to plant

emergence

005

Cultivars 000 038












9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








9



grains


Stover weight






4 Discussion









































radiation
















References















2522





10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








10
















402101B 11











227ndash242





USA pp 1ndash28



















































298ndash305















the 37th








articleview485










11








USA pp 751ndash782


















Cary NC USA








11








USA pp 751ndash782


















Cary NC USA




