Floral biology and crossing techniques in GROUNDNUT

ManjappaM Sc. Scholar

Dept. of Genetics & Plant Breeding

GROUNDNUT(Arachis hypogaea)

• 2n=4x=40 (Allotetraploid)

• O: Papilionaceae

• Synonym: peanut, Mungphalli, China Badam, Badam , wonder

legume (for its flowering, pegging & pod formation pattern)

• It is a herb, erect/trailing, photo insensitive.

• Used as oilseed, vine for fodder/manure

• Distribution: 80 countries, between 400 N to 400 S latitude in

tropical warm climate

• India is second in production after China

• In India G.nut ranks first(36%).soybean(28%),rape seed

mustard(23%), sunflower(5%)

• King of oilseed- is the largest oilseed in India in terms of

production as it accounts 35.99% of total oilseed production

Area & Production of Groundnut (Kharif and Rabi) in India

year Kharif Rabi Total Area (m.Ha.)

2008-09 5.62 1.55 7.17 5.292010-11(target) 7.22 2.46 9.68 -

Production in m.tonne

State-wise production(2009-10) & Area(2008-09)

State Production (.000 tonne)

Area (.000 Ha.)

Gujarat 1863 1795.4Andra Pradesh 1024 1500Tamil Nadu 875 327.3Karnataka 512 694Maharastra 414 254Rajastan 357 321.5

• Although it is C3 plant, some of its physiological characters like

photosynthetic efficiency approaches the C4 plants

• 19% of total area under irrigated condition

• About 83% of total area is grown in kharif season mainly

rainfed(60% is sole crop)

• Soil type: well drained, light colored, loose, friable, sandy

loam soils well supplied with Ca & moderate amount of OM

• Heavy & stiff clays are unsuitable for rainfed G.nut as they

cause difficulties in pod growth & harvesting

Research centers

• International: ICRISAT(1972)-Sorghum, Pearl millet, chickpea, pegionpea, G.nut (ICGS 1,44,11)

• National: NRC on Groundnut- JUNAGARH (Oct 1 1979)

Nutritional qualities of groundnut

• Oil content 44-55%

• Protein content 22-32%

• Soluble sugars 8-14%

• Ca, Fe, Vit. B & E

• Oil contain 30% of Linoleic acid

• Cake contain 45-50% protein- rich in all amino acids except

Leucine & Methionine

• An adult requires protein-55g/day. G.nut supply 10%in India

Cont…

• It has antinutritional factors- Trypsin inhibitor & Phytic acid

(inactivated by boiling & roasting)

• Aflatoxin (mycotoxin): produced my Aspergillus flavus & A.

parasiticus, both are f. saprophytes invades G.nut before or

after harvest, during storage & transit

• During drought period pods are crack or damage by insects,

which makes way to fungi

• Aflatoxin cause liver cirrosis, cancer in animals(also human)

• Upper limit of aflatoxin for human use-30µg/kg

HISTORY

• It was first found in the Anion located in the Peruvian coast near Lima in pre-historic cemetery.

• Cultivated as early as 1200-1500BC (carbon dating investigation)

• It’s cultivation was widely distributed in S America

• Krapovickas: Peruvian type carried from American West coast Mexico Philippines China & India(16th C)

• Origin: A. hypogaea – Bolivia & N-W Argentina(Krapovikas-1969)

• Wild proginatorss: Smalt Itle(1978)- probable ancestors of A.

hypogaea are-

A. duranensis (A genome)

A. ipaensis (B genome)

• According to centromeric bands & RFLP data A. villosa & A.

apaensis are diploid proginators of A. hypogaea & A. monticola

• Arachis Genus has more than 70 wild species existing in nature

CLASSIFICATION

• Based on growth habit

a) Spreading: branches are spreading, main shoot may erect or

bent

b) Semi-spreading: main shoot always erect

c) Bunch: branches makes acute angle with the erect main shoot

Varietal classification of Groundnut

Virginia Peruvian runner Valensia Spanish

4 cultivated species of Arachis are-Diploid species (2n=2x=20) A villosulicarpa (N-W Brazil) A repens (fodder & cover crop)Tetraploid species (2n=4x=40) A glabrata (fodder & cover crop) A hypogaea (oil seed) - Segmental amphidiploid33 species named A. monticola is only a wild Arachis taxon which can be crossed

with A hypogaea to produce fertile progeny

Distinguishing characters Spanish-valensia & Verginia groupsCharacters Spanish-Valencia Virginia

Seed size Medium to small Medium to big/very big

Seeds/pod 2-4, rarely 5 2, rarely 3

Seed dormancy Very little / absent Medium to long

Flowers on main shoot Present Absent

Branching pattern Continuous Alternate

No. of branches Few to medium Medium to heavy

Length of primary branch Smaller than main shoot Bigger than main shoot

Growth habit Bunch Spreading / semi-spreading, bunch

Duration(days) 100-125 135-175

Leaf color Light green Dark green

Peak flowering stage 6-10 weeks 8-12 weeks

Leaf tip shape Round Acute

Growth of plant after pod formation

Absent present

Floral Biology

Floral Biology • Inflorescence: solitary or raceme

containing flowers in the axils of cataphylls

• Flower: Zygomorphic, sessile, looks pedicillte late when peg starts developing(hyponthium)

Std petal: very in color, central area(std crescent)

has darker lines radiating from base to the

periphery.

Wings: leathery yellow, wrap around keel

Keel: pale yellow, closely wrap around stamens &

upper part of the style & stigma

calyx: 5 Sepals(lobed), 1-seperated,justaposed to

keel & 4-fused except at tip

• Stemens: 10 monodelphous

Globose filaments are initially shorter than oblong one, later become equal or longer than them after pollination

• Ovary: present at the base of hyponthium, superior, 2-4 ovules, occasionally 5, rarely 6

• Style: two sharp bends• Stigma: club shaped,

protrude above anther & gets pollinated after dehiscence.

• Receptive before anthesis, enclosed in keel petal(self poll.), but when it is exerted out effect cross pollination(1-3.9%), based on season, bees & variety.

Floral diagram & Formula

Br., Brl., %, KK (4)+1, C5, A (10) , G 2

Flowering• A flowering branch never occurs at the same node as a

vegetative branch.• Indeterminate growth, better at good sunshine• Anthesis - 5.30 to 7.30am • Stigma becomes receptive about 24 h before anthesis

and its receptivity persists for about 12 hours after anthesis

• Pollination is affected 7-8 hrs before blooming• If anther dehiscence gets affected due to cloudy weather,

the style continues growth & stigma become protrude & pollinated by alien pollen through insect

Flowering cont…

• Pollen grains are smooth, oval, and sticky, Fertilization occurs

about 6h after pollination.

• All flowers don not end up in forming pods

• 2/5 flowers- shed off at beginning

• 2/5 flowers- do not form pod even after pod formation

• On an avg. 1/7 forms pod

Pegging

Pegging cont…• within 7 days after fertilization the intercalary meristem below the

ovary starts become activate & female whorl located on the third

internode also starts getting enlarged

• This in later stages takes the shape of thick root & carry the

fertilized ovary in its tip – called peg

• Movement geotropic penetrate soil up to 7cm depth & become

diageotropic

• The pod formation will start after growth of peg stops

• Time taken by peg to reach the soil surface is 2-8 days in bunch type

& 5-10days in spreading type

Pegging cont…

• Only 44% pegs form pod

• Soil should be soft to facilitates peg insertion

• Pods are slightly or deeply constricted (depends on variety,

soil-type, season)

Difference between bunch & spreading type

Characters Bunch type ( DAS) Spreading type( DAS)

Flowering 20-24 24-30

Pegging insertion in soil 28-32 34-40

Pod devt.(Starting) 33-37 39-45

Starting of pod formation 88-92 99-105

Fully developed pods 105 135

Peak vegetative growth 15 DAF 28-43 DAF & 59-74 Days

Max. flowering time 20-30DA Ist flowering 35-45 DA Ist flowering

Flower duration 20-36 DAF 31-80 DAF

NO. of flowers/plant 98-137 40-250

Crossing technique

• Emasculation will be doing at evening hours(4 pm onwards)

• Select those buds which are bulged, which are about to open in immediate morning

• Bend the lower lip of calyx(separated one), carefully open wing petals & make a slight slit on keel petal to open the stamens

• Remove all fertile anthers(8) to see that stigma should not damage

• Close the emasculated bud with its petals to avoid contamination

• Pollination will done in the next morning between 7-10am.

Collect anthers from male plant & squeezed by needle on

slide, pollinate emasculated bud with needle

• Tie the small thread to calyx tube for identification

• Success is judged by the resultant peg emergence, developing

peg should carry a withered flower & the piece of thread

attached earlier

Checking for success

Imp insect pest

• Leaf minor (Aproerema modicella)• White grub (Holotrichia sp.)• Hairy catterpillar (Armsacta albistraga)• Termite (Microtermus sp. & Nasutitermus sp.)

Imp diseases

• Early leaf spot (Circospora arachidicola)• Late leaf spot (phaeoisariopsis personata)• Rust (Puccinia arachids)• Pea nut necrosis• Root knot nematode• Bacterial leaf spot

Imp varieties

• Spanish type: MS 1, GG 2, J 11, TG 11, ICGS 11,TMV 57981

• Valencia type: MH 2, Kopergao-3, TMV 11• Virginia bunch: Kadiri-2&3, TMV-6,8&10• Virginia runner: M-13, GG-11,F-230

TMV-1,3&4

Breeding Objectives

Breeding for-• for-High yield• Moisture stress(drought)- 80% of area under rainfed• Earliness• Pest & disease resistance • Fresh seed dormancy- Spanish type lacks

dormancy(sprouting of seeds when caught by rain)• increased seed viability• High temp., cold, salinity, Al toxicity tolerance-(opt

temp.30-350C)

Cont…

• Increased biological N2 fixation(BNF)-By proper choice of

combination of host genotype & Rhizobium strain we can

increase N fixation(G.nut fix 124kg/annum)

• Resistance to lime induced chlorosis: common in calcarious &

alkaline soil

• Quality characters: Large seeded /confectionary types (ICGS

49) – high protein, sucrose & less oil content

• Oil content & quality(linoleic acid)

• Resistance to Aflatoxin contamination(ICGV 86168)

Cont…

• Nutrition Use Efficiency

• Efficient adaptation to different cropping systems

• For fodder- Arachis pintoi & A. glabrata

Future Thrusts• Yield level is at plateau in developing countries because of

lack of effective breeding programmes.• Pest, diseases, drought stresses. Use of transgenics will be an

imp tool in breeding for stress resistance • Enhancement of gene pool through an extensive use of the

whole gamut of core germplasm variability, so that genes in the pool are utilized fully. Identification of markers can be an imp component in gene pool enhancement

• Breeding for quality aspects • Some of the wild species have 46-63% oil content as

compared to cultivated(43-56%), so still scope to improve.