Plant Breeding Practices in Groundnut (Arachis hypogaea, 2n=4x=40)
Groundnut ( Arachis hypogaea, 2n =4x=40) is major oil seed crop in India, occupies 45% of total seed area in the world and contributes 55 % of oil seed production. India ranks first in the world in terms of both area and production. The productivity of groundnut is low and it ranks 10th in worlds groundnut productivity. The crop is widely cultivated in Gujarat, Karnataka, Andhra, Tamilnadu, Maharashtra, Madhya Pradesh, and Punjab.
Groundnut has primary centre of origin Brazil. Similarly South America, and Africa are considered as secondary centres of origin as wide variability in the cultivated species. The cultivated species A. Hypogaea probably originated from wild tetraploid species A monticola and is most likely proginator of A. hypogaea.
Botany and Floral Biology:
Groundnut is herbaceous annual plant, basically interlineate in growth habit. The habits are bunch ( erect) , semi spreading ( ovate) and spreading ( prostate). In spreading forms the axis is very short and erect and primary branches spread horizontally along with ground. In bunchy type main axis is long and erect and primary branches are oblique to the main axis. The intermediate forms between these two are classified as semi spreading.
The plant has tap root system consist of numerous lateral roots. Being leguminous crop root nodules are developed on roots that help fix atmospheric nitrogen. An inflorescence products cataphylls at first node that give rise to flower. The flower developed either above or below the ground level. They are sessile orange to yellow in colour complete and papilonaceous in nature. The corolla having five petals i.e a standard two wings and partially united two keels. It is placed in end of the long calyx tube having five sepals in gamosepalous condition with three lobes. The stamens are 8-10 in number and only eight bear anthers. They are in monoadephous condition. The stigma usually protrudes above the anther level.
Groundnut is self –pollinated crop but out crossing may occur up to 2.5% . It is extremely difficult for crossing. The flower opens early in the morning. i.e. 6-9 a.m. and anther dehisce 1 to 2 hours before opening the flower. Next day all flower parts except small sessile ovary withers. Normally the flowering period last 3 to 6 weeks in case of bunch and 6 to 8 weeks in case of spreading types. After fertilization gynophores i.e. stalk of the ovary, elongate forming peg, curved downward pushing the ovary into the soil where the pod develops.
It is done in late afternoon or evening between 5.00 to 6.00 p.m the flower buds which will open on the next day morning are selected for emasculation. The flower bud is gently held in left hand and with the help of forceps, the standard petal, wings and keels are opened and all anthers are removed. Petals are placed in their original position to serves as the protective covering on the stigma. Hence, the bagging may or may not be done in order to avoid damage to the flower.
In the next day morning between 5.00 to 8.00 a.m. the flowers of selected parents are directly used for pollination or pollen grains are collected in petri dish and applied over stigma of emasculated flower with the help of hair brush. The pollinated flower bagged and labelled. After fertilization gynophores starts elongating. Tagging is done after identification as the pods are developed below the soil surface.
Breeding varieties with
1. High pod yield
2. Early maturity
3. High shelling percentage with high oil content
4. Resistant to Tikka, bud necrosis, Rust and Virus.
5. Resistant to Leaf minor, White grub, Aphid and Thrips.
6. Tolerant to drought and cold.
7. Erect type plant with dormancy period.
The varieties developed and released in other states or counties imported and after evaluation may be released for commercial cultivation. For example:
a. UF 70-103 introduction from university of florida
b. M-13 introduction from Ludhiana- Punjab
c. Robout introduction from Nigeria.
From local land races desirable types suited to the environmental conditions are selected and evaluated along with existing varieties if found superior selected strains released as improved varieties.
a. JL-24 ( Phule Pragati) selection from 94943.
b. Kopergoan 3 selection from local collection.
c. Karad 4-11 selection from local collection.
d. ICGS 11 selection from Robout 33-1.
3) Pedigree Method:
The elite lines are mated to produce the desirable progeny to combine deisirbale characters from two different varieties and selections are made F3 and onward generations for yield and desirable characters. The selected strains after attaining homozygosity evaluated in multi location trails and if founds superior released as improved variety, E.g. SB-XI ( AH4298 X 4354), Koyana ( M13 X Sulamit), Gaug 1 (AK 10 X AK 124).
4) Mutation Breeding:
Natural mutation or induced mutation can also be used in development of improved varieties.
1. TMV 10 natural mutation from Argentina
2. TG 1 ( VIKRAM) X ray induced mutation from Spanish.
3. TAG 24 X-ray induced mutation.
4. TG 26 X-ray induced mutation.
International Crop Improvement:
ICRISAT establish 1972, Patancheru, Hyderabad, varieties developed ICGS 1, ICGS11, ISCG44 and ICGS FDRS 10.
1. Directorate of oil seed research (DOR) Hyderabad
2. National centre for groundnut (NRCG) Junagad, Gujarat.
Conduct multidisciplinary research on groundnut with collaboration of AICRPO centres in the country.
AICRPO centres working on groundnut are ARS Digras, M.P.K.V, Rahuri, ARS Jargon, P.D.K.V, Akola, M.K.V, Parbhani ARS Latur and BARC in Maharashtra.