Elucidating the genetics and physiology of seed longevity in soybean {Glycine max (L.) Merrill
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Date
2009-09
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation was carried out at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India. Using soybean as experimental material with objectives; to screen out different soybean genotypes for seed longevity; to study the genetics of seed longevity; to evaluate the selected genotypes (parents and crosses) for the level of ABA content and to study the ABA response for expression of LEA proteins level and seed germination. Three soybean genotypes viz., AGS 334, Bhatt and T-49, were selected to investigate the genetics of seed longevity. The significant differences were reported for seed longevity at different time periods of seed storage for both methanol stress and standard germination test at room temperature. The genotypic and phenotypic coefficients of variation for standard germination test was high after eight months of seed storage followed by six months of seed storage, while for methanol stress, the genotypic and phenotypic coefficients of variation was high after two months of seed storage fallowed by at after four months of seed storage. ABA content was highest in T-49 (10.04) and lowest in AGS 334 (1.01). The progenies which had T-49 in its pedigree showed that ABA content was half of the ABA content of T-49. High heritability estimates were reported for ABA content, plant height, germination percentage and 100 seed weight. High genetic advance was recorded for plant height followed by germination per cent, ABA content and 100 seed weight. ABA content reported to have significant and positive genotypic and phenotypic correlation with plant height. Four out of six crosses except for AGS 334 x Bhatt and Bhatt x AGS 334 exhibited highly significant positive standard heterosis for ABA content with Bhatt used as check parent. Highly significant combining ability variances due to GCA, SCA and reciprocals for plant height, germination, ABA content and 100 seed weight indicated presence of additive, non-additive and maternal gene effects for these traits. Segregation pattern of crosses AGS 334 x Bhatt; AGS 334 x T-49; and their reciprocals in F2 and F3 generation revealed the presence of one dominant gene whereas, cross Bhatt x T-49 and its reciprocal crosses revealed the presence of two dominant genes responsible for seed germinability. SDS-PAGE analysis of nine genotypes using NTSYS-pc v 2.1., separated the genotypes into two main cluster I and II at 0.794 similarity coefficient, comprising of four and five genotypes, respectively. SDS-PAGE analysis revealed the presence of good amount of LEA like proteins in the genotype T-49 and in the progenies involving it as one of the parents in the cross.
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Thesis-PhD
Keywords
genetics, plant physiology, seed longevity, soyabeans, Glycine max