Gene Action For Yield and its Components in Soybean (Glycine max (L.) Merrill)

Gene action, interaction and linkage relationship of genes creating continuous phenotypic variation of various metric traits are dedicated to breeding methods. Thus both additive and non-additive components of genetic variance, along their allied characteristics are of great use for plant breeders under different situations. An estimate of additive variance and nonadditive variance provides a measure of how likely particular traits can be selected for or against and that of whether hybridization or a population improvement program. Five generations viz. P1, P2, F1, F2 and F3 were evaluated in experiments under a compact family block design to estimate gene effects for major agro-morphological traits in four soybean single crosses (Bragg x RKS 18, JS 335x RAUS 5 and Bragg x JS 335 and RAUS 5 x Birsa Soy 1). The results showed additive gene effects that determined the inheritance of agromorphological traits viz. days to 50 percent flowering, days to maturity, plant height and harvest index. Dominance gene action was critical in determining the yield. Duplicate epitasis was significantly important in inheritance of most traits studied. On the basis of results obtained from the present investigation, it is suggested that these major quantitative traits in the desirable genotypes play a major role in the improvement of high yielding varieties of soybean through exploitation of additive and non-additive variances.