Abstract:

Six soybean culitivars with great difference in isoflavone content were used as parents to make incomplete diallel crossing (6×6) in accordance with the Griffing method Ⅱ and study the genetics of isoflavone content in soybean by using a full genetic model for quantitative traits of seed for diploid plant. Analyses of diploid embryo, cytoplasm and diploid maternal genetic effects, their GE interaction effects for soybean quality traits, and the genetic correlation among quality traits were conducted by using two year data. The genetic relationship between soybean quality traits was also analyzed by using a mixed model approaches, which could estimate the genetic covariances between two traits with unequal design matrices. The values of parents were also analyzed in this experiment. The results showed that isoflavone content in soybean was mainly controlled by maternal and embryo effects, followed by cytoplasmic effects (Table 2). The main effects of different genetic systems on isoflavone content trait were more important than environment interaction effects. The strong dominance effects on isoflavone from residual were easy changed by environmental conditions. Based on the genetic effects, Yudou 29 and Yudou 25 were better than other parents for increasing isoflavone content in progeny and improving the quality of soybean (Table 3). The significant effects of maternal and embryo dominance effects in variance showed that the embryo heterosis and maternal heterosis were existed simultaneously and not influenced by environmental interaction effects. It was suggested by the larger additive and cytoplasmic variances and their interaction variance that additive and cytoplasmic effects were more important than other genetic effects for isoflavone content in soybean. Better effects for improving isoflavone content in soybean could be achieved by selection in early generations.

Key words: Genetic effect, Heterosis, Isoflavone content, Quality, Soybean