Genetic effects for heading date in indica-japonica crosses of rice (Oryza sativa L.)

Abstract

The longer growth period of hybrid is one of the limitations for the utilization of intersubspecific indica-japonica heterosis in rice. In this study, three indica cytoplasmic male sterile lines and four japonica restorer lines with wide compatibility were used as parents to make crosses. The additive and nonadditive genetic effects on heading date were analyzed using an additive-dominance-epistatic model. The results showed that the genetic variation of heading date could be attributed to additive, dominance and additive x additive epistatic effects, with dominance genetic effects being predominant, followed by additive x additive epistatic effects. Analysis of genetic effects showed that the additive genetic effect from R 348 increases heading time, while the additive x additive epistatic effects from Zhensan 97A, R 456 and R 496 reduce heading time. In the progenies of crosses heading time was reduced by dominance genetic effects, whereas it was increased by additive x additive epistatic effects.