Distribution of Seven Grain Genes and Evaluation of Their Genetic Effects on Grain Traits

Grain size is one of the most important factors determining rice yield. Several major QTLs for grain size control have been molecular characterized, and their roles in the regulation of grain size or weight have been explored but still remained obscure. In this study, we systematically examined the distributions of GW2, GS3, qSW5, qGL3, GS5, GW8, and TGW6 in 240 RIL of TD70 and Kasalath, compared the phenotypic differences between functional (additive) and non-functional alleles of the seven genes by monogenic lines and analyzed the interaction effect of gs3, gw2, and qgl3. The results showed that the 7 genes could be randomly combined, and an individual gene has its specific roles in grain length, grain width, and grain thickness, the seven functional genes regulating grain weight follows the order as qgl3 >gw2>gs3> GS5>qsw5> GW8>TGW6, and the combination effect among gs3, gw2, and qgl3 were revealed. These findings provide novel insight into grain size regulation in rice and are likely to be useful for marker assisted breeding in rice grain size.