Rice Agronomic And Quality Traits In Gene Mapping Studies

Hybrid rice has, played a key role in the increase of crop production in China. However, some widely-used hybrids still exist several big shortcomings such as low quality. It is necessary to improve the quality of hybrids. To elucidate the geneticbasis of yield and quality traits and to utilize the useful gene by present biotechnologies will be helpful to the improvement of hybrids.In this study, a RIL population derived from SLG and Zhenshan97 was used to construct a genetic map and measure the traits. QTLs for different traits were mapped. The main results are summarized as following:1. 179 polymorphic SSR marker covering 12 chromosomes were used for constructing a genetic map. 1676 cM was apanned across the whole genome with an average marker interval of 9.5 cM. The markers order on chromosomes accorded well with that in previous report.2. Transgressive segregation was observed for all traits in the RILs. The performances between grain weight and yield showed to be none correlations. Significant positive correlations were found between grain weight and appearance quality. No correlations was between grain weight and grain filling.3. The entire genome was searched for QTLs for 12 traits by composite interval mapping. The number of QTLs varied according to the different traits. Each of the main-effect QTLs individually explained 3.5% to 71.1% of the phenopytic variations. QTLs for some traits were from the same parent.4. Grain length and grain width were each controlled by a major QTL accounting for a very large proportion of the genetic variation.5. Some QTLs appeared to be pleiotropic effects.6. Grain length, grain width and grain thickness controlled grain weight.