Genetic Research Of Yield-related Traits And OTL Mapping In Rice

Most of agronomic traits for rice production show genetically continuous distribution with characteristics of quantitative trait, rather than Mendelian inheritance. It is usually not controlled by a single gene, but affected by a large number of quantitative trait loci (QTL). So far, as the staple food and model organism, rice has been studied genetically with various genetic populations based on genetic linkage maps to QTL analysis on a major QTL for particular trait, QTL Fine mapping. Grain weight is one of the main factors of rice yield and affects the production of rice directly. Grain weight also affected by some factors, such as grain length, grain width, grain thickness and aspect ratio, on which have been focused by researchers and breeders. At present, grain weight is characterized by1,000grains weight. The super hybrid rice, Liang-you-pei-jiu was derived from crossing between the indica93-11and the thermo-sensitive male sterile line Peiai64s. In this paper, we used93-11and Peiai64s as the parents to construct115recombinant inbred lines with focus on grain weight. With high-density genetic linkage map, we mapped some QTLs which influence grain length, grain width, aspect ratio and grain weight in rice. And the major QTL for grain width, qGW2was fine mapped via map-based cloning strategy using F5population. Our study analyzed the bases for the production of rice with cross of Indica varieties, which facilitated elucidation of the molecular mechanism for rice yield and breeding of super hybrid rice. The results are listed as follows:A total of21QTLs were detected including4QTL for grain length,10QTL for grain width,6QTL for aspect ratio,1QTL for grain weight; qGLl-1, qGL3, qGW2, qLW1, qLW4-1, qLW4-2and qTGW11had significantly positive additive effects, qGL-2, qGW1-2, qGW4, qLW5, qLW8and qLW11had significantly negative additive effects; Positive additive effect is from the paternal93-11, and negative effect the maternal Peiai64s; Mapped on long arm of chromosome2, qGW2had high contribution to grain width with up to13.5%; According to sequences of the two parents, we designed and developed a series of STS markers, eventually fine mapped qGW2in approximate100kb physical distance between STS2-5and STS2-9markers.