水稻产量主要由有效穗数、每穗粒数和谷粒重三要素组成。谷粒重一般由“千粒重”表示，是粒长、粒宽和粒厚的综合体现。本申请以一个从武运粳7号的EMS诱变库中获得的高秆大粒突变体gs9（grain size on chromosome 9）为研究材料，在已精细定位并确定候选基因的研究基础上，拟进一步完成细胞形态观察，分离和克隆该粒形控制基因；开展生长激素的处理及测定，探明GS9促进茎秆和颖壳细胞生长的调控途径；同时构建不同的功能和表达载体及与其它粒形材料构建的双突变体，开展GS9的功能研究；结合RNA-seq和酵母双杂交分析，开展上下游基因和互作蛋白的筛选、验证和分析，初步探明GS9基因在水稻籽粒发育中的遗传机制及分子调控机理。本研究为丰富水稻粒形的基因调控网络，开展分子设计育种，培育高产水稻新品种打下了良好的理论和材料基础。

Rice yield is mainly determined by three components of panicles per plant, grain numbers per panicle and grain weight. Grain weight is usually represented with 1000-grain weight and is the comprehensive embodiment of grain length, grain width and grain thickness. In this study, the big grain recessive mutant gs9 (grain size on chromosome 9) was obtained from mutant library of the WYJ7 after EMS mutagenesis. On the base of fine mapping and identifying candidate gene, we will carry out the cell morphology observation, isolation and cloning of the grain size gene，ascertaining the regulation approach of promoting culm and glume cells development by GS9 with the plant hormones treatment and measurement, gene function analysis by constructing different function and expression vectors and double mutant analyzing, RNA-seq and yeast two-hybrid system to screening, verifying and analyzing of upstream and downstream genes and interacting proteins of GS9. This research will preliminarily ascertain the genetic and molecular mechanism of the GS9 gene in grain size development, and benefit our understanding of the gene regulatory networks, provide theoretical and materials basis of molecular design breeding for high yield in rice.