上海科技大学知识管理系统

Background Grain size is an extremely important aspect of rice breeding, affecting both grain yield and quality traits. It is controlled by multiple genes and tracking these genes in breeding schemes should expedite selection of lines with superior grain yield and quality, thus it is essential to develop robust, efficient markers. Result In this study, 14 genes related to grain size (GW2,GS2,qLGY3,GS3,GL3.1,TGW3,GS5,GW5,GS6,TGW6,GW6a,GLW7,GL7andGW8) were selected for functional marker development. Twenty-one PCR-gel-based markers were developed to genotype the candidate functional nucleotide polymorphisms (FNPs) of these genes, and all markers can effectively recognize the corresponding allele types. To test the allele effects of different FNPs, a global collection of rice cultivars including 257 accessions from the Rice Diversity Panel 1 was used for allele mining, and four grain-size-related traits were investigated at two planting locations. Three FNPs forGW2,GS2andGL3.1were genotyped as rare alleles only found in cultivars with notably large grains, and the allele contributions of the remaining FNPs were clarified in both theindicaandjaponicasubspecies. Significant trait contributions were found for most of the FNPs, especiallyGS3,GW5andGL7. Of note,GW5could function as a key regulator to coordinate the performance of other grain size genes. The allele effects of several FNPs were also tested by QTL analysis using an F(2)population, andGW5was further identified as the major locus with the largest contribution to grain width and length to width ratio. Conclusions The functional markers are robust for genotyping different cultivars and may facilitate the rational design of grain size to achieve a balance between grain yield and quality in future rice breeding efforts.