Wuhan Zhang;Pingyong Sun;Qingfang He;Shu Man Fu;Jie Wang;Huafeng Den

State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, Hunan 410125, Chin;State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, Hunan 410125, China

Rice Big-grain;Fine mapping;GS2 Grain shape;NATURAL VARIATION;WEIGHT;YIELD;SIZE;LENGTH;ENCODES;PROTEIN;WIDTH;QT

Grain shape as a major determinant of rice yield and quality is widely believed to be controlled by quantitative trait loci (QTL). We have identified a novel gene "GS2" to largely regulate grain length and width in rice. The GS2 allele in the big-grain rice line 'CDL' functioned in a dominant manner. In the present study, we employed a chromosome walking strategy in the residual heterozygous lines from recombinant inbred population between cultivar "R1126" and CDL, and located the GS2 gene in an interval of similar to 33.2 kb flanked by marker GL2-35-1 and GL2-12 in the long arm of rice chromosome 2. According to genome annotations, three putative gene loci, LOC_Os02g47280, LOC_Os02g47290 and LOC_Os02g47300, exist in this candidate region. In addition, allelic analysis with previously reported genes demonstrated that GS2 was novel for regulating rice grain shape. These results will help promote the cloning and functional characterization of the GS2 gene and further develop linked markers to be used in marker-assisted breeding. (C) 2013 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. All rights reserved.