To explore the effect of grain width gene GW5 on rice grain shape,the analysis of genomic DNA sequence and PCR were conducted in sequenced wild species of genus Oryza,rice mini core collection(RMCC) and certificated japonica varieties in Jiangsu province from 2007 to 2013.We found that GW5 involved 1212-bp seuqence in the wild rices.The phylogeny demonstrated an apparent differentiation on DNA sequence of GW5 among these species.In the RMCC,rice varieties with the Del genotype of GW5 had shorter grain lengt...