Improving rice grain length through updating the GS3 locus of an elite variety Kongyu 131

BACKGROUND: Traditional crop breeding has made significant achievement meet food needs worldwide. However, the way has some inevitable problems including time-consuming, laborious, low predictability and reproducibility. In this study, we updated the GRAIN SIZE 3 (GS3) locus to improve the grain length of a major cultivate variety of Kongyu 131 at Heilongjiang Province, the northernmost region of China. High-resolution melting (HRM) analysis is used for single nucleotide polymorphism (SNP) genotyping. RESULTS: The improved line introgressed about 117 kb segment including gs3 allele from donor GKBR by using five SNP markers designed within and without GS3 locus, and the background recovery ratio of the recurrent parent genome is about 99.55% that are detected by 219 SNP markers evenly distributed on the 12 chromosomes. The field trial indicates that grain length, 100-grain weight and total grain weight per plant of the improved line raised by 12.05%, 16.30% and 4.47%, respectively, compared with Kongyu 131. CONCLUSIONS: This result demonstrates that update the GS3 locus is a feasible and efficient and accurate way can be applied to improve grain size of rice.