Scanning QTLs for Grain Shape using Two Sets of Introgression Lines in Rice

Abstract

Grain shape determines both appearance quality and grain yield. In this study, two sets of introgression line populations derived from three parents were used to dissect the genetic basis of grain shape and illustrate the genetic background effects on QTL expression. Among the three parents, IR75862 was the common donor parent, and Ce258 and Zhongguangxiang1 were two recipient parents. The two introgression line populations were evaluated for grain shape traits in the summer of 2012 at Jingzhou, China. A total of 23 QTLs were detected in all 12 chromosomes except chromosome 1, 3 and 9 for grain length, grain width, grain thickness and length to width ratio, 11 and 12 detected in Ce258 and Zhongguangxiang1 background, respectively. They explained 6.95-38.27% of phenotypic variation. Among these QTLs, only three (26%) named qGL8, qLWR5 and qLWR10 stably expressed in both genetic backgrounds, clearly indicating that genetic background had large effects on QTL expression for grain shape. IR75862 alleles at these QTLs decreased GL and LWR in both backgrounds. Our findings will facilitate the gene cloning and breeding application for improvement of grain yield and quality in future.

Identification of QTLs for rice grain size and weight by high-throughput SNP markers in the IR64 x Sadri population

“…The important finding of this study is a major QTL on chromosome 8 which was controlling both grain size and grain weight with a high phenotypic variation. This QTL was previously reported for grain breath and shape by Iranian scientists (Rabiei et al, 2004;Nili et al, 2017;Qiu et al, 2017), while using Iranian traditional varieties. We identified SNP alleles for grain-related traits in the genetic background of non-aromatic varieties; furthermore, these SNP markers can be used for QTL mapping studies and can be substituted by SSR or other molecular markers.…”