Mapping of the QTLs for grain shape using single segment substitution lines in rice

【Objective】Grain shape(grain length,grain width and length-width ratio)is a main index of rice appearance quality.For molecular breeding in rice,two QTLs controlling grain shape were mapped.【Method】The mapping populations were developed from the single segment substitution lines(SSSLs)in indica background of Huajingxian 74 and the two QTLs of grain shape were mapped using SSR markers.【Results】The grain width QTL,Gw-8,was mapped on the long arm of chromosome 8 between RM502 and RM447 with genetic distance of 0.3 cM.RM502 and RM447 located on the same clone AP005529 and the physical distance between RM502 and RM447 was 55.0 kb.The grain length QTL,gl-3,was located near the centromeric region of rice chromosome 3 between RM6146 and PSM377 with genetic distance of 1.5 cM and 11.0 cM,respectively【.Conclusion】The QTLs for grain shape in rice can be mapped using SSSLs.Mapping of Gw-8 and gl-3 has laid a foundation for cloning of the QTLs and molecular breeding of appearance quality in rice.