利用龙稻5号/中优早8号RIL群体定位粒形QTLOACSTPCD

[Objective]Grain shape significantly influences the yield,quality,and commercial value of rice.This study aimed to identify Quantitative Trait Loci(QTLs)controlling grain shape using a rice recombinant inbred line population,thereby facilitating the mining of rice grain shape genes and the breeding of long-grain japonica rice.[Method]A population of 176 recombinant inbred lines was developed by crossing the japonica super rice variety Longdao 5(LD5)with short round grain and the early maturing indica rice variety Zhongyouzao 8(ZYZ8)with long slender grain.Grain shape traits,including grain length(GL),grain width(GW),grain length to width ratio(LWR),and grain thickness(GT),were measured for three years using Smart Grain software,and the interrelationship between these traits was analyzed.Complete Interval Mapping(CIM)and Multi-Environment Trials(MET)were employed for QTL mapping and comparative analysis.[Result]Eight QTLs,comprising three for grain length(qGL3,qGL7,and qGL11),two for grain width(qGW3 and qGW5),two for grain thickness(qGT3 and qGT6),and one for grain length to width ratio(qLWR3),were identified on chromosomes 3,5,6,7,and 11 using the CIM method.These QTLs explained 4.69%-18.89%of the phenotypic variation,with an LOD range from 2.52 to 8.74.Additionally,qGL3,qGL7,qGW3,qGW5,and qLWR3 were consistently detected over three years.Fourteen QTLs,including four for grain length,two for grain width,three for grain thickness,and five for grain length to width ratio,were detected on chromosomes 2,3,5,6,7,and 11 using the MET method.These QTLs explained 2.28%-15.78%of the phenotypic variation,with an LOD range from 4.20 to 20.90.Comparison with cloned grain shape genes revealed the proximity of qGL3/qLWR3a to GL3.1,qGW5 to GW5,and qLWR3b/qGT3 to TGW3.[Conclusion]A total of 8 and 14 grain shape QTLs were identified using the CIM and MET methods,respectively,including three cloned grain shape genes(GL3.1,TGW3,and GW5).