SNP-based identification of QTLs for thousand-grain weight and related traits in wheat 8762/Keyi 5214 DH lines

As important yield-related traits,thousand-grain weight(TGW),grain number per spike(GNS)and grain weight per spike(GWS)are crucial components of wheat production.To dissect their underlying genetic basis,a double haploid(DH)population comprised of 198 lines derived from 8762/Keyi 5214 was constructed.We then used genechip to genotype the DH population and integrated the yield-related traits TGW,GNS and GWS for QTL mapping.Finally,we obtained a total of 18942 polymorphic SNP markers and identified 41 crucial QTLs for these traits.Three stable QTLs for TGW were identified on chromosomes 2D(QTgw-2D.3 and QTgw-2D.4)and 6A(QTgw-6A.1),with additive alleles all from the parent 8762,explaining 4.81–18.67%of the phenotypic variations.Five stable QTLs for GNS on chromosomes 3D,5B,5D and 6A were identified.QGns-5D.1 was from parent 8762,while the other four QTLs were from parent Keyi 5214,explaining 5.89–7.08%of the GNS phenotypic variations.In addition,a stable GWS genetic locus QGws-4A.3 was detected from the parent 8762,which explained 6.08–6.14%of the phenotypic variations.To utilize the identified QTLs,we developed STARP markers for four important QTLs,Tgw2D.3-2,Tgw2D.4-1,Tgw6A.1 and Gns3D.1.Our results provide important basic resources and references for the identification and cloning of genes related to TGW,GNS and GWS in wheat.