A major and stable QTL controlling wheat thousand grain weight: identification, characterization, and CAPS marker development

Thousand grain weight (TGW) is one of the three crucial determinants of wheat (Triticum aestivum) grain yield. The identification of functional genes and development of closely linked markers are urgently needed for wheat yield improvements. In this study, quantitative trait locus (QTL) mapping for TGW was carried out using one RIL population in four environments. A total of 8 QTL controlling TGW were detected across four chromosomes. Of them, QGW4B.4-17 was confirmed as a major and stable QTL for TGW increases of 2.19-3.06 g and high PVE of 22.5-36.3% in three environments. It was located in an interval (Rht1-TaGW-4B) of 2 Mb in physical distance that contains the Rht1 locus. Three high-confidence (HC) genes were predicted as potential candidates according to their annotated functions and expression profiles. Furthermore, a cleaved amplified polymorphic sequence (CAPS) marker, TaGW-4B, was developed and verified in a panel of 205 wheat cultivars and showed a highly significant correlation with TGW, demonstrating high value for efficient marker-assisted selection. The study provided a basis for cloning the functional genes underlying the QTL and a practical and accurate marker for molecular breeding.