Analysis of QTL for high grain protein content in Canadian durum wheat

Non-Peer ReviewedDurum wheat (Triticum turgidum L. var. durum) varieties with high grain protein concentration (GPC) produce pasta products with greater cooking firmness and increased tolerance to overcooking. However, the large environmental effect on expression of GPC and the negative correlation between GPC and grain yield slow breeding progress of durum wheat varieties with elevated GPC. Identification of molecular markers associated with high GPC would aid durum wheat breeders to select for this important trait earlier. The objectives of this study were to identify molecular markers associated with quantitative trait loci (QTL) for elevated GPC in durum wheat. A preliminary genetic map was constructed by screening polymorphic microsatellite markers on a set of 95 double haploid lines derived from the cross Strongfield (high GPC) X DT695 (low GPC). QTL analysis using single marker regression was performed on GPC data collected at Swift Current and Regina in 2002 and Swift Current, Regina and Saskatoon in 2003. To date, we have identified two QTL for GPC flanked by Xgwm448 and Xgwm558 on chromosome 2AS, and on chromosome 2BL at wmc332. No QTL for high GPC could be detected on chromosome 6BS, the location of a high GPC gene isolated previously from durum, wheat suggesting that Strongfield contains novel QTL for high GPC not previously reported in the literature. The molecular markers flanking the QTL identified in this study can be used by durum wheat breeders to enhance selection of high GPC in durum wheat