Confirmation of three quantitative trait loci conferring adult plant resistance to powdery mildew in two winter wheat populations

Hypersensitive, race specific genes primarily have been deployed to control powdery mildew (Blumeria graminis (DC) EO Speer f. sp. tritici) in wheat (Triticum aestivum L.); however, recent efforts have shifted to breeding for more durable resistance. Previously, three quantitative trait loci (QTL) for adult plant resistance (APR) to powdery mildew in the winter wheat cultivar Massey were identified in a Becker/Massey (BM) F (2:3) population. Fourteen new simple sequence repeat (SSR) markers were added to the pre-existing BM F (2:3) linkage maps near the QTL for APR on chromosomes 1BL (QPm.vt-1BL), 2AL (QPm.vt-2AL), and 2BL (QPm.vt-2BL). Genetic linkage maps comprised of 17 previously and newly mapped SSRs from the BM population on chromosomes 1BL, 2AL, and 2BL were constructed in a USG 3209/Jaypee (UJ) F (6:7) recombinant inbred line (RIL) confirmation population, wherein the APR resistance of USG 3209 was derived from Massey. Interval mapping analysis of mildew severity data collected in 2002 (F (5:6)) and 2003 (F (6:7)) field experiments with marker genotypic data obtained in 2003 (F (6:7)) confirmed the presence of the three QTL governing APR to powdery mildew in the UJ RILs. The QTL QPm.vt-1BL, QPm.vt-2AL, and QPm.vt-2BL explained 12-13, 59-69, and 22-48% of the phenotypic variance for powdery mildew severity in the UJ confirmation populations, respectively, in two field experiments. The current study verified that the elite wheat cultivar USG 3209 possesses the same QTL for APR as its parent Massey.