Abstract

Quantitative trait loci (QTLs) associated with resistance to net blotch and their chromosomal locations were determined from analyses of doubled haploid progeny of Alexis/Sloop, Arapiles/Franklin, Sloop/Halcyon, and recombinant inbred lines of Sloop-sib/Alexis. Five QTLs on chromosomes 2H, 3H, and 4H were found to be associated with seedling resistance to the net form of net blotch. In Arapiles/Franklin and Alexis/Sloop populations, 4 significant QTLs explaining 9–17% of the variation in net blotch resistance were detected on 2H and 3H. A major locus, QRpts4L accounting for 64% of the variation in infection type, was detected on 4H in the Sloop/Halcyon population. In Sloop/Halcyon, 2 microsatellite markers, EBmac0906 and GMS089, and AFLP marker P13/M50-108, co-segregated and detected maximum variability for net blotch resistance as revealed by bootstrap analysis. EBmac0906 and Bmac0181 were validated in F₂ progeny of an Ant29/Halcyon population and reliably predicted phenotypes of 93% of lines resistant and susceptible to net blotch. These markers may be used within breeding programs to select alleles favourable for net blotch resistance derived from Halcyon.