Mapping QTL Associated with Stripe Rust, Leaf Rust, and Leaf Spotting in a Canadian Spring Wheat Population

Stripe rust, leaf rust, and the leaf spot complex are economically important diseases of wheat (Triticum aestivum L.) in western Canada, and genetic host resistance is the most successful management strategy. This study was conducted to identify quantitative trait loci (QTL) associated with these diseases and to provide wheat breeders with sources of potential disease resistance genes. A total of 208 recombinant inbred lines derived from a cross between Canadian spring wheat cultivars 'Peace' and 'Carberry' were evaluated from 2014 to 2017 in stripe rust, leaf rust, and leaf spot nurseries in Alberta and British Columbia. All lines were genotyped with sequencing-based Diversity Arrays Technology (DArTseq) markers. Using the least square means of the combined environments, two stripe rust resistance QTL, two leaf rust resistance QTL, and three leaf spot resistance QTL were identified. The stripe rust QTL were located on chromosomes 3A and 4B, the leaf rust QTL were located on chromosomes 4A and 3D, and the leaf spot QTL were located on 2A, 4B and 7D. The stripe rust resistance QTL on 4B, contributed by 'Carberry', was previously identified in other studies using a population derived from 'Carberry'. Results from this study suggest that 'Carberry' may be an attractive parental source for breeders to enhance resistance against stripe rust and leaf spot with minor resistance alleles.