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Mapping quantitative trait loci (QTLs) controlling adult plant resistance in oat against Puccinia coronata f. sp. avenae

Eric Nazareno: Department of Plant Pathology, University of Minnesota

<div>Crown rust, caused by the fungus <em>Puccinia coronata</em> f. sp. <em>avenae </em>(<em>Pca</em>), is the most devastating disease in oat worldwide. Losses due to this disease can reach up to 50%, and breeding for resistance is a preferred management method for its cost-effectiveness and sustainability. Adult plant resistance (APR) or partial resistance has been shown to provide durable resistance against <em>Pca</em>. In this study, we are mapping APR loci in three recombinant inbred populations generated from three biparental crosses: CI1712 x Otana, PI260616-1 x Otana, and CI8000-4 x Otana. These populations were phenotyped in the Buckthorn nursery in St. Paul, MN for three years (2011, 2012, and 2017). In CI1712 x Otana population, 24 resistant and 24 susceptible lines were selected and genotyped using the 6K Oat SNP Chip. Results showed that two QTLs are associated with the resistance phenotype in CI1712: one in Linkage Group 6 (chromosome 14C) with five markers and one in Linkage Group 11 (chromosome 1C) with 13 markers. Kompetitive Allele-Specific PCR (KASP) markers were developed to confirm the presence of these QTLs in the whole population. For PI260616-1 x Otana and CI8000-4 x Otana, a total of 48 resistant lines and 48 susceptible lines were selected for the genotyping. Once the resistance loci from each population are mapped, we aim to pyramid all QTLs into a single line and forward it to breeding programs for the development of new varieties with durable resistance against crown rust.</div>