QTL Analysis of Snow Mold Resistance in Soft White Winter Wheat Cultivar ‘Eltan’.

Winter wheat accounts for 70-80% of wheat production in the United States and is prone to snow mold infection. Although snow mold is not a threat in all wheat-growing regions, it is serious enough in Washington that resistant cultivars are widely planted. Because snow mold infection depends on environmental conditions, it is inconsistent year to year and very difficult to phenotype, thus breeding for resistance is challenging.  Our objective is to identify QTL and DNA markers for the resistance found in ‘Eltan’. Four years of replicated field data have been collected from a population of 151 Finch x Eltan RILs planted in Washington and Idaho. The population was genotyped with 9,000 SNP and 200 SSR markers. Polymorphic markers were assigned to linkage groups using JoinMap. QTL Cartographer analysis identified three putative QTLs on chromosomes 5A, 3B, and 6B. The 5A QTL is located between 159 and 172 cM, has a LOD score ranging from 20 to 115, and accounts for approximately 49% of phenotypic variation. The 3B QTL is located between 6 and 33 cM, has a LOD score ranging from 14 to 63, and accounts for approximately 7% of phenotypic variation. The 6B locus is in a 34 cM interval, has a LOD score ranging from 13 to 67, and accounts for approximately 15% of phenotypic variation. Additional polymorphic SNP markers are being run in the population to better characterize and narrow these regions. The resulting QTL and associated markers will be applicable to marker assisted selection for snow mold resistance.