Fine Mapping of Adult Plant Resistance to Powdery Mildew in the Soft Red Winter Wheat Cultivar Massey.

Fine Mapping of Adult Plant Resistance to Powdery Mildew in the Soft Red Winter Wheat Cultivar Massey

Camron Clark¹ & Tiffany Sikes¹

^1.Crop and Soil Environmental Sciences, 330 Smyth Hall, 185 Ag Quad Lane, Virginia Tech, Blacksburg, VA 24061.

Powdery mildew, caused by the pathogen Blumeria graminis is a major disease of wheat (Triticum aestivum). Race-specific resistance genes have often been deployed in breeding programs because they are highly heritable and confer complete resistance during all stages of plant growth. This type of resistance however, is easily overcome by the pathogen and may only remain effective for a few years. The implementation of race-nonspecific resistance, such as adult plant resistance (APR) in breeding programs provides a more durable form of resistance that can remain effective over a wide range of geographic area and time. Although several studies have been conducted to identify simple sequence repeat (SSR) markers that are tightly linked to the quantitative trait loci (QTL) governing APR to powdery mildew in the soft red winter wheat cultivar Massey and its derivative ‘USG 3209’, large distances still remain between QTL and SSR markers. This study uses a new mapping population, Massey/‘MPV57’, to further saturate the QTL regions previously identified using new SSR markers and single nucleotide polymorphism (SNP) markers. Multiple years of phenotypic evaluations conducted in NC, MD and VA, and genotypic data were used to construct linkage maps for QTL analysis. Currently, four QTL have been identified on chromosomes 2AL, 2BL, 2DS, and 4DL. The markers identified in this study are more tightly linked to their associated QTL on chromosomes 2AL and 2BL than previously reported and the new QTL on chromosomes 2DS and 4DL are flanked by tightly linked markers making them useful for marker assisted selection (MAS).