Mapping of Stemphylium Blight Resistance Genes in Lens culinaris.

Mapping of stemphylium blight resistance genes in Lens culinaris Saha, G.C.1*, A. Sarker2, W. Chen1, P.N. Rajesh1, G.J. Vandemark, and F.J. Muehlbauer 1 1Grain Legume Genetics and Physiology Research Unit, USDA-ARS, Washington State University, Pullman, WA 2 ICARDA, Aleppo, Syria. * Presenter F.J. Muehlbauer (muehlbau@wsu.edu) Stemphylium blight caused by Stemphylium botryosum is a major disease of lentil in Southeast Asia and North America. In order to identify and map the genes for resistance we developed a population of recombinant inbred lines (RILs) from a cross of ILL 6002 (resistant) x ILL 5888 (susceptible) and advanced the progeny to the F7 by single seed decent. The resulting 206 F7 derived RILs were planted in disease sick plots in Bangladesh following a RCB design with three replications. The results indicated significant variation among the RILs for disease symptoms and frequency distributions of disease scores indicated complex inheritance. The RILs were genotyped using different types of molecular markers (isozyme, SSR, RFLP, RAPD) and the data was used to develop a genetic linkage map of the population and to identify markers linked to resistance genes. A rudimentary linkage map of seven linkage groups has been developed. Marker density is currently being increased by adding SRAP and AFLP loci to the map. When the higher density genetic map is available we intend to conduct quantitative trait loci analyses to identify regions of the genome linked to genes for resistance to stemphylium blight.