Multi-Environment Quantitative Trait Loci and Association Mapping Analyses for Adult Plant Resistance to Stripe Rust and Cephalosporium Stripe in Wheat

Stripe rust (caused by Puccinia striiformis f.sp. tritici) and Cephalosporium stripe (caused by Cephalosporium gramineum) can result in severe yield and grain quality loss of wheat (Triticum aestivum L.) in the Pacific Northwest, USA. Favorable weather conditions and the appearance of new races are becoming an important factor for annual development of stripe rust in the region. Cephalosporium stripe can be a limiting factor in the adoption of conservation tillage practices and little is known about the inheritance of resistance. Two recombinant inbred lines (RILs) populations were assessed for quantitative trait loci (QTL) analysis for resistance to stripe rust and Cephalosporium stripe. For each population a linkage map was created using diversity array technology (DArT) and simple sequence repeat (SSR) markers. Field screenings for stripe rust were done in six environments under natural inoculation. Field screenings for Cephalosporium stripe were done in five environments under artificially inoculated conditions. Results from the QTL analysis identified common regions previously reported and associated with resistance to stripe rust and Cephalosporium stripe. In addition, association-mapping analysis using wheat varieties from the Pacific Northwest USA was performed to compare and validate QTL analysis results from this study.