QTL Mapping and Developing KASP Markers for High-temperature Adult-plant Resistance to Stripe Rust in Argentinian Spring Wheat William Som (PI 184597)

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a destructive disease of wheat worldwide. William Som (WS), an Argentinian spring wheat landrace, has consistently exhibited high level resistance to stripe rust for over 20 years in our field evaluations in Washington state, USA. A previous study showed high-temperature adult-plant (HTAP) resistance in WS. To map the HTAP resistance quantitative trait loci (QTL) in WS, 114 F5-8 recombinant inbred lines (RILs) from the cross AvS/WS were evaluated for stripe rust response in seven field environments in Washington. The RILs and parents were genotyped with the Infinium 90K SNP chip. Four stable QTL, QYrWS.wgp-1BL on chromosome 1B (669-682 Mb), QYrWS.wgp-2AL on 2A (611-684 Mb), QYrWS.wgp-3AS on 3A (9-13 Mb), and QYrWS.wgp-3BL on 3B (476-535 Mb) were identified, and they explained 10.0-19.0%, 10.2-16.7%, 7.0-15.9%, and 12.0-27.8% phenotypic variation, respectively. The resistance in WS was found to be due to additive interactions of the four QTL. For each QTL, two Kompetitive allele-specific PCR (KASP) markers were developed, and these markers should facilitate the introgression of the HTAP resistance QTL into new wheat cultivars.