Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat in the world.

Genetic resistance is the best strategy for protecting wheat crops from stripe rust damage. Spring wheat landrace PI 181410, originally from Afghanistan, has shown high level resistance to stripe rust in germplasm screening since 2006. The four-way tests of PI 181410 with five predominant or most virulent races of Pst in both seedling and adult-plant stages at low (4-20oC) and high (10-30oC) temperature profiles showed that it has both all-stage resistance to some races and non-race specific high-temperature adult-plant (HTAP) resistance. To map genes for the resistance in PI 181410, it was crossed with Avocet S, from which a mapping population consisting of 170 recombinant inbred lines was developed. The F5 – F8 populations were phenotyped for infection type (IT) and severity in both Pullman and Mount Vernon, Washington in 2015-2018 under natural Pst infection, and the F7 population was phenotyped for IT on seedlings inoculated with avirulent races PSTv-4 and PSTv-14 at the low-temperature profile in the greenhouse. The F7 population was genotyped using the 90K wheat SNP chip. Three quantitative trait loci (QTL), QYrPI181410.wgp-1BS, QYrPI181410.wgp-4AL, and QYrPI181410.wgp-4BL, were identified on chromosome arms 1BS, 4AL, and 4BL, respectively.

The 4BL QTL, likely a new gene for stripe rust resistance, was most robust and detected in all phenotype tests. Three Kompetitive Allele Specific PCR (KASP) markers developed for this gene were highly polymorphic when tested with 155 U.S. Pacific Northwest wheat cultivars and breeding lines. These markers are useful for incorporating the effective resistance gene into wheat cultivars.