Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a globally devastating wheat disease. The identification of novel loci for durable resistance is crucial for sustainable control of the disease. Chinese wheat landrace Xuxumai (XXM) has exhibited consistent high-level adult-plant resistance to stripe rust in China. To elucidate the genetic basis of its resistance, a recombinant inbred line (RIL) population was developed from a cross between XXM and susceptible cultivar Taichung 29. Disease severity (DS) of the parents and 149 RILs was evaluated across multiple field seasons. High-density SNP genotyping facilitated the construction of a genetic linkage map, which was used for quantitative trait locus (QTL) mapping. Three stable QTL, designated QYr.XXM-1AL, QYr.TC29-1BL, and QYr.TC29-2BS, were identified on chromosomes 1A, 1B, and 2B, respectively. Collectively, they explained up to 20.86% of the phenotypic variance. Comparative analysis indicated that QYr.XXM-1AL and QYr.TC29-1BL are likely novel loci, while QYr.TC29-2BS coincides with a known gene-rich region. RILs possessing all three QTL showed significantly lower DS (mean reduction of 50%) compared to those with 0 to 2 QTL. Furthermore, Kompetitive allele-specific PCR (KASP) markers closely linked to QYr.XXM-1A were developed and validated. This study reveals novel genetic resources for stripe rust resistance in XXM. The major QTL QYr.XXM-1A and its associated KASP markers hold substantial promise for enhancing the efficiency of marker-assisted selection in wheat breeding programs.

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), poses a persistent threat to wheat production in China. The Sichuan cultivar Chuanmai 62 (CM62) has exhibited stable adult-plant resistance (APR) for over a decade. To elucidate its genetic basis, we evaluated a recombinant inbred line population (CM62 × Avocet S) across 13 environments and genotyped it using the 55K SNP array. QTL mapping identified six QTL distributed on chromosomes 1BL, 2AS, 2BL, 5AL (two loci), and 5BL. Among these, three major QTL (QYr.CM62-1BL, QYr.CM62-2AS, and QYr.CM62-2BL) were detected. Notably, QYr.CM62-2BL was the preeminent locus, explaining 8.97–50.59% of phenotypic variance and exhibiting high stability across 11 of the 13 environments; this locus is closely linked to the previously reported QYR1 region, although whether it is allelic to QYR1 remains unclear. QYr.CM62-2AS corresponded to Yr17/YrM1225, while QYr.CM62-1BL aligned with Yr29. A significant finding was the identification of QYr.CM62-5BL, a novel minor-effect QTL mapped to the rearranged 5BL·7BL segment resulting from a 5B/7B reciprocal translocation present in both parents. Furthermore, two Kompetitive Allele-Specific PCR (KASP) markers (KASP-AX-109507945 and KASP-AX-109844182) were developed for QYr.CM62-2BL. Polymorphism screening of 328 cultivars confirmed their utility for marker-assisted selection. Collectively, our results demonstrate that the durable APR in CM62 is governed by multiple additive QTL. The newly developed KASP markers, together with the novel QYr.CM62-5BL locus and prioritized candidate genes from in silico annotation of the QYr.CM62-2BL interval, provide valuable genetic resources for pyramiding resistance alleles and future map-based cloning in wheat breeding programs.