High-Density Genetic Map Construction of the Stripe Rust Resistance Gene YrTX47 in Wheat Cultivar Tianxuan 47

Stripe rust, caused by Puccinia striiformis f. sp. tritici, severely impacts global wheat production. Tianxuan 47 has shown stable resistance since 2004. To determine its genetic basis, Tianxuan 47 was crossed with the susceptible cultivar Mingxian 169, and phenotype evaluations of the derived progenies were conducted across multiple environments. Combining infection type (IT) and maximum disease severity (MDS) data with genotypic information from the GBW16K array of F2:3 lines, a major and stable quantitative trait locus (QTL), YrTX47, was identified on chromosome 5BS. Spanning a genetic interval of 6.30 cM, this QTL explained 37.51-52.22% and 36.10-47.46% of the phenotypic variation in IT and MDS across all tested environments, respectively. Subsequently, using KASP markers developed from our previous 660K SNP array, the YrTX47 interval was further narrowed to 0.45 cM, corresponding to a physical region of 404.77 kb. Based on its resistance response, chromosomal position, marker genotypes, and donor origin, YrTX47 is likely a novel gene on 5BS. The mapping interval contains six annotated genes, four of which are implicated in plant-pathogen interactions, making them potential candidates. This discovery highlights the breeding potential of YrTX47, offering a valuable genetic resource to broaden the resistance background.