High‑density mapping of stripe rust resistance gene YrH8 in wheat line Hangmai 8

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a major fungal disease threatening global wheat production. Identifying resistance genes and breeding resistant cultivars represent the most sustainable and cost-effective strategies for disease control. Genetic analysis of F₂ and F_2:3 populations derived from the cross Xiaoyan 22/Hangmai 8 indicated that the resistance to the prevalent Chinese Pst race CYR32 in Hangmai 8 is controlled by a single dominant gene, temporarily designated as YrH8. By applying bulked segregant exome sequencing (BSE-Seq) combined with SNP-index and Euclidean distance (ED) analysis, the candidate region for YrH8 was predicted to be within a 680-720 Mb interval on chromosome 7BL. Kompetitive allele-specific PCR (KASP) markers developed from polymorphic SNPs within this interval mapped YrH8 to a 2.9 cM genetic interval. After extensive screening of 2531 F₃ plants, the candidate interval was subsequently narrowed to 0.7 cM, spanning a 3.7 Mb physical region (689.7-693.4 Mb) on the Chinese Spring reference genome. These results not only provide a foundation for YrH8 map-based cloning, but also supply practical KASP markers for marker-assisted selection in wheat breeding programs.