TY - JOUR AU - Kong, Dehui AU - Chen, Yiming AU - Wang, Linghan AU - Li, Xiao AU - Shi, Miaomiao AU - Ding, Zijun AU - Wen, Mingxing AU - Jiao, Chengzhi AU - Sun, Li AU - Wang, Zongkuan AU - Wang, Wei AU - Fei, Xinru AU - Guo, Hong AU - Sun, Bingjian AU - Wang, Haiyan AU - Xiao, Jin AU - Wang, Xiu’e PY - 2026 TI - Fine mapping of Wheat yellow mosaic virus resistance gene Ym5 and its application in breeding JO - The Crop Journal SN - 2095-5421 SP - 1298 EP - 1307 VL - 14 IS - 4 AB - Wheat yellow mosaic virus (WYMV) poses a significant threat to global autumn-sown wheat production. Growing wheat varieties with WYMV resistance is the most effective strategy for disease control. In this study, we fine-mapped a major WYMV resistance gene Ym5 (previously designated as QYm.njau-5A.1) in the Japanese wheat variety Xifeng. We delimited Ym5 to a 4.6 Mb linkage block (534.6–539.2 Mb in chromosome 5A) by genome-wide association study of 266 wheat accessions (excluding those carrying Ym1). Comparative genomic analyses revealed that resistant haplotypes, shared by Xifeng and European line ArinaLrFor, represent a putative alien introgression from Triticum monococcum. Twelve InDel and one KASP markers were developed and confirmed as diagnostic. Twenty-four recombinants were identified from a Xifeng × Yangmai 158 F2 population consisting of 6882 individuals, and Ym5, flanked by markers ARI_106 and ARI_218, was narrowed down to a 1.1 Mb interval (534.8–535.9 Mb in ArinaLrFor). The use of Ym5 in Chinese breeding programs was traced to two sources: Xifeng and Australian variety Quality. Further investigation showed Ym5 introgression conferred no obvious yield penalty. UR - https://doi.org/10.1016/j.cj.2026.03.023 DO - 10.1016/j.cj.2026.03.023