Identification of the major QTL for adult plant resistance to wheat powdery mildew.

Developing effective and durable host plant resistance is crucial for controlling powdery mildew, a devastating disease caused by f. sp. (). In the present study, we dissected the genetic basis of the adult plant resistance to powdery mildew using a recombinant inbred line (RIL) composed of 176 F RILs population derived from a cross between PuBing 3228 (P3228) and susceptible cultivar Gao 8901. P3228 exhibits stable adult-plant resistance to powdery mildew in the field over consecutive years. We identified two QTLs on chromosomes 7DS () and 1AL () contributed by P3228, and one QTL on 3DS () contributed by Gao 8901, which could explain 65.44%, 3.45%, and 2.18% of the phenotypic variances, respectively. By analyzing the annotated genes in the 1.168 Mb physical interval of the major QTL , we locked a previously cloned adult-plant resistance gene that was most probably the candidate gene of Sequence alignment analysis revealed that the candidate gene of in P3228 was identical to the reported sequence. Two haplotypes and were identified in the whole genomic regions between P3228 and Gao 8901. To apply in wheat breeding, we developed a kompetitive allele-specific PCR (KASP) marker that is closely linked with these haplotypes. It is worth mentioning that the haplotype significantly decreased TKW and underwent negative selection for higher yields in China wheat breeding. In this study, we identified a major QTL and revealed the relationship between its resistance and yield, which could be beneficial for further applications in wheat disease resistance and high-yield breeding.