QTL mapping for adult-plant resistance to powdery mildew in Chinese elite common wheat Chuanmai104

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a major fungal disease of wheat worldwide. The economic and environmentally friendly strategy is developing the wheat varieties with resistance to powdery mildew in wheat-breeding program. Chuanmai104 (CM104, Triticum aestivum L.), derived from synthetic hexaploid wheat, was an elite wheat variety with high adult-plant resistance to powdery mildew. The phenotype of powdery mildew resistance was conducted on a set of 234 recombinant inbred lines (RIL, F8) derived from the cross of CM104 and high susceptible wheat landrace Baimaomai (BMM) in five environments in this study. Three QTLs were identified on chromosomes 7D and 4A by the high-density wheat 50 K single-nucleotide polymorphism array, designed as QPm.saas-7DS, QPm.saas-4AL and QPm.saas-4AS, respectively. Of the three QTLs, QPm.saas-7DS derived from BMM and QPm.saas-4AL derived from CM104 were minor locus, QPm.saas-4AS derived from CM104 was detected as a new major locus for adult-plant resistance to powdery mildew in all environments and localized in a 1.06 Mb interval of the genomic region on chromosome arm 4AS referenced to Chinese Spring genome explained up to 26.5% of the phenotypic variances. The newly major locus QPm.saas-4AS would be supplied as a resistant source in wheat-breeding program.