Identification of QTLs for adult-plant stripe rust resistance in Chinese wheat landrace Yizhanghongkemai and assessment of their utility for decreasing yield loss

Stripe rust is prevalent in the wheat-growing region of southwestern China. Frequent changes in stripe rust pathogen virulence in this region lead to a rapid loss of disease resistance among wheat varieties. However, Chinese wheat landrace Yizhanghongkemai (YZHK) has exhibited adult-plant stripe rust resistance for more than one decade in a disease nursery in southwestern China. To elucidate the underlying genetic basis, quantitative trait loci (QTLs) for adult-plant stripe rust resistance in YZHK were analyzed using an inclusive composite interval mapping method. Six QTLs for adult-plant stripe rust resistance were detected on chromosomes 1BL, 2BL, 3DS, 5BL, 5DL, and 7DS in multiple environments. Notably, QYrYZHK.saas-1B, QYrYZHK.saas-2B and QYrCY.saas-5D were likely new disease resistance loci. By comparing the effects of QTL alleles on yield and its components in field trials in which stripe rust was severe and effectively controlled, we determined that three QTLs significantly decreased yield losses due to stripe rust, among which the QTLs on chromosomes 1BL and 7DS were from YZHK, whereas the QTL on chromosome 5DL was from the other parent Chuanyu 12. These QTLs represent elite genetic resources for developing wheat varieties with adult-plant stripe rust resistance in the wheat-growing region of southwestern China.