QTL for resistance to black point caused by Bipolaris sorokiniana in bread wheat

Abstract Black point disease has emerged as a serious concern in wheat production worldwide. In this study, we aimed to identify the major quantitative trait loci (QTL) for resistance to black point caused by Bipolaris sorokiniana and develop molecular markers for marker-assisted selection (MAS). A recombinant inbred line (RIL) population derived from a cross between PZSCL6 (highly susceptible) and Yuyou1 (slightly susceptible) was evaluated for black point resistance at four locations under conditions of inoculation with B. sorokiniana . Thirty resistant and 30 susceptible RILs were selected to form resistant and susceptible bulks, respectively, that were genotyped by the wheat 660K SNP array. Two hundred and four single-nucleotide polymorphisms (SNPs) were identified, among which 41(20.7%), 34 (17.2%), 22 (11.1%), 22 (11.1%) were located on chromosomes 5A, 5B, 4B and 5D, respectively. The genetic linkage map of RIL population was constructed using 150 polymorphic SSR and dCAPS markers. Finally, five QTL were detected on chromosomes 5A, 5B and 5D, designated QBB.hau-5A , QBB.hau-5B . 1 , QBB.hau-5B . 2 , QBB.hau-5D.1 and QBB.hau-5D .2, respectively. All resistance alleles were contributed by Yuyou1. QBB.hau-5D . 1 may represent a new locus for black point resistance. The markers Xwmc654 and Xgwm174 linked to QBB.hau-5A and QBB.hau-5D . 1 , respectively, have potential utility in MAS-based breeding.