Identification of Genetic Loci of Black Point in Chinese Common Wheat by Genome-Wide Association Study and Linkage Mapping.

Black point is a common disease in wheat all over the world. The disease could downgrade wheat quality and cause human health problems. In this study, 406 wheat cultivars were used to investigate black point resistance. In the field tests, 20, 65.5, and 14.5% of the tested cultivars were resistant, moderately resistant, and susceptible, respectively, suggesting that improving black point resistance is necessary in Chinese wheat breeding. A genome-wide association study (GWAS) identified 386 single-nucleotide polymorphisms (SNPs) significantly related to black point resistance in the tested wheat cultivars, and they were located on all chromosomes. Linkage mapping in a biparental population identified three quantitative trait loci (QTL) for black point resistance-QBP.hau-3A, QBP.hau-6D, and QBP.hau-7D-with 6.76, 7.79, and 8.84% phenotypic variation explained, respectively. Based on both the GWAS and linkage analyses, QBP.hau-6D covered six significant SNPs from the GWAS, and the position of these SNPs indicated that this QTL is a new locus for black point resistance. This study provides valuable germplasm for breeding wheat cultivars with resistance to black point and information for further understanding of molecular and genetic basis of black point resistance.