GWAS for resistance against black point caused by Bipolaris sorokiniana in wheat

Black point is a severe wheat grain disease caused by complex pathogens, of which Bipolaris sorokiniana is dominant. Analysis of effective resistance genes/quantitative trait loci (QTL) is an essential prerequisite for breeding by marker-assisted selection (MAS). In this study, we aimed to identify the loci resistant to black point caused by B. sorokiniana in 10 wheat genotypes by performing a genome-wide association study with an incomplete diallel cross population. Twenty-three major marker-trait associations (MTAs) resistance to B. sorokiniana black point were identified, which could explain more than 11% of the phenotypic variations. They were located on 1B, 1D, 2B (2), 2D, 3A (2), 3B (2), 3D, 4A, 5A (2), 5B (2), 6B (3), 6D, 7A (2), and 7D (2), respectively. The average number of major MTAs in the 10 resistant lines was 20.2, whereas that in the susceptible lines was 9.8. All the major MTAs in the parents were detected in the F1 hybrids. Three PCR markers were developed for detecting two MTAs using two recombinant inbred line populations. These PCR markers linked to black point resistance and accessions with a larger number of resistance alleles can be used to improve wheat resistance by QTLs pyramiding via MAS.