Characterization of Pre-Harvest Sprouting Resistance in a White Wheat Cultivar Danby.

Pre-harvest sprouting (PHS) is one of the most important factors that affect the wheat grain yield and quality worldwide. Breeding PHS-resistant cultivars is the most economic method to reduce the losses caused by PHS. Danby is a recently released white wheat cultivar and shows a high level of PHS resistance, but its resistance mechanism has not been fully understood yet. In this study, a wheat double haploid (DH) population were derived from a cross between Danby and Tiger, a PHS-susceptible cultivar, and genotyped by genotyping-by-sequencing (GBS). A total of 1800 single nucleotide polymorphism (SNP) markers were mapped and the resulting linkage map was used to map quantitative trait loci (QTL) for PHS resistance using two seasons’ phenotypic data. Three QTL were detected on chromosomes 3A, 5A and 3B and explained 44%, 6% and 3% phenotypic variations, respectively. The QTL on 3A was mapped in the same position as TaPHS1 located, however, the previously reported diagnostic SNP for TaPHS1 is not polymorphic between the two parents.  Further sequence analysis identified a SNP in the promoter region that shows a strong correlation with the PHS phenotype in the DH population. This SNP explained 39% phenotypic variation. Significant correlation between the SNP marker and PHS phenotype was also detected in a group of 46 elite breeding lines developed from Kansas-Hays wheat breeding program. This SNP might be useful in marker assisted selection for PHS improvement.