SNP markers for early identification of high molecular weight glutenin subunits (HMW-GSs) in bread wheat

Key message A set of eight SNP markers was developed to facilitate the early selection of HMW-GS alleles in breeding programmes. In bread wheat ( Triticum aestivum ), the high molecular weight glutenin subunits (HMW-GSs) are the most important determinants of technological quality. Known to be very diverse, HMW-GSs are encoded by the tightly linked genes Glu - 1 - 1 and Glu - 1 - 2 . Alleles that improve the quality of dough have been identified. Up to now, sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE) of grain proteins is the most widely used for their identification. To facilitate the early selection of HMW-GS alleles in breeding programmes, we developed DNA-based molecular markers. For each accession of a core collection ( n = 364 lines) representative of worldwide bread wheat diversity, HMW-GSs were characterized by both genotyping and SDS-PAGE. Based on electrophoresis, we observed at least 8, 22 and 9 different alleles at the Glu - A1 , Glu - B1 and Glu - D1 loci, respectively, including new variants. We designed a set of 17 single-nucleotide polymorphism (SNP) markers that were representative of the most frequent SDS-PAGE alleles at each locus. At Glu - A1 and Glu - D1 , two and three marker-based haplotypes, respectively, captured the diversity of the SDS-PAGE alleles rather well. Discrepancies were found mainly for the Glu - B1 locus. However, statistical tests revealed that two markers at each Glu - B1 gene and their corresponding haplotypes were more significantly associated with the rheological properties of the dough than were the relevant SDS-PAGE alleles. To conclude, this study demonstrates that the SNP markers developed provide additional information on HMW-GS diversity. Two markers at Glu - A1 , four at Glu - B1 and two at Glu - D1 constitute a useful toolbox for breeding wheat to improve end-use value.