Survey and new insights in the application of PCR-based molecular markers for identification of HMW-GS at the Glu-B1 locus in durum and bread wheat

Wheat, among all cereal grains, possesses unique characteristics conferred by gluten; in particular, high molecular weight glutenin subunits (HMW-GS) are of considerable interest as they strictly relate to bread-making quality and contribute to strengthening and stabilizing dough. Thus, the identification of allelic composition, in particular at the Glu-B1 locus, is very important to wheat quality improvement. Several PCR-based molecular markers to tag-specific HMW glutenin genes encoding Bx and By subunits have been developed in recent years. This study provides a survey of the molecular markers developed for the HMW-GS at the Glu-B1 locus. In addition, a selection of molecular markers was tested on 31 durum and bread wheat cultivars containing the By8, By16, By9, Bx17, Bx6, Bx14 and Bx17 Glu-B1 alleles, and a new assignation was defined for the ZSBy9_aF1/R3 molecular marker that was specific for the By20 allele. We believe the results constitute a practical guide for results that might be achieved by these molecular markers on populations and cultivars with high variability at the Glu-B1 locus.