Development of a germplasm master set covering the variability of high molecular weight glutenin subunits for the GLU-B1 locus in Triticum sp.

. Gluten quality is a critical determinant of the end-use properties of wheat. The viscoelastic protein network that constitutes gluten is primarily composed of glutenins and gliadins, with high molecular weight glutenin subunits (HMW-GS) playing an important role in determining gluten strength and extensibility. In common wheat, HMW-GS are encoded by the GLU-A1 , GLU-B1 and GLU-D1 loci. For the GLU-B1 locus, up to 98 alleles have been described and compiled in the Wheat Gene Catalogue (WGC); however, the true extent of this variability remains uncertain, as many alleles have not been compared in conjunction and the associated germplasm is not always accessible. The present study aimed to collect and characterise the germplasm associated with GLU-B1 variability described in the WGC, to verify the allelic composition of each accession by SDS-PAGE and to assess whether the variability currently recorded is accurate. The identity of the majority of alleles was confirmed, while some cases of duplicated entries were identified, and others could not be verified due to the unavailability of the representative germplasm or genetic drift occurring in gene banks over time. Based on these findings, we propose the development of a master set of accessions representing the current GLU-B1 variability as confirmed by SDS-PAGE. The availability of this master set will improve the quality of future studies on HMW-GS variability and facilitate the use of a broader range of GLU-B1 alleles in breeding programs aimed at enhancing processing and end-use quality.