End-use quality of bread wheat is greatly influenced by the quantity and composition of glutenins (High and Low-Molecular-Weight Glutenin Subunits (HMW-GS and LMW-GS, respectively), both aspects genetically controlled and affected by the genetic background. This study analysed a set of intra-variety biotypes to accurately estimate the effects of allelic variation and glutenin quantity on quality traits, performed through grain protein content (GPC) and Sodium Dodecyl Sulfate Sedimentation test (SDSS), being the last one used to evaluate gluten strength. The GLU-D1 locus, which controls x-type HMW-GS, was the primary determinant of quality, HMW-GS amount and HMW/LMW ratio, as well as the relationship between glutenin content and quality. Within genotypes carrying the same GLU-D1 allele, the relation between HMW-GS content and GPC was strengthened, with GPC being the parameter influencing most gluten strength. To improve gluten strength in genotypes with the same LMW-GS composition, it is essential to consider both allelic variation at the GLU-D1 locus and the quantitative composition of glutenin fractions. Selection strategies should prioritize: increasing GPC, HMW-GS and LMW-GS levels in genotypes with Glu-D1a; enhancing GPC, HMW-GS levels and HMW/LMW ratio in genotypes with Glu-D1c; and boosting HMW-GS content and HMW/LMW ratio for genotypes with Glu-D1l.

This research Project has been funded by the Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Politécnica de Madrid (project MEJOR-TRIGO, APOYO-JOVENES-21-Q0U62P-86-BF6LSV) and by the grant PID2021–124041OB-C21.RESUENA-Legumes funded by MCIN/ AEI/10.13039/501100011033/ [Spanish Science and Innovation Ministry]. Naima Bouabdellah is financed by an excellence grant from the Government of Algeria.

Peer reviewed