Impact of drought on gluten strength and dough rheological properties in durum wheat

Water availability and increasing temperatures are major constraints for durum wheat production and strongly influence end-use quality. This study evaluated variation in gluten strength and dough rheological properties in a panel of 254 elite durum wheat genotypes grown under full irrigation and drought conditions across two growing cycles, and assessed the contribution of high- and low-molecular-weight glutenin subunits to these traits. Analysis of variance indicated that genotype was the primary source of variation for most gluten and rheological parameters, explaining up to 62.6% of the phenotypic variance. Environmental effects were most pronounced for grain and semolina protein content, while genotype × environment interactions were significant for several gluten traits but less influential than the main effects. Drought conditions increased protein content, gluten strength, and most rheological parameters, but reduced dough extensibility. Correlation and multivariate analyses revealed stable relationships among traits across environments. Gluten index was strongly associated with mixograph and alveograph parameters related to dough strength, whereas extensibility showed negative associations with elasticity and tenacity-related traits. Allelic variation was primarily detected at the GLU-B1 and GLU-B3 loci. GLU-B1 had the largest effect on gluten strength and rheological properties, while GLU-B3 was more closely associated with sedimentation volume and extensibility. The Glu-B1e (20+20) allele was associated with weaker gluten, whereas Glu-B1c (7+9) and Glu-B1f (13+16) were associated with stronger gluten properties, although the effects of the latter two alleles should be interpreted with caution because they were each identified in only two genotypes. Several novel glutenin combinations were identified. These results highlight the predominant role of genetic factors in determining gluten functionality and provide valuable targets for quality-oriented durum wheat breeding under contrasting water regimes.