Bread wheat technological quality is jointly influenced by genotype, environment, and their interaction (G × E). Although Mixolab^® has been used to characterize rheological variation among wheat genotypes, its combined application with stability analysis remains limited in Moroccan multi-environment trials. Rheological variability and relative stability were evaluated using wholemeal flour from 13 bread wheat varieties grown across three contrasting agro-ecological zones in Morocco. Under a fixed hydration level of 60%—rather than the sample-specific hydration used in the standard ICC 173 procedure—nine Mixolab^® 2 parameters (C1–C5, α, β, γ, and mixing stability time) were measured. Two-way ANOVA, REML-based BLUPs, principal component analysis (PCA), and inter-environment stability indices were applied to evaluate varietal performance and relative stability. Highly significant effects (p < 0.001) of genotype, environment, and G × E were observed for all parameters. Under fixed hydration, the observed responses may reflect differences in flour composition, water-binding properties, and dough development at a common water level. Environmental contributions were largest for α and mixing stability time, whereas genotype-associated contributions were largest for C4 and C5. The first two principal components explained 72.6% of the total variability and identified three rheological groups under fixed hydration conditions: low-consistency genotypes, varieties with balanced rheological profiles, and starch-oriented genotypes. Within the three-environment, single-season network, Kenz, Najia, Khadija, Malika, and Ibtissam showed the lowest inter-environment variation, whereas Lina and Irchad showed the greatest. Whether these rankings remain consistent under the standard ICC 173 sample-specific hydration procedure remains unknown. These results illustrate the potential of combining Mixolab^® 2 parameters with mixed-model and stability analyses to characterize rheological patterns under fixed hydration conditions. Additional environments and cropping seasons are required before broad adaptation or environment-specific recommendations can be made.

Wheat occupies a prominent place at the national and international levels. This food crop is considered a main source of human and animal nutrition. Water stress is one of the main causes of the decline in bread wheat production in Morocco. Therefore, breeding for resilient varieties is of great importance to overcome this challenge. In this context, the main objective of this study is to assess the impact of drought on the productivity of bread wheat and to determine the key selection criteria for drought tolerance in a Mediterranean environment. To do this, 31 varieties and lines of bread wheat were evaluated at two contrasted INRA experimental stations during the 2020–2021 cropping season. Five productivity and quality parameters were assessed: grain yield, biomass, number of fertile spikes, thousand grain weight, and protein content. The results demonstrate the negative impact of water stress on the various parameters studied, except for the protein content which was higher in arid conditions compared to the favourable ones. Based on correlation analysis, the number of fertile spikes and the biomass could constitute the potential selection criteria for drought resistance. These trials will be repeated for several years under the effect of other intensities of stress and agro-ecosystems and by incorporating other parameters to confirm the results obtained. The line “BT19I5” showed great yield potential under both conditions and can be of great interest for farmers and for potential release at the national program.