Yield Stability and Adaptation of Common Bean (Phaseolus vulgaris L.) Genotypes Under Contrasting Moisture Regimes in the Bajío, Mexico

Common bean (Phaseolus vulgaris L.) production is severely constrained by water deficit, affecting approximately 60% of global production. Identifying genotypes that combine high yield with phenotypic stability under rainfed and water-limited conditions is critical for sustainable production in climate-variable regions. One hundred bean genotypes were evaluated across six environments defined by two locations (Celaya, Guanajuato, and La Llave, Querétaro), two growing seasons (2023–2024), and two moisture regimes at Celaya (rainfed and rainfed plus rescue [2023] or supplemental drip [2024] irrigation), using a randomized complete block design (RCBD) with three replications per environment. Drought tolerance indices (GMP, STI, DSI) calculated from the Celaya 2023 rainfed versus rescue-irrigation contrast and GGE biplot analysis were applied to characterize genotypic adaptation and stability. The environment explained 44.1% of the total sum of squares for grain yield, and the G × E interaction (22.5%) exceeded the genotype effect (12.5%). Compared with 2024, a moisture deficit (14.7 mm vs. 88.2 mm in 2024) in September 2023 reduced the mean rainfed yield at Celaya by 24%, and rescue irrigation increased the yield by 57.3%. STI and GMP identified genotypes with high productive capacity under contrasting moisture conditions (STI > 1.30 and rainfed yield > 1450 kg ha−1): FJ 6X6 T33 (STI = 2.169), GPO 69 1E 18 FM (STI = 1.769), FR21 Gpo 69 8 L7 FJ (STI = 1.697), SCR 16 (STI = 1.679), G69 SEL 16 FM (STI = 1.558), Trat 9 SEG 61 FJ (STI = 1.480), and FR-21 GP 061 60 L-7 (STI = 1.322). Among these, G69 SEL 16 FM, Trat 9 SEG 61 FJ, and FR-21 GP 061 60 L-7 also showed lower relative susceptibility to moisture deficit (DSI = 0.785, 0.958, and 0.997, respectively), a performance dimension not captured by STI or GMP alone. The Celaya 2023 stress-tolerance ranking showed a significant positive association with grain yield performance across four additional, independent environments not used in the index calculation (Spearman’s ρ = 0.495, p < 0.001), and SCR 16 ranked first among all 100 genotypes in terms of both the independent and overall six-environment means. Interspecific lines P. SaltilloXTA-245-1-2-2 and P. SaltilloXTA-245-1-2-4 showed superior specific adaptation under severely limiting rainfed conditions at La Llave in 2023. GGE biplot analysis differentiated three preliminary environmental groupings in the Bajío region, suggesting differential patterns of genotypic adaptation across contrasting production conditions. Multi-environment evaluation revealed germplasm accessions with both broad and specific adaptations to rainfed and water-limited conditions in the Bajío region. The integrated approach combining tolerance indices, independent-environment validation, and GGE biplot analysis provides a useful methodological framework for the breeding of drought-resilient common bean.