Morpho-agronomic Responses and Yield Stability of Common Bean ( Phaseolus Vulgaris L. ) Genotypes Under Contrasting Moisture Regimes

Moisture deficit heavily constrains common bean ( Phaseolus vulgaris L .) production in Ethiopia, serving as a critical limitation in areas characterized by erratic rainfall. To address this challenge, forty-three common bean genotypes were evaluated in a greenhouse experiment at Hawassa University in 2022 to identify drought-tolerant materials. The trial was arranged in a Randomized Complete Block Design (RCBD) with three replications under two distinct moisture regimes: a well-watered control and a post-flowering moisture-stressed regime. Significant genotypic variation was observed for most evaluated Mopho-agronomic traits, underscoring the genetic diversity available within the germplasm. Post-flowering moisture stress severely disrupted key plant processes, resulting in a 31.6% reduction in grain yield and a 33.2% decrease in pod number per plant. Discussion points reveal that terminal moisture stress compromises carbon assimilation, triggers premature leaf senescence, and severely impairs flower retention and pod setting. Furthermore, a significant genotype × regime interaction across several parameters indicated inconsistent performance, proving that bean genotypes employ distinct adaptive mechanisms to cope with water deficits. Under non-stress conditions, variety Tatu achieved the highest production at 12.7 g plant⁻¹. Based on comprehensive selection genotypes DAB 96, SER 125, and TATU emerged as the most resilient materials. These promising genotypes are highly recommended for direct production in moisture-stressed regions and can serve as valuable donor parents in future breeding programs targeting climate-resilient agriculture in moisture-limited environments.