EFFECT OF DEFICIT IRRIGATION ON THE GROWTH PARAMETERS, YIELD AND WATER USE EFFICIENCY OF COMMON BEANS (PHASEOLUS VULGARIS L) UNDER FOLIAR SELENIUM APPLICATION

Water scarcity remains a major constraint to sustainable crop production, particularly in arid and semi-arid regions. This study investigated the effects of foliar selenium (Se) application as water stress management strategy on common bean (Phaseolus vulgaris L.). It assessed growth and water productivity under Deficit Irrigation (DI). A greenhouse experiment was conducted at the Tatton Agricultural Park at Egerton University for one season using a randomized complete block design with three replicates. The experiment consisted of three irrigation regimes;100%, 70%, and 50% of crop evapotranspiration (ETc) and four selenium concentrations (0, 0.5, 1.0, and 1.5 mg/L). The results revealed that full irrigation 100% ETc and moderate water deficit at 70% ETc, combined with foliar application of 1.5 mg/L Se, significantly (p < 0.05) improved growth and yield parameters. Further, water productivity was highest under the 70% ETc and 1.5 mg/L by Se treatment, suggesting enhanced physiological efficiency and drought resilience. Selenium application mitigated the adverse effects of water stress by supporting plant metabolism, antioxidative defense, and stomatal regulation. Furthermore, the highest total pod yield (13177.8Kg/Ha) was obtained at 100% ETc combined with 1.5mg/L of foliar selenium, but statistically on pair with 70% ETc and 1.5mg/L of selenium concentration compared to the control treatment 100% ETc and no foliar selenium application (8785.2Kg/Ha), while the lowest pod yield (2288.9Kg/Ha) was attained at 50% ETc combined with no foliar selenium application. These findings demonstrate that supplying 70% ETc with 1.5 mg/L of selenium concentration instead of full water requirement can be a good strategic approach to improving water use efficiency and sustaining common bean production under limited water availability. The study provides valuable insight for developing climate-smart irrigation practices thus contributing to sustainable water management.