Vol. 6, Issue 2, Part A (2024)

Mung bean (Vigna radiata L. Wilczek) is a short-duration legume of high nutritional and economic value, extensively cultivated in tropical and subtropical regions. However, its productivity is often constrained by a range of agro-climatic stresses, including drought, heat, salinity, and erratic rainfall patterns, which are intensifying under the influence of climate change. Recent breeding programs have generated improved mung bean cultivars with enhanced resilience, yet a comprehensive understanding of their physiological and biochemical mechanisms of adaptation under multi-stress environments remains limited. This study evaluates the adaptive responses of selected improved mung bean cultivars to distinct and combined agro-climatic stressors, integrating field and controlled-environment trials across contrasting agro-ecological zones. Physiological parameters—including leaf water potential, stomatal conductance, chlorophyll fluorescence (Fv/Fm), and canopy temperature—were measured to assess photosynthetic performance and water-use efficiency. Biochemical assays quantified osmolyte accumulation (proline and soluble sugars), antioxidant enzyme activities [superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)], and lipid peroxidation levels through malondialdehyde (MDA) content. Results indicate that improved cultivars maintained higher chlorophyll stability indices, greater osmolyte concentrations, and more robust antioxidant defenses under stress compared to conventional landraces. Correlation and principal component analyses revealed strong linkages between osmolyte accumulation, antioxidative enzyme activity, and physiological stability, underscoring the importance of coordinated biochemical and physiological traits in conferring stress tolerance. The findings provide critical insights into the adaptive strategies of improved mung bean cultivars and highlight trait combinations that can be targeted in breeding programs to enhance resilience in climate-vulnerable regions. This integrative approach bridges knowledge gaps and offers a physiological-biochemical framework for the strategic deployment of mung bean in diverse agro-climatic conditions.