Physiological Resilience of Bambara Groundnut (Vigna subterranea L. Verdc) Genotypes to Intermittent Periods of Drought Stress at Different Growth Stages

Different genotypes of Bambara groundnut (Vigna subterranea L. Verdc) grow well under conducive environmental conditions, provided that adequate soil moisture is available during vegetative and reproductive phases. However, drought stress is the major limiting factor to bambara production, which accounts for up to 40% of yield losses. This situation could worsen due to drastic and rapid changes in the global climate. Landraces grown by farmers are low-yielding. Understanding the physiological response of different genotypes to drought stress is key to achieving food security through crop improvement and diversification. This study focused on variations in the response of Bambara groundnut genotypes to intermittent drought stress during the crop’s critical growth (vegetative and reproductive) stages. The experiment was undertaken at CSIR-Crops Research Institute Screen-house. The treatments were used in a factorial experiment with three replications in a randomized complete block design. The Bambara genotypes showed considerable variability in tolerance to drought stress. Drought stress during vegetative and reproductive stages significantly reduced crop growth indices, the leaf relative water content, chlorophyll content and leaf area. Drought stress during vegetative and reproductive stages had a more severe impact on the seed yield of genotype Nav Red, reducing it by 69% and 13%, respectively. Farmers should pay more attention to adopting drought-tolerant and high-yielding varieties for improved Bambara groundnut productivity and livelihoods.