Abstract
Among the environmental constraints, the growth and yield of crops are seriously impaired by moisture stress. With this view, an experiment was conducted to observe genotypic differences in water relation, gas exchange characteristics and yield performance of mungbean under low soil moisture conditions. Experimental variables consisted of five drought tolerant genotypes (G88, G108, G141,varietiesG186), one susceptible genotype (G43) and two standard check variety (BU mug 5, Binnamoog-8) which assigned to two moisture regimes viz., water regime A ((80 to 90% field capacity (FC)) and water regime B (40 to 50% FC). Results showed that water saturation deficit, water uptake capacity and transpiration rate were the lowest in tolerant genotypes G88 followed by genotypes G141, while those were the highest in susceptible genotype G43 under low soil moisture conditions. Contrarily, the highest amount of relative water content and water retention capacity were found in tolerant genotypes G141, G108 and G88 and the lowest was recorded in susceptible genotype G43 under low soil moisture conditions. In the case of the photosynthetic rate and stomatal conductance, the tolerant genotype G141, G88 and G108 showed the higher values at moisture stress condition. The highest total chlorophyll content and proline content were also found in tolerant genotype G88 followed by G141 and G108, and the lowest was found in susceptible genotype G43 under moisture stress conditions. Irrespective of genotypes, moisture stress significantly decreased the yield attributes and yield of mungbean genotypes. However, the highest seed yield per plant (12.11 g) was found in tolerant genotype G88 under low soil moisture conditions because of its lowest reduction rate of yield attributes under moisture stress. Similar responses were also observed in tolerant genotypes G141 and G108. Therefore, the genotypes G88, G108 and G141 showed better performance in the case of water relation and gas exchange characteristics which might be contribute to higher yield of those genotypes.