Effect of water supply on the water use-related physiological traits and yield of snap beans in dry seasons

Abstract

Four snap bean varieties (Phaseolus vulgaris L.) with different pod type were grown under three water supply conditions (well-irrigated, water deficit, non-irrigated) to examine the stomatal resistance, stomatal density and leaf area index (LAI) and their relationship with the yield. The highest stomatal resistance of the leaves and the smallest LAI and harvest index concerning the pods were measured under non-irrigated growing conditions. During flowering and pod development, significant differences were found in stomatal density on both leaf surfaces between the green-podded and yellow-podded varieties under water deficiency. Under non-irrigated conditions, stomatal resistance measured during flowering had a large effect mainly on the individual pod yield. Under these conditions, close significant correlations were found between stomatal resistance and LAI and water use (WUc) during the generative period of plants and the pod weight per plant. Under moderate water deficiency, the stomatal resistance, adaxial stomatal density of the leaves, and LAI were more effective to evaluate the difference in the productivity of snap bean genotypes than those measurements in severe drought. WUc-related traits can be used for the selection of bean genotypes adapted to drought, while the difference in water use efficiency (WUEy) between the snap bean varieties is suitable to evaluate their productivity under deficit irrigation.