Influence of field drought on yield, yield components and antioxidant defense system in reproductive tissues of tolerant and susceptible Chickpea (Cicer arietinum L.) cultivars

The objective of this study was to evaluate the role of the antioxidative defense system in imparting tolerance against drought-induced oxidative stress in seven chickpea comprising of two drought tolerant (desi-PDG 3 and PDG 4) and five drought susceptible (desi-PBG 1, GPF 2, PBG 5 and kabuli-L 550 and BG 1053) cultivars, when subjected to field drought stress. The study was conducted in reproductive tissues (podwall and seed) at 10, 20, 30 and 40 days after flowering (DAF) under irrigated and rainfed conditions. Drought susceptibility index (DSI) in the tolerant cultivars was comparatively lower than susceptible cultivars. Effect of water deficit conditions on plant growth led to decline in harvest index of all chickpea culitvars. However, in tolerant cultivars decline in harvest index was lower. During early pod development, the activities of antioxidative enzymes SOD, CAT, GR, POX and APX were more and as development progressed towards maturity the activities declined. Drought resulted in an increase in H₂O₂ accumulation and lipid peroxidation at different reproductive developmental stages. Drought-tolerant cultivars have higher antioxidant enzymes activities as compared to that of susceptible cultivars resulting in maintenance of lower H₂O₂ content and lipid peroxidation and higher growth, yield and yield components under water stress condition. In developing pods, susceptible cultivars failed to modulate the activities of antioxidative enzymes according to the ROS under field drought. Poor capacity of the antioxidative defense system in reproductive tissues of susceptible cultivars seems to be partly responsible for reduced yield potential under drought stress. Moreover, the higher status of antioxidative enzymes in pod wall of tolerant cultivars might protect the developing seeds from deleterious effects of drought.