Assessing the impact of chlorpyrifos on growth, photosynthetic pigments and yield in Vigna radiata L. at different phenological stages

Abstract

The application of an insecticide is a common practice in the cultivation of mungbean (Vigna radiata L.). It therefore seems important to test the changes that are occurring in this food crop under chlorpyrifos treatments in order to identify the extent to which it tolerates the insecticide application thereby making it an economical food crop. 20 day old seedlings were exposed to different concentrations ranging from 0 to 1.5 mM of chlorpyrifos through foliar spray in the field condition. The seedlings were uprooted for analyses and observed at the preflowering (5 days after treatment, DAT), flowering (10 DAT) and post-flowering (20 DAT) stages for various morphological parameters such as plant height, number of branches, leaves per plant, total leaf area, plant biomass and photosynthetic pigments namely Chlorophyll (Chl) a, Chl b, Total Chl, and Carotenoid (Car) content. Yield attributing characters like number of pods plant-1, number of seeds pod-1 and weight of 100 seeds were analyzed from both control and treated plants after physiological maturity. All the growth parameters, pigments’ activity and yield parameters increased at 0.3 mM insecticidal treatment, when compared with control. Further increase in insecticide level had a negative impact upon all parameters studied. The data suggests that the application of chlorpyrifos at lower concentration may be a useful tool to increase the seed quality as well as quantity in mungbean plant, apart from their insecticidal properties. Key words: Chlorophyll, insecticide, mungbean, stress.