Effect of Plant Growth Regulators on Cowpea (Vigna unguiculata (L.) Walp) Productivity under High Temperature Stress

High temperature stress severely interrupts the physiological and biochemical functions in plants which hinders the growth, development and productivity of cowpea. The present study evaluates the potential roles of Naphthalene Acetic Acid and Brassinolide for mitigating the adverse effects of high temperature in cowpea. The study was carried out during the year 2021 in cowpea variety CO 7 using Temperature Gradient Tunnel (TGT) located at Agro Climate Research Centre, Tamil Nadu Agricultural University (TNAU), Coimbatore. The experimental design followed was Factorial Completely Randomized Design (FCRD). Different treatments were imposed on plants exposed to ambient and ambient +2oC temperature. The effect of treatments on leaf area index, photosynthetic rate, chlorophyll index and seed yield were studied. The application of brassinolide @ 0.2ppm showed a positive effect on stressed plants and produced the highest seed yield of 8.78 g plant-1.