Foliar Application of Silicon Improved Physiological Indicators, Yield Attributes, and Yield of Pearl Millet (Pennisetum glaucum L.) Under Terminal Drought Stress

Tremendously rapid global climate change creates different types of ecological issues such as various types of abiotic stresses. Like other environmental stresses, terminal drought stress has greatly affected growth and productivity of various crops by lowering the plant water status. Silicon (Si) being second most abundant element in the earth crust is an important stress reliever which improves plant growth and development under stressful conditions. So this study aimed to assess the exogenous application of silicon in drought mitigation in pearl millet. A field study was conducted during kharif season of 2018 and 2019. Two pearl millet cultivars (YBS-98 and BY-18) were planted in two irrigation regimes, i.e., normal irrigation and drought stress at flowering stage and four levels of silicon (Si), i.e., (0, 2, 4, 6 mg L−1) was foliarly applied. Different physiological (proline contents, SPAD-chlorophyll value, membrane stability index) and yield attributes were observed in millet during both years. Results showed that terminal drought stress decreases all the physiological, growth, and yield attributes of pearl millet except proline contents. Proline contents were increased under drought stressed condition. However, foliar application of 6 mg L−1 Si enhanced grain yield of millet due to improved membrane stability index, relative water contents, SPAD-chlorophyll value, and yield attributes in millet under both normal irrigation and terminal drought stress. Among the pearl millet genotypes, BY-18 performed best under all the treatments as compared to the YBS-98. Results revealed that exogenous application of Si improved relative water contents and membrane stability index in terminal drought conditions in millet which depicts its role in drought mitigation. Based on these facts, it is concluded that foliar application of 6 mg L−1 Si could be the best option to attain sustainable millet yield under terminal drought condition.