Abstract
Temperature is a key factor influencing plant growth and productivity, but its sudden rise can cause severe consequences on crop performances. Early sowing and application of growth promoting agents as a foliar spray can be a sustainable approach to cope with high temperature stress at grain filling stage of cereal crops. Therefore, a test was designed to explore the potential of different growth helping agents including sorghum water extract (SWE, 10 ml L-1), moringa leaf extract (MLE, 3%), hydrogen peroxide (H2O2, 2 μM), salicylic acid (SA, 50 mg L-1) and ascorbic acid (ASA, 50 mg L-1) as foliar agents at different sowing dates (early and optimum) to cope with temperature stress in maize. The results stated that foliar application of growth promoting substances successfully persuaded high temperature tolerance at reproductive phase of maize in early and optimum sowings when compared to control. However, SWE + ASA, MLE + H2O2 and SWE + ASA + SA + H2O2 were the best combinations for improving growth, development, and physiological variables under both sowing dates even under suboptimal temperature. All foliar applications significantly increased maize grain and biological yields while maximum was observed in SWE + ASA followed by SWE + ASA + SA + H2O2 or MLE + H2O2 that were statistically at par with ASA + SA + H2O2 but plants without spray or distilled water application did not improve grain and biological yields. Overall, the foliar applications of growth promoting substances enable the plant to enhance its growth, development, morphology, yield and biochemical variables.