Evaluating the integrative response of moringa leaf extract with synthetic growth promoting substances in maize under early spring conditions

The performance of spring maize is severely hampered by high temperature at reproductive phase, causing marked reduction in grain yield. Early sowing of spring maize can be a good adaptive approach however, due to low temperature causes adverse effect on germinating seeds and young seedlings, thus being detrimental to early planting. Exogenous application of natural and synthetic growth promoting substances may induce tolerance against temperature constraints. For this purpose, field experiment was conducted to explore the potential of moringa leaf extract (MLE, 3%), sorghum water extract (SWE, 10 ml L-1), ascorbic acid (ASA, 50 mg L-1), salicylic acid (SA, 50 mg L-1) and hydrogen peroxide (H2O2, 2 mu M) as priming agents on maize hybrid under early and optimum sowing dates. The performance of early planted maize crop was severely influenced by low temperature in comparison to optimum sown crop nevertheless exogenous application of growth promoting substances proved effective in improving stand establishment, phenotypic behavior, key physiological and biochemical attributes of maize crop. Low temperature persuaded inhibition in growth of maize was mainly ameliorated by seed priming with MLE + H2O2 and SWE + ASA. It can be concluded that application of growth promoting substances as priming agents proved to be the most successful strategy in conferring better thermotolerance at early sowing through improved antioxidant defense system and physiological mechanism of spring maize. Better crop performance with combined application of natural and synthetic growth enhancers was linked to improvement in crop stand establishment, better growth and development, dry matter partitioning and yield attributes. (c) 2020 SAAB. Published by Elsevier B.V. All rights reserved.