Morpho-physiological and yield responses to exogenous moringa leaf extract and salicylic acid in maize (Zea mays L.) under water stress

Two field experiments were executed to investigate the effects of foliar-applied moringa (Moringa oleifera) leaf extract (MLE; 1:30w/v) and salicylic acid (SA; 0.5mmol), singly or in combination, on growth, physio-biochemical, yield attributes and water use efficiency (WUE) of maize (Zea mays L., Three Ways Cross 329) under full and deficit irrigation conditions. Deficit irrigation was carried out by withholding water for 36 d from 12 to 48days after sowing (DAS). At vegetative stage, deficit irrigation significantly decreased all growth criteria, chlorophyll a concentration, and relative water content (RWC). In contrast, deficit irrigation considerably increased the concentrations of carotenoids, proline, membrane permeability (MP) and malondialdehyde (MDA). Similarly, grain yield, most yield components and WUE were significantly depressed in drought-stressed plants. However, foliar-applied treatments particularly MLE+SA significantly increased growth traits, photosynthetic pigments, RWC and proline accumulation associated with a simultaneous decrease in MP and MDA concentration under full and deficit irrigation conditions. The application of MLE+SA markedly increased grain yield, yield components and WUE over control (spray tap water). Overall, the combined application of MLE and SA could be used for alleviating the adverse effects of growth, physiology, yield criteria and WUE in drought-stressed maize plants.