Changes in morphology and grain yield of maize in response to salicylic acid under drought stress

Due to the water limitation in Iran and the widespread use of maize in human and animal feeding, this research was carried out to evaluate the effects of different salicylic acid levels on some morphological traits and grain yield of this crop under drought stress during reproductive stages. A field experiment was conducted as a split-plot based on a randomized complete block design with three replications in 2020 to investigate the effect of salicylic acid (SA) levels (0, 1, 2 and 3 mM) on morphological traits, grain yield and yield components of maize under normal irrigation and irrigation disruptions at reproductive stages. Irrigation and SA levels were assigned to the main and sub plots, respectively. The results revealed that irrigation disruptions from initial flowering up to maturity caused a significant decrease in the mean plant height, ear length, grains per ear and plant, 1000-grain weight, grain yield, plant biomass and harvest index. Foliar spray of salicylic acid, especially with 3 mM concentration increased most of these traits as well as 1000-grain weight, leading to an improvement in grain yield per unit area. The 1000-grain weight, harvest index, plant biomass, ear length, grains per plant and ear had the highest positive correlation with grain yield of maize. Water supply during grain filling stage is necessary to obtain a higher yield in maize. Foliar application of 3 mM salicylic acid was the superior treatment for increasing maize yield under normal and limited irrigation conditions.