Effect of salicylic acid on stay-green efficiency in maize (Zea mays L.) varieties

A field experiment was conducted during the spring and autumn seasons of 2024 at a farm located northwest of Ramadi city to evaluate the effects of foliar application of salicylic acid at four concentrations (0, 150, 300 and 450 mg L-1) on six maize genotypes. The study utilised a split-plot arrangement within a randomised complete block design (RCBD) with three replications. Results showed significant effects of salicylic acid concentration, genotype and their interaction on physiological and yield traits. The highest concentration (450 mg L-1) significantly increased the number of stay green, duration leaf area, kernels per row, 1000-kernel weight and overall grain yield, especially during the autumn season. The genotype Rabee exhibited the greatest number of stay green (14.75) and the highest grain yield (12.33 t ha-1). Salicylic acid also enhanced the stay-green characteristic, which correlated strongly with yield improvement by supporting photosynthetic efficiency and grain filling. Genotypes Rabee and Al-Maha demonstrated superior performance across most measured traits, highlighting their genetic potential. Additionally, salicylic acid application accelerated flowering by reducing the days to 50 % silking, particularly in spring. Environmental conditions in autumn provided greater stability in growth and reproductive phases. Based on these findings, applying 450 mg L-1 salicylic acid to responsive maize genotypes is recommended to improve physiological function and maximise yield under semi-arid conditions.