Physiological and Yield Responses of Sesame Plants to Foliar Application of Ascorbic Acid and Varying Irrigation Intervals

Abstract

A field experiment was conducted in Iraq during summer 2024 to evaluate the effect of different irrigation intervals and foliar application of ascorbic acid on the vegetative growth, physiological traits, and yield of sesame. The aim of the study was to increase plant growth and improve water-use efficiency under conditions of fluctuating water availability. The experimental design of this study was split-plot with a randomized complete block design RCBD comprising three replications. The main plots incorporated irrigation intervals of 5, 9, and 13 days, while the subplots were assigned foliar applications of ascorbic acid at concentrations of 0, 1000, 2000, and 3000 mg L−1. The findings indicated that the highest concentration of ascorbic acid yielded the most favorable outcomes across most of the measured traits. This treatment achieved the greatest mean values for plant height (148.67 cm), leaf area (13499.3 cm2 plant−1), relative water content (40.610%), membrane stability index (29.323), number of capsules per plant (140.90 capsules plant−1), and seed yield (1772.6 kg ha−1). The results further reveal that the 9-day irrigation interval proved superior in developing both the physiological parameters and yield-related attributes, whereas the longest irrigation interval of 13 days produced the lowest measurements for those traits. These results suggest that integrating foliar application of ascorbic acid with an optimal irrigation interval, particularly of 9-days, can contribute to improved water-use efficiency and higher sesame productivity under conditions of limited or variable water supply