The physiological effect of soaking seeds with ascorbic acid on some growth characteristics of sweet corn under water stress condition

A field experiment was conducted in the experimental field of the Crop Sciences Department at the College of Agricultural Engineering Sciences (Al-Jadriyah) - University of Baghdad. The aim was to study the physiological effect of soaking seeds in ascorbic acid on some vegetative growth traits of sweet corn (Zea mays L. var saccharata) under water stress conditions for the fall seasons of 2021 and 2022 respectively. A randomized complete block design (RCBD) according to the split-plot arrangement was used with three replications. The main plot included three levels of water stress, which were irrigation after depleting 40%, 60%, and 80% of the available water, coded W1, W2, and W3, respectively. The seed soaking concentrations of ascorbic acid at 50, 100, and 150 mg L-1, coded A1, A2, and A3, respectively, in addition to the control treatment (dry seeds), coded CO allocated to the sub-plots. The seeds were soaked for 24 hours, then dried to their original moisture content. The results showed no significant differences between the two water stress treatments when depleting 40% and 60% of the available water regarding the number of days from planting until 75% of male flowering, plant height, leaf number, leaf area, leaf area index, dry weight of plants, and crop growth rate for the two seasons. The irrigation treatment when depleting 80% caused a significant decrease in all studied traits. On the other hand, the soaking treatments with ascorbic acid significantly affected most of the studied traits, with the soaking treatment with 50 mg L-1 of ascorbic acid performing significantly with the highest average plant height of 145.01 and 143.91 cm, stem diameter of 2.55 and 2.54 cm, leaf number of 13.61 and 13.64 leaves plant-1, leaf area of 4672.30 and 4634.00 cm2 plant-1, leaf area index of 2.49 and 2.47, dry weight of plants of 162.41 and 162.29 g plant-1, and crop growth rate of 3.44 and 3.37 g m-2 day-1 compared to the control treatment for both seasons, respectively. The soaking treatment with 150 mg L-1 of ascorbic acid gave the lowest average number of days from planting until 75% of male flowering of 46.67 and 46.89 days compared to the control treatment, which gave the highest average number of days from sowing up to 75% male flowering, 50.44 and 52.44 days, respectively, for the two seasons. The interaction between water stress and ascorbic acid significantly affected most of the studied traits for the two seasons. Therefore, we recommend that, in the case of limited irrigation water, the possibility of irrigation by depleting 60% of the available water without a significant decrease in the vegetative growth characteristics of the sweet corn crop when the seeds were soaked in ascorbic acid at a concentration of 50 mg L-1 to improve their ability to withstand water stress.