Effect of drought stress on light absorption, radiation use efficiency and yield of different maize varieties (Zea maize. L.) under Ilam conditions

In order to investigate the light absorption and radiation use efficiency and grain yield of maize varieties in irrigation different levels, split plots experiment in randomized complete block design were conducted with three replications at Ilam University Research Field. Irrigation at three levels was assigned to the main plots (irrigation after 70, 105 and 140 mm evaporation from evaporation pan Class A) and four single cross corn hybrid varieties (524, 666, 677 and 704) were sub plots. Irrigation levels were significantly different in grain and biologic yields and harvest index. Grain yield decreased by 19% and 42% at I105 and I140 irrigation levels, respectively. Harvest index decreased by 0.8% at I140 Irrigation level. Results showed that maximum grain and biologic yields were observed in SC704, SC677 varieties, respectively. The effect of irrigation levels was significant on radiation use efficiency. The highest radiation use efficiency was observed in the studied varieties at I70 irrigation level (with an average of 2.43 g/mJ). Water deficit at I140 Irrigation level, radiation use efficiency was reduced by 25.11% relative to optimum moisture conditions. Based on the results, although all maize varieties showed reduced radiation use efficiency under drought stress, SC677 variety had the highest radiation use efficiency under stress and optimum irrigation conditions, compared to other varieties and cultivation of this variety is recommended, especially under stress conditions.