Effect of ultrasound and drought stress on some traits of corn

The positive effect of irradiation of seeds with ultrasonic waves on seedling growth has recently been considered by researchers. However, most experiments in this regard, have been focused on germination and early establishment of seedlings. The objective of this research was to investigate the response of corn plants to this waves under drought stress conditions. A filed experiment was conducted as factorial based on randomized complete block design with three replications at research field of Shahrood University, Shahrood, Iran, in 2014. The treatments were three levels of drought stress (control, irrigation interruption from flowering stage and irrigation interruption from grain dough stage) and five irradiation times (control, 2, 4, 6 and 8 minutes). The results indicated that unlike the main effects of factors that had significant effect on the most traits studied (except the effect of ultrasonic waves on stem and leaf dry weight), the interaction effect of drought and irradiation was significant on plant stem diameter. This shows that irradiation effect on the most traits studied does not change with thev change in drought stress intensity. Irradiation of seeds with six minutes could increase the average of these traits by 8, 10 and 12%, respectively. In total, irradiation of corn seeds with the ultrasonic waves under both stress and non-stress conditions was resulted to produce the stronger plants, especially under drought stress conditions where irradiation could decrease the unfavorable effect of drought stress.