The effect of irrigation levels in various growth stages on morphological characteristics and yield components of Zea mays L.

Drought stress globally affects the growth and production of plants. Corn is an important crop whose research in this aspect is highly noticeable related to food quality. In recent study the effects of drought stress and irrigation in various growth stages was evaluated at Agriculture research center located in Arsenjan city in Iran, during summer 2009. Experiment design study was according to split plot and randomized complete blocks in three replications. In addition, water deficit was induced in three growth stages, vegetative (S1), reproduction (S2) and seed filling (S3), respectively. We considered three irrigation levels named as I1, I2 and I3 as well. Irrigation was carried out once the cumulative evaporation from Pan Class A come to 40, 70 and 100 mm. The results demonstrate that regimens with 40 and 100 mm accumulative evaporations showed maximum and minimum contents in parameters such as leaf area index, plant height, dried matter content, fresh matter content, ear length, ear weight, seed depth, row number/ear, kernel number/ row, Cob diameter, Cob weight, 1000 - kernel weight, harvesting index, flag area index and finally seed yield in each treatment follows a decreasing trend through vegetative stage by drought stressinduction while a significant integration of water deficit at vegetative and reproductive stage was obtained respectively. Furthermore the reduction in seed yield is the result of decrease in row number/ear and kernel number/row.The results demonstrate that By definition, at vegetative stage once evaporation comes to 40 mm, the seed yield was much higher that 9 ton/h in contrast to reproductive stage with 70 mm evaporation and 7 ton/h seed yield. It should be noted that drought stress at grain filling stage with the average evaporation of 100 mm showed the greatest impact on physiological parameters changes (8 ton/h seed yield). In recent research, two factors of drought stress and irrigation performance in several regimens through different growth stage of corn represent no significant integrations.