Comparison of Different Irrigation Methods on the Agronomic and Physiological Traits of Maize (Zea mays L.) Cultivars in spring and summer in Ahvaz Weather Conditions

In order to evaluate the effect of different irrigation methods on agro physiological traits of grain corn cultivars, a split plot experiment based on randomized complete blocks design with three replications was conducted at the research farm Islamic Azad University of Ahvaz Branch during 2014-15 and 2015-16 cropping years. The main factor consisted of four different irrigation regimes and a sub factor including Single Cross 704, Single Cross 701 (Karoon) Single Cross 616 (Mobin). The obtained results of variance analysis showed that the effect of different irrigation regimes and genotype on seed yield and yield components, biological and economic of water use efficiency, chlorophyll a and chlorophyll b were significant in spring and summer planting season. Comparison of spring and summer planting showed a significant superiority of summer planting in the all measured traits. The superiority of Single Cross 704 compared to other hybrids in the agro physiological traits can be attributed to higher yield potential, early maturity and more adaptation to environmental conditions. The results of the mean comparison indicated that the I2 treatment (alternate furrow irrigation along the stages of 4 to 12 leaf and 12 leaf till the emergence of silk and conventional irrigation along the emergence of silk till to ripening) had minimum seed yield and yield components, chlorophyll a and b content and water use efficiency (both economic and biological) and allocated the highest percentage reduction in the measured traits than to I1 treatment (conventional irrigation in all growth stages). Therefore, deficit irrigation in the early and middle growth stages (four leaves until the silk emergence) is not recommended. Comparison of the I3 and I4 treatments indicated that the alternate furrow irrigation in the 12 leaf stage until the silk emergence (I3 treatment) led to the lowest reduction in seed yield and yield components than to conventional irrigation treatment (I1). In the other words, deficit irrigation in the middle stage of growth (12 leaf till to silk emergence) and conventional irrigation in the 4 to 12 leaf stage and the silk emergence until ripening to manage water availability limitation is recommended.