The effect of irrigation cut off in different irrigation periods on yield and physiological indices of four maize cultivars

Considering the necessity of saving water resources, to study new cultivars of maize to reduce the negative effects of water scarcity, the split-plot in the (RCBD) design with three replications was conducted at Research Field of Islamic Azad University, Arak was carried out in the years of 2016 and 2017. The treatments consisted of different levels of irrigation in the main plots, including I1(7-days control), I2(10-days), I3(12-days), I4(14-days) until the end of the course.  Irrigation was cut off during vegetative growth period after planting the seedlings from stage 3-7, and hence, irrigation interval was once applied to I5(10-days), I6(12-days) and I7(14-days). In sub plots, single-cross cultivars were considered in 704, 703,705 and 706 corn. According to the current study, irrigation and corn cultivars had a significant effect on yield and physiological indices. Decreasing irrigation levels resulted in decreased yield, relative water content and chlorophyll content in leaf compared to control treatment. In interactions between irrigation intervals and cultivars, I1 to I3 irrigation intervals showed cultivar 703 with the highest average maintenance power and growth indices, while in the irrigation interval from I4 to I7, single cross 705 varieties were superior to other cultivars shows. In all irrigation intervals single- cross 704 with the least power was recorded compared to other cultivars. The highest water use efficiency on cultivar 705 was at irrigation interval I5 with 39.54% superiority than to control irrigation and cultivar 704.