Afshin Charabeh - Department of Agriculture, Islamic Azad university, Science and Research Branch Tehran, Iran
Hossein Heidari Sharifabad - Department of Agriculture, Islamic Azad university, Science and Research Branch Tehran, Iran
Seyed Mohammad Javad Mir Hadi - Department of Agriculture, Islamic Azad university, Science and Research Branch Tehran, Iran
Ghorban Noor Mohammadi - Department of Agriculture, Islamic Azad university, Science and Research Branch Tehran, Iran

To investigate the effect of different levels of N-fertilizer in diverse-content irrigation and drought-stress on yield and yield components of various hybrids of corn, an experiment has been conducted for two years (۲۰۱۶-۲۰۱۷) as split plot based on a randomized complete block design with four replications at Natural Resource and Agricultural Research Station, Kermanshah Province, Western Iran located in West Eslamabad (۶۳ km west of Kermanshah). The amount of water-requirement has been assigned as main plots in three levels including ۱۰۰%, ۸۰% and ۶۰% of water-requirement as perfect, moderate- and extreme-stress levels, respectively. Different levels of N-fertilizer (in the form of urea) were determined based on results of soil-experiment consisting of suggested-amount equal to ۱۷۰ Kg N ha-۱, ۳۰% higher than the suggested-amount (۲۲۱ Kg N ha-۱), ۳۰% lower than the suggested-amount (۱۱۹ Kg N ha-۱), as well as corn hybrids (ksc۲۶۰, ksc۵۰۰, ksc۷۰۳) were dedicated as subplots. In normal states, increasing N-fertilizer level of ۱۱۹ Kg N ha-۱ to ۲۲۱ Kg N ha-۱ improved these attributes, however, imposing drought-stress declined. While in stress-drought accompanied with increasing N-fertilizer from ۱۱۹ Kg N ha-۱ to ۱۷۰ Kg N ha-۱ improved these attributes. Meanwhile, the N-fertilizer effect has not been so important. The grain yield of ksc۷۳۰ hybrid was higher than the others in the normal and moderate-stress, while reaction to N-fertilizer by ksc۲۶۰ hybrid was better and led to more enhanced yield in the extreme drought-stress particularly accompanied via applying ۲۲۱ Kg N ha-۱.

Zea mays L, Grain yield, Yield components, Drought stress, N-fertilizer level