اﺛﺮ ﺗﻨﺶ ﻗﻄﻊ آب در ﻣﺮﺣﻠﻪ روﻳﺸﻲ و زاﻳﺸﻲ و ﻣﻘﺎدﻳﺮ ﻧﻴﺘﺮوژن ﺑﺮ ﻋﻤﻠﻜﺮد داﻧﻪ و ﺑﺮﺧﻲ ﺻﻔﺎت ﻓﻴﺰﻳﻮﻟﻮژﻳﻚ ذرت ﻫﻴﺒﺮﻳﺪ4 Sc70

In order to study the effect of nitrogen rates and drought stress at different growth stages of corn (Zea mays) hybrid Sc. 704, this experiment was conducted in 2012. The experiment was factorial with randomized complete block design and three replicates. Treatments consisted nitrogen fertilizers (100, 150 and 200 kg N ha-1) and drought stress at vegetative and reproductive stages. Results indicated that, grain yield reduction in vegetative drought was due to grain number and weight reduction. Reproductive drought stress reduced number of fertile florets and grain number per ear, resulting in grain yield reduction. The effect of drought stress on chlorophyll and relative water content reduction was significant. Chlorophyll content increased with higher rates of nitrogen application. Generally, drought stress in reproductive has higher negative impact on grain yield and estimated physiological traits and this negative effect has not compensated in higher rates of nitrogen.