عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The most cultivation area of wheat is in arid and semiarid regions. Therefore, the water requirement of wheat plants in all developmental stages can not be fully provided. In this research, the effects of post anthesis drought stress on grain yield and it’s components, gas exchange and other physiological characteristics of four wheat varieties were assessed. A pot experiment was carried out in factorial experiment based on randomized complete block design with three replications in Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran, during 2011 to 2012. The studied factors were including moisture stress in two levels, non-stress and drought-stress at reproductive growth stage (maintenance of soil moisture about 30% of the field capacity from the anthesis to maturity stage) and four wheat genotypes (Pishtaz, DN-11, Sivand and Marvdasht). Results showed that post anthesis drought stress significantly decreased grain yield by decreasing 1000-grain weight. Marvdast and DN-11 genotypes had the lowest grain yield under drought stress. The occurrence of post anthesis drought stress significantly decreased photosynthesis rate, transpiration rate, sub-stomatal CO2 concentration and stomatal conductance, but the photosynthetic water use efficiency wasn’t affected. Also, the leaves senescence led to decrease in the other physiological traits. According to the results of this research, it seems that redusing of the grain yield under post anthesis drought stress was related to decrease in 1000-grain weight due to decreasing of the photosynthetic rate. Also, leaves senescence by decreasing the photosynthetic rate was likely to be more severe than the transpiration rate for reducing of the water use efficiency under drought stress.