Mahdiye Askary - PhD student of Agronomy and Plant Breeding, University of Birjand, Birjand, Iran and former MSc student, Shahid Bahounar University, Kerman, Iran
Aliakbar Maghsoudi Moud - Agronomy and Plant Breeding, Shahid Bahounar University of Kerman, Kerman, Iran
Vahid Reza Saffari - Agronomy and Plant Breeding, Shahid Bahounar University of Kerman, Kerman, Iran
Afsoun Askari - Agronomy and Plant Breeding, University of Birjand, Birjand, Iran

This study was conducted to determine the effect of drought stress on yield and some physiological characteristics of wheat cultivars. Six cultivars were grown under normal and drought stress in greenhouses and field conditions. Leaf samples were taken for physiological measurement including relative water content, transpiration rate, membrane stability, chlorophyll content and chlorophyll fluorescence parameters and stomatal frequency and length. Grain yield was determined for plants grown under field condition. Results showed that treatments have a significant impact on plant traits. Drought stress decreased leaf chlorophyll content and photochemical efficiency of PSII due to increasing F۰ and decreasing Fm and increased ion leakage. Drought stress also decreased grain yield and the highest yield was obtained in plots with normal condition. Cultivars Alvand and Chamran showed the highest level of photochemical efficiency of PSII, membrane stability and grain yield under drought stress and were considered as the more tolerant cultivars to drought stress than other cultivars under conditions of this investigation.

Chlorophyll fluorescence, Drought Stress, Photosystem II efficiency, Wheat, Yield