Evaluation of 20 Barley Genotypes under the Terminal Drought Condition

To study the response of barley genotypes to terminal drought stress, 20 promising barley genotypes were compared under two stress and non-stress conditions, in a split plot experiment based on randomized complete block design with three replications at the Agricultural Research Center of Southern Khorasan during 2007-2008 growing season. Drought stress levels consist of control (complete irrigation) and irrigation up to the 50% heading stage. Results showed that skipping irrigation at 50% heading stage resulted in 14.64 reduction in seed yield and 8.12 percent in biological yield compared to control condition. Spike length, plant height and flag leaf area in drought condition decreased by 12.4, 7.65 and 24 percent against complete irrigation treatment. Also, irrigation up to the 50% heading caused increasing of chlorophyll index and cell membrane permeability and declining of relative water content of flag leaf. There weren’t any significant differences among barley genotypes in terms of biological yield but the highest and lowest grain yield achieved from genotype number 18 (5997.2 kg.ha-1) and genotype number 16 (3420.8 kg.ha-1) respectively. Cultivar number 5 and 13 had the highest rate of chlorophyll index, and also number 8 had the highest relative water content (80.7%) in flag leaf. Based on the results of this study, genotypes number 18 and 20 had higher yields in both normal and drought stress conditions.