Effect of drought stresses on the physiological traits of hull-less barley (Hordeum sativum L.) in Eghlid region, Fars province, Iran

In the most arid and semi-arid regions, the growth and production of cereals are reduced due to drought and salinity stresses. Indeed, barley is a reliable crop for there conditions. At the moment, barley and hulles barley genotypes are being investigate to overcome the problems. In this study, four hull-less barley genotypes (UH3, U46M, EHM81-12 and CM67) were grown in Research Station of Eghlid Islamic Azad University under drought stress for two years (2006 and 2007). Four water supply treatments (irrigating after the soil moisture potential reached -.0.5 bar (control), 1.5 bar, -3 and -5 bar) were applied. The experimental design was a split plot in which drought treatments was arranged in the main plots and genotypes in subplots, based on a randomized complete block design with four replications. The measured characteristics were photosynthetic rate, respiration rate, chlorophyll content, amount of ABA and proline, superoxide dismutase (SOD) and peroxides (POX) activity in flag leaves. Variance analysis showed that drought. Stress decreased chlorophyll content and the photosynthesis rate, but stress increased Pox, SOD, ABA and proline contents as the respiration rate. In general, the UH3 genotype showed as well the lowest photosynthetic rate and ABA content, highest respiration rate and CM67 was in contrast. Indeed, CM67 was tolerant and UH3 was susceptible to drought stress.