Effect of Drought Stress on Barley ( Hordeum vulgare L.) in Germination Stage

Abstract

The Present study was aimed to evaluate the responses of sixteen species of barley Hordeum vulgar L. cultivated in Iraq against drought stress through treatments of seedling with varying concentrations of Polyethylene glycol (PEG6000) to reach the water stress(-3,-6,-9) in addition to control (without PEG 6000). The results showed variation of barley species in their ability to tolerate the drought stress. For instance, Boraq and Arefat were shown to be the most tolerable species, since  their percentage of seeds germination were non significantly affected by the highest water potential (-9)  bar, while (bawadi,amal,nor alqadsea and nomar) were shown to be moderately drought tolerable, since their percentage of  seeds germination were significantly affected at water potential (-9)bar. In contrast, the rest of species,i.e. Alkhair,alwarkaa, ebaa99 ,shoaa ,alrafidian ,sameer ,rehana3 ,forat9 ,Jazera1 and ebaa7 species, were all shown to be the most drought sensitive species, since their percentages of seeds germination were significantly affected at-3  and -6 bar.The results also showed that the averages of seeds percentage germination ,root length, dry weight, vigor index lowered significantly at (-6,-9) bar but they were significantly affected in -3 bar, while plumule length  and fresh water significantly affected from -3 bar. The ratio of root to plumule length gave significantly increasment at -6,-9 bar and it was not affected significantly at -3 bar.        In conclusion, barley species showed great variation in their response to the different water stress, This means that, there was a wild range of barley riddling tolerating the drought in germination stage and seedling growth.