Effect of drought stress on osmotic adjustment, proline and soluble sugars in root and shoot and relationship with drought tolerance in 12 genotypes of Chickpea (Cicer arietinum L.)

Environmental stresses such as drought have important effects on plant growth and development. In order to evaluate the effect of drought tolerance, 12 chickpea genotypes were treated with drought stress in hydroponic condition in greenhouses. Treatments were a control and two stress treatments -3 and -6 bar that was created with polyethylene glycol in hydroponic condition. Two weeks after the stress treatments on the genotypes, moisture content, osmotic potential, proline and soluble sugars were evaluated in their shoot and root. Results showed that drought stress reduced moisture content in shoot, but moisture content in the root had no significant changes. On the other hand amount of osmotic potential, osmotic compounds and proline increased in response to drought stress in shoot and root. Drought tolerance index in genotypes showed positive significant correlation with amount of the root osmotic compounds in -3 bar treatment. Despite the absence of significant changes in leaf soluble sugars, the amount of root soluble sugars declined in stress treatments compared to control. In addition, the positive significant correlation was observed between the drought tolerance index in -6 bar treatments and root soluble sugars of this treatment. Leaf and root proline levels had not significantly correlation with drought tolerance in genotypes. Despite some correlations between traits and drought tolerance index it seems that osmotic adjustment, moisture content, proline and soluble sugars alone not to be a suitable indicator to evaluate drought tolerance in chickpea genotypes.