Evaluation of Triticum durum–Aegilops tauschii derived primary synthetics as potential sources of drought stress tolerance for wheat improvement

Depleting groundwater resources, climate change and erratic rainfall necessitate the development of way outs to improve crop productivity with limited water availability. One of the strategies is to explore and evaluate the genetic resources especially wild relatives of crop for water stress tolerance. Thus, an experiment was conducted to screen eighty Triticum durum × Aegilops tauschii wheat synthetics along with 10 controls for drought tolerance under in vitro conditions in completely randomized design under polyethylene glycol (PEG)-induced water stress. The synthetics were assessed for seedling growth, physiological parameters and photosynthetic pigments. A significant variation was exhibited by the synthetics of all the studied traits under control as well as stress condition. For all the traits, a declining trend was observed with decreasing water potential of PEG. Positive correlation between stress tolerance index with seedling growth traits, relative water content membrane thermostability index, chlorophyll and carotenoid content under severe stress, indicated the significance of these traits for selection of drought tolerant genotypes. Principal component analysis highlighted the contribution of only root–shoot ratio toward water stress tolerance. Based on various studied traits, TA 84-5, TA 73, TA 156-3, TA 41-1, TA 63, TA 93, TA 96, TA 129b and TA 154 were identified as potential synthetics which can be used for developing drought tolerant wheat varieties.