Effect of drought stress on some morphological and physiological traits in Aegilops tauschii genotypes

Aegilops tauschii is one of the ancestors of bread wheat and is the main source of genes for resistance to biotic and abiotic stresses. The present research was performed as a factorial experiment based on a completely randomized design to determine the effect of drought stress on some morphological traits in 23 A. tauschii genotypes. Some important morphological and physiological traits were evaluated in the greenhouse conditions. The results showed that root length, the number of leaves and tillers, chlorophyll content, shoot and root fresh weight, shoot and root dry weight, percentage of yellow and rolled leaves at seedling stage and shoot and root dry weight, flag leaf, peduncle and spike length and the number of spikes at maturity stage increased in drought stress. Instead, RWC and shoot length were reduced at the seedling stage in the drought stress condition. In the seedling stage, the highest values obtained for root length, number of leaves, root fresh and dry weight, percentage of yellow and rolled leaves were 44.67 cm, 24.00, 3.35 g/plant, 0.40 g/plant, 50% and 80.79% under drought condition, respectively. In the maturity stage, the highest values obtained for shoot and root dry weights were 26.58 and 41.77 g/plant obtained in genotypes KC-55 and KC- 2122 under drought condition. The highest values for flag leaf length, peduncle length, spike length and the number of spike were 12.30 cm, 15.65 cm, 9.08 cm and 30 observed in genotypes KC- 2123, KC-2225, KC-2115 and KC-621 at control, respectively. Based on the ward’s cluster analysis, A. tauschii genotypes were divided into four different groups. The results of this study showed genotypes KC-621, KC-1772 and KC-2225 were tolerant to drought stress and therefore, they are recommended for use in wheat breeding programs.