Evaluation of drought stress tolerance in several populations of Aegilops triuncialis based on some physiological characteristics

For evaluation of some physiological characteristics in several populations of Aegilops triuncialis under drought stress،a factorial experiment was conducted based on completely randomized design with three replications at Mohaghegh Ardabili University during 2011 under greenhouse conditions. Three moisture regimes as levels of the first factor were full irrigation، irrigation until booting stage and irrigation until 50% heading، and 8 different populations of A. triuncialis considered as levels of the second factor. Components of chlorophyll fluorescence (FM، FV/FM) and number of stomata decreased with increasing severity of drought stress. There was a marked decrease in leaf chlorophyll and carotenoid content under drought stress condition particularly at booting stage. Drought stress also reduced 26% of leaf relative water content at both levels of stresses، as compared with non-stress conditions. Stomatal conductance decreased 46% and 55% in drought stress at booting and heading stages، respectively، but proline content increased. Under drought stress at heading stage، Hurand، Maku and Marand populations in terms of leaf relative water content were relatively superior to other populations and these populations could be considered as drought tolerant populations for future research.