Drought stress memory in a germplasm of synthetic and common wheat: antioxidant system, physiological and morphological consequences.

Plants have evolved mechanisms of adaptation to fluctuations in their environmental conditions that have been given the term "stress memory". Synthetic wheat offers new hope for breeders to restore useful genes lost during the genetic bottleneck. We aimed to test whether drought priming and seed priming could improve drought tolerance in a diverse germplasm of synthetic and common wheat under field conditions. In this research, 27 wheat genotypes (including 20 synthetics, 4 common local and 3 common exotic bread wheat) were field evaluated under four water environments. These treatments included: 1) normal condition (N), plants were irrigated when 40% of the total available soil water was depleted from the root-zone, 2) seed priming-secondary stress (SD2), only water stress was applied at anthesis when 90% of the total available soil water was depleted and seeds were planted for evaluating, 3) primary stress- secondary stress (D1D2), primary water stress was applied at jointing stage when 70% of the total available soil water was depleted then secondary water stress was applied at the anthesis stage when 90% of the total available soil water was depleted, and 4) secondary stress (D2) only water stress was applied at the anthesis when 90% of the total available soil water was depleted. Our results indicated that improved efficient enzymatic antioxidant system leads to less yield reduction in D1D2 treatment. However, the positive effects of drought priming were more pronounced in drought primed (D1D2) than seed primed treatment (SD2). Synthetic wheat genotypes had a significant superiority in terms of yield, yield components and drought tolerance compared to common wheat genotypes. Nevertheless, the response of genotypes to stress memory was very different. Drought sensitive genotypes had better response to stress memory. Superior genotypes were identified as high yield and drought tolerant genotypes which can be used for future studies.