Comparative physiological attributes of cultivated and wild relatives of barley in response to different water environments

Drought tolerance in wild species of barley (Hordeum vulgare ssp. vulgare L.) (especially Iranian species) and the relationship of physiological traits with yield indices to explore inter- and intraspecific variation is poorly understood. Drought tolerance of 83 genotypes belonging to 16 species of genus Hordeum were evaluated under normal (well-watered), mild, and intense drought stress conditions during 2012-2014. High inter- and intraspecific variation was observed for yield, physiological traits, and drought tolerance. Proline content was identified as the best physiological index for indirect selection of drought-tolerant genotypes in this study. The same species were grouped together to a great extent based on physiological and morphological attributes. Superior genotypes were characterized within each stress environment. In the wild species groups, three genotypes (Genotypes 40, 44, and 45) from Hordeum murinum and two genotypes (Genotypes 3 and 4) from Hordeum brachyantherum were identified as drought tolerant within both mild and intense drought environments. These genotypes may be used in future studies to characterize genes and mechanisms related to drought stress.