Among the abiotic stresses, drought influences plant growth and productivity, and plant stress responses depend on stress intensity and genotype. The effects of simulated drought stress on germination parameters were tested for tolerance and sensitivity in 59 barley accessions from all regions of Iraq and phenotypic, physiological and biochemical responses associated with drought stress were investigated. Stress treatments with polyethylene glycol (PEG) reduced the germination rate and dramatically delayed the development of the seedlings. Significant changes in the physiological and biochemical profiles in barley accessions were observed. A smaller reduction in water absorption of seeds was observed across all accessions, while all biochemical characteristics except total flavonoid content were increased with the increase in water deficiency in most accessions. Among the 59 barley accessions, ABN was the most tolerant accession, while Black-Garmiyan was the most drought-prone. Significant relationships were found between most trait pairs, with 32 significant associations under no stress, 39 significant correlations under the 10.25% PEG treatment, and 81 significant correlations under the 20.50% PEG treatment. According to the key importance analysis, seed water uptake, total phenol content, soluble sugar content and catalase are classified as relative significance traits for germination percentage, root and shoot length under stress conditions.

All data were collected from an in vitro experiment. The data represent three replications of various phenotypic, physiological and biochemical characteristics obtained from barley seedlings.All data were collected from an in vitro experiment. The data represent three replications of various phenotypic, physiological and biochemical characteristics obtained from barley seedlings.

Full name of abbreviation: