Diversity of germination and seedling traits in a spring barley (Hordeum vulgare L.) collection under drought simulated conditions

This research evaluated the genotypic variation in a diverse set of 233 barley genotypes including 57 landraces in the context of early drought tolerance using polyethylene glycol-(PEG) induced osmotic stress on germinating seeds. The effect of PEG treatment ranged from accelerating to delaying the germination rate. PEG showed inhibitory effects on all seedling traits. Expressions of root and shoot traits recorded under optimum and under PEG- induced drought stress were positively and signifi- cantly correlated. Combined analysis of variance over experiments and treatments showed intermediate to high broad sense heritability values ranging from 0.42 to 0.76 for germination rate and seedling traits. Higher heritability values were obtained under optimum conditions as compared to PEG-induced drought stress conditions, indicating that the selection for genotypes with a more vigorous root system would be more efficient under optimum conditions. The exten-sive genetic variation for root morphology-related traits found in this diverse collection opens the opportunity to further investigate the analyzed root traits as selection criteria to improve barley perfor- mance under drought stress and to reveal the genetic basis for the observed stress tolerance by a genome- wide association study.