Fertile crescent region as source of drought tolerance at early stage of plant growth of wild barley (Hordeum vulgare L. ssp. spontaneum)

Drought is one of the most important types of abiotic stress that affects stability and amount of yield. This study was conducted to screen for drought tolerance at early seedling stages for 318 ecogeographically diverse wild barley (Hordeum vulgare L. spp. spontaneum) diversity collection (WBDC). Considerable variation was observed for all the seedling characters examined. Seedling growth was significantly reduced by 17% polyethyleneglycol-induced drought stress with significant variation among accessions. Shoot length was the most sensitive trait, however, rootshoot length ratio increased under osmotic stress. Correlation studies indicated that the root length was the most important trait, followed by shoot length and root-shoot length ratio. Principal components analysis (PCA) was performed and the first two principal components (PC) explained 78.3% of the variation present in the WBDC with PC1 (50.1%) associated with shoot length and seedling length. PC2 (28.1%) was related with root length and root-shoot length ratio. PCA showed that accessions from the Fertile Crescent particularly from Jordan and Israel showed high drought tolerance than other geographical regions at the early seedling stage. The accessions WBDC009 (Jordan), WBDC075 (Libya), WBDC211 (Uzbekistan), WBDC242 (Jordan), WBDC254 (Jordan) and WBDC289 (Israel) exhibited the highest drought tolerance index, indicating high level of drought tolerance. Consequently, these accessions showed tolerance to drought at the early seedling stage and are considered to be good sources of drought tolerance for cultivated barley