Wide genetic diversity of salinity tolerance, sodium exclusion and growth in wild emmer wheat, Triticum dicoccoides

Wild emmer (Triticum dicoccoides) is a progenitor of tetraploid wheat and currently grows in environments subject to abiotic stresses, including high salinity. Fifty-four genotypes originating from nine geographical populations in Israel, and five standard wheats (three durum and two bread wheats) were assessed for salinity tolerance using supported hydroponics. In this study, we summarize two key components that contribute to salinity tolerance: shoot growth in saline conditions relative to control conditions (relative dry weight); and Na+ accumulation in leaves of salinised plants. An additional third component (shoot growth under control conditions) has an indirect role but is important for salinity tolerance in an agricultural context. Variability in these three components was high. Some genotypes showed high overall relative dry weight, having the ability to maintain growth in moderately saline solution, a low-to-moderate Na+ accumulation, and high biomass production under control conditions. Genotypes from other populations had very high relative dry weight but grew very slowly, so were of limited agricultural relevance. Six selected genotypes possessing useful qualities for at least one of the tested components of salinity tolerance were re-analyzed, and a genotype from Gitit in the eastern Samaria steppes was identified as the most promising salt-tolerant line for further investigation.