Evaluation of salinity tolerance indices in North African barley accessions at reproductive stage

Soil salinity is one of the main factors limiting cereal productivity in worldwide agriculture. Exploitation of natural variation in local barley germplasm is an effective approach to overcome yield losses. Three gene pools of North African Hordeum vulgare L. grown in Tunisia, Algeria and Egypt were evaluated at the reproductive stage under control and saline conditions. Assessment of stress tolerance was monitored using morphological, yield-related traits and phenological parameters of reproductive organs showing significant genetic variation. High heritability and positive relationships were found suggesting that some traits associated with salt tolerance could be used as selection criteria. The phenotypic correlations revealed that vegetative traits including shoot biomass, tiller number and leaf number along with yield-related traits such as spike number, one spike dry weight, grain number/plant and grain number/spike were highly positively correlated with grain yield under saline conditions. Hence, these traits can be used as reliable selection criteria to improve barley grain yield. Keeping a higher shoot biomass and longer heading and maturity periods as well as privileged filling ability might contribute to higher grain production in barley and thus could be potential target traits in barley crop breeding toward improvement of salinity tolerance. Multiple selection indices revealed that salt tolerance trait index provided a better discrimination of barley landraces allowing selection of highly salt-tolerant and highly productive genotypes under severe salinity level. Effective evaluation of salt tolerance requires an integration of selection indices to successfully identify and characterize salt tolerant lines required for valuable exploitation in the management of salt-affected areas.