Identification and characterization of hull-less barley (Hordeum vulgare L.) germplasms for salt tolerance

The assessment of hull-less barley germplasm for salt tolerance is crucial for future barley breeding programs, as it allows them to be classified for their adaptability to salt stress. Here, the salt tolerance of 224 hull-less barley genotypes was assessed under different NaCl concentrations during the seedling stage. Three hydroponic experiments were conducted, with morpho-physiological characters collected 10, 7 and 10 days after treatment, respectively, for a preliminary, and two subsequent experiments. Results of the first and second experiments revealed that salt-induced the deterioration of various morpho-physiological characters was most pronounced in the number of leaves per plant, shoot heights, root lengths, shoot and root fresh and dry weights. An integrated score (IS) was used to rank the salt tolerance ability and the four highest (X89, X166, X327, and X349; salt-tolerant) and the two lowest ranking accessions (X66 and X386; salt-sensitive) were selected. Principal component analysis (PCA) and hierarchical cluster analysis of the seedling morpho-physiological characteristics among the hull-less barley genotypes showed strong correlations among most characters, which could be used as selection criteria for identifying salt tolerance in the barley germplasm. Furthermore, the combination of IS rank and PCA can be used to identify salt-tolerant and salt-sensitive genotypes of the barley during the seedling stage. These salt-tolerant genotypes hold the potential for developing new barley cultivars with enhanced salt tolerance, and offer opportunities to advance our understanding of the genetic factors involved in barley’s ability to withstand salt stress.