OPPORTUNITIES FOR DEVELOPING SALT-TOLERANT WHEAT AND BARLEY VARIETIES

Salinity is a major constraint limiting crop yields around the world. While considerable research to understand and enhance the salinity tolerance of plants has occurred, few commercially available salt-tolerant bread wheat (Triticum aestivum), durum wheat (Triticum durum), or barley (Hordeum vulgare) varieties have been developed for farmers. This lack of salt-tolerant varieties is despite all publications highlighting issues around global food security, the need to increase crop production to feed an increasing human population, the effects of more variable climate and farmland being degraded by abiotic stresses. We explore the progress to date in using forward and reverse genetic approaches to identify loci and candidate genes linked to plant salinity-tolerance sub-traits, and why, despite substantial research in understanding salt tolerance mechanisms, very few genes or loci have been introduced into commercially available varieties. We propose the need for a greater focus on validating glasshouse-based findings of salt tolerance in saline fields, the fine mapping of quantitative trait loci linked to salt-tolerance sub-traits to underlying genes, and the use of marker-assisted selection and speed breeding to pyramid beneficial salinity-tolerance sub-traits to develop high-yielding bread wheat, durum wheat, and barley varieties.