Genetic diversity in the Batini barley landrace from Oman: II. Response to salinity stress

Understanding the diversity for salt tolerance in barley (Hordeum vulgare L.) landraces will facilitate their use in genetic improvement. Our objectives were to screen a collection of 2308 accessions in seven subpopulations of the Omani Batini barley landrace under salinity stress, quantify genetic variation in germination and early seedling growth attributes, establish the forage yield-salinity response functions for 10 families within each subpopulation, and select genotypes with high yield potential under salinity. Subpopulations displayed high levels of genetic diversity and differed significantly for seed germination and seedling growth attributes at 0.0 and 20.0 dS m^-1, and at tillering stage for forage yield at 0.85, 10.0, and 20.0 dS m ^-1. A multivariate-based selection criterion for high forage yield at tillering stage under salinity stress, based on simultaneous selection for low temporal variation in germination and high shoot dry weight under 20.0 dS m ^-1, identified highly salt tolerant accessions. Twenty-five out of 70 families representing seven subpopulations were classified as salt tolerant on the basis of their salinity susceptibility indices at 20.0 dS m^-1. Accessions with short rachilla or with high root number and root length under salinity stress ranked highest in salt tolerance. Forage yield at 10.0 and 20.0 dS m^-1 can be predicted with high (R² = 0.67, P < 0.0001) and moderate (R² = 0.23, P < 0.01) accuracy by forage yield under 0.85 dS m^-1. On average, forage yield was reduced by 2.4 and 7.9% per dS m^-1 at 10.0 and 20.0 dS m^-1, respectively. Although genetically not improved, the landrace, in general, and subpopulation Batini 4, in particular, contain diversity that remains to be exploited.