Screening of diverse tall fescue population for salinity tolerance based on SSR marker-physiological trait association

Abstract

Soil salinity is a notorious abiotic stress which constrains plant growth and limits crop productivity. Recent advances in phytogenetics especially the discovery of marker-trait association have facilitated the efficient selection of stress-tolerant crops. The objective of this study was to evaluate tall fescue (Festuca arundinacea Schreb.) accessions growing under salt stress in order to identify salt-tolerant and salt-sensitive genotypes using physiological and molecular markers. The population consisted of 114 diverse tall fescue accessions which were assessed using 99 simple sequence repeat (SSR) markers and five functional physiological traits i.e., turf quality, leaf water content, chlorophyll content, relative growth rate, and evapotranspiration rate. Salinity stress induced great variations among the functional physiological traits and there were significant correlations among them. The population structure analysis revealed two distinct populations, while association mapping between the SSRs and phenotypic traits identified significant associations. In addition, the accessions that maintained relatively higher physiological traits had a significantly lower accumulation of Na+ and Cl− in the roots compared to those whose functional traits declined. We identified six most salt-tolerant accessions due to their high values of physiological parameters and significantly low accumulation of Na+ and Cl− in the roots. Similarly, we identified six accessions we considered to be most salt-sensitive as observed by high Na+ and Cl− accumulation plus a decline in the physiological activities. Our findings are helpful to tall fescue breeders with a goal of producing tall fescue cultivars with enhanced salt tolerance.