Salt tolerance of seven genotypes of zoysiagrass (<i>Zoysia</i> spp.)

Abstract

Seven zoysiagrass genotypes were evaluated for salt tolerance in a greenhouse study. The plant materials included <italic>Zoysia matrella</italic> 'Diamond', <italic>Z. japonica</italic> 'Palisades', three <italic>Z</italic>. <italic>matrella</italic> × <italic>Z. japonica</italic> hybrids DALZ 1701, DALZ 1713, and 'Innovation', and two <italic>Z.</italic> <italic>minima</italic> × <italic>Z. matrella</italic> hybrids (DALZ 1309 and 'Lazer'). Treatments included a control (nutrient solution) and two saline treatments representing moderate and high salt levels. The electrical conductivity (EC) was 1.3 dS m⁻¹ for control and moderate (EC5) and high salinity (EC10) were 5.0 and 10.0 dS m⁻¹, respectively. At the end of eight-week treatments, the relative (percent control) shoot dry weight (DW) was greatest in 'Diamond' in EC10, and the relative root DW was greatest in DALZ 1309 in EC5. A cluster analysis based on the relative tissue dry weight identified 'Diamond', DALZ 1309, and DALZ 1713 as the most salt tolerant genotypes. Additionally, the green leaf area (GLA) index of 'Diamond' and DALZ 1713 were 98.8% and 100%, respectively, indicating excellent visual appearance under high salt levels. Bi-weekly clipping DW showed that ‘Diamond’ continued to produce biomass throughout the duration of the study under the EC10 treatment. Sodium (Na⁺) and chloride (Cl⁻) content in the shoot tissue of the seven turfgrass genotypes indicated that lower concentrations corresponded to greater salt tolerance indicating exclusion of Na⁺ and Cl⁻ from the shoot tissue. Taken together, the genotypes 'Diamond' and DALZ 1713 were determined to be the most salt tolerant and recommended for use in areas with high soil or water salinity.