Variation of Salinity Tolerance in Zoysia Clones Collected from Different Habitats in Taiwan

Abstract

One hundred and fifteen clones of Zoysia spp. collected around the coast of Taiwan were examined for the variation of salinity tolerance. Zoysia spp., native of Taiwan, showed a wide range of salinity tolerance among the clones collected from various regions. The clones from the regions with higher annual rainfall and limestone showed lower NaCl tolerance, and some of them showed 100% shoot mortality under 3% NaCl within 3 weeks. On the contrary, some clones from the regions with lower rainfall retained a few green leaves even at 7.5% NaCl for 3 weeks. A positive correlation was observed between the percentages of 100% shoot mortality in clones treated with 6% NaCl and the rainfall of the regions where the clones were collected. However, based on the same level of rainfall, the clones collected from the limestone region showed higher percentages of shoot mortality than those collected from the other regions. Using four clones including NaCl-tolerant and NaCl-sensitive, the effect of Ca on the salinity stress was further examined. Addition of CaCl₂ to the nutrient solution could alleviate the leaf firing and electrolyte leakage from the leaf of Zoysia clones caused by NaCl. The geographical variation of salinity tolerance in Zoysia might be caused by the differences in the salt and calcium concentrations in soil, which were affected by rainfall and geology of their habitats.