Development of ‘Halla Green 7’: A Zoysiagrass Cultivar with Greening Period Extending Phenotype at Lower Temperatures

The ‘Halla Green 7’ cultivar is a hybrid of Zoysia matrella and Zoysia japonica . The inflorescences of Z. matrella lines were collected from Jeju Island near the border between Z . matrella and Z. japonica wild plants, respectively. After their harvest, the seeds were sown and various interspecific lines were obtained. In 2021, a line with greening period extending phenotype during the low temperatures of winter was registered under the cultivar name of ‘Halla Green 7’ (Registration No. 245). The main morphological characteristics of the ‘Halla Green 7’ variety are as follows: genetically short length of plant (12.2±0.58 cm), very wide angle of leaf (68.6°), short length of leaf blade (8.38±0.37 cm), medium-leaf (3.29±0.09 mm), and very low leaf sheath (2.18±0.19 cm). The short length of leaf sheath makes it easy to manage the turf grass with low height. A very wide leaf angle has a high photosynthetic efficiency. The ‘Halla Green 7’ cultivar is morphologically classified as Z. matrella × Z. japonica hybrid line by medium-width of leaf blade and the presence of trichomes on the leaf surface. The colors of the leaf blade, leaf sheath, and stolon are green, light green, and light purple, respectively. During the low temperature period of winter, chlorophyll content of the leaves of ‘Halla Green 7’ shows a 10.1-fold from that of the control Z. japonia ‘Yaji’ and about 4.2-fold from that of the control Z. matrella Zm-6. This greening period extending phenotype is expected to contribute to the industrialization of zoysiagrass (Registration No. 245).