Determination of shade tolerance in candidate Zoysia grass varieties

Zoysiagrasses (Zoysia spp.) are warm-season grasses commonly used in lawns, parks, golf courses, and other sports fields in tropical, subtropical, and transitional climate zones. Shade tolerance is one of the most important characteristics desired in turfgrass species and cultivars used in green spaces. For this reason, there is a need for zoysiagrass cultivars with improved shade tolerance. The aim of this study is to determine the shade tolerance of 27 local hybrid Zoysia cultivars along with 6 commercially available zoysiagrass cultivars. The research was conducted at Akdeniz University, Faculty of Agriculture, Grass Research and Application Field, using a randomized block design with split plots and three replications. To create shade stress, a shading material (net-file) with 70% reduced light transmission was used. During the course of the study, data on bi- weekly turfgrass quality, chlorophyll and NDVI values, as well as shoot density and root tear resistance, were collected. It was found that shade stress reduced overall turf quality, shoot density, and root resistance, although this varied depending on the variety. It was determined that chlorophyll values decreased by up to 48% in some cultivars and increased by up to 97% in others under shade stress. The shoot density and root tear resistance decreased by an average of 42% and 14%, respectively, under shade stress. It was determined that shade stress reduced overall turf quality by 75%-9% in commercial cultivars and by 69%-9% in hybrid cultivars, except for MJ46 and MJ73. As a result of the study, 10 local zoysia hybrids (MJ46, MJ100, MJ13, MJ30, MJ73, MJ79, MJ92, MJ59, MJ67, and MJ26) with shade performance equivalent to or better than commercial controls were identified. It is predicted that these selected candidates will offer good potential for use in shaded areas, with acceptable turf quality and, shoot density and root resistance close to their controls under shade stress, and that they may be eligible for registration.