Evaluation of Zoysiagrass Genotypes for Shade Tolerance

Abstract

Establishing turfgrass in shaded environments can create a unique maintenance challenge. Shading reduces zoysiagrass (Zoysia spp.) photosynthesis and results in reduced turfgrass aesthetic quality. Zoysiagrass is a warm-season, perennial turfgrass that forms a dense, uniform turf through the production of rhizomes and stolons. It has demonstrated good tolerance to growth in reduced light intensity environments. Greenhouse experiments were conducted in 2006 and 2007 to evaluate the relative difference in growth response to three light intensities (0%, 50%, and 90% shade) among six zoysiagrass genotypes under artificial shade conditions. Percent change in zoysiagrass plug diameter decreased as shade level increased 6 and 12 weeks after planting (WAP) regardless of year or genotype. ‘Diamond’ and ‘Shadow Turf’ exhibited the greatest percent change in plug diameter 12 WAP (60% to 69%) followed by the remaining zoysiagrass genotypes (21% to 56%) when grown under 50% shade, regardless of year. In 2006, no zoysiagrass genotype maintained acceptable turfgrass quality (6 or greater) 12 WAP when grown under 50% shade. However, ‘Diamond’ and ‘Shadow Turf’ exhibited acceptable turfgrass quality ratings (7.0 and 6.3) 12 WAP in 2007, whereas all other genotypes exhibited unacceptable turfgrass quality ratings (5.0 to 5.7). In 2006, ‘Shadow Turf’ zoysiagrass exhibited the greatest percent increase in plug diameter (21%) followed by ‘DALZ 0501’ (15%) and ‘Diamond’ (5%) 12 WAP when grown under 90% shade. All other zoysiagrass genotypes exhibited decreases in plug diameter (31% to 87%). In 2007, ‘Shadow Turf’ and ‘Diamond’ exhibited the greatest percent change in plug diameter (11%) followed by ‘DALZ 0501’ (7%) 12 WAP when grown under 90% shade. All other zoysiagrass genotypes exhibited decreases in plug diameter (17% to 38%). Turfgrass quality declined as shade level increased 6 and 12 WAP regardless of year or genotype. ‘Shadow Turf’ and ‘Diamond’ exhibited the highest turfgrass quality ratings (4.7 and 3.7, respectively, in 2006 and 5.3 in 2007) 12 WAP when grown under 90% shade. Proper zoysiagrass cultivar selection may improve turfgrass growth and quality under low light intensity while increasing turfgrass options for shaded environments.