Cover Story
Quantifying the Light Requirements
of Ultradwarf Putting Green Establishment By Benton Hodges, Graduate Research Assistant, and Christian Baldwin, Ph.D., Assistant Professor, Mississippi State University
B
ermudagrass is the most widely used warm-season grass on golf courses, including putting greens, in warm climatic regions of the world. Before bermudagrass putting green cultivars were available, many putting greens throughout the southern United States used only a sand putting surface. The first commercially available bermudagrass putting green cultivar, ‘Tifgreen’, was released in 1956. Tifgreen experienced natural mutations, and from those mutations, turfgrass breeders released ‘Tifdwarf’, an improved putting green cultivar. Through continued breeding efforts, “ultradwarf” cultivars were developed and released in the late 1990s. Since the development of ultradwarfs, many golf courses renovated or converted their putting greens to these new cultivars. Some golf courses have replaced their older bermuda10 • Mississippi Turfgrass • Winter 2015
grass cultivars in favor of ultradwarfs, and throughout the Southeast and transition zone, courses are also continuing to convert from creeping bentgrass to bermudagrass putting greens. Patrick O’Brien, director of the USGA Green’s Section Southeast Region, recently estimated that there are 70 to 80 conversions from creeping bentgrass to an ultradwarf each year in the Southeast. These ultradwarf bermudagrasses have allowed courses to maintain a high-quality putting surface, while improving playability during the peak summer season, compared to creeping bentgrass.
Research studies suggest that when bermudagrass is subjected to shade, the turfgrass plant has elongated stems and internodes, weak rhizomes and a decrease in density, canopy photosynthetic rates and root biomass. Putting greens are often surrounded by mature trees, significantly reducing the amount of sunlight available for the turfgrass plant. Although trees are valued by golf courses for their aesthetics and functionality, they can adversely affect putting greens’ health and performance. Greens committees, members, players and owners are often resistant to tree removal or thinning.
The shade factor
Prior research
A major challenge for bermudagrass putting greens, however, is turf performance and overall health under shade or reduced light environments.
Solar radiation has previously been measured in the hours of sunlight a plant receives each day. Light intensity is not constant throughout the day,