Bermudagrass Characteristics Affected by Shade.

Bermudagrass (Cynodon spp.) is the most commonly recommended warm season grass in the transition zone and the southern United States due to its excellent drought, heat, and salt tolerance and resistant to many pests. Bermudagrass, however, has shown poor shade tolerance. Bermudagrass has a high light compensation point and rarely performs well in shade. Shade causes distinctive physiological and morphological changes in turfgrass plants such as thinner and longer leaves, lower root to shoot ratio, reduced tillering, upright growth habit, and less density (Danneberger, 1993). A bermudagrass collection has been amassed to screen bermudagrass selections for their effectiveness in shaded environments at Oklahoma State University. Forty five bermudagrasses and four standards; TifGrand, Tifton10, Celebration, and Patriot were evaluated to determine turfgrass characteristics that may be useful for rapid screening of future selections for potential shade tolerance. Photosynthesis was measured in the five best performing selections, five worst selections and four standards in spring, summer, and fall 2010 and 2011 with a LI-6400 photosynthesis analyzer (LiCor, Lincoln, NE). Internode length and density were measured monthly in 2010 and 2011. Photosynthesis data did not suggest a relationship between the rate of photosynthesis in shade or in sun with bermudagrass performance. Bermudagrass density in full sun was not consistently related with its density in shade. Longer internode in shade was a consistent occurrence in the best performing selections but was not a consistent occurrence in the poorest performing selections. Internode length may have some promise for rapid selection of shade tolerant varieties.