Quantifying a Daily Light Integral for Bermudagrass Putting Green Establishment.

A major constraint for successful ultradwarf bermudagrass (Cynodon dactylon (L.) Pers. x C. transvaalensis) putting green establishment is a reduced light environment (RLE) due to the overall poor shade tolerance of bermudagrass.  Currently, no research studies exist determining the light requirement for bermudagrass putting green establishment. Therefore, the objective of this research was to determine a daily light integral (DLI) requirement for successful bermudagrass putting green establishment. A field trial was initiated in June 2013 and will be repeated in 2014 at the Foil Plant Science Research Center in Starkville, MS. Four bermudagrass cultivars ('Champion', 'TifEagle', 'MiniVerde' and 'MSB-285') were established under full-sunlight (control), 30%, 55%, and 80% full-day shade using a neutral density, polyfiber black shade cloth. Data collection included percent cover using digital image analysis, clipping yield, plant height, turfgrass color, shoot chlorophyll concentration, and daily light integrals were generated using quantum light meters and data loggers. In order to determine the daily light integral needed to reach 70% cover, data was analyzed using nonlinear regression analysis with the NLIN procedure of SAS to obtain dose-response curve (Seefeldt et al., 1995). In 2013, MiniVerde required 26.9 moles of light per day (mols d^-1), while Champion, TifEagle, and MSB-285 needed 29.9, 30.1, and 31.3 mols d^-1, respectively.