Effects of Trinexapac-ethyl and Winter Overseeding on the Morphological Characteristics and Traffic Tolerance of Bermudagrass Cultivars

Common bermudagrass [Cynodon dactylon (L.) Pers.] and hybrid bermudagrass [C. dactylon (L.) Pers. X C. transvaalensis Burtt-Davy] are some of the most common turfgrasses used on athletic fields. Subsequently, the traffic tolerance of commercially available cultivars and the effects of trinexapac-ethyl (TE) on bermudagrass athletic fields with or without perennial ryegrass are often limited. A two year study at the University of Tennessee was conducted under simulated athletic field traffic to evaluate the performance of bermudagrass cultivars as affected by TE and overseeding. Bermudagrass cultivars evaluated were Tifway, Riviera, Patriot, and Celebration. TE treatments consisted of an untreated control, TE at 76.3 g a.i. ha^-1 every 14 days until 14 days prior to trafficking (TE A), and TE at 76.3 g a.i. ha^-1 every 14 days until 14 days after trafficking (TE B). Overseeding treatments consisted of no overseeding and overseeding at 670 kg ha^-1 of perennial ryegrass (Lolium perenne L.). Plots were rated for percent green cover using digital image analysis after every 5 traffic events. Soil physical characteristic measurements were performed after every traffic season. Morphological data was determined by measuring number of leaves, internode lengths, leaf angle, and leaf width of the bermudagrass. Cultivar was significant for percent green cover for both years of this study with Tifway and Celebration having the highest ratings and Patriot having the lowest rating. TE was also significant for percent green cover for the first 10 traffic events with TE treatment B having lower percent cover values. Morphological characteristic was significant for leaf angle for both years of the study. A more vertical leaf angle to the shoot occurred in the more traffic resistant cultivars Tifway and Celebration. Finally, both TE treatments yielded higher percent green cover values in 2008 when morphological characteristic data was collected and a more vertical leaf angle to the shoot occurred compared to the untreated control. Tifway, Celebration, and Riviera when applied with trinexapac-ethyl before the traffic season and overseeded with perennial ryegrass would be beneficial for athletic field managers.