Development of Improved Turf-Type Bermudagrasses

Abstract

Study I: Patriot and OKC 70-18 hybrid bermudagrasses (C. dactylon L. Pers. X C. transvaalensis Burtt-Davy) were evaluated for sod tensile strength (STS) and sod handling quality (SHQ). Tifway (Tifton 419),and Midlawn (A-22) were included as standards of comparison. The STS was measured as peak force (kg dm-2) to tear apart sod pads that were 30.5 cm wide by 1.5-1.6 cm thick. The SHQ was rated on a 1 to 5 scale where 5 was excellent. Five sod harvests were conducted over 4 years. Study II: Thirty-two final stage bermudagrass (Cynodon species) selections were evaluated from 2004 to 2007 for visual performance (VP) features, STS and SHQ under golf course fairway (1.3 cm mowing height) conditions, Tifway, Patriot, TifSport and Riviera were included as standards of comparison. The VP ratings included spring green-up, shoot density, leaf texture, genetic color, seedhead expression, scalp damage, fall color retention and turf quality which were rated on a 1 to 9 scale where 9 was ideal. Percent living cover was evaluated on a 0 to 100 scale. Study I: The SHQ strongly correlated with STS (r=0.89, p=0.001, N=20) for the five sod harvests comparing Tifway, Patriot, OKC 70-18, and Midlawn. Patriot provided STS greater than or equal to Tifway in 4 of 5 harvests. OKC 70-18 provided lower STS than Tifway in all 5 harvests. OKC 70-18 provided STS equal to Midlawn in 3 harvests and less than Midlawn in 2 harvests. Results agreed well with sod producer comments in that Patriot and Tifway have good sod handling characteristics while Midlawn has minimally acceptable to poor sod handling characteristics. Alternative methods of production and harvest should be explored for Midlawn and OKC 70-18. Tifway and Midlawn may serve as useful standards for future sod research. Study II: Substantial variation in visual performance traits were found amongst the entries evaluated. Experimental entries 21 and 29 generally performed equal to or better than Tifway for STS, SHQ and most visual characteristics. The STS and SHQ were well correlated (r=0.73, p=0.001, N=72) for the sod harvests with the 36 selections. Promising selections 21 and 29 have been sponsored for testing in the 2007-2011 National Turfgrass Evaluation Program (NTEP) bermudagrass trial as OKC 1119 and OKC 1134 respectively.