Drought Tolerance and Leaf Firing Resistance of Twenty Turf Bermudagrasses.

Bermudagrasses (Cynodon spps) are the most widely utilized turfgrass in the southern U.S. Knowledge of the relative drought tolerance of bermudagrass cultivars is crucial so that turfgrass managers can make informed cultivar selection and use decisions. The objectives of this research were to determine the leaf firing resistance and drought tolerance of twenty bermudagrasses. The cultivars evaluated were ‘Contessa’, ‘NuMex Sahara’, ‘Princess 77’, ‘TifGrand’, ‘Tifway’, ‘Tiftsport’, ‘Riviera’, ‘Yukon’, ‘Premier’, ‘Quickstand’, ‘Patriot’, ‘OKC 70-18’, ‘Celebration’, ‘U-3’ (Southern IL Univ source), ‘U-3’ (Northcutt Sod Farm source), ‘U-3’ Tulsa Grass & Sod Farm source), ‘Astro’, ‘OKC 1119’, ‘OKC 1134’, and ‘OKS 2004-2.’ A greenhouse was used to eliminate interference from natural rainfall. Turf was grown in pots measuring 7.6 cm (dia) by 76.2 cm deep filled with calcined clay. Grasses were grown to maturity under non-limiting soil moisture and mowed as needed at 3.8 cm. At maturity, irrigation was withheld leading to severe soil moisture deficit stress. After approximately 95 d without irrigation, watering was resumed and recovery was assessed for 60 to 90d. Drought tolerance was assessed via measures of turfgrass quality, percent living cover, and leaf firing. Soil water content was also measured. The experiment was conducted three times, each as a completely randomized design with five replications of each cultivar. A SAS non-linear model procedure (Proc NLIN) was used for curve fitting. The fitted equations were then solved for the average number of days required to reach the midpoint of the scale for each parameter for both the dry down and the recovery cycle. Differences in drought tolerance as measured by each parameter were present amongst the cultivars. Clones with presumed improved drought tolerance were selected from seeded lines. Drought tolerance rankings from this work in conjunction with previously measure performance traits may aid turfgrass managers in making informed cultivar selection decisions.