Quantifying Freeze Tolerance of Hybrid Bermudagrasses Adapted for Golf Course Putting Greens

Abstract

The susceptibility of warm-season turfgrasses such as bermudagrass (Cynodon spp.) to winter injury in the transition zone is a major concern. Therefore, the objective of the study was to evaluate five golf course putting green-type experimental genotypes (OKC6318, OKC0805, OKC1609, OKC0920, and OKC3920) and three commercially available bermudagrasses (‘Champion Dwarf’, ‘TifEagle’, and ‘Tahoma 31’) for freeze tolerance by subjecting them to 11 freezing temperatures (–4 to –14 °C) under controlled environment conditions. The experiment was conducted in batches, with four genotypes per batch, and each batch was replicated in time. The mean lethal temperature to kill 50% of the population (LT50) for each genotype was determined. There were significant differences in LT50 values among the bermudagrass genotypes. ‘Champion Dwarf’ had an LT50 value ranging from –5.2 to –5.9 °C across all three batches. The experimental genotypes tested in this study had LT50 values ranging from –7.0 to –8.1 °C and were each lower than that of ‘Champion Dwarf’. ‘Tahoma 31’, the top performing genotype, had an LT50 value ranging from –7.8 to –9.0 °C across all three batches. OKC 3920 was the only experimental genotype with an LT50 value in the same statistical group as ‘Tahoma 31’. The information gained from this research would be useful for breeders to gauge the genetic gain in freeze tolerance in breeding golf course putting green-type bermudagrass.

Keywords

• artificial freezing
• controlled environment
• cynodon dactylon
• cynodon transvaalensis
• lethal temperature
• winter