Evaluating the freeze tolerance of bermudagrass genotypes

Abstract

Bermudagrasses (Cynodon spp.) are commonly used in golf courses, athletic fields, and home lawns in the transitional climatic region of the United States. Winterkill, however, is a major concern for bermudagrasses grown in this region. Controlled environment testing is a reliable method to evaluate freeze tolerance contributing to the selection of freeze tolerant genotypes. Therefore, this study was designed to test the freeze tolerance of two elite experimental genotypes, OKC1873 and OKC1406, along with two industry standards ('Tifway' and 'Tahoma 31'), by exposing them to various freeze temperatures (−4 to −14°C) in a controlled environment. The freezing test was replicated in time, and the mean lethal temperature to kill 50% of the population (LT 50 ) for each genotype was determined. Tifway (freeze-sensitive standard) had an LT 50 value of −7.0°C. The genotype OKC1873 (−7.2°C), was in the same statistical group as Tifway. Tahoma 31 was the best-performing genotype with the lowest LT 50 value of −9.1°C. The genotype OKC1406 (−8.8°C) was in the same statistical group as Tahoma 31. Top-performing experimental genotypes will move on for further screening in replicated field trials for future consideration for commercial release based on qualities such as improved freeze tolerance, desirable turfgrass quality, and sufficient disease resistance.