Moving warm-season forage bermudagrass (Cynodon Sp.) into temperate regions of North America

Authors: BAXTER, L - University Of Georgia; Anderson, William - Bill; GATES, R - University Of Georgia; RIOS, E - University Of Florida; Hancock, Dennis

Submitted to: Grass and Forage Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2022
Publication Date: 7/7/2022
Citation: Baxter, L.L., Anderson, W.F., Gates, R.N., Rios, E.F., Hancock, D.W. 2022. Moving warm-season forage bermudagrass (Cynodon Sp.) into temperate regions of North America. Grass and Forage Science. 77:141-150. https://doi.org/10.1111/gfs.12568.
DOI: https://doi.org/10.1111/gfs.12568

Interpretive Summary: Grass forage systems in the United States are generally divided into temperate regions that support cool-season grasses and warm-season grasses. Cool-season grasses are less productive in warmer climates due to their tendency to produce reproductive growth with warm temperatures, while warm-season grasses generally cannot survive winter freezes as they are moved north. There is a transition zone between these regions in the United States where a mixture of cool-season and warm-season grasses can survive. Livestock producers and hay producers would prefer to grow warm-season grasses since the C4 photosynthetic system is more efficient in producing biomass, if these perennial warm-season grasses can survive long-term freezing temperatures. This manuscript documents the transition of grass forage production systems in Georgia, explores the climate changes driving this transition, and highlights previous and on-going research. The predominant perennial warm-season grass in southern US is bermudagrass. Research has been performed to evaluate freeze or cold tolerance of the two predominant species of bermudagrass. Cynodon dactylon cultivars exhibit more cold tolerance than Cynodon nlemfuënsis (stargrass) since they are more rhizomatous and rely less on above-ground stolons for regrowth and winter survival. However, C. dactylon cultivars tend to have poor nutritive value and are susceptible to insect damage. Development of highly productive and high quality cold-tolerant bermudagrass genotypes would benefit growers in the transition zone and as climate changes expand areas of adaptation.

Technical Abstract: Georgia, located in the Southeastern USA, has been historically dominated by two perennial grass forage production systems. Tall fescue (Lolium arundinaceum) is more prevalent in the northern parts of the state, while bermudagrass (Cynodon dactylon) is ubiquitous to the southern portion. Climatologists have documented notable changes in temperature and precipitation patterns in the state that have contributed to an invasion of warm season species in the northern portion of the state. In the transition zones, between warm season and cool season perennial grass dominated regions of North America, C4 grasses can maintain productivity at high temperatures while C3 grasses are transitioning to a reproductive stage with minimal vegetative growth. For this reason, warm season grasses could replace a portion of the grasslands at latitudes greater than 35°. This manuscript documents the transition of grass forage production systems in Georgia, explore the climate changes driving this transition, and highlight previous and on-going research. We specifically focus on evaluating freeze or cold tolerance of bermudagrass germplasm. The C. dactylon cultivars exhibit more cold tolerance than C. nlemfuënsis (stargrass) since they are more rhizomatous and rely less on above-ground stolons for regrowth and winter survival. Conversely, these cultivars tend to have poor nutritive value and are highly susceptible to insect damage. On-going research is identifying germplasm that can provide adequate cold tolerance to meet the needs of farmers transitioning to warm-season production systems in the lower transition zone.