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

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

Submitted to: Grassland International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/15/2021
Publication Date: 10/25/2021
Citation: Anderson, W.F., Baxter, L., Hancock, D.W., Gates, R.N., Rios, E.F. 2021. Moving warm-season forage bermudagrass (Cynodon sp.) into temperate regions of North America. Grassland International Congress Proceedings. pp. 1-4. https://uknowledge.uky.edu/igc/24/2/8.

Interpretive Summary: Warm-season perennial grasses have an advantage over cool-season grasses due to a different photosynthetic pathway. However, many of the warm-season species are not cold tolerant and cannot survive in colder climates. Thus, it is desirable to genetically incorporate cold tolerance into warm-season species. Bermudagrass (Cynodon sp.) is one of the most productive perennial warm-season grasses. Some of the common bermudagrasses (Cynodon dactylon (L.) Pers.) can grow beyond the 30°N and 30°S latitudes, but they do not have yields as high as other species such as (Cynodon nlemfuënsis Vanderyst). Breeding efforts have occurred to break that barrier, but further improvements are needed. Cold tolerance screening has been done in cold chambers at Oklahoma State University and in the field by USDA/ARS in a northern high-elevation location in Georgia, United States. Some plant accessions were better than the current cold tolerance cultivar ‘Tifton 44’. A breeding line (Tifton 79-16) had significantly higher yields at the northern Georgia location than Tifton 44.

Technical Abstract: Warm-season (C4) perennial grasses are grown over millions of hectares in the Southeastern United States. These grasses produce optimal growth at 30 to 38°C diurnal temperature. Bermudagrass (Cynodon sp.) has been adopted as the preferred forage for many livestock and hay producers. Compared to other native and introduced warm-season perennial grass species, improved bermudagrass varieties produce high biomass with enhanced digestibility for ruminant grazing or feed. Until the 1930’s pastures in the region consisted of unimproved ‘common’ bermudagrass (Cynodon dactylon (L.) Pers.) that had been introduced earlier. However, in the early 20th century, new germplasm, including stargrass (Cynodon nlemfuënsis Vanderyst) was collected, primarily from Africa. This germplasm provided a source for major improvements in yield and digestibility. Unfortunately, stargrass is not cold tolerant, limiting it to regions between 30°N and 30°S. Intercrossing of C. nlemfuënsis with C. dactylon has produced highly successful cultivars, such as Tifton 85, which can survive at northern latitudes of at least 35°. However, there has been a desire to extend adaptation further north into the warm-season/cool-season grass transition zone. This would require a combination of breeding to improve cold tolerance in clonally propagated varieties and development of seeded varieties that could be re-seeded following extremely cold winters. Earlier work at Oklahoma State University indicated that some cultivars had significantly different tolerance to freeze. Screening the Tifton, GA, USA core collection of 175 accessions in a northern, high-altitude location, has identified germplasm with promising cold tolerance. A breeding line (Tifton 79-16) had significantly higher yields at the northern Georgia location than the cold tolerant cultivar (Tifton 44). A number of plant introductions had numerically higher yields as well.