Defining stem diameter categories for forage‐type bermudagrass

Abstract Bermudagrass ( Cynodon spp.) is an important forage in the southeastern United States. Bermudagrass is incredibly diverse and includes numerous important cultivars for forage use. Most published research compares forage accumulation, nutritive value, or establishment among bermudagrass cultivars. There is a need to document bermudagrass stem diameters and to define classifications or groupings. The objectives of this study were (a) to compare the stem diameters of popular Cynodon cultivars currently grown in the southeastern United States, and (b) to assign these cultivars to defined‐diameter categories. Three categories were defined based on the general stem size of popular hybrid bermudagrass cultivars and experimental genotypes. (1) Fine‐stemmed cultivars have stem diameters <0.04 in. They have rapid drying times and establishment rates but exhibit poor tolerance to the bermudagrass stem maggot (BSM; Atherigona reversura Villeneuve) and tend to have lower nutritive value and production. (2) Intermediate‐stemmed cultivars have stem diameters between 0.04 and 0.06 in. Many experimental genotypes fall into this category and show potential for optimizing drying time, establishment, and production capabilities. (3) Coarse‐stemmed cultivars have stem diameters >0.06 in. These cultivars demonstrate documented improvements in production and BSM tolerance, but slow drying times and establishment hinder their adoption. Defining these categories will aid bermudagrass breeders and researchers to more easily classify forage‐type bermudagrass germplasm in future evaluations.