Genetic Diversity of Greens-type Bermudagrass Genotypes as Assessed with SSR Markers

Fine-textured, ultradwarf interspecific triploid (2n = 3x = 27) bermudagrass cultivars [Cynodon transvaalensis (2n = 2x = 18) × C. dactylon var. dactylon (2n = 4x = 36)] have been the turfgrass industry standards for golf putting greens in the southeast, southwest, and transition regions of the United States. Winterkill is one of the major challenges when ultradwarf bermudagrasses are used in the transition zone. Narrow genetic diversity among the ultradwarf bermudagrass cultivars is considered a likely and important reason for their susceptibility to prevalent diseases. This research was conducted to characterize genetic diversity among greens-type experimental bermudagrass genotypes as compared with ultradwarf cultivars assessed with simple sequence repeat (SSR) markers. Fifteen elite Oklahoma State University (OSU) experimental bermudagrass genotypes and four commercial standards (Champion Dwarf, Mini Verde, TifEagle, and Tifdwarf) were genotyped with 45 SSR markers selected from a recently developed bermudagrass genetic linkage map in our laboratory. In the cluster analysis, the four commercial cultivars formed one group with a genetic similarity coefficient of 1.00, whereas the similarity coefficients among the experimental selections ranged from 0.64 to 0.93. The percentage of polymorphic bands was increased by 98.31%, and the Nei’s genetic diversity increased from 0 to 0.3329. These results indicated that the OSU experimental genotypes increased genetic diversity over the commercial bermudagrass standards as expected and that they could be released as new greens-type turf bermudagrass cultivars if they can withstand field testing.