Use of Molecular Markers for Identity Preservation In St. Augustinegrass: Elucidating the Authenticity of ‘Raleigh' Samples From Sod Farms Across the Southeastern United States.

St. Augustinegrass (Stenotaphrum secundatum (Walt.) O. Kuntze) is a popular turfgrass in the southeastern United States due its superior shade tolerance and relatively low input requirements. However, among warm-season grasses, it is the most susceptible to severe freezing injury. In the early 1980’s, North Carolina State University released cultivar ‘Raleigh’ for its superior cold tolerance. Given that more than 25 years after its release, Raleigh is still the industry’s standard for cold tolerance, it is important to investigate whether or not St. Augustinegrass produced and sold as Raleigh across the Southeastern U.S. is true to putative ‘Raleigh’ selected in the late 1980s. The objective of this study was to use AFLP markers to assess genetic variability among five samples of original Raleigh and 46 samples of Raleigh obtained from sod farms in six different states. Foundation class and commercial samples of ‘Palmetto’ were included in the study as reference standards to gauge genetic diversity. To differentiate between Raleigh samples, fifteen AFLP primer combinations generated one hundred and twenty-three polymorphic loci, sixty-four percent of which could be attributed exclusively to seven samples. AFLP based genetic similarities among Raleigh samples in comparison with putative Raleigh ranged from 0.95 to 0.99. Phenetic analyses based on both unweighted pair-group cluster analysis and principal coordinate analysis revealed separation between putative Raleigh and the majority of the commercial samples into four different clusters. AMOVA results indicated that 87.78% and 12.22% of the total AFLP variation could be explained by differences among and within UPGMA clusters, respectively. Molecular markers analysis of vegetatively propagated cultivars is a useful tool to aid in identity preservation and identification of off-types.