Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 8, 1997
Publication Date: N/A
Interpretive Summary: Water spinach is currently listed in the U. S. Federal Noxious Weed Act and is also listed on the Florida Invasive Species List as a Class I category weed. The plant is cultivated in Florida, Texas, and California, however, because of availability of domestic and international markets for the vegetable crop. A pertinent question related to the regulation of the species has been whether the upland agricultural cultivar would become invasive in aquatic habitats. We determined that the cultivated form in Florida was closely related genetically to the aggressive wild forms, and all forms are Ipomoea aquatica. DNA fingerprints were developed for identification of these water spinach genotypes in Florida.
Technical Abstract: The genetic relationship between three genotypes of water spinach (Ipomoea aquatica Forks.), including one upland agricultural cultivar and two floating wild forms collected from Hillsborough County, Florida, were evaluated using Random Amplified Polymorphic DNA (RAPD) markers. Forty- eight decamer primers were screened; eighteen of these were informative and yielded 188 bands, of which 58 (31 percent) were polymorphic. Five primers produced unique DNA fingerprints useful for identification of the genotypes. Analysis of the banding patterns grouped the three genotypes within unique clusters. Furthermore, the cultivated genotype clustered somewhat closer to the White than to the Red wild type, as might be expected from phenotypic characteristics. A comparison with other RAPD studies within different taxonomic groupings indicates that the 31 percent polymorphism obtained for water spinach is at the lower end of the species range, and upper end of the subordinate classification category. Furthermore, the percentage of polymorphic bands within each genotype ranged from 2 to 11 percent, indicating that they differ at level usually described in literature as cultivars, varieties, strains, races, lines, or populations within a given species.