Evaluation of Genetic Variation Among Native Pawpaw Patches in Henry County, Kentucky

Pawpaw [Asimina triloba (L.) Dunal] is a tree-fruit that is a native understory tree in Kentucky and the eastern region of the United States. How pawpaw patches have spread in this region is poorly understood. Native Americans may have spread seed to promote fruit production. Animals may consume fruit and spread seed in scat. Viable pawpaw seeds are buoyant and can float down streams to form new patches. Clonal patches can develop through root suckering. The objective of this study was to determine if DNA fingerprinting of patches at the KSU Environmental Education Center in Henry County, Kentucky near a stream would suggest if root suckering (clonal patches) or water transport of seeds (many genotypes) were mechanisms of patch establishment. DNA was extracted using the DNAMITE Plant Kit from leaf samples collected from 20 trees per patch on a transect line in three native patches at the EEC. Patch 1 was located on a hill, while patches 2 (downstream) and 3 (upstream) were located on a stream about 100 feet apart. Primers B3, B103, B129, C104, and G119 were used to amplify SSR products, and products were separated with a 3130 Applied Biosystems capillary electrophoresis system. All three patches were genetically distinct, with patches 2 and 3 being more similar. Patch 3 was clonal with only one genotype. The high genetic variation in patch 2 supports involvement of water transport of seed from patch 3 in the establishment of the patch; however, animal transport of seed could also have led to patch establishment