Kentucky State University
Using DNA Markers to Evaluate Genetic Diversity Among Native Pawpaw Patches in Iowa and Kentucky
Institution
Kentucky State University
Faculty Advisor/ Mentor
Li Lu; Kirk Pomper; Jeremiah Lowe; Sheri Crabtree
Abstract
The pawpaw [Asimina triloba (L.) Dunal] is in the early stages of domestication and wild collected plant material is still important in the commercial production of pawpaw. Native pawpaw patches can be found in hardwood forests growing in large patches as understory trees and can be found in 26 states in the eastern United States, ranging from northern Florida to southern Ontario (Canada) and as far west as eastern Nebraska. Kentucky State University serves as the USDA-National Clonal Germplasm Repository for pawpaw, therefore assessing genetic diversity across the pawpaw’s native range is a high priority. The objective of this study was to determine whether pawpaw trees from native patches in Iowa and Kentucky display genetic differences using the simple sequence repeat (SSR) marker system. DNA was extracted using the DNAMITE Plant Kit from leaf samples collected from 20 individual trees per patch from two native patches near Lake Cumberland in Kentucky, and in two native patches eastern Iowa. Primers B3, B103, B129, C104, and G119 were labeled with FAM and used to amplify SSR products. These products were then separated using a 3130 Applied Biosystems capillary electrophoresis system. The SSR primers yielded markers in the pawpaw selections examined that were useful in separating the pawpaw genotypes. The Iowa and Kentucky patches had at least two pawpaw genotypes in each patch but were mainly clonal in structure. The Iowa and Kentucky patches were separated easily based on high genetic variation in the marker alleles.
Using DNA Markers to Evaluate Genetic Diversity Among Native Pawpaw Patches in Iowa and Kentucky
The pawpaw [Asimina triloba (L.) Dunal] is in the early stages of domestication and wild collected plant material is still important in the commercial production of pawpaw. Native pawpaw patches can be found in hardwood forests growing in large patches as understory trees and can be found in 26 states in the eastern United States, ranging from northern Florida to southern Ontario (Canada) and as far west as eastern Nebraska. Kentucky State University serves as the USDA-National Clonal Germplasm Repository for pawpaw, therefore assessing genetic diversity across the pawpaw’s native range is a high priority. The objective of this study was to determine whether pawpaw trees from native patches in Iowa and Kentucky display genetic differences using the simple sequence repeat (SSR) marker system. DNA was extracted using the DNAMITE Plant Kit from leaf samples collected from 20 individual trees per patch from two native patches near Lake Cumberland in Kentucky, and in two native patches eastern Iowa. Primers B3, B103, B129, C104, and G119 were labeled with FAM and used to amplify SSR products. These products were then separated using a 3130 Applied Biosystems capillary electrophoresis system. The SSR primers yielded markers in the pawpaw selections examined that were useful in separating the pawpaw genotypes. The Iowa and Kentucky patches had at least two pawpaw genotypes in each patch but were mainly clonal in structure. The Iowa and Kentucky patches were separated easily based on high genetic variation in the marker alleles.