Potter, Kevin M. , Dvorak, William S. , Frampton, John , Jetton, Robert M. , Whittier, W. Andrew , Tighe, Michael E. .
Genetic Diversity and Conservation of Carolina Hemlock (Tsuga caroliniana), a Rare and Threatened Southern Appalachian Conifer.
Carolina hemlock (Tsuga caroliniana) is a species endemic to the southern Appalachians of Virginia, North and South Carolina, Tennessee, and Georgia. Occurring only rarely across its limited range, this conifer is facing possible extinction because of infestation by the hemlock woolly adelgid (Adelges tsugae), an exotic insect from Asia. We employed amplified fragment length polymorphism (AFLP) molecular markers (1) to investigate the genetic relationships among 15 populations of Carolina hemlock from throughout its range, and (2) to compare the genetic diversity of seed collected in 2003 from nine populations, for ex situ gene conservation, to the sample encompassing all 15 populations. The AFLP results indicate that Carolina hemlock exhibits a moderate amount of overall genetic variation and a fairly high amount of genetic differentiation among populations (GST â‰ˆ 0.4), and that populations along the eastern edge of the species’ range tend to be more genetically diverse. This last result may suggest that the Pleistocene glacial refuge for the species was located southeast of the Appalachian mountain chain. Additionally, the results indicate that the nine-population ex situ seed collection has more than adequately conserved the genetic variation present throughout the range of the species. Seeds collected from these populations, through a cooperative effort of the Camcore International Tree Conservation and Domestication Program at North Carolina State University and the USDA Forest Service Region 8 Forest Health Protection, are being used to establish Carolina hemlock conservation plantings in Brazil, Chile, and the Ozark Mountains of Arkansas, where the adelgid does not occur. The results of the AFLP analyses also should help guide future gene conservation efforts for Carolina hemlock, including decisions about which populations should receive priority for in situ protection to maximize genetic variation and maintain a broad and adaptive genetic base.
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1 - North Carolina State University, Camcore, Department of Forestry and Environmental Resources, Campus Box 7626, Raleigh, NC, 27695, USA
2 - North Carolina State University, Department of Forestry and Environmental Resources, Campus Box 8002, Raleigh, North Carolina, 27965-8002, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Williford A/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:45 AM