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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #357322
Research Project: Evaluation and Genetic Improvement of Woody Ornamental Landscape Plants

Location: Floral and Nursery Plants Research

Title: Genetic diversity of the U.S. collection of Chinese hemlock Tsuga chinensis (Franch.) E. Pritz. based on simple sequence repeat markers

Author
item THAMMINA, CHANDRA - Rutgers University
item Conrad, Kevin
item Pooler, Margaret

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2018
Publication Date: 1/19/2019
Citation: Thammina, C., Conrad, K.P., Pooler, M.R. 2019. Genetic diversity of the U.S. collection of Chinese hemlock Tsuga chinensis (Franch.) E. Pritz. based on simple sequence repeat markers. Genetic Resources and Crop Evolution. 66:847-855.

Interpretive Summary: Hemlocks play an important role in forest ecosystems as well as in cultivated landscapes. The most significant species in the U.S., the Canadian hemlock, is under attack by the hemlock woolly adelgid, an insect that has caused widespread loss of these trees. Biological or chemical control of this insect is difficult on large trees in the landscape or in forest environments, so finding resistant species of hemlock has become increasingly important. While several Asian species are tolerant to the pest, the Chinese hemlock appears to have the combination of resistance, shade tolerance, adaptability to poor soil, cold hardiness, and vigorous growth that make it especially promising for cultivation in landscapes and possibly managed forest ecosystems. ARS scientists in Beltsville, MD evaluated the genetic diversity of 35 accessions of Chinese hemlock held in collections in the U.S. They determined that significant genetic diversity is available in the existing U.S. collections of T. chinensis, and, based on collection data, represents the wild gene pool well. This characterization of germplasm can be important in driving decisions about collections management, breeding methods, and forest or ecosystem management.

Technical Abstract: The Chinese hemlock, Tsuga chinensis (Franch.) E. Pritz., is becoming more well-known in U.S. landscapes as the native U.S. species (T. canadensis (L.) Carr.) is under attack from the hemlock woolly adelgid. It is important to understand the genetic diversity and relatedness among accessions of T. chinensis to drive decisions about collections management, breeding methods, and forest or ecosystem management. We used SSR markers to evaluate the genetic diversity of 96 samples representing 35 accessions of Chinese hemlock held in collections in the U.S. Using 88 alleles from eleven SSR loci, we found high levels of diversity between and within accessions. Our results indicate that significant genetic diversity is available in the existing U.S. collections of T. chinensis, and, based on collection data, represents the wild gene pool well. This characterization of germplasm can be valuable in choosing accessions for use in horticultural and landscape applications or as part of a hemlock breeding program.