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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Management and Evaluation of Woody Landscape Plant Germplasm Resources and Associated Information

Location: Floral and Nursery Plants Research Unit

2013 Annual Report


1a.Objectives (from AD-416):
1) Strategically expand and improve collections of priority woody landscape plant germplasm and associated information to close/minimize gaps of genetic, taxonomic, and/or ecogeographical coverage. Priority genera include, but are not limited to: boxwood (Buxus), ash (Fraxinus), magnolia (Magnolia), oaks (Quercus), and hemlocks (Tsuga). Coordinate efforts to extend and strengthen the North American Plant Collections Consortium’s (NAPCC) continent-wide ornamental plant germplasm conservation program. 1a. Survey existing domestic and international holdings of woody ornamental taxa to identify materials that would refine and fill significant gaps in National Plant Germplasm System (NPGS) collections. Sub-objective 1b. Coordinate efforts to extend and strengthen the NAPCC continent-wide ornamental plant germplasm conservation program..
2)Conserve and regenerate priority NPGS woody landscape plant germplasm efficiently, and distribute samples and associated information worldwide. Regenerate, store, and/or maintain ex situ plantings of priority germplasm and associated information, emphasizing Lonicera, Magnolia, Rosa, Tsuga, and Viburnum. Increase to more than 40 percent the proportion of the collection holdings backed up at second sites, emphasizing critical back-ups of priority genera. 2a. Regenerate, store, and/or maintain ex situ plantings of priority germplasm and associated information, emphasizing Lonicera, Magnolia, Rosa, Tsuga, and Viburnum. 2b. Increase to more than 40 percent the proportion of the collection holdings backed up at second sites, emphasizing critical back-ups of genera identified in 2a. 2c. Distribute accessions and information that meet the specific needs of researchers, breeders, and growers. .
3)Characterize and evaluate priority NPGS woody landscape plant germplasm for key traits, such as their taxonomic identity, genetic variability, tolerances to biotic and abiotic factors, invasiveness, and ornamental merit, thereby enhancing the utility of these genetic resources for research and breeding. Develop and apply new genetic markers for taxonomic identity, genetic diversity analyses, and population genetic structure for selected priority genera including Fraxinus americana and related species. Ensure that existing Acer accessions are correctly identified taxonomically, adequately documented, and noteworthy material released appropriately. Update and apply phenotypic descriptors for Acer, Viburnum and other priority taxa into Germplasm Resources Information Network (GRIN). 3a. Develop and apply new genetic markers for taxonomic identity, genetic diversity analyses, and population genetic structure for selected priority genera including Fraxinus americana and related species. 3b. Ensure that existing Acer accessions are correctly identified taxonomically, adequately documented, and noteworthy material released appropriately. Update and apply phenotypic descriptors for Acer, Viburnum and other priority taxa into GRIN.


1b.Approach (from AD-416):
Survey existing domestic and international holdings of woody ornamental taxa to identify materials that would refine and fill significant gaps in National Plant Germplasm System (NPGS) collections. Strategically acquire samples and associated information for these taxa via exploration, contract collecting, and exchange, focusing on threatened, disjunct, or unique provenances. Ensure that all data are entered into the Germplasm Resources Information Network (GRIN). Train field reviewers, and develop regional recruiters and mentor network for public garden participation in national collections program. Emphasis will be placed on expanding efforts to address logistical issues such as preservation of genera which cross climatic zones and require multiple sites to preserve living accessions, e.g. multi-institutional approach to collections management. Increase quantity and quality of orthodox seed for long term storage and increase effective preservation of recalcitrant species through distribution and establishment of active collections. Regenerate threatened or historical accessions at WLPGR and USNA. Maintain current availability lists of germplasm for distribution, coordinate with the USNA main collections, and upload GRIN data on a regular basis for new accessions and matriculating germplasm from active collections. Screen Fraxinus germplasm samples for ploidy level that are deposited at the USDA-ARS NPGS repository at the North Central Regional Plant Introduction Station, Ames, Iowa and supplement with new collections to expand the range of F. americana covered. Use molecular markers to assess diversity and relationships within Fraxinus americana. Collect herbarium vouchers of Acer in WLPGR and USNA living collections, verify identities, and elucidate taxonomic problems in cultivated Acer. Identify elite material in WLPGR collections for nursery evaluation and introduction. Distribute accessions and information that meet the specific needs of researchers, breeders, and growers.


3.Progress Report:
The Woody Landscape Plant Germplasm Repository (WLPGR) of the U.S. National Arboretum continues to progress on the collection, conservation, evaluation and distribution of woody landscape plants. In support of these efforts, the WLPGR has carried out five germplasm expeditions to Florida, Tennessee, and Massachusetts, the southern portion of Vermont, Maryland and Mississippi. These collecting efforts and our collaboration with plant collectors, primarily targeting the U.S., have resulted in 79 new accessions from natural populations. We continue to support the national effort, lead by the North Central Regional Plant Introduction Station in Ames, Iowa and their Curator as well, in the collection of Fraxinus species native to the U.S. in response to the loss of genetic diversity caused by the Emerald Ash Borer. The WLPGR is co-leading a planned expedition to Mississippi and Louisiana in the fall of 2013 with the primary target to collect Fraxinus in support of this conservation effort, and new populations for flow cytometry and genetic analysis.

The northernmost populations of Cornus florida have been identified in New York and Michigan and collections scheduled. Additional populations at the edge of the species range have been identified in Florida, Texas, and Kansas and collections scheduled. Our magnolia efforts have focused on the comprehensive collection of Magnolia ashei, a threatened species endemic to Florida, in order to conserve this important ornamental taxon. Initial site visits in March 2013 identified target populations, and collections are scheduled for August 2013. We have also taken the lead on facilitating the import of 30 new varieties of flowering cherry (Prunus species) from England and Japan. This effort supports ongoing plant breeding efforts of the Research Unit and the living collections of the National Arboretum and our nursery stakeholders.

New pollination cages have been installed to facilitate seed regeneration of critical taxa. We have expanded the development of back-up collections and seed orchards through collaborations with the ARS Beltsville Area, local universities, and Regional Park and planning commissions.

The WLPGR/U.S. National Arboretum continues to distribute germplasm. During FY 2013, 1004 accessions of plants, seeds and DNA samples were distributed to private and public intuitions as well as private citizens. Our efforts continue at updating our inventories, and making them available online through Germplasm Resource Information Network, using a GIS/GPS (TRIMBLE) data system, to capture all of our holdings. We have also added inventory control software that will enable us to continue adding as well as subtracting data in a timely fashion. This will give the WLPGR an accurate map of our off site inventory as well as a similar map for our main holdings at South Farm and the National Arboretum.


Last Modified: 10/21/2014
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