US National Arboretum


Floral and Nursery Plants Research Unit

Woody Landscape Plant Germplasm Repository

Collection, Maintenance, and Evaluation

      The overall objectives of the Woody Landscape Plant Germplasm Repository (WLPGR) are to introduce, maintain, and distribute diverse and wild-origin genetic resources of trees and shrubs for landscape use through collection, exchange, and evaluation.   Woody plant germplasm is also evaluated for production potential and further characterized using biochemical and molecular DNA technologies.

Picture of Lilac 'Betsy Ross'

Germplasm Repository Activity

The Woody Landscape Plants Germplasm Repository (WLPGR) is responsible for maintaining 182 genera that range from Abelia to Zelkova.   More than 1,400 accessions of seeds are maintained in a mid-term storage facility, and 2,800 plants are maintained "on the grounds" at Beltsville and Glenn Dale, MD, and Washington, D.C. Not all accessions are available for distribution. Accessions that are available for distribution are for research purposes only to qualified institutions.

    Fall leaf bullet   Click here for a List of Woody Landscape Plant Species held by the US National Arboretum

Germplasm Repository Approaches

Tree Bullet   Identify target genera and species:

- The needs of germplasm will be identified while working closely with scientists and Crop Germplasm Committee for the Woody Landscape Plants (CGC-WLP).

- Special emphasis will be given not only to winter hardiness, but also heat tolerance and species/hybrids that are not too sensitive to fluctuating temperatures early in the spring.

- The following genera will be emphasized:  Acer, Celtis, Cornus, Exochorda, Halesia, Hamamelis, Illicium, Lindera, Styrax, Staphylea, Stewartia, Tilia, Tsuga, Ulmus, and Zelkova.

Tree Bullet   Explore, acquire, and identify germplasm: Picure of Flowering Cherry

- National and international germplasm exploration trips have been made in collaboration with the North America/China Plant Exploration Consortium (NACPEC), and germplasm was acquired in exchange with various botanical gardens.

- Acquired germplasm is identified and documented in cooperation with the Floral & Nursery Plants Research Unitís Plant Taxonomist and other experts.

Tree Bullet   Maintain germplasm:

Picture of Halesia plant

- The most effective maintenance program for newly acquired or for already existing germplasm will be developed while maintaining living plants in the fields at Beltsville, MD, and Washington, D.C.

- Seed germination as influenced by mid-term storage duration is investigated and seed viability is evaluated.

- Germination percentage and optimum germination conditions as influenced by temperature and light and dormancy are documented and early growth and development of seedlings is recorded.

- Seeds that can not be stored long-term are identified, and new germplasm maintenance programs are developed.

- Propagation of woody landscape plants by rooting of stem tip cuttings and/or in vitro tissue culture methods is evaluated.

Tree Bullet   Distribute germplasm and educate consumers:

- Germplasm is distributed to research scientists and industry (and sometimes private individuals) in line with the National Plant Germplasm System {NPGS} distribution policy.

- Provide the basic germplasm information along with the material, such as the year and site of collection, germination percentage, as well as other horticultural traits, such as the size of plants, if requested germplasm is maintained as a whole plant.

- Coordinate with other arboreta and botanic gardens in germplasm exchange, preservation, and maintenance of the germplasm as whole plants and in education programs.

   Record data and computerize:

GRIN Logo image

- Acquisition, characterization, inventory, and evaluation data is recorded on the Germplasm Resources Information Network {GRIN} database.

- Record evaluation information and relate pertinent horticultural information.

   Research and Evaluation:

Picture of MRI of germination test

- The specific objectives are to observe any difference in plant growth and development in response to stresses, such as water and temperature, and to investigate the effect of seed maturity and dormancy on seed germination.

- Production protocols of selected germplasm will be developed by investigating the effect of light, temperature, and nutrition on growth and flowering.

- Selected germplasm will be identified and characterized using molecular DNA technologies.


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Last Updated   January 18, 2005 4:50 PM

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