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United States Department of Agriculture

Agricultural Research Service

Research Project: Ornamental Plant Germplasm Center

Location: Application Technology Research Unit

2012 Annual Report


1a.Objectives (from AD-416):
The objectives of this cooperative project are to conserve, distribute, and characterize ornamental plant germplasm, and incorporate new or existing technologies for conserving primarily seed and secondarily clonally propagated germplasm for effective utilization in ornamental horticulture.


1b.Approach (from AD-416):
The Ornamental Plant Germplasm Center was established in 1999 and since then, it has become a fully operational repository for herbaceous ornamental plants and an integral part of the U.S. National Plant Germplasm System. The core mission of the OPGC is “to furnish genetic raw materials and associated information to enhance American floricultural productivity to ensure a high-quality supply of herbaceous ornamentals.” To accomplish this mission, priority genera have been identified to most effectively accomplish its mission including Begonia, Coreopsis, Lilium, Phlox, Rudbeckia, and Viola. Three components inherent within the core OPGC mission include; conservation of genetic resources, characterization of those resources, and education and outreach including distribution of OPGC germplasm to appropriate users. Conservation -- The priority genera collection will continue and include representatives of selected priority species within the genera. Priority species will be identified in collaboration with stakeholders including seed companies, commercial nurseries, and genera-specific technical working groups. Species will be collected primarily through donations and collection trips. Characterization -- Collected material must be adequately characterized to ensure that the germplasm captures genera diversity and that the germplasm is used correctly. Characterization will include genetic “fingerprinting” or mapping as well as phenotypic descriptions based on approved descriptor lists. This information will be entered into the Germplasm Resources Information Network (GRIN) database to increase the accessibility and value of the collection to the industry. Education and Outreach -- Distribution of germplasm to bona fide users will continue to fulfill a need for the industry and establish OPGC as a leading herbaceous ornamental plant repository. By hosting workshops and distributing newsletters, OPGC can educate the industry regarding technologies created, used, and refined through its efforts. OPGC will also maintain its linkage to the industry and professional organizations through participation and memberships in appropriate scientific societies and working groups.


3.Progress Report:

The primary outcome of the previous year has been a continuation to safeguard and utilize ornamental plant genetic resources for the long-term benefit of the floriculture and nursery industry. The project is conserving 3,557 accessions of herbaceous ornamental plants. In 2011, conservation efforts have included the regeneration of 133 accessions in the field and sending 57 seed lots for long-term storage at the National Center for Genetic Resources Preservation in Ft. Collins, CO. Monitoring the viability of stored seeds remains a core function; 78 seed lots were assessed; in addition, 173 germination tests were done in newly regenerated material. A major initiative for 2011 was the development of tissue culture capabilities for safeguarding some of the clonal collection, especially Begonia. Thus far half of the 123 Begonia accessions have been established in vitro and work is continuing on the remaining accessions. A long-term goal of the in-vitro collection is to eliminate viruses that tend to accumulate in clonal collections; this is particularly important for Pelargonium. The acquisition of germplasm among some of our priority genera has expanded, especially for Phlox, where 31 accessions were collected from unique environments (serpentine and shale barrens) in the Mid-Atlantic region and an additional 30 accessions from the Cumberland Plateau and along the Kentucky River. These collection efforts were supported by an Exploration Grant from the USDA National Plant Germplasm System. Additional acquisitions include the rare Lilium iridollae from Florida, various Rudbeckia from KY and TN, and Begonia species from the Ft. Worth Botanic Garden and local breeders. The OPGC has shared germplasm with US commercial companies, state agencies and universities, as well as foreign institutions. 104 orders were received for 932 items that were distributed in 2011. Requested accessions came principally from Pelargonium, Oenothera, Zinnia, Begonia, Tagetes, Rudbeckia, Petunia Iris, Stokesia and Coreopsis. Preservation and acquisition efforts are meant to provide material that is useful to the floriculture and nursery industry. Characterization of this captured genetic diversity is an integral part of our activities. In Phlox, an extensive survey was performed of the ploidy (number of sets of chromosomes) among accessions to better understand the potential for interspecific hybridization that would provide novel combination of traits eventually leading to new products. Accessions of some species appear to have fairly consistent ploidy levels whereas those of other species vary significantly by population and sometimes have variable ploidy within the population. Over 10,000 pollinations have been performed among 20 species of Phlox. The pattern that’s emerging is that distinct barriers exists between some species, but wide hybridization is possible in other, sometimes unexpected, combinations. DNA samples have also been obtained for all Phlox accessions and the extent of genetic diversity is being assessed with microsatellite markers. The use of butterflies to pollinate Phlox for seed increases is being explored since bees do not pollinate this group of plants; seed production in the nearly 240 accessions of Phlox is a major undertaking but essential for long-term safeguarding of germplasm. In Begonia, the production of seed has continued within accessions both for long-term storage and for study of seed germination and longevity. The seed germination protocol was modified for more efficient assessment of viability using agar plates. In Coreopsis and Rudbeckia, the third year of field characterization was continued of most wild accessions and comparison to commercial cultivars in the trade. DNA has been isolated from all of the accessions to develop appropriate markers for describing genetic diversity. Ploidy assessment of Rudbeckia using flow cytometry has continued; there appear to be significant variation in ploidy among the species in our collection. In Viola, a field study of environmental (mainly heat) tolerance was undertaken among selected cultivars and wild collected accessions of Viola tricolor; in 2012, the study is being repeated with the top performers in the previous trial.


Last Modified: 4/19/2014
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