Location: Floral and Nursery Plants Research
2022 Annual Report
Objectives
Objective 1: Efficiently and effectively acquire priority temperate-adapted woody landscape plant genetic resources; maintain their safety, genetic integrity, health and viability; and distribute them and associated information worldwide. [NP301, C2, PS2A; C1, PS1B]
Sub-objective 1.a. Acquire samples and associated information of select taxa via exploration, contract collecting, and exchange. Targeted taxa include: Cladrastis kentukea, Viburnum species, Quercus species, Acer saccharum subsp. leucoderme and floridanum, Lindera benzoin, and Hamamelis ovalis.
Sub-objective 1.b. Maintain and backup plant germplasm, including conduct germination tests on stored seed to determine viability of older germplasm; update seed collection and GRIN-Global database to reflect inventory; prioritize and regenerate or re-collect vulnerable accessions.
Sub-objective 1.c. Distribute accessions and information that meet the specific needs of researchers, breeders, conservationists, nursery professionals, and other stakeholders.
Objective 2: Develop more effective genetic resource maintenance, evaluation, and characterization methods and apply them to priority temperate-adapted woody landscape plant genetic resources. Record and disseminate evaluation and characterization data via GRIN-Global and other data sources. [NP301, C2, PS2A]
Sub-objective 2.a. Develop and apply molecular markers for analysis of genetic diversity, taxonomic identity, and/or population structure for Tsuga chinensis and other priority taxa.
Sub-objective 2.b. In collaboration with nurseries, botanic gardens, and university cooperators, evaluate horticultural merit of accessions collected under sub-objective 1.a and those already included in our living collections; disseminate information and superior germplasm or selections.
Objective 3: With other NPGS genebanks, Crop Germplasm Committees, and customers/stakeholders, develop, update, document, and implement best management practices and a Crop Vulnerability Statement for temperate-adapted woody landscape plant genetic resource and information management. [NP301, C2, PS2A]
Approach
High-quality germplasm identified from in situ populations or ex situ collections will be acquired in the most efficient manner. For many acquisitions, this will be through germplasm requests, exchanges, and local collecting. Domestic collections for the eight taxa identified as priorities (Cladrastis kentukea, Viburnum, Quercus, Hamamilis ovalis, Lindera benzoin, Fagus grandifolia, Sassafras albidum, and Acer saccharum subsp. leucoderme and floridanum) will focus primarily on eastern North America. Our approach will be to collaborate with local experts including other scientists, botanists, and collectors. The number of species targeted and collection goals in each specific effort will depend in part on the extent of the collaborators’ involvement and ease of access to sites.
We will use a contracted service for seed viability testing. Seed that is more than ten years old will be prioritized for viability testing based on the quality of passport data, its conservation status, and the number of requests received for that taxon. Seed that has no viability will be deaccessioned or inactivated following the NPGS Inactivation Guidelines developed by the PGOC. Seed will also be regenerated in-house or recollected. Seed from regenerated or collected accessions will be sent to the NCGRP in Ft. Collins for long-term backup.
We will follow our established protocols for meeting distribution requests that come through GRIN-Global for accessions already in the system. We will also distribute seeds of newly acquired taxa to collaborators for conservation or evaluation. Basic passport data (taxonomic information, collection locations, dates) are maintained in GRIN-Global for each accession. We will supplement these data with evaluation and descriptive information and images from collaborative evaluation projects which will add value to the germplasm.
To evaluate germplasm, we will use SSR markers to determine relationships among and diversity within accessions of Tsuga chinensis and Lindera benzoin. We will also evaluate the horticultural merit of germplasm accessions through collaborative agreements with several cooperators. Plants will be evaluated for various horticultural and production traits. Data will be collected after three years of field trials, and for two to five years subsequently, depending on the genus.
In order to update and implement best management practices and a Crop Vulnerability Statement for germplasm, we will maintain and establish collaborations with WLPGR users and other stakeholders to ensure that the collections are relevant, well-curated, accessible, and effectively utilized. We will work with the Crop Germplasm Committee to develop a list of targeted genera or species which are most vulnerable or otherwise in need of conservation. We will also update our internal “Operations Manual”, which provides specific guidance on identification, collection, maintenance, distribution, and evaluation of germplasm specific to the WLPGR, and also addresses database management, invasiveness, staffing, equipment and facilities, the WLPCGC, and safeguarding germplasm.
Progress Report
Substantial progress was made on all project objectives during FY2022. Within Objective 1, we added 130 new accessions to GRIN-Global that are available for public request through the National Plant Germplasm System (NPGS). New accessions represent 110 unique taxa, of which 65% originated from direct-wild origin, 21% are named cultivars, and 14% originated from cultivated sources. Among genera that have been prioritized for conservation within our plan, we added nine accessions of Quercus representing five species, one accession of Lindera, five accessions of Viburnum representing five species, and six accessions of Acer representing four species.
Plant germplasm was backed up for existing accessions using clonal propagation and controlled-pollination seed increases. Within our living plant accessions, we assessed taxa that met the following criteria: the taxon consists of a single accession, has no local congeners, and is considered to have desiccation-tolerant seeds. We collected seed from 20 of these accessions and incorporated those seeds within the USNA seed bank for NPGS orders. Seed germination and viability testing is ongoing, and samples with sufficient quantity and viability will be shipped to NLGRP for offsite backup. The entire USNA seed bank collections were inventoried, and the seed quantities checked against GRIN-Global. Inventories whose quantities are below our critical threshold of 100 seeds have been prioritized for regeneration or recollection. Routine seed testing has indicated significant to complete loss of viability for some seed accessions, and these inventories have been removed from NPGS availability.
Germplasm distributions included 193 accessions representing 130 unique taxa. Distributions were made in the form of seeds (75%), vegetative cuttings (19%), and bare-rooted plants (6%). This material fulfilled a total of 66 orders that originated as web-requests via GRIN-Global. To better understand the needs of our broad stakeholder base, we analyzed word-frequency among our requestor’s descriptions of intended germplasm usage that were submitted as part of the online ordering process. Among these open-ended responses within 66 orders, the frequency of major use terms included research (85), breeding (26), public (18), education (16), native (16), conservation (13), collections (12), archaeological (11), genetic (11), arboretum (10), demonstrations (9), taxonomic (7), cultivars (6), and teaching (4). These data confirm the broad scope of woody plant germplasm users and will help inform ongoing acquisitions and development of the germplasm collections. In total, germplasm requests were fulfilled for 51 organizations across 30 US states and three countries. The requestors comprised academia (26%), public gardens (25%), industry (17%), state and federal government (12%), private individuals (11%), and plant nurseries and growers (9%).
Within Objective 2, ongoing genetic sampling of Sassafras albidum from across the species’ extant range continued in collaboration with the USNA FNPRU Breeding Project. We collected leaf tissue from the southernmost localities in Alabama, Florida, and Mississippi, fulfilling a significant geographic gap in sampling. We also began genetic sampling of Hamamelis ovalis from across it’s known range. This endangered species was first described in 2006 and is known to occur in only four states. We made 84 H. ovalis collections including dried leaf tissue, herbarium vouchers, and geospatial data from all known populations in Alabama, Florida, and Mississippi (the type locality). Also reported in eastern Texas, we plan to collect from Texas populations in collaboration with local botanists next year.
We initiated a multi-site planting for the evaluation of Tsuga chinensis heat tolerance. Wild sourced material representing three Chinese provinces was sent in replicate to collaborators in Florida, Mississippi, and Texas, with a fourth planting initiated at the USNA. Data will be collected by collaborators and shared on an annual basis to assess survival, growth, and health of this evergreen, adelgid-resistant conifer in the deep south. We continue to evaluate Lindera benzoin plants that were subjected to chemical mutagenesis in effort to develop compact forms of this native shrub. The first year of growth revealed some treated plants are significantly smaller than control plants; we will continue to monitor this material for potential evaluation by cooperators. We have also begun propagating two unique forms of Tilia species that were identified at South Farm. Once large enough, these propagules are intended for offsite evaluation. Finally, a 20-year evaluation of a compact Viburnum nudum selection was submitted for review in consideration of a new cultivar release.
Under Objective 3, stakeholder collaborations were maintained and continue to be a source of synergy for international plant conservation efforts. In our collaborative partnership with the American Public Gardens Association’s Plant Collections Network (PCN), we planned and hosted a workshop on how to prepare a collection development plan which was attended by over 100 public garden professionals. This workshop provided guidance for drafting relevant and tangible plant collection development goals and is expected to increase the number of PCN applications for collection accreditation now that development plans are a mandatory application component. The National Arboretum’s own applications and reviews of our Magnolia and Quercus collection were approved with full accreditation status this year. Both Magnolia and Quercus are multi-site collections maintained in close collaboration with other public gardens. These groups will support our repository’s ability to share data and germplasm to efficiently conserve these species-rich genera.
We have continued a close collaboration with the Botanical Gardens Conservation International (BGCI) as part of parallel, global efforts with multi-site Magnolia and Quercus conservation consortia, as well as a working group for crop wild relatives of U.S. native trees. BGCI working groups provide another method for collaborating on conservation goals and reducing redundant research efforts through regular communication and data exchange.
As a founding member of the North America-China Plant Exploration Consortium (NACPEC), we continue to work collaboratively to advance plant acquisition, conservation, and evaluation goals. We are currently developing protocols to receive excess plant material from NACPEC collaborators that can be consolidated with our repository’s NPGS distribution program. With NACPEC members and the USNA Herbarium staff, we are preparing to migrate voucher images and data from 30 years of NACPEC expeditions within GRIN-Global. These efforts will yield a common, accessible resource for the public to search and view this information.
Accomplishments
