PRESERVATION AND QUALITY ASSESSMENT OF PLANT GENETIC RESOURCES
Location: Plant And Animal Genetic Resources Preservation Research Unit
Title: OVERVIEW, THE NATIONAL CENTER FOR GENETIC RESOURCES PRESERVATION AND THE NATIONAL PLANT GERMPLASM SYSTEM
| Ellis, David |
Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: August 1, 2004
Publication Date: August 30, 2004
Citation: Ellis, D.D. 2004. Overview, the national center for genetic resources preservation and the national plant germplasm system. International Plant Genetic Resource Institute. August 30 - September 01, 2004 Rome, Italy. Meeting Abstract.
Interpretive Summary: The primary concern of the NPGS is to maintain absolute genetic integrity for all collections. This is done by hand pollination, use of screened cages, isolation from other pollen sources, extreme care in seed collection and the use of well trained, expert seed production staff. Phenotypic screening of all seed is done, yet the relatively small amounts of seed regenerated, often less than 3000 seed/accession, as well as resources, limit the ability for other testing. In our case, we feel our regeneration processes are the best that can be achieved and the limited resources available for germplasm collections are best spent maintaining this high degree of genetic integrity of all collections during every stage of the genebank process.
The National Center for Genetic Resources Preservation (NCGRP) is part of the larger National Genetic Resources Program which includes germplasm collections and genebanks for plants, animals, insects and microbes. The NCGRP serves as a back-up repository for both animals and plants. At present the NCGRP has over 100,000 animal accessions and almost 500,000 plant accessions. The NCGRP facilities include over 465 meters square of -18C storage for seeds and capacity for 110 liquid nitrogen storage tanks measuring 1.5 meter in diameter for the cryopreservation of plant meristems, seed, and the animal germplasm. There are two plant-related units within the NCGRP:
1. The Seed Viability and Storage Research Unit whose primary responsibility is the operation of the seed bank as well as preservation of vegetatively propagated crops.
2. The Plant Germplasm Preservation Research Unit whose focus is basic and applied research to provide the tools for seed storage and the cryopreservation of vegetative propagules, study of the long-term effects of storage and to investigate the population genetics of stored and wild populations.
NCGRP serves as the long-term storage genebank for the National Plant Germplasm System (NPGS), International genebanks, conservation/nature societies, International Research Organizations, National Park and Wildlife Organizations and other national and foreign entities.
The NPGS consists of more than 20 germplasm genebanks throughout the US including Alaska, Hawaii and Puerto Rico. Each site is responsible for seed regeneration, acquisition, characterization and distribution for the regional crops of interest in their area. In 2003, NPGS distributed over 150,000 samples from over 500 genera. Of these, almost 30% were distributed internationally to over 75 countries.
The primary focus of the NPGS is to maintain all germplasm accessions in the best quality condition possible by maintaining the unique and distinct genetic make-up of every accession. The NPGS takes extreme care in all phases of the collection, storage, regeneration and distribution of accessions to ensure the absolute maintenance of genetic integrity of every collection. In each case, all possible measures are taken to prevent admixing of seed or cross pollination from non-wanted pollen sources. Examples of this extreme care include:
1. In maize, regeneration is done by hand with 100% of the ear shoots bagged in place as early as possible, 100% hand pollination and 100% hand harvesting of ears. Regeneration fields are isolated from other sources of pollen and following storms the curatorial team inspects all pollination set-ups and discards any they believe to be compromised.
2. With canola, 100% of the regeneration is done in screened cages which prevent outside pollinators or outside pollen from pollinating the accessions. Individual pollinators are hand introduced into the cages and all inflorences are harvested by hand. To further ensure genetic fidelity all seed extraction equipment is completely dismantled and cleaned between accessions.
3. In soybean, a closed flower acts as a natural barrier to help ensure genetic integrity. To further ensure genetic purity of each accession, soybean regeneration is done in an area low in natural pollinators and accessions are planted in four row plots with seed harvested from only the center two rows. As with maize, all regeneration is done in an isolated field.
4. With potatoes, true potato seed is regenerated in large screened houses which exclude all pollinators. All pollinations and seed collection is done by hand and the screened houses are spatially separated from other potato plots.
5. In cotton, the corolla of the flower forms a 'candle' prior to opening and to maintain genetic purity, the corolla is tied shut at this stage to completely isolate the tied flower from outside pollen. Seed is hand collected only from those bolls still maintaining a tied corolla at the time of harvesting. As with the other examples, regeneration of seed for the NPGS in cotton is done in fields isolated from breeding or other cotton production activities.
In summary, the primary concern of the NPGS is to maintain absolute genetic integrity for all collections. This is done by hand pollination, use of screened cages, isolation from other pollen sources, extreme care in seed collection and the use of well trained, expert seed production staff. Phenotypic screening of all seed is done, yet the relatively small amounts of seed regenerated, often less than 3000 seed/accession, as well as resources, limit the ability for other testing. In our case, we feel our regeneration processes are the best that can be achieved and the limited resources available for germplasm collections are best spent maintaining this high degree of genetic integrity of all collections during every stage of the genebank process.