«Project Number: S-009 Project Title: Plant Genetic Resources Conservation and Utilization Period Covered: 08/2014 through 8/2015 Date of this Report: ...»
Project Number: S-009
Project Title: Plant Genetic Resources Conservation and Utilization
Period Covered: 08/2014 through 8/2015
Date of this Report: September 16, 2015
Annual Meeting Dates: July 21 – July 22, 2015
Accomplishments and Impacts:
USDA – Plant Genetic Resources Conservation Unit Plant genetic resources collected or obtained from throughout the world are valuable sources of genetic diversity for use in agronomic and horticultural crop improvement programs in the U.S. This project forms part of a comprehensive nationwide program, National Plant Germplasm System, to preserve plant genetic resources for use today and for use by future generations. The primary objectives of this project are to 1) acquire and conserve genetic resources of crops and related wild species of importance to the Southern Region such as sorghum, peanut, watermelon, chili peppers, warm-season grasses, cowpea, clover, tropical/subtropical legumes, and others; 2) conduct genetic characterizations and phenotypic evaluations of the conserved crops and related wild species for commercially important genetic and agronomic traits; 3) incorporate characterization and evaluation information into the Germplasm Resources Information Network (GRIN-Global) or other public databases; and 4) distribute genetic resources and associated information to researchers, educators, and plant breeders in the Southern Region and worldwide.
Seed and clonal genetic resources acquired, maintained, characterized, evaluated, documented, and distributed by this project will provide researchers with a broad range of clearly-identified crop genetic diversity to utilize. This broad genetic diversity enables research programs to efficiently produce new cultivars, develop new knowledge, discover value-added uses, and preserve food security for the general public.
This project has grown from 811 accessions of 41 genera in 1949 to one of the largest collection of the four NPGS regional multistate projects with 92,232 accessions of 257 genera and 1,548 species in 2014. In 2014, a total of 34,884 seed, tissue culture, and clonal accessions were distributed to researchers and educators at universities, private companies, agricultural and medical research foundations, seed conservatories, federal agencies, farmer-owned cooperatives, and foreign universities and companies. All accessions were requested from the Griffin location directly by researchers and distributed in 964 orders to users in 47 states and 40 foreign countries with 15,172 accessions distributed to users in the Southern Region. Genetic resources maintained at the Griffin location are in great demand by the research community and provide a valuable resource for crop improvement research. The quantity and quality of plant genetic resources maintained at Griffin make this location one of the leaders in the National Plant Germplasm System.
Germplasm Maintenance A new 4C seed storage facility was completed and an existing 4C facility was converted to -18C freezer storage. This storage space enabled almost 5,000 more accessions to be stored at
-18C. Currently, 19% of the accessions are maintained solely at -18 C and 80.9% of the accessions (73,495 accessions) have at least one inventory in -18C long-term storage. Most plant genetic resources in genebanks are maintained under short-term (4C) rather than long-term (C) storage temperatures, which increases the need for frequent seed regeneration that can reduce genetic variability. At Griffin, GA, original seed and seed of species rarely requested are maintained solely at -18 C. Other accessions are maintained as split samples with the bulk of the seed maintained at -18 C and a small distribution sample maintained at 4 C. When needed, seed will be removed from the -18 C sample to replenish the distribution sample. These plant genetic resources will remain viable longer with reduced need for regeneration and better retention of genetic variability of the original sample for users.
Prior to 2002, seed samples of over 84,000 accessions of plant genetic resources maintained at the Griffin location had not been tested for germination, and the quality of seed distributed to researchers was not known. A concentrated effort was made to conduct germination tests on this large collection. Currently germination tests have been completed for 82,436 accessions (90.7% of the collection) including almost all available accessions of most crops maintained at Griffin. Viability of most crops (sorghum, cowpea, mung bean, watermelon, okra, eggplant, cucurbits, legumes, annual clover, pearl millet, and sesame) was very good for most accessions in these collections. Warm-season grass, pepper, and peanut collections have several accessions with low viability. This germination testing enables curators to properly identify accessions with poor quality seed that need to be regenerated resulting in better quality seed being distributed to researchers upon request.
Biosecurity and availability of plant genetic resources are of major concern to the U.S.
agricultural research community. Preserving germplasm by maintaining accessions at two sites reduces the risk of losing valuable germplasm. A total of 90,307 accessions (97.9% of collection) have been deposited for safety back up at the National Center for Genetic Resource Preservation, Ft. Collins, CO, and 89.6% of the accessions are available for use by the research community. For the large sorghum germplasm collection, only 239 of 38,202 sorghum accessions are not available for distribution to researchers. Additionally, 12,090 accessions (13.1% of the collection) are also backed up at the Global Seed Bank in Svalbard, Norway.
Backing up safely secures these plant genetic resources for future use by researchers and good availability provides users with a wide array of currently available germplasm.
Curation and Research Acquisitions made to the collection included 30 sorghum, 29 okra, 131 warm-season grass, and 8 other accessions. Seed regenerations and characterization were conducted on 381 wild and cultivated peanut, 96 warm-season grass, 43 cowpea, 120 legume, new, and misc. crop, 38 annual clover, 20 cucurbits, 4 squash, 17 okra, 6 chile pepper, 10 eggplant, and 16 other vegetable accessions. Over 1,200 sorghum accessions were regenerated in St. Croix. Long-term maintenance of 207 wild peanut and 435 warm-season grass clonal accessions was continued in the greenhouse or field. A total of 1,100 peanut accessions regenerated in Citra, FL, in 2013 and 2014 were shelled and will be added to the collection shortly. The peanut core, mini collection, and commercial standards were evaluated in the field at Citra, FL, for multiple morphological, genetic, and biochemical traits over a two year period. Molecular markers are being utilized to analyze the genetic diversity as well as associate markers with the traits evaluated in the field.
Permanent PI numbers were assigned to all clonal GRIF peanut accessions. Over 5,000 images of peanut seed, pods, flowers, and plots were uploaded to the GRIN database. The finger millet core collection of 85 accessions was grown in the greenhouse for nutritional characterization.
Fatty acid content, 100 seed weight, protein, amino acid content, mineral content, and seed image data were collected using harvested seeds. Three ornamental little bluestem cultivars are being developed in cooperation with the University of Georgia. A total of 34 little bluestem selections were made for ornamental potential. With cooperators in St. Croix, 52 cowpea and 40 legume accessions are being regenerated. Hydroponic systems are being used to regenerate poor viability Vigna and Macrotyloma species in the greenhouse. A total of 741 sweetpotato accessions were maintained in tissue culture and backed up in Ft. Collins. The remaining 18 accessions in the chile pepper core collection infected with Pepper Mild Mottle Virus were increased in the greenhouse and virus-free seed was produced for distribution. Virus testing was conducted on 15 sweetpotato and 12 cowpea accessions prior to regeneration or distribution.
Germination testing has been conducted on 82,436 accessions (almost 91% of collection) since 2002. Over 190 sorghum accessions tested in 2002 were retested to determine the change in viability while stored in -18C freezer storage. Seed oil content and fatty acid composition was determined for 200 accessions of Solanum melongena. Clean seed was produced for eight Citrullus accessions with low seed numbers and fungal infections. To clarify taxonomic relationships among specific vegetable crop species, pollen was subjected to scanning electron microscopy (SEM) for characterization. Several anomalies were noted and are being further investigated. Genomic characterization of sweetpotato and its allied species continues. An assessment was made of existing sweetpotato-related germplasm available globally and related taxa deserving of further collection were identified. Genomic characterization revealed the expression of Agrobacterium genes in the cultivated sweetpotato and several related species. Oil content has been determined for 5,500 peanut accessions and fatty acid composition has been determined for 4,800 accessions so far in an evaluation of the entire peanut collection. Two peanut accessions from Pakistan have been identified as high oleate types. In collaboration with ARS locations in Puerto Rico and Lubbock, TX, 212 sweet sorghum accessions have been evaluated for early-spring cold tolerance in both lab and field conditions. Two accessions with good tolerance to early-spring cold temperature were identified. A total of 13 guar accessions were evaluated for the identification of superior flavonoid accessions. The sesame FAD2 gene for fatty acid desaturase was sequenced. Genetic diversity of 7-15 Neonotonia wightii accessions for morphological traits, anthocyanin, and genistein was determined. Leaf protein content and amino acid composition of 95 bamboo accessions has been quantified from samples collected for two years. A sesame mutagenesis project was continued with 500 M3 lines from 1,414 M2 mutant lines evaluated for morphological changes and fatty acid composition alteration.
Improved Germplasm Availability and Safety: Valuable plant germplasm preserved in cold storage is of immediate value to researchers if it is available for distribution and safely preserved at more than one location. ARS researchers at Griffin, GA, have improved sample availability and safe preservation of the USDA germplasm collection maintained at Griffin to the highest levels in the past 19 years. Almost 90% of the samples are currently available for distribution to researchers worldwide and 98% of all samples are safely preserved at a second location. Researchers now have a greater range of crop and wild relative genetic variability to utilize in their research program and almost all samples are safely preserved at a second location for research utilization in the future.
Selection of the most Viable Seed Samples for Distribution for Research: Germination testing of seed samples of the same germplasm accession grown in different years is critical to ensure that the most viable seed sample is distributed to researchers. Following germination testing of most accessions and inventories in the last 13 years, ARS researchers in Griffin, GA, selected the most viable seed inventory from each accession for distribution when multiple inventories of the same accession were tested for germination. This has resulted in few (15%) seed samples available for distribution having viability of less than 50% and the majority (58%) of the seed samples available for distribution having viability of greater than 75%. Researchers are receiving seed samples that have the best viability for utilization in their research program.
Identification of Wild Relatives Useful for Sweetpotato Improvement: Crop wild relatives of sweetpotato have the potential to improve sweetpotato. The limited availability of germplasm and the difficulty of incorporating genes from wild species into sweetpotato has limited their utilization and conservation. ARS researchers at Griffin, GA, identified wild species with the potential to contribute desirable agronomic traits such as adaptation to extreme temperature, precipitation, and soil characteristics. Most of these wild species were underrepresented in germplasm collections. Specific wild species and geographic locations for future collection of additional samples of these valuable wild species were identified.
Identification of High Oleate Peanut Accessions: High oleate peanuts are used in peanut breeding for improved seed quality including improved shelf life and health benefits. ARS researchers at Griffin, GA identified two peanut accessions with 80% oleate and the mutation responsible for this increased oleate content by screening over 4,800 accessions of the USDA peanut germplasm collection. These high oleate peanuts are new genetic sources for high oleate content that will be used by breeders to improve peanut seed quality.
Florida The state of Florida was very active in 2014 for plant genetic resources distribution.
According to records provided by S-9, 36 different individuals requested materials from 47different plant species and a total of 385 PIs distributed. Sixteen of the 36 individuals requesting material appear to be private individuals requesting one to 3 accessions of one or two species, while the remainder appear to be research focused projects. Affiliation of research focused individuals include University of Florida scientists, USDA scientists, private research organizations, and public schools. Most individuals who responded to a request for information indicated a high level of satisfaction with materials provided and appreciation for the availability of the germplasm. Listed below are reports submitted by cooperators.
Dr. Scott Adkins, Research Plant Pathologist (Virology), USDA ARS USHRL, 2001 South Rock Road Fort Pierce, FL 34945 provided the following report: In April 2014 we requested 36 PIs of bottle gourd (Lagenaria siceraria) for evaluation for resistance to a variety of viruses (known and unknown). The experiments are ongoing.