Location: Small Grains and Potato Germplasm Research
2021 Annual Report
Objectives
The long-term objective of this project is to maintain and enhance NSGC as a worldwide resource of small grains germplasm for the research community. Specifically, during the next five years we will focus on the following objectives. Objective 1. Efficiently and effectively acquire genetic resources of small grains and their wild relatives; maintain their safety, genetic integrity, health and viability; and distribute them and associated information worldwide. 1A. Acquire crop wild relatives of wheat, barley, rice, and oat that are under-represented by taxonomy or geography and other threatened small grains germplasm. 1B. Maintain and back-up NSGC accessions. 1C. Regenerate NSGC accessions on a continuing basis with priorities determined by seed inventory and viability. 1D. Distribute on request NSGC accessions and information that meet the specific needs of researchers worldwide. Objective 2. Develop more effective genetic resource maintenance, evaluation, and characterization methods and apply them to priority small grains genetic resources; screen for host-plant resistance to virulent diseases, such as the Ug99 wheat rust strain. Record and disseminate evaluation and characterization data via GRIN-Global and other data sources. 2A. Assess putative duplicate accessions for barley and wheat. 2B. Characterize resistance to bunt and stem rust in NSGC wheat accessions. 2C. Collect remaining priority characterization data and record in GRIN-Global. Objective 3. With other NPGS genebanks and Crop Germplasm Committees, develop, update, document, and implement best management practices and Crop Vulnerability Statements for small grains genetic resource and information management. 3A. Review and update NSGC standard operating procedures for all aspects of curation and implement best management practices in coordination with other NPGS sites. 3B. Engage with small grains Crop Germplasm Committees (CGCs) to update crop vulnerability statements and identify germplasm acquisition and evaluation priorities of interest to the respective committees.
Approach
Objective 1. Acquisition priorities include the wild relatives of Triticum, Hordeum, Avena, and Oryza to fill species and ecogeographic gaps in the crop collections. Highest priority will be primary genepool relatives of these genera, identified in collaboration with the Crop Germplasm Committees (CGCs). These gaps will be addressed by collection expeditions and exchanges with other genebanks. Seed of NSGC accessions are held in medium-term storage under controlled temperature (5-6o C) and relative humidity (25%). Detailed inventory records are maintained in GRIN-Global. Seed will be provided to NLGRP for safety back up. Accessions in need of regeneration will be grown at several locations as follows: Aberdeen, Idaho in fields of the University of Idaho Research and Extension Center and in USDA-ARS greenhouses; Parlier, California at the USDA-ARS National Arid Land Plant Genetic Resource Unit; and Stuttgart, Arkansas at the USDA-ARS Dale Bumpers National Rice Research Center. Accessions will be scheduled for regeneration based on a priority matrix. Viability tests are scheduled every five years. Standard procedures for GRIN-Global Order Processing will be followed. Distributions outside of the U.S. will follow phytosanitary requirements of the recipient country, including import permits, phytosanitary certificates, and additional declarations. USDA-APHIS will be consulted regularly for the latest information on seed export. Seed shipments to other countries will be coordinated with the National Germplasm Resources Laboratory (NGRL), Plant Exchange Office. Noxious weeds will be distributed under a USDA-APHIS permit. Accessions that fall under the International Treaty for Plant Genetic Resources for Food and Agriculture will follow appropriate guidelines and will include agreement to the Standard Material Transfer Agreement by the recipient. Objective 2. Molecular markers and morphological traits will be used to develop a method to assess variation within and between NSGC wheat and barley accessions. After establishing the method, the barley and wheat collections will be sampled to measure the degree of duplication within each. Using the data from this study, verified duplicate accessions may be combined. Using genome wide association and bi-parental mapping approaches, genes for bunt and stem rust resistance will be sought within the NSGC wheat collection. Markers associated with novel resistance to the Ug99 stem rust group of races will be validated in various genetic backgrounds. Remaining priority characterization data will be collected and recorded in GRIN-Global. Objective 3. SOPs for all aspects related to acquisition, maintenance, regeneration, characterization, evaluation, and distribution will be reviewed, updated, and compiled into a complete NSGC operations manual of procedures. Through meetings and discussions with the small grains CGCs the priorities of these research communities will be identified and reflected in crop vulnerability statements and NSGC descriptors. Ongoing dialogue with the CGCs will be maintained.
Progress Report
ARS researchers at Aberdeen, Idaho, currently hold 147,996 accessions of small grains, which include wheat, barley, oat, rye, triticale, rice and related wild species. Seed distributions to scientists totaled 22,230 accession samples in 483 separate requests, and scientists from foreign countries continue to make up one-third of these requests. In support of Objective 1, research continued in acquiring genetic resources of small grains and their wild relatives, while maintaining safety, genetic integrity, health and viability, while distributing associated information worldwide.
In support of Objective 2, the National Small Grains Collection (NSGC) wheat and oat accessions were tested and genetically characterized for resistance to virulent diseases including rusts and bunts. Researchers completed screening all NSGC available winter and facultative bread wheat accessions for resistance to U.S. and Ug99 stem rust variants, with 9,192 accessions being tested since 2014. A research manuscript based on the results from this study entitled "Identification of winter habit bread wheat landraces in the NSCG with resistance to emerging stem rust pathogen variants" was submitted for publication.
Researchers organized three U.S. wheat and barley breeding nurseries for testing in East Africa against Ug99 variants of stem rust in cooperation with the International Center for Maize and Wheat Improvement (CIMMYT) in Mexico City, Mexico, and the Kenya Agriculture and Livestock Research Organization (KALRO) in Nairobi, Kenya. In two separate nurseries, 1,985 and 2,350 entries were sent to Njoro, Kenya, and 1,901 entries were sent to Debre Zeit, Ethiopia. Included in the East Africa nurseries were two populations derived from PI 94439 with unique field resistance to Ug99 and U.S. races of wheat stem rust. Three additional wheat populations derived from landrace accessions PI 117494, PI 184221, and PI 625285 were tested as seedlings for resistance to Ug99 stem rust in collaboration with the USDA Cereal Disease Lab in St. Paul, Minnesota. Two wheat populations, derived from CItr 15026 and PI 94439, were sent for stripe rust testing in Mt. Vernon, Washington. In cooperation with researchers at the University of Idaho in Moscow, Idaho, and Utah State University in Logan, Utah, 138 NSGC accessions were tested for resistance to dwarf bunt in Logan, Utah.
All available NSGC diploid Avena accessions were tested as seedlings with four oat stem rust variants. In cooperation with researchers at Agriculture and Agri-food Canada in Ottawa, Canada, these phenotypes were used in conjunction with sequencing to fine map the position of Pg6, an important oat stem rust resistance gene. A manuscript entitled "Comparative sequencing and SNP marker validation for oat stem rust resistance gene Pg6 in a diverse collection of Avena accessions" was submitted for publication based on results from this work. In cooperation with researchers at the USDA Cereal Disease Lab in St. Paul, Minnesota, Louisiana State University in Baton Rouge, Louisiana, and the University of Florida in Gainesville, Florida, 50 accessions were screened for field resistance to crown rust and three, CIav 6956, PI 258731, and PI 504851 were resistant across testing sites and selected for further crown rust resistance studies.
Accomplishments
Review Publications
Mergoum, M., Johnson, J.W., Sutton, S., Lopez, B., Bland, D., Chen, Z., Mailhot, D.J., Buck, J.W., Buntin, G.D., Babar, M.A., Mason, R.E., Harrison, S.A., Murphy, J.P., Ibrahim, A.M., Sutton, R., Simoneaux, B.E., Bockelman, H.E., Baik, B.V., Marshall, D.S., Cowger, C., Brown Guedira, G.L., Kolmer, J.A., Jin, Y., Cambron, S.E., Boyles, R. 2021. Soft red winter wheat, ‘GA 051207-14E53’: Adapted cultivar to Georgia and the USA southeast region. Journal of Plant Registrations. 15(1):132-139. https://doi.org/10.1002/plr2.20102.
Mergoum, M., Johnson, J.W., Buck, J.W., Sutton, S., Lopez, B., Bland, D., Chen, Z., Buntin, G.D., Mailhot, D.J., Babar, M.A., Mason, R.E., Harrison, S.A., Murphy, J., Ibrahim, A.M., Sutton, R.L., Simoneaux, B.E., Bockelman, H.E., Baik, B.V., Marshall, D.S., Cowger, C., Brown Guedira, G.L., Kolmer, J.A., Jin, Y., Cambron, S.E. 2021. A new soft red winter wheat cultivar, 'GA 07353-14E19', adapted to Georgia and the US Southeast environments. Journal of Plant Registrations. 15(2):337-344. https://doi.org/10.1002/plr2.20113.
