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United States Department of Agriculture

Agricultural Research Service

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Research Project: Temperate Forage Legume Genetic Resource Management, Characterization, and Evaluation

Location: Plant Germplasm Introduction and Testing

2013 Annual Report


1a.Objectives (from AD-416):
Objective 1: Conserve, regenerate, back-up, and distribute genetic resources and associated information for temperate forage legume genetic resources and related wild species. Sub-objective 1A. Regenerate 150-200 accessions of Medicago, Trifolium, and Lotus per year, and develop pure lines for the entire Medicago truncatula germplasm collection. Sub-objective 1B. Acquire and conserve Medicago, Trifolium and Lotus Crop wild relatives (CWR) and help develop a national strategy for conserving U.S. CWR.

Objective 2: Elucidate geospatial patterns of genetic divergence, diversity, and adaptation in temperate forage legumes, and apply that knowledge to manage ex situ genetic resources and in situ, dynamic conservation of selected taxa. Sub-objective 2A. Spatially analyze patterns of genetic, morphologic and ecogeographic diversity in the Medicago truncatula collection to validate and refine the core subset, and better understand how diversity is distributed in the NPGS HAPMAP subset. Sub-objective 2B. Assess whether 120 annual medic accessions collected in the Crimea peninsula in 2008 should be incorporated into the NPGS collection. Sub-objective 2C. Examine patterns of genetic differentiation, diversity and adaptation among 200 accessions of alfalfa crop wild relatives to identify traits that can be used in breeding efforts since they are positively associated with adaptation to stress environments.

Objective 3: Conduct small-scale characterizations and evaluations of forage legume genetic resources for priority genetic and agronomic traits. Sub-objective 3A. Digitally capture diagnostic images of floral, fruit, and seed characteristics of regenerated germplasm. Sub-objective 3B. Using existing GRIN characterization and observation data and ecogeographic data based on collection site, conduct a Focused Identification of Germplasm Strategy (FIGS) to evaluate the red and white clover collections for priority agronomic traits, including disease and insect resistance.

Objective 4: Characterize landscape-scale transgene flow for alfalfa, and apply that knowledge to develop mitigation strategies for maintaining genetic purity of alfalfa germplasm accessions and for commercial production of alfalfa hay and seed stocks for genetically engineered-sensitive markets. Sub-objective 4A. Assess the flow of Round Up Ready genes along commercial-scale genetically engineered alfalfa hay and seed production pathways taking into account different landscape factors and pollinators. Sub-objective 4B. Monitor for the presence of transgenic alfalfa pollen at the Prosser, WA regeneration site and determine the feasibility of routinely testing new acquired accessions from domestic sources and newly regenerated germplasm for adventitious presence of GE traits.


1b.Approach (from AD-416):
Regeneration will use best management practices to maintain genetic integrity of individual accessions. Due to the commercialization of GMO alfalfa, additional measures will be implemented to ensure the collection remains free of transgene contamination. Acquisition of new germplasm will be achieved through collecting and germplasm exchange. Using techniques of geospatial analysis, molecular, morphological and environmental data will be used to elucidate geospatial patterns of genetic divergence, diversity, and adaptation in temperate forage legumes. Field-based characterization and evaluations will be conducted for priority genetic and agronomic traits, including digitally captured diagnostic images of floral, fruit, and seed characteristics of regenerated germplasm. Characterization/evaluation data will be uploaded into the Germplasm Resources Information Network (GRIN-Global) database. Using techniques of spatial modeling, landscape-scale transgene flow will be examined for alfalfa, and information used to develop mitigation strategies for maintaining genetic purity of alfalfa germplasm accessions and for commercial production of alfalfa hay and seed stocks for genetically engineered-sensitive markets.


3.Progress Report:
This project started in January of 2013 replacing 5348-21000-022-00D, "Acquisition, Evaluation and Conversation of Temperate Forage Legume Genetic Resources". This progress report addresses the work conducted by the National Temperate Forage Legume Germplasm Resources Unit in Prosser, Washington. The project focuses on effectively acquiring, maintaining, characterizing and distributing 15,000 accessions of temperate forage legume germplasm, in order to enhance the use and conservation of these important genetic resources and aligns with National Program 301 Action Plan Component 1: Plant and Microbial Genetic Resource Management. Problem Statement 1A: Efficiently and Effectively Manage Plant and Microbial Genetic Resources. From October 2012 to August 2013, we distributed over 4,000 packets of seed samples to researchers worldwide. During the year we focused on regenerating 250 accessions, and assisting users to select germplasm in our collection. We surveyed alfalfa fields to identify source and sink fields to study Roundup Ready transgene flow in Fresno County, California, Canyon County, Idaho, and Walla Walla County, Washington. We have identified a total of 40 sink fields to study in 2013 and 2014. Pollinator surveys were conducted on sink fields in June, and seed from 1,000 individual plants were harvested around the edges of sink fields in August. Progress on this research was reported at the NIFA BRAG Project Director Meeting in June. We are monitoring for the presence of the Roundup Ready Alfalfa (RRA) transgene by harvesting and testing sentinel strips along the edges of 17 surrounding hay fields around the Prosser regeneration site.


4.Accomplishments
1. Safeguard the genetic integrity of our alfalfa germplasm collection. There has been an increasing concern about maintaining the purity of our alfalfa seed stocks since the commercialization of Genetically Modified Organisms (GMO) alfalfa. ARS researchers are studying the Roundup Ready transgene flow in alfalfa growing areas in California, Idaho and Washington. Through field surveys in May and close cooperation with seed companies and individual growers, we identified Round-up Ready transgene source and sink fields in three counties: Fresno, California, Canyon, Idaho and Walla Walla, Washington. Pollination surveys were conducted in these fields in June and seed was harvested from 1000 individual plants in each of the sink fields in August. The results will enable us to formulate effective strategies to minimize the chance of GMO contamination in our germplasm collection.


Last Modified: 8/29/2014
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