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United States Department of Agriculture

Agricultural Research Service

Research Project: Acquisition, Evaluation and Conversation of Temperate Forage Legume Genetic Resources

Location: Plant Germplasm Introduction and Testing Research

2011 Annual Report

1a. Objectives (from AD-416)
Objective 1: Strategically expand the genetic diversity in genebank collections and improve associated information for priority Medicago, Trifolium, and Lotus genetic resources. Sub-objective 3C In cooperation with U. S. and Russian researchers, produce an Interactive Agricultural Atlas of Russia and Neighboring Countries which will be accessible on the internet and on CD-ROM. Sub-objectives 1A. Acquire samples and associated information to fill identified gaps in the NPGS collections of Medicago, Lotus, and Trifolium. Sub-sub-objective 1A1. Collect or obtain from the United States, the Mediterranean Basin, and Central Asia, targeted species. Sub-sub-objective 1A2. Survey existing holdings of Medicago truncatula genetic stocks (a model species for legume genomics) and acquire priority materials. Sub-objective 1B. Identify and establish in situ sites for endemic species of Lotus, and Trifolium. Sub-sub-objective 1B1. In cooperation with the U. S. Forest Service and other public land agencies, survey and identify in situ seed collection sites. Sub-sub-objective 1B2. Using a model trifolium species, define in situ conservation parameters needed for outcrossing, insect-pollinated wild legume species. Sub-objective 1C. Based on earlier research, collaborate with Kazakh researchers to identify and establish sites in Kazakhstan for in situ conservation of wild relatives of alfalfa. Objective 2: Conserve and regenerate priority Medicago, Trifolium, and Lotus genetic resources efficiently and effectively, and distribute pathogen-tested samples and associated information worldwide. Sub-objective 2A. Regenerate, conserve, and distribute more than 12,000 accessions of temperate forage legume genetic resources and associated information, emphasizing accessions with low germination, open-pollinated seed stocks, few seeds in storage, or those not yet backed-up at second sites. Sub-objective 2B. Increase to 90 percent the proportion of the collection backed-up at second sites, emphasizing critical back-ups of Medicago, Trifolium, and Lotus. Sub-objective 2C. Regenerate 150-300 accessions of Medicago, Trifolium, and Lotus per year, emphasizing controlled pollination of original or “next best” seed lots for Trifolium and Lotus, so as to systematically replace open-pollinated seed lots. Objective 3: Strategically characterize (“genotype”) and evaluate (“phenotype”) priority Medicago, Trifolium, and Lotus genetic resources for molecular markers, morphological descriptors, and key agronomic traits. Sub-objective 3A. With cooperators, apply newly developed DNA genetic marker data to phylogenetic and genetic diversity analyses of priority crops, especially M. truncatula, to develop core subsets. Incorporate characterization data into the Germplasm Resources Information System (GRIN) and/or other databases. Sub-objective 3B. Update and apply phenotypic descriptors for forage legume collections with an emphasis on capturing key floral, fruit, and seed characteristics of regenerated germplasm, and characterizing forage nutrient value.

1b. Approach (from AD-416)
Acquisition of new germplasm for these genera will be achieved via plant exploration/collecting and germplasm exchange. On the ground surveys of the Blue Mountains will continue to identify key areas where in situ collection sites can be designated for multiple Trifolium species. Accessions being regenerated will be evaluated for basic descriptors in the field; data will be placed in GRIN. Field evaluations will occur during the flowering year, which is usually the seedling year. Molecular markers will be used for identifying genetic diversity within and among accessions, identifying geographical or environmental associations, and assisting in identification of redundancy and gaps in collections. Formerly 5348-21000-018-00D (3/08).

3. Progress Report
This progress report addresses the work conducted by the National Temperate Forage Legume Germplasm Resources Unit in Prosser, WA. 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. During the year we focused on regeneration, acquisition and distribution activities in the Medicago, Trifolium and Lotus germplasm collections. We completed a gap analysis of Medicago crop wild relatives in the area covered by the Former Soviet Union (FSU). We completed an inventory of CWR and economically important plants that are native or naturalized in the United States and reported the results. The AgroAtlas project conducted 6 GIS training workshops throughout Russia. We initiated a collaborative project with VIR and the Noble Foundation to evaluate the ecotypic diversity of alfalfa wild relatives collected throughout the FSU, using morphological and molecular markers. An important activity has been implementing strategies to minimize transgene contamination from recently deregulated roundup ready alfalfa (RRA) into our germplasm collections. We are also poised to begin several studies to better understand pollen flow from RRA hay and seed fields to conventional fields.

4. Accomplishments
1. Forage legume germplasm maintenance, characterization and distribution. Gene bank seed inventories decline as we distribute seed or seed ages, so a main priority is to increase seed stocks using best practices that maintain seed purity. Responding to collection users who stressed the importance of maintaining U.S. alfalfa germplasm free from the adventitious presence (AP) of genetically engineered (GE) traits when roundup ready alfalfa was deregulated in February of 2011, the WRPIS, Area Office and National Program contributed $88,000 to replace aging pollination cages which will better protect our forage legume collections from cross contamination. Other best practices explored this year to prevent AP of GE traits include monitoring the presence of the Roundup Ready transgene in the immediate vicinity of our planting sites and implementing a feasibility study to move our seed increase site to a more isolated location at Central Ferry, WA. ARS scientists in Pullman, WA also replenished 160 seed stocks, tested seed viability of 230 accessions, gathered over 5000 observation data and distributed 89 trefoil (Lotus), 2380 alfalfa (Medicago), and 630 clover (Trifolium) accessions. These activities ensure the temperate forage legume germplasm collection continues to serve as a resource to researchers and breeders around the world.

2. Gap analysis of alfalfa wild relatives in the Former Soviet Union. Around the world important crop wild relative (CWR) species are being ignored in conservation activities. An alfalfa CWR gap analysis was carried out by ARS and Russian scientists to pin point global inadequacies in ex situ germplasm collections and highlight geographic areas in the FSU that have rich concentrations of CWR. The gap analysis will help us target collecting efforts and identify current protected areas that can serve as in situ reserves for alfalfa CWR. Considering today’s focus on protecting CWR and also utilizing CWR to breed crops adapted to climate change, this work not only identifies conservation shortcomings but allows us to focus our efforts on collecting CWR not currently available to support efforts to breed alfalfa adapted to climate change.

Last Modified: 06/22/2017
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