Project Number: 6619-13000-002-04
Project Type: Specific Cooperative Agreement

Start Date: Mar 01, 2009
End Date: Aug 30, 2009

Objective:
A collection tour for rhizobia strains able to nodulate the native legumes species of interest for the project was completed in April 2006. Work to be performed under this Agreement includes: 1) Authentification and preliminary selection of rhizobia strains for the ability to fix nitrogen under controlled conditions; 2) Characterization of selected strains using biochemical and molecular technologies; 3) Production of experimental inoculants and preliminary evaluation in the field; and 4) Interchange and conservation of rhizobia strains from the project.

Approach:
A rhizobium collection mission was conducted in April 2006 in California by ARS personnel, Uruguayan cooperators and UF collaborators to secure a diverse array of rhizobium strains (n=200-300) associated with targeted native North American Trifolium spp. identified as having potential in Uruguay. Strain assays will be conducted in Uruguay under controlled conditions (light room) using a randomized block design with four replicates using two controls (without inoculating, in presence and absence of nitrogen). In some cases, interactions between strains and legume species will be studied. Selected rhizobia isolates will be characterized by biochemical (profile of isoenzimes, and others) and molecular (PCR) technologies. Inoculants will be prepared at the Dept. of Soil Microbiology in Montevideo in liquid or peat base according to the requirements of the cultivar development programs, and strain selection tests will be done for every legume species. Rhizobia isolations will be added to the MGAP, Dept. of Soil Microbiology collection (http://www.chasque.net/microlab), and a database will be generated using edafo-climatic geographical information. Duplicate materials will be deposited at the USDA, ARS, National Rhizobium Genetic Resource Center.