Location: Soybean Genomics and Improvement
Project Number: 8042-21000-269-00
Start Date: May 09, 2013
End Date: May 08, 2018
Rhizobial cultures will be managed by their preservation, quality control and disbursement to ARS customers upon request. Technical information about rhizobia, their isolation, culturing and symbiosis and advice will be given. New rhizobial cultures will be isolated from soil samples. Emphasis will be placed on preparing and sending cultures for long-term backup at the USDA, ARS, National Center for Genetic Resources Preservation, Fort Collins, CO. The goal is to send the most important rhizobia accessions for the grain legumes and forages. Research will be conducted to determine the impact of soybean genotype, location and year on the genotype of Bradyrhizobium that forms nitrogen-fixing nodules in typical U.S. soybean production fields. The soybean genotypes will consist of a diverse set of genotypes including the major ancestral cultivars that form the genetic base of U.S. soybeans, elite cultivars, and a highly diverse sets of Glycine max landraces and G. soja (wild soybean) genotypes selected based upon the genetic analysis of the USDA Soybean Germplasm Collection with 50,000 single nucleotide polymorphism (SNP) DNA markers. Nodules will be harvested from these field-grown plants and analyzed to determine the strain of B. japonicum or B. elkanii that form nodules. The resulting nodule occupancy data will be used to determine if differences among the genotypes are present for % nodule occupancy by B. japonicum genotypes and/or % occupancy by B. elkanii genotypes.