Abstract

Indigenous populations of Rhizobium leguminosarum bv. trifolii nodulating red clover (Trifolium pratense L.) were sampled from two field sites, in northern Sweden and northern Norway, at different times of the growing season. A total of 431 nodule isolates were characterised genetically by targeting both chromosomal and symbiotic genes. The chromosomal analysis revealed considerable genetic variation within the isolated populations that was more influenced by geographical origin than sampling time. Restriction fragment length polymorphism analysis of the nodEF gene on the symbiotic plasmid revealed a high proportion of nod genotypes common to the two sites. The symbiotic efficiency of eight isolates, representing both dominating and rare nod genotypes, was measured in a greenhouse experiment using the 15N isotope dilution method. All tested isolates except one, representing a very rare genotype, showed high N2 fixation rates in symbiosis with the host plant. There was thus no correlation between relative abundance and symbiotic efficiency amog the sampled rhizobial genotypes, and we conclude that effective N2-fixing strains of Rhizobium leguminosarum bv. trifolii nodulating red clover are common and genetically diverse in these northern Scandinavia soils

Published in

Grassland Science in Europe
2008, volume: 13, pages: 239-241
Book title: Biodiversity and Animal Feed. Future Challenges for Grassland production
ISBN: 978-91-85911-47-9
Publisher: European Grassland Federation

Conference

22nd General Meeting of the European Grassland Federation

Authors' information