Techniques for the selection and development of elite inoculant strains ofRhizobium leguminosarum in southern Australia

The task of matching rhizobial strains to host legumes is not a new one. Ho wever, as the price Australian farmers receive for their goods continues to decline relative to the cost of their inputs, more than ever they require optimal performance from their legumes. The suite of legumes in use in sout hern Australia has changed dramatically during the last decade, and will co ntinue to do so. We report on the development of a successful four phase pr ogram for selecting optimal microsymbionts for these legumes such that comm ercial inocula are available when required. Elite inoculant strains have be en selected following screening for nitrogen fixation, edaphic adaptation a nd performance in situ of rhizobial germplasm originally collected from tar getted locations in the Mediterranean region.