THE RHIZOBIUM COMPONENT OF THE NITROGEN-FIXING SYMBIOSIS

Abstract

Rhizobia may be classified as either fast or slow growers, or alternatively into different cross-inoculation groups depending on the host plants they can nodulate. The clover, lucerne, lotus-lupin. and sainfoin cross-inoculation groups are of importance in New Zealand grasslands. Within each group there are numerous strains which differ in many respects, in particular in their ability to fix nitrogen with different host species. The clover and slow-growing lotus rhizobia are now widespread in New Zealand pasture soils but the others are not.