The Symbiotic Specialization of African Trifolium Spp. In Relation to their Taxonomy and their Agronomic Use

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Nurris D. O.
Mannetje L. 't
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Twenty-six introductions of 15 species or subspecies of Trifolium indigenous to Africa, south of the Sahara, were screened in the greenhouse against 24 Rhizobium isolates obtained from Trifolium species in the central African region. Unreplicated screening trials were, made first to select those strains of Rhizobium likely to be effective on each species. These were then further tested to determine the best inoculant strain for each species. Results confirmed earlier work that these Trifolium spp. are highly specialized in their Rhizobium requirements. Apart from strain specificity between species, it is also shown that specialization exists between varieties and to a certain extent even between different introductions of the same species. General inoculant recommendations cannot be made, but a list of species, varieties and introductions, with the best strain of Rhizobium found in these studies, is presented. On the grounds of Rhizobium affinities between the taxa dealt with, a tentative relationship grouping is put forward which could be of value to the taxonomist. Evidence suggests that T. rueppellianum Fres. var. lanceolalum Gillett should be elevated to specific rank.
East African Agricultural And Forestry Journal, XXIX (No. 3), p. 215-235