Influence of the test host on measurements of the effectiveness of Rhizobium trifolii isolated from naturalised Trifolium repens L

The effectiveness of Rhizobium trifolii cultures isolated from white clover growing at 14 sites in Taranaki was determined using both"Grasslands Huia" white clover seed and seed collected from the site of isolation as sources of test plants. At 2 sites, 3 of the 4 cultures tested were more effective on the naturalised white clover than on Huia, suggesting adaption of the soil rhizobia to the naturalised white clover. No evidence for such adaptation was found at the remaining 12 sites. An inoculant strain was generally less effective on the naturalised white clovers (11 to 14 sites) than on Huia. This provides indirect evidence that Huia was not a dominant component of the white clover populations at these sites.