A comparison of the nodulation of diploid and tetraploid varieties of red clover inoculated with different Rhizobial strains

Summary The effectiveness of three different strains ofRhizobium trifolii on a diploid and a tetraploid variety of red clover (Trifolium pratense) grown in aseptic mineral-agar culture was compared. It was found that with two of the rhizobial strains tested, the tetraploid plants were slower to nodulate than the diploid plants, but that a hundred per cent nodulation was obtained in both cases. With the third strain, however, a sixty-six per cent nodulation of the diploid plants was reduced to an eight per cent nodulation of the tetraploids.In general, over a given period, fewer nodules were formed on the tetraploid plants, but these tended to be larger than on the diploids. The fresh weight of the tetraploid plants always exceeded that of the diploids, but less so in cases of poorly nodulated plants.