Four Trifolium repens (white clover) cultivars were evaluated under field conditions to determine the potential of these cultivars
to sucessfully develop Rhizobium-associated root nodules. Nodulation of T. repens is often poor, because of suboptimal
environmental conditions or absence of host-specific rhizobia. The cultivars Huia, Haifa, Ladino and Regal were selected, as these
are popular cultivars available in South Africa. Thousand seed mass (TSM) of each cultivar was measured to determine viability of
seed and the possible interaction between TSM and nodulation. Mean TSM values of the cultivars differed significantly, with Huia
having the highest TSM followed by Haifa, Ladino and Regal. Biomass production was also measured as an indicator of nitrogen
fixation efficiency. The cultivar Huia, with the highest TSM values, resulted in the highest biomass production. Nodulation indices
were determined from the size, number and colour of the nodules. All plants, regardless of cultivar, formed nodules within 8 weeks.
It was concluded that TSM had no effect on nodulation. Planting date with associated temperature effects and the intrinsic cultivar
effect also had no influence on nodulation. It was therefore concluded that nodulation potential of the four cultivars tested was
similar under environmental conditions that prevailed during the study.