The influence of perennial ryegrass (Lolium perenne L.) cultivars on white clover (Trifolium repens L.) establishment and morphology: A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science with Honours at Lincoln University

Perennial ryegrass pastures (Lolium perenne L.) were sown on 27 March 2012 with eight different cultivar treatments of a perennial ryegrass varying in ploidy (diploid or tetraploid), maturity (early or late flowering) and phenotype (open, broad leaf or fine, dense leaf) characteristics. A 50:50 mix of two white clover (Trifolium repens L.) cultivars was hand sown on 28 March in all plots 2012. Ryegrass and white clover herbage production, botanical composition, seedling development, shoot: root ratios, plant numbers and clover morphology of autumn sown pastures were assessed with particular reference to maturity and phenotype appearances. There was no advantage in terms of dry matter production from sowing different cultivar treatments. In September the dry matter production of the treatments ranged from 1529.77 kg DM/ha (One 50) to 1882.76 kg DM/ha (Commando). However, these results were not significantly different. In September, Abermagic treatment contained the highest amount of weeds, however it is unknown why. Kamo and Commando treatments contained a much higher percentage of dead matter in the sward compared to One 50 which contained the least. Perennial ryegrass content and white clover content in the swards did not differ significantly in any of the treatments. Significant differences were also found between development and cultivar however, it was unclear why this result occurred as it contradicted what was expected. Overall, cultivar effects on white clover do not occur in the first year of establishment due to ryegrass cultivars not mature enough to express characteristics that may influence the growth of white clover in the sward. Sowing rate, nitrogen application and severity of grazing should be incorporated into future studies to understand more about clover content in different ryegrass cultivar swards. Future studies after establishment should give more significant differences between ryegrass cultivars due to differences in characteristics such as leaf size, heading date and ploidy.