EVALUATION OF CLOVERS IN DRY HILL COUNTRY .2. SUBTERRANEAN AND WHITE CLOVER AT KAIKOHE, NEW-ZEALAND

Nine subterranean clover (Trifolium subterraneum) cultivars and 10 white clover (T. repens) lines were compared under grazing in a hill pasture. In the subterranean clover trial, cultivar 'Clare' of the subspecies brachycalycinum, was high producing in the first year but did not regenerate. Among the subsp. subterraneum cultivars, 'Nangeela' and 'Woogenellup' yielded less than the standard 'Mt Barker' over 4 years (-22 and -9% respectively), 'Seaton Park' about the same, and 'Howard' and 'Tallarook' yielded more (+28 and +30%). However, on this site, 'Trikkala' and 'Larisa' of the subsp. yanninicum were more productive than all other cultivars yields of (+63 and +165% compared to 'Mt Barker') and maintained good sward contents when normal intensive grazing resumed at the end of the trial. Both were relatively susceptible to leaf disease in spring but still had highest seedling densities in autumn (average > 500/m2). 'Larisa' and 'Trikkala' had better autumn/winter growth than 'Tallarook' and 'Mt Barker' and should complement these cultivars on winter-wet/summer-dry soils in Northland. Of the white clover lines, 'Haifa', 'Tamar', 'Louisiana S1', and 'Clarence Valley' had first-year yields similar to or below 'Grasslands Huia', but their persistence was poor. Yields of the small-leaved 'Kent' and 'Hill Country', and the medium-leaved 'Grasslands Pitau' and 'Italy X New Zealand', were similar to 'Grasslands Huia'. Most productive was the large-leaved cultivar 'Grasslands Kopu' (27% better than 'Grasslands Huia' for white clover yield and 8% better for whole sward yield). The poor persistence of four varieties and the superior performance of 'Grasslands Kopu' is attributed to their relative resistance to stem nematode (Ditylenchus dipsaci).