EVALUATION OF CLOVERS IN DRY HILL COUNTRY .9. WHITE CLOVER AT BALLANTRAE, AND IN CENTRAL WAIRARAPA, NEW-ZEALAND

Herbage production, vegetative persistence, and seedling regeneration of 10 white clover (Trifolium repens L.) lines were evaluated on a steep, dry hillside at Ballantrae Hill Country Research Station, and at a drought-prone site in the central Wairarapa, New Zealand. New Zealand-bred lines produced more herbage than overseas lines in both measurement years (1982/83 and 1983/84) at Ballantrae, and in the first of two measurement years at the Wairarapa site. Production of most lines increased between 1982/83 and 1983/84 at Ballantrae; 'Hill Country' selection showed the greatest increase (from 240 to 715 kg dry matter (DM)/ha per year). Severe drought at the Wairarapa site during early 1983 depressed mean clover production by 23% in 1983/84 compared with the previous year, and altered the relative ranking of lines. 'Tamar' and 'Louisiana S1' emerged as the most productive lines after the drought, though contamination by resident clover probably contributed heavily to measured herbage yields in these two cultivars. Recovery of the stolon material which survived drought appeared to play a large role in re-establishing white clover populations at the Wairarapa site. Seedlings of all genotypes were observed in 1982 and 1983 at both sites, but they had little impact on subsequent herbage accumulation or stolon density.