EFFECT OF TIME OF HARVEST AND PACLOBUTRAZOL ON SEED YIELD IN WHITE CLOVER CV GRASSLANDS PITAU

Maximum potential harvestable and actual seed yield of white clover (Trifolium repens L.) cv. Grasslands Pitau following a mid November closing at Palmerston North, New Zealand, was obtained at a harvest 25 days after peak flowering. Seed yield did not differ significantly when harvest was delayed from 25 to 35 days after peak flowering, but was significantly lower with harvests at 40 and 45 days after peak flowering. This response to time of harvest was not altered by applying the growth retardant paclobutrazol (applied at 1.0 kg a.i./ha on 27 November), as peak flowering and seed development (as recorded by seed weight and moisture content) did not differ between treatments. There was, therefore, no evidence to suggest that paclobutrazol-treated plots should be harvested at a different time to that of control plots. Paclobutrazol significantly increased inflorescence number at peak flowering and the first harvest, but the 56% difference in seed yield between the treatments failed to reach significance. Possible reasons for this result are briefly discussed.