HEIGHT CONTROL OF POT CHRYSANTHEMUMS WITH PRE- AND POST-PLANT TREATMENTS OF DAMINOZIDE AND UNICONAZOLE

Abstract

This study investigated the effects of growth retardants uniconazole [(E) - (p-chlorohenyl) -4, 4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol] and daminozide (butanedioic acid mono 2,2-dimethylhydrazide) on three chrysanthemum (Dendranthema grandiflora Tzvelev.) cultivars. Uniconazole applied as a soil drench (0.02 mg a.i. pot−1) or foliar spray (0.014 mg a.i. pot−1) 10 d after removal of the shoot tip reduced plant height at harvest in cultivars Deep Luv, Tip and Tara. Higher doses of uniconazole resulted in further plant height reduction in Tip and Tara but not in Deep Luv. Daminozide spray (14 mg a.i. pot) and uniconazole spray (0.028 or 0.056 mg a.i. pot−1) produced plants of similar height. Pre-plant dips of both growth retardants were less effective than sprays or drenches in controlling height. Flower area and flower dry weight were reduced with uniconazole drench and spray, and daminozide spray in each cultivar. Shoot dry weight was similarly affected in Tip and Tara but not in Deep Luv. Flowering was delayed in each cultivar by post-plant treatments of uniconazole drench and spray and by daminozide spray (0.08, 0.014 and 14 mg a.i. pot−1, respectively), and by daminozide and uniconazole pre-plant dips (5.0 mg L−1 and 4000 mg L−1, respectively).Key words: Sumagic, XE-1019, B-Nine, Alar, Chrysanthemum × morifolium, Dendanthema grandiflora