Comparative effects of daminozide, dikegulac-sodium, paclobutrazol and uniconazole on the plant height of Petunia hybrida

Abstract

Two experiments were carried out on ‘Bonanza’ and ‘Velvet Carpet’ petunia seedlings using four growth regulators (daminozide, dikegulac-sodium, paclobutrazol and uniconazole) at four different concentration levels and three application frequencies. The aim of these experiments was to determine which treatments produced acceptable bedding plants (±80 mm high) for sale. Daminozide was the most effective in producing plants within the optimum range in both experiments despite differences in plant size and time of final treatment. In both experiments the concentrations of uniconazole and dikegulac-sodium used were most inhibiting to height increase while paclobutrazol was the least effective. At higher concentrations and application frequencies, uniconazole and dikegulac-sodium reduced height below optimum. Suggested concentrations of each regulator to limit plant height are given.