Influence of Paclobutrazol on in Vitro Growth of Sweet Cherry Shoots

Abstract Shoot tips from in vitro-established shoot tip cultures of Prunus avium L. cv. Hedelfingen and cv. Starkrimson were cultured on sweet cherry propagation medium to which several concentrations of paclobutrazol (PP333) were added and gibberellic acid (GA 3 ) omitted, in order to reduce the elongation of the shoots. A reduction in both shoot length and bud number was achieved even with the lowest concentration of paclobutrazol (0.2 mg·liter –1 ). Shoot tips from the inhibited cultures when replanted on regular propagation medium overcame the inhibition at the first transfer. In order to use this system for cold preservation experiments, the cultures were examined under dark and low temperature conditions (0.5° ± 0.5°C). There was a significant difference between the PP333 system and the control after certain periods of cold preservation. The survival ratio of the PP333-inhibited culture was higher than the control after removing from the cold preservation conditions and recultured. Chemical name used: β-[(4- chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1 H -1,2,4-triazole-1-ethanol.