Response of chrysanthemum to uniconazole and daminozide applied as dip to cuttings or as foliar spray

Abstract

Uniconazole and daminozide were used as dip on unrooted cuttings or as foliar spray on pinched Dendranthema grandiflora Tzvelev. ‘Dalvina’ to control height. Stem elongation was determined on cuttings dipped in solutions of 0, 1.25, 2.5, 5, or 10 mg/L uniconazole or cuttings were dipped and later treated with foliar sprays in concentrations of 1.25/5, 1.25/10, 2.5/10, and 5/5 mg/L uniconazole, respectively. Other plants were sprayed once or twice with uniconazole at 10 mg/L. Daminozide treatments included a pre-plant dip/foliar spray application of 1000/2000 mg/L, respectively, or two foliar sprays of 2,000 mg/L. Uniconazole dip alone retarded stem elongation linearly up to 8 weeks after propagation, 5 weeks after pinching, but was not discernible from the control treatment 8 weeks after pinching. Uniconazole at 2.5/10 and 5/5 mg/L as a dip/spray combination resulted in plants 33% shorter than the control at the end of the production. Doubling uniconazole dip or spray treatments from 5 to 10 mg/L provided no additional reduction of stem elongation. The single uniconazole spray and both daminozide treatments had no effect on final height, although daminozide treatments reduced stem dry weight compared to the control. Stem dry weight was reduced by uniconazole dip/spray combinations compared to dip treatments alone. Similarly, inflorescence and root dry weights were also reduced by the highest uniconazole concentrations. Higher concentrations of uniconazole reduced transpiration on a per leaf area basis up to 47% compared to the control at the end of production. In contrast to previous work, leaf area and leaf thickness increased with some uniconazole treatments, while time to anthesis was not affected by any of the treatments.