Indolbutyric Acid and Time of the Year Influence on Rooting of Chrysanthemum Cuttings

Abstract

The objective of this study was to analyze the effect of the seasons and indol butyric acid (IBA), as well as the preparation of IBA solutions on rooting growth of “ Fine Time ” chrysanthemum cuttings. The first experiment was arranged in a 4 × 2 factorial scheme: IBA concentrations (0, 1000, 2000 and 3000 mg · L -1 ) during summer and winter with 4 replicates of two pots and six cuttings per pot. In the second experiment, the storage of IBA solution (1000 mg·L -1 ) at 15 °C was studied with four replicates of 10 cuttings per plot in a period of four weeks. In the third experiment, dilution and supply of IBA (1000 mg · L -1 or 1000 mg · kg -1 ) were studied; there were eight treatments: (1) IBA mixed with industrial talc; (2) IBA diluted in 50% alcohol and oven dried at 30 °C; (3) IBA diluted in 50% alcohol and oven dried at 70°C; (4) IBA diluted in NaOH and supplied via aqueous solution; (5) IBA diluted in acetone and supplied via aqueous solution; (6) IBA diluted in alcohol 92.8% and supplied via alcoholic solution; (7) IBA diluted in alcohol 50% and supplied via alcoholic solution; (8) IBA mixed and supplied via lanolin; with four replicates of 10 cuttings per plot. Twenty-one days after cutting implementation, the following variables were evaluated: rooting percentage, number, average length and root dry mass. Statistical analysis and time-of-year averages were compared using the Tukey test at 5%; polynomial regression for IBA concentration and preparation data. The means of dilution and delivery were compared by the Scott-Knott test. Treatment with IBA at a concentration of 3000 mg · kg -1 resulted in 90% rooting in the winter and 100% in the summer for all treatments. Results suggest the concentration of 2000 mg · L -1 in the summer and 2000 and 3000 mg · L -1 during the winter provided better quality for the root system. Cuttings treated with IBA diluted in 50% alcohol and oven dried at 30 °C showed higher number, length and vigor of the roots.