Cutting propagation of blueberry in seasons of the year with indolebutyric acid and bottom heat

The objective of this work was to evaluate the effects of the application of concentrations of indolebutyric acid (IBA) and of bottom heat on rooting of stem cuttings of the blueberry cultivars Bluebelle, Bluegem, and Powderblue in the four seasons of the year. A completely randomized design was used, with a 4x5x2 factorial arrangement (seasons x concentrations of IBA x with and without heat), with 4 replicates and 20 stem cuttings as an experimental unit. The percentage of rooted cuttings, dead, alive and with callus, and the number and average length of the roots were evaluated. The highest rooting percentages were 57.1% for 'Bluegem' in summer, 30% for 'Bluebelle' in spring, with heating, and 63% for 'Powderblue' in summer with heating. IBA at the concentration of 2,000 mg L-1 increased the rooting of cuttings of the cultivars Bluegem and 'Powderblue'. Bottom heat increases the rooting of the cuttings harvested during autumn and winter in all cultivars, and also the cuttings harvested during summer and spring in the Bluebelle cultivar.