ISHS Acta Horticulturae 474: III International Symposium on Olive Growing
PACLOBUTRAZOL DECREASES THE HARMFUL EFFECT OF HIGH TEMPERATURES ON FRUIT SET IN OLIVE TREES |
| Authors: | I.C. Porlingis, D.G. Voyiatzis |
| Keywords: | olive, paclobutrazol, fruit set, heat tolerance |
| Abstract:
Since high temperatures (>32°C) during the flowering and the immediately following period reduce or even eliminate fruit set in the olive, the possibility of preventing this damaging effect by using PBZ was tested in three experiments. Potted trees of the cvs. Amphissis and Chalkidikis were treated with PBZ, applied as a drench, at least 25 days before the beginning of the flowering period. In "Amphissis" trees, treated with PBZ (500 mg/plant) and exposed outdoors to a max. T° of 32°C in the blooming period and to 35°C for one week after its termination, an increase in the fruit set compared with the control (23.1% vs 12.6%) was observed. Exposure of "Chalkidikis" trees to a maximum T° of 35°C during the flowering period and 37°C afterwards resulted in 1.4% and 14.8% fruit set in control and PBZ (500 mg/plant) treated plants, respectively. In the third experiment, control and treated plants of both cultivars remaining outdoors under normal T° (max. T°: 17–32°C) set almost equal number of fruits. In similar trees subjected to high T° (36–41°C) in a greenhouse for 5 days after the end of the flowering period, fruit set was reduced, the reduction being much greater in the control plants. PBZ, by inducing tolerance in olive trees to high T° and possibly to low relative humidity ensured a satisfactory fruit set. In the year after the PBZ application, under normal T° Conditions, fruit production of treated trees was equal or smaller than that of the control trees. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
