ISHS Acta Horticulturae 903: IX International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems
IMPROVEMENT OF THE FRUIT SET OF 'JONAGOLD' APPLE |
| Authors: | J. Vercammen, A. Gomand |
| Keywords: | Malus × domestica, Amid-thin, GA4/7, Prohexadione-Ca, anti-ethylene effect, June drop |
| DOI: | 10.17660/ActaHortic.2011.903.109 |
| Abstract:
We investigated plant growth regulator treatments in several field experiments to improve fruit set of ‘Jonagold’, especially in a year with (severe) frost damage or in the “off” year in biennial orchards when there are only few flower buds. A treatment with a low dose of Amid-thin (0.25 kg/ha) or GA4/7 (0.5 L/ha Novagib) 3 to 7 days after full bloom showed a trend toward improved fruit set. Such a treatment with a low dose of Amid-thin or GA4/7 can be an insurance and the effect is comparable with a spraying with boron at low doses during flowering time. The combination of Amid-thin and GA4/7 resulted in reduced fruit set. The increased fruit set observed after a treatment with Amid-thin or GA4/7, is often transient and is often lost during June drop. Regalis (Prohexadione-Ca) sprayed between 2 and 4 weeks after full bloom showed a trend of reducing June drop, but the moment of spraying may be important and the effect is short (4 to 5 days). In contrast to pears we do not recommend to combine Amid-thin or GA4/7 and Regalis with apple. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
