ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
CENTRIFUGAL TRAINING IN APPLE - APPRAISAL OF A TWO-YEAR EXPERIMENT ON 'GALAXY' IN SOUTHEAST FRANCE |
| Authors: | P.-E. Lauri, X. Crété, G. Ferré |
| Keywords: | extinction, centrifugal training, regularity of bearing, fruit size |
| Abstract:
Most training systems suitable for intensive apple orchard production are based on a simple tree shape composed of a central, usually vertical, trunk bearing regularly spaced side branches. Apart from the planting distances and the support system, the training and planting systems determine the trunk height, scaffold length and number, and the use of training tools such as timing and pruning intensity, and shoot bending. In France, since the beginning of the 1990s, the Vertical Axis system has evolved towards the Solaxe system, which involves less pruning and more shoot bending. Within the last few years, spur density and crop regulation have been achieved through artificial extinction, which is the complete and definitive removal of fruiting spurs. According to this concept, chemical- and hand-thinning are used as complementary tools to adjust crop load. As a general rule, especially on colored cultivars, extinction is carried out more specifically in the center of the tree and on the underside of branches to remove potentially poor-quality fruits and to improve light distribution within the tree. This training procedure is known as centrifugal training. An experiment was carried out for two years on 'Galaxy' trees with two objectives. The first one was to compare two methods of crop regulation: chemical and hand-thinning only, on original solaxe-trained trees, and extinction with complementary thinning on centrifugal-trained trees. The second objective was to compare the effects of the phenological stage at which extinction was performed on centrifugal-trained trees. In both experiments, the differences in yield and return bloom were analysed. Centrifugal training with extinction carried out at a period from bloom to fruit-set improved fruit size in the same year, as well as return bloom and fruit size in the following year. | |
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