ISHS Acta Horticulturae 451: VI International Symposium on Integrated Canopy, Rootstock, Environmental Physiology in Orchard Systems
VEGETATIVE GROWTH AND REPRODUCTIVE STRATEGIES IN APPLE FRUITING BRANCHES - AN INVESTIGATION INTO VARIOUS CULTIVARS |
| Authors: | P.E. Lauri, J.M. Lespinasse, E. Térouanne |
| Keywords: | Apple, Malus x domestica Borkh., fruiting branch, extinction, bourse-over-bourse, spur pruning |
| DOI: | 10.17660/ActaHortic.1997.451.86 |
| Abstract:
A large proportion of modern French apple growers have adopted management systems based on manipulating "free growing" fruiting branches (Solen, and recently Solaxe). Basically, these systems need only light pruning and use the natural bending of the fruiting branch brought about by the progressive development of fruiting. In the case of erect branches (spur-type cultivars), weights are also used to hasten bending. In this context, one of the main objectives of apple growers is to improve the sustainability of these fruiting branches and the regularity of fruit production from year to year. A comprehensive approach was developed to study the type of each axillary structure (either latent, vegetative, inflorescence without a fruit or with at least one fruit, scar) on unpruned fruiting branches belonging to trees trained as Solen. Since it first developed on 1-year-old wood, the objective was to study its subsequent development in the following years. Each initial node of the fruiting branch was then characterized by a sequence of letters corresponding to the type of terminal bud of laterals observed each successive year. In a previous study we showed that two phenomena may interact in the regulation of the vegetative growth fruiting relationship of the fruiting branch. One phenomenon is the cessation of growth of a certain proportion of sequences (‘extinction’ phenomenon) and the other is the ability to string bourse over bourse in the remaining sequences. This paper reports further results which show that on regular bearing cultivars, such as ‘Granny Smith’ and ‘Red Winter’, this regulation occurred essentially within the first 2 years of sequences. The precocity of this natural regulation mechanism suggests that the effectiveness of artificial spur pruning, which is recommended for spur-type cultivars, may be enhanced if it is carried out as early as on 1- or 2-year-old wood. | |
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