Résumé
There is a strong demand from growers to improve knowledge of the natural tree growth and fruiting habit to adapt plantation density and training methods to each cultivar. Since 1995, INRA Montpellier worked on this theme at three levels: whole tree, branch, and annual growth. For three years (2001 to 2003), an analysis of vegetative growth and entrance into fruit production was carried out on young (5th to 7th year of growth in the orchard) untrained own-rooted olive trees belonging to ten cultivars (Aglandau, Arbequina, Cailletier, Cornicabra, Cypressino, Grossane, Lucques, Olivière, Picholine du Languedoc and Verdale de l'Hérault) grown in Southern France. Five vegetative variables (trunk bottom diameter, tree height, tree width in and across row axis, tree volume) and one reproductive variable (weight of fruits per tree) were measured. It was observed that for all data, whatever the cultivar, there were strong correlations between vegetative variables (r ≥ 0.60). On the other hand there was no relationship between vegetative growth variables and fruit weight. Cultivars were well characterized by their vegetative growth characteristics, with the same ranking of the cultivars along the three-year study. Thanks to ANOVA, they were categorized into four groups of trunk bottom diameter, three groups of inter-rank width and two groups of entrance into production (five cultivars with an already strong alternate bearing trend, the others for which it is not yet defined). The practical implications of this study are discussed in relation to plantation density in the orchard according to tree vigour and volume.