Résumé
Tree architecture is of major importance for the agronomic performance of fruit tree orchards. It influences tree adaptability to cultivations systems, but also yields and fruit quality. In the present study, we aim at investigating the genetic determinism of architectural traits in the olive tree. A F1 hybrid population was created between two genotypes with contrasted architectures, ‘Olivière’ and ‘Arbequina’. A phenotyping methodology was applied to analyze traits related to growth, branching and fruiting behaviour, that were measured during the first 4 years of tree growth. Taking into account the influence of tree ontogeny, the phenotypic variability was decomposed into genotypic and residual effects in order to identify the most heritable characters. Topological and geometrical variables showed relatively low to medium broad sense heritability values. The highest heritability values were found for the number of internodes and short laterals per growth unit, and the mean internodes length with H2 value greater than 0.5. Flowering variables showed high heritability values exceeding 0.6. A first QTL (quantitative trait loci) was detected for the number of lateral inflorescences, on the basis of a framework genetic map constructed with 44 SSR loci and 494 AFLP markers.