Architectural characteristics of six olive cultivars with respect to their suitability for high density orchards

In a high density (1,250 trees ha-1) olive orchard in central Italy, the architectural characteristics of ‘Arbequina’, ‘Arbosana’, ‘Koroneiki’, ‘FS17’, ‘Don Carlo’ and ‘Giulia’ cultivars was studied. Tree height, canopy dimensions, trunk diameter at 0.20, 0.75, 1.5, 2.0 m from the ground, branch intersection height along the trunk, diameter and length of the primary branches were measured in 2010, when trees were 2-year-old. On sampled branches at different height, all the productive and vegetative shoots were spatially described. Tree height, trunk diameter and canopy volume were not significantly different among cultivars, while the number of primary branches was lower in ‘FS17’ compared to ‘Arbequina’, ‘Arbosana’ and ‘Koroneiki’. The studied cultivars had different branching patterns along the trunk: a low density between 1 and 1.5 m trunk height in ‘FS17’ and a high between 1.5 and 2.0 m in ‘Arbequina’. Moreover, the length/diameter ratio of the primary branches was low and high in ‘Arbosana’ and ‘Giulia’ and in ‘Arbequina’, respectively. ‘Arbequina’ also showed a uniform shoot density along the main axis of the primary branch, whereas an alternate shoot density with the presence of empty portions was observed in the other cultivars. A higher shoot density in the medium-proximal portion of the branch was seen for ‘Arbosana’ and ‘FS17’. Results presented in this study supply helpful information about the different canopy and branch architectural characteristics of the six studied olive cultivars with respect to their suitability to high density plantations.