Olive cultivars suitability for high-density orchards

Abstract

A new olive orchard type, based on high-density planting, was introduced in Tunisia in 2000 by some investors, using mainly ‘Arbequina’, the most utilized cultivar up to that time in Spain and in some other countries. Limited cultivar choice is in fact considered one of the main inconvenients for using high planting densities in olive. Therefore, a comparative trial was set up in 2003 to evaluate the suitability of four olive cultivars (‘Arbosana’, ‘Arbequina i-18’, ‘Chemlali’ and ‘Chetoui’) to a planting density of 1250 trees ha–1. The results showed that the local cultivars ‘Chemlali’ and ‘Chetoui’ were more vigorous than ‘Arbosana’. However, ‘Arbosana’ and ‘Arbequina i-18’ presented the highest fruit yield in comparison to the local ones. Furthermore, ‘Arbosana’ showed the highest accumulated fruit yield after the first five harvests and the highest crop efficiency (0.56-1.52 kg m–3 of tree canopy). Also, ‘Arbosana’ and ‘Arbequina i-18’ presented the lowest alternate bearing indexes (0.38 and 0.44, respectively) during that period of time. Significant differences among cultivars for oil content and fatty acid composition were observed. The oleic acid content was high in ‘Arbosana’ and ‘Chetoui’ (69.4-66.7%) and intermediate to low in ‘Arbequina-i18’ and ‘Chemlali’ (64.9-56.1%). The high vigour and low production of the studied Tunisian cultivars show that it is not advisable to use them in high-density orchards. ‘Arbosana’ was the most adapted cultivar to this new planting density system in this trial.