Dwarf olive trees for ornamental use: A morphological evaluation

Olive (Olea europaea L.) has played a important role in human civilisation and has been central to the development of culture and food. The use of olive trees as ornamental plants has been recorded since ancient times. However, among perennial species olive is rarely recommended for decorative purposes due to its dimensions and large canopy size, which limit its use alongside roadways, for example. A dwarf olive derived by tissue culture methods was characterised morphometrically for its potential use as an ornamental tree.The morphological characters measured in dwarf and micropropagated control plants of the olive cultivar 'Frangivento', were subjected to univariate (i.e., analysis of variance) and multivariate (i.e., principal components analysis) analyses. Compared to control plants, the dwarf plants showed reduced tree height, reduced dimensions of leaves and inflorescences, and the presence of many prompt shoots (i.e., those that originated from buds that differentiated in the same year that they were formed). All these morphological characters contributed to the architecture of the dwarf plant, and were related to the regular ''rounding-off'' of the canopy. The aesthetic, ecological, and growth-habit characteristics of those biotechnologicallyproduced dwarf olive trees support their use as an ornamental plant.