Preliminary results on the encapsulation of vitro-derived explants in olive.

In the last twenty years the in vitro plant propagation had a remarkable impulse, with a particular interest for the great potentialities that this technique offers in the search and in the nursery activity. The interest for plant tissue culture is increasing also in the olive nursery, because it is more productive in comparison with the traditional methods employed for vegetative multiplication. To prevent the introduction of pests or diseases, many Countries have restrictive laws when they import plant material produced in other Countries by cutting or grafting. In vitro propagation techniques can overcome these problems and permit to produce a large number of genetically homogenous and pest free plants. However, the transport of micropropagated plantlets is difficult because temperature and/or fluctuation in relative humidity can damage plantlets, just after acclimatization or during transport in glass-container. The encapsulation in sodium alginate matrix of the in vitro-derived explants can represent one solution for these difficulties. In accord to these considerations, experiments were conducted to examine the possibility to encapsulate uninodal explants (microcuttings), collected from proliferated shoots of several olive cultivars (‘Coratina’, ‘Correggiolo’, ‘Dolce Agogia’ and ‘Raggia’). Three-four millimetre long microcuttings were encapsulated in a sodium alginate matrix and sown in agar medium; after 45 days in growth chamber, viability and regrowth ability were monitored. The results of the experiments permit to consider the encapsulation technology, applied to micropropagated microcuttings of olive, potentially able to ensure transport of olive genotypes for long distance. In fact, in ‘Coratina’ were recorded 72.2% of viability and from 61.1% of the encapsulated microcuttings shoots were sprouted. Encapsulated microcuttings of the other olive cultivars showed viability and regrowth ability values ranging from 33,3 to 56,7%.