Moltiplicazione dell'olivo e vivaismo olivicolo in Italia - Review

The olive nursery industry was founded in Tuscany (Italy) in the second half of the nineteenth century, and today the main production centers are located in Tuscany, Apulia, Calabria and Sicily. In these centers the most important propagation techniques used are grafting, cutting and, to a lesser extent, micropropagation. The paper comments, through an historical analysis, on the innovations achieved in the field of olive propagation (by grafting, cuttings and micropropagation) and highlights the "weak points" of the Italian olive nursery system. The mist system is now the standard method for olive propagation, and mist propagation is made effective by a combination of modern propagating facilities and automated systems. IBA and NAA are still the most effective auxins for rooting, and their action has been improved by associating polyamines or cyclodextrins. New compounds should be tested, other than auxins, to have a more effective activity in stimulating the formation of adventitious roots, and the molecular basis of the process should be understood. This would allow the cuttings to be pretreated or cotreated, for them to respond to auxin applications with high rooting percentages. As far as grafted plants are concerned, the nurseries have achieved a top efficiency, with success rates of almost 100%, and the technique is very functional since it allows cultivars with low or nil rooting ability (particularly in the case of many cultivars intended for table olive production) to be propagated. Presently research is focused on the selection of clonal rootstocks, able to increase plant resistance to biotic and abiotic stress, and whole plant architecture. In vitro propagation of olive cultivars has been used with success, and could be an important sector of the olive tree nursery. At present some 33 olive varieties have been micropropagated. Micropropagated plants, though, are expensive because they are extremely labor intensive; it is therefore necessary to focus research on the automation of the process to reduce costs. Plant growth in the nursery is based on the “container system”; the improvements in plant production, to increase the performance and reduce plant prices, concerned the introduction of new types of containers and substrates, the setting up of a protocol of fertigation and symbiotic complex between the olive roots and arbuscular mycorrizhae. Finally, particular attention is given to the genetic true-to-typeness and plant health certifications of the plants produced. The broadening of the varietal standard, advances in propagation techniques and nursery plant production, and certified plants are the key points for the development of the olive nursery industry in Italy. Riassunto Il vivaismo olivicolo in Italia nasce nella seconda metà dell’ottocento in Toscana e ad oggi i principali centri di produzione sono localizzati in Toscana, Puglia, Calabria e Sicilia. Le tecniche di propagazione principalmente utilizzate in questi centri sono innesto, talea e, in minor misura, micropropagazione. La produzione di olivo italiana risulta essere soddisfacente malgrado problemi strutturali e tecnologici che accompagnano il settore. Il lavoro propone, attraverso un’analisi temporale, le innovazioni ottenute nel settore della propagazione dell’olivo (innesto, talea e micropropagazione) ed evidenzia “i punti deboli” del sistema vivaistico italiano. Una particolare attenzione è data alle normative per la certificazione genetico-sanitaria delle piante prodotte. L’ampliamento della base varietale, i progressi nelle tecniche di propagazione e produzione e la disponibilità di piante certificate sono i punti chiave dello sviluppo del vivaismo in Italia.