In vitro propagation of olive (Olea europaea L.) cv. Koroneiki

Single node explants of 'Koroneiki' olive trees werecultured for one month on a modified Driver-Kuniyuki for Walnut medium, lackinggrowth regulators. The explants were subcultured once a month on a mediumsupplemented with zeatin riboside, 6-(γ-γ-dimethylallylamino)purine,6-benzyladenine or thidiazuron. Zeatin riboside proved to be superior to othercytokinins in inducing shoot proliferation. The combination of olive knotextract at 25 or 50 mg l−1 with cytokininssuppressed shoot proliferation. After two months at the proliferation stage,theexplants were cultured for one week in the dark in 1 ml liquidWoody Plant Medium supplemented with IBA, α-NAA or IBA+α-NAA. Theexplants were then transferred to the same solid medium lacking growthregulators, with a small layer of perlite on the surface. The combination ofthetwo auxins at 1+1 mg l−1 resulted in almost 76%rooting. The combination of olive knot extract at 50 mgl−1 with auxins increased the rooting percentage up toalmost 87%. Artificial infection of explants with the bacteriumPseudomonas savastanoi pv. savastanoiinhibited rhizogenesis, even in the presence of auxins. Rooted explants weresuccessfully acclimatised under a mist system, with the survival rate reachingalmost 75%.