In vitro propagation of the Greek olive cultivar `Chondrolia Chalkidikis'

The effect of basal media (Woody Plant Medium (WPM), Quoirin and Lepoivre (QL) and Olive Medium (OM)) and of various concentrations of cytokinins (6-benzyladenine (BA), zeatin, 6-(,-dimethylallyl-amino) purine (2iP)), solely or in combinations with each other and with gibberellic acid (GA₃), on in vitro shoot proliferation of the greek olive cultivar `Chondrolia Chalkidikis' was investigated. WPM proved to be the most effective one, resulting in better morphological appearance of the microshoots produced. The highest number of new microshoots/explant (1.68), with a 3.0 cm shoot height and a 4.2 proliferation rate, was obtained when this medium was supplemented with 20 M zeatin. The number of microshoots/explant and proliferation rate increased to 1.85 and 6.8, respectively, by using the combination of 5–20 M zeatin with 1 M BA, but shoot height was reduced. 2iP was the least effective of the cytokinins tested. Combination of 20 M zeatin with 10 M GA₃ affected positively shoot proliferation resulting in 1.80 microshoots/explant, 3.0 cm shoot height and 7.0 proliferation rate. However, the same concentration of GA₃ in combination with 1 M BA reduced the number of new microshoots/explant (0.48) as well as the proliferation rate (2.4), although shoot height remained nearly the same (2.7). The effect of indole-3-butyric acid (IBA), -naphthaleneacetic acid (NAA) and putrescine on root induction was also studied. A rooting percentage of up to 70% and 2.3 roots/microshoot were achieved by the combination of 12 M IBA + 3 M NAA, however, abscission of shoot tips and leaves appeared. Both variables were increased, up to 93% and 4.0, respectively, by the addition of 30 M putrescine in the medium, without any undesired side effect. After acclimatization, survival of rooted microshoots was high (90%) while that of non-rooted ones was low (30%).