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-(γ,γ-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 micromolar zeatin. The number of microshoots/explant and proliferation rate increased to 1.85 and 6.8, respectively, by using the combination of 5-20 micromolar zeatin with 1 micromolar BA, but shoot height was reduced. 2iP was the least effective of the cytokinins tested. Combination of 20 micromolar zeatin with 10 micromolar 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 micromolar 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), α-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 micromolar IBA + 3 micromolar 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 micromolar 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%).