The influence of mychorrizae on the vegetative growth of five Olea europaea cultivars

The artificial mychorrization, in nursery phase, becomes useful particularly when the populations of native fungi are not present or have been reduced by intensive agricultural practices. We show preliminary results on the effects of mychorrizic symbiosis induced in five cultivars of Olea europaea: Carolea, Coratina, Maiatica of Ferrandina, Leccino and Tondina. During the experimentation, self-rooted cuttings, approximately 500 per each cultivar, were inoculated, in correspondence of the two transplants in pot, with: Glomus intraradices, Glomus spp., Glomus spp. + Trichoderma sp. + bacteria. The plants have been grown, according the ordinary management techniques, guaranteeing an optimal water status and apporting limited fertilization. The percentage of mychorrizic colonization has been high, with values to 100%, while the intensity of mychorrization results variable, from 20 to 50%. Destructive and not-destructive biometric measurements were carried out to estimate eventual variations in terms of plant growing rate and stored dry matter. Altogether, in the first eighteen months, all the inoculated treatments showed greater increments, from 8 to 20%, than controls; Glomus intraradices determined the best result, +20%. However, a strong interaction inoculo-cultivar emerges; Maiatica cultivar, in fact, reached higher stem diametrical increments, +20%, with the Glomus spp.; Carolea cultivar, +11%, and Coratina, +33%, with the Glomus spp. + Trichoderma sp. + bacteria; Leccino and Tondina confirmed the efficiency of Glomus intraradices, +29% and +24%, respectively.