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A cyclic system of somatic embryogenesis from mature tissues of olive (Olea europaea L.) and subsequent plant recovery were developed. The primary embryos originated from morphogenetic masses derived from petioles of shoots regenerated from tissues of two micropropagated cultivars: Canino and Moraiolo. The rejuvenation acquired by the shoots by regeneration, directly from petiole tissues or indirectly from petiole callus, seems to be essential for the subsequent somatic embryogenesis induction. Cyclic embryogenesis, both from normal embryos or teratoma, was obtained on modified olive medium (OMe) plus 0.5 μM; 6dimethylaminopurine, 0.44 μM 6-benzylaminopurine, 0.25 μM 3-indolebutyric acid and 0.42 mM cefotaxime. The production of normal embryos was higher, faster and often more clustered on a filter paper liquid medium or on a media solidified with phytagel than with agar. The capacity to produce continuous cycles of successive embryos has been maintained for over two years only in the dark, since the light inhibited embryo induction. The embryogenetic capacity was qualitatively and quantitatively enhanced by adding 0.42 mM cefotaxime. Mature embryos germinated easily by increasing the amount of liquid medium with shake culture. Although the majority of embryos appeared vitrified when transplanted to Jiffy-7 pots, they subsequently grew normally and were similar to those derived from nonvitrified embryos. The plantlets obtained from somatic embryos appeared to be morphologically similar to those produced from axillary buds.

Leaf discs from olive (Olea europaea L.) grown in vitro and immature zygotic embryos collected at 50, 75, 90 and 105 days after full bloom were tested for their somatic embryogenic capacity. The embryos were grown in half-strength MS medium and halfstrength OM medium with BAP combinated with either 2,4-D or NAA. Incubation was either in an initial dark period followed by 16h daylight or in 16h daylight throughout. Somatic embryogenesis, approx. 40%, mostly directly from the embryos, was observed only in 75-dayold embryos in medium containing low cytokinin and auxin concentrations. Differentiation was inhibited by 2,4-D whereas NAA did not. In leaf discs and younger and older zygotic embryos, only callus and root formation was observed. Somatic embryos were germinated and then potted-up to soil.

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