Field Performance of Olive Somaclones Derived from Somatic Embryos

Mature olive plants were obtained from embryogenic tissue induced on immature cotyledon portions (seeds of 1989) of 'Frangivento'. The embryogenic tissues were subcultured for three years (long term embryogenic cultures). A part of the somaclonal plantlets, derived from the same cotyledon, was established in the greenhouse and cultured in pots from 1993 until 1997. In 1998, the somatic plants were planted in the field, and 'Frangivento' micropropagated plants were used as putative control. Phenotype evaluation of the 9 year old plants was carried out. The somatic olive plants showed different developmental behaviour. Statistical analysis on thirty morphological traits of the plants showed two types of variation: BOS (bushy olive somaclone) characterized by reduced plant height, reduction of dimensions of leaf, inflorescence and fruit and increase of feather shoots number and COS (columnar olive somaclone) characterized by increased plant height, canopy projection, canopy volume, fruit and pit dimensions in respect to the putative control plants. At this time, the cause of the variations is unknown, but the research shows the somaclonal variation could be found in olive plants regenerated through somatic embryogenesis; this appears in mature plants cultured in the field.