Somaclonal Variation in Olive

Tissue culture is commonly used in olive with different purposes. Apart from commercial large-scale plant production, it is applied as a complement for genetic improvement, by both conventional and unconventional methods, with efficient protocols available for genetic transformation, in vitro selection or cryopreservation. However, uncontrolled variations can be observed during tissue culture due to somaclonal variation. These alterations can suppose an important problem in culture systems requiring plant fidelity. However, somaclonal variation can also constitute an alternative source of genetic variability in breeding programs. Therefore, evaluation of somaclonal variation is recommended in order to determine the reliability of each in vitro culture procedure before its practical application. Moreover, analyzing the effect on somaclonal variation of different factors under specific in vitro culture conditions may help to control its occurrence, for either increasing its frequency or limiting its appearance, depending on the objectives of the tissue culture system. Investigations carried out in olive revealed a significant influence of the genotype, the in vitro propagation method and the length of culture period. The genotype played a main role in most works in which somaclonal variation was observed.