Most transformation systems rely on antibiotic-based selection markers as mentioned above. In edible crops, the use of these genes are now expected to be avoided because of public fear for their possible toxicity or allergenicity to humans and other organisms, even though such possibility is quite low. Another problem caused by the use of antibiotics is the difficulty for gene stacking by repeated introduction of foreign genes because of the difficulty to use the same selection markers for the transformation. Although orchids are non-consumables and may have minimized problems for public perception, repeated transformation with several desirable genes will eventually be needed for producing desirable commercial cultivars. On this point, marker-free systems such as the MAT (Multi-Auto-Transformation) vector system (Ebinuma and Komamine, 2001) and Cre-Lox or other site-specific recombination systems (Lyznik et al., 2007) have been developed and successfully applied for some ornamental plants although there are no reports yet on orchids. The escape of transgenes into the environment or into cultivated crops are also factors that need to be carefully assessed when developing transgenic orchids (Dobres, 2008 and Schnell et al., 2011).