Morphogenic competence of Vitis rupestris S. secondary somatic embryos with a long culture history

A protocol for preserving grape embryogenic cultures indefinitely has been defined, and through recurrent cycles of secondary embryogenesis, Vitis rup estris Scheele cultures are still regenerating after 10 years. The morphoge nic competence of a sample of 1,204 somatic embryos with such a long histor y has been evaluated. Within a 15-month-long culture, secondary embryogenes is regeneration reached an average efficiency of 23%, proving that morphoge nic competence is retained during prolonged culture times. While the cultur e maintenance described here was one of the crucial aspects of our genetic transformation protocol, several V rupestris plants with various exogenous genes have been regenerated during these last 10 years.