Optimization of in vitro regeneration in European Plum.

In vitro regeneration is the fundamental technology for development of a genetic transformation method which can be used for introduction of Plum pox virus resistance into the plum (Prunus domestica L.) crop. Research was conducted to evaluate and optimize different factors for European plum regeneration. Different sections of hypocotyl explants showed significantly different degrees for shoot induction and proximal region exhibited the highest for regeneration response. This indicates cells in different parts of the hypocotyls are genetically different with respect to cell dedifferentiation. Cotyledons of mature stored seeds showed active response for in vitro culture. The proximal region of cotyledons was more responsive to shoot induction compared to distal region. Research indicated that cotyledons are a new type of explants for plant regeneration for European plums. Shoots can be induced from different types of media using hypocotyls and cotyledons. However, B5 medium was more effective for shoot induction using different sections of hypocotyls and cotyledons. Addition of 2,4-D in medium can enhance regeneration but optimal time exposure to the growth regulator is important for effective stimulation for cell dedifferentiation.