AbstractRed raspberry, commercially the most important of the Rubus species, has proven extremely recalcitrant in tissue culture. This has led to problems in the micropropagation of new and existing varieties for release to industry, and has greatly hampered the application of technologies such as genetic modification to raspberry improvement. The activity of N- (2-chloro-4-pyridyl)-N-phenylurea (CPPU), a synthetic compound with cytokinin-like activity, was investigated for use in improving the micropropagation of whole shoots and on its ability to induce organogenesis in raspberry. Significantly improved micropropagation rates and whole-plant regeneration through organogenesis were achieved by the use of medium containing low concentrations of CPPU for recalcitrant red raspberry cultivars, typical of the available germplasm. The effect of CPPU on a blackberry and a red raspberry x blackberry hybrid, both of which can efficiently be induced to undergo micropropagation and organogenesis was also examined, although the results were less successful than those achieved in previous work. A pilot transformation experiment was set up to ensure that the ability of CPPU to induce organogenesis was not eliminated when combined with Agrobacterium infection and with antibiotics in the regeneration/selection medium.