Modification of cultivar-specific regeneration capacity of potato expiants by phytohormones and byAgrobacterium oncogenes

To overcome low, genotype dependent regeneration capacity of some commercially important potato cultivars, two alternative treatments of stem primary expiants were employed: modification of the hormonal composition of inductive MS medium and insertion of someAgrobacterium oncogenes. A replacement of 6-BAP with zeatin in the inductive MS medium stimulated bud/shoot formation in only two of three tested cultivars with naturally low regeneration capacity. GA3 did not affect the bud initiation phase (i.e. regeneration capacity of cultivars), it only stimulated shoot development. The insertion of some bacterial oncogenes (in particular genes 4, rolB, C and 5) enhanced bud/shoot formation, especially in the case of low-regenerating cultivars.