Study of Effective Factors on in vitro Regeneration from Dwarf Rootstock of Apple, Malus domestica Borkh cv Gami Almasi

Gami Almasi is a dwarf rootstock of apple which was originated from North West of Iran. This rootstock can be used as a dwarf rootstock for most cultivars of the apple. Shoot regeneration step is a critical factor in apple’s in vitro proliferation and Agrobacterium mediated gene transformation. The regeneration potential is different among cultivars and must be optimized for individual genotypes. In this experiment، we tested different kind of factors that may affect the regeneration efficiency. Two explant type، leaf & callus، two regeneration medium with MS & N6 (modified) basal medium and also various combinations of BA and NAA level were used. Callus and leaves were taken from in vitro established shoots as explants. After eight weeks shoot regeneration rate، callus induction rate and mean of shoot number per leaf were measured. Results indicated that MS medium was better than N6 for shoot regeneration and optimum phytohormons concentrations were achieved in 7. 5mg/l BA and 2mg/l NAA. Regenerated shoots were obtained only from in vitro leaves، and callus didn''t regenerate any shoot. Cutting the surface of the shoots usually enhanced the regeneration from leaves.