Gemesne et al. (2006) as well as Lantos et al. (2009) reported on similar results by applying the method of a-six-day incubation in vitro on the medium containing 400 mg dm-3 of colchicine, both for rooted plants and for apical plant parts. In the present experiment in the first cycle of colchicine treatment, despite the same concentration of the compound and the treatment time, the diploidization effectiveness ranged from 17% to 27%.