In the first part of the experiment mixoploids which somatic cells contained from 1C to 8C of DNA comprised a large group of regenerants. Therefore, in the second diploidization
treatment the colchicine concentration was decreased by half and the incubation time was extended to six and nine days. Four weeks after the second colchicine treatment the growth
disorder was observed, which proved to be directly proportional to the time of explant incubation on the colchicine-containing MS medium (Table 2).