FACTORS INFLUENCING THE REGENERATION CAPACITY OF OILSEED RAPE AND CAULIFLOWER IN TRANSFORMATION EXPERIMENTS

The efficiency of Agrobacterium-based transformation technique in oils eed rape and cauliflower was influenced by cultivar specificity, donor plant age and explant type. Marked differences in demands for plant h ormone contents in the regeneration medium were recorded already among different types of nontransformed explants. The highest regeneration capacity was recorded with stem and leaf segments isolated from one-mo nth-old aseptically grown plants. The regeneration was markedly specie s-dependent. Regeneration of transformed plants from stem segments and thin layers isolated from field-grown oilseed rape plants (at the mos t 2 % of regenerating explants) and from oilseed rape hypocotyls (0.8 % of regenerating explants) and cauliflower (1.2 % of explant regenera ted transformed shoots) was achieved after disarmed Agrobacterium trea tment. Hypersensitive reaction of explants could be prevented by using prolonged in vitro precultivation and delayed application of the sele ctive agent.