Factors influencing the regeneration capacity of oilseed rape and cauliflower in transformation experiments

The efficiency ofAgrobacterium-based transformation technique in oilseed rape and cauliflower was influenced by cultivar specificity, donor plant age and explant type. Marked differences in demands for plant hormone 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-month-old aseptically grown plants. The regeneration was markedly species-dependent. Regeneration of transformed plants from stem segments and thin layers isolated from field-grown oilseed rape plants (at the most 2% of regenerating explants) and from oilseed rape hypocotyls (0.8% of regenerating explants) and cauliflower (1.2% of explant regenerated transformed shoots) was achieved after disarmedAgrobacterium treatment. Hypersensitive reaction of explants could be prevented by using prolongedin vitro precultivation and delayed application of the selective agent.