Increased regeneration efficiency of _Brassica napus_ L. cultivars Star, Westar and Cyclone from hypocotyle and cotyledonary explants

The comparative organogenesis of _Brassica napus_ L cultivars Cyclone, Star and Westar was studied. The cotyledonary explants gave a higher response to all the combinations of 0.5 mg/L 2,4-D and BAP (0.5, 1.0,1.5 and 2.0 mg/L} used for optimizing the conditions for callus induction. The best mean weight and mean length of callus was obtained at 0.5 mg/L 2,4-D and 1.5mg/L BAP for Star cotyledonary explants. For the complete plant regeneration the new method of exposing the explants culture to Growth regulator free medium was performed. The method was applicable to both hypocotyl and cotyledonary explants. The Shoot Induction Frequency for hypocotyl (6-34%) in the three cultivars is higher than the cotyledonary explants (3-23%). The method is speedy and almost all of the shoots and some unshooted calli (78%) form roots on the same media without prior transfer to rooting medium