Microspore culture of winter oil rapeseed (Brassica napus) - II. Embryo conversion, plant regeneration and double haploid production of Brassica napus L.

Somatic embryos obtained via microspore culture of Brassica napus have been used for study plant regeneration and double haploid production. Two mode of plant regeneration were ob- served: direct embryo germination and secondary adventitious buds formation. Different number of plants have been obtained for studied genotypes. Improved direct embryo development was achieved when ABA in concentration 10 mu mol for 14 days at 15 degrees C was applied. Plants were successfully colchicine treated in in vitro rooting stage by double layer media. Colchicine solution in 0.1% concentration added as a second layer for 24 hours was optimal for double haploid production and did not suppress significantly plant development. Colchicine treatment of pot plants by cuttings or roots delay 3-4 months seeds harvesting. Sufficient number of double haploid plants for breeding purposes have been obtained.