Extraction of disomic addition lines of Brassica napus – B. nigra

The hybrid Brassica napus × B. nigra was produced and backcrossed three times to rapeseed. BC3 genotypes with one or two additional chromosomes were either selfed or haplodiploidized by using anther culture followed by colchicine doubling. Thirty-four fertile disomic addition lines have so far been obtained. Meiotic pairing in most of them was close to 20 II at metaphase I of meiosis. Their characterization is in progress. This material obtained for the first time in B. napus should be of great interest in the study of genome structure and basic chromosome number in Brassica species.Key words: Brassica, genome, disomic addition lines, meiotic behaviour.