Integration of a transgene into a C-genome chromosome plays an important role in reducing ecological risk of transgenic Brassica napus To obtain C-genome transgenic B. napus, herbi- cide-resistant bar gene was firstly transferred into B. oleracea var. alboglabra mediated by Agrobacterium tumefaciens strain LBA4404. Then using the trans- genic B. oleracea as paternal plants and 8 non- transgenic varieties of B. rapa as maternal plants, C- genome transgenic B. napus with bar gene was arti- ficially resynthesized by means of ovary culture and chromosome doubling. Among 67 lines of the resyn- thesized B. napus, 31 were positive, and 36 were negative according to PCR test for bar gene. At least 2 plants from each line were kept for PPT spray con- firmation. The result was in consistence with the PCR test. Genomic Southern blotting of three randomly chosen lines also showed that bar gene had been integrated into the genome of resynthesized B. napus lines. Integration of a transgene into a C-genome chromosome plays an important role in reducing ecological risk of transgenic Brassica napus To obtain C-genome transgenic B. napus, herbi-cide-resistant bar gene was transferred into B. oleracea var. Alboglabra mediated by Agrobacterium tumefaciens strain LBA4404. Then using the trans-genic B. oleracea as paternal plants and 8 non-transgenic varieties of B. rapa as maternal plants, C-genome transgenic B. napus with bar gene was arti- ficially resynthesized by means of ovary culture and chromosome doubling. Among 67 lines of the resyn- thesized B. napus, 31 were positive, and 36 were negative according to PCR test for bar gene. At least 2 plants from each line were kept for PPT spray con- firmation. The result was in consistence with the PCR test. Genomic Southern blotting of three randomly selected lines also showed that bar gene had been integrated into the genome of resynthesized B. napus lines.