ASSESSMENT OF TRANSGENE ESCAPE FROM BRASSICA-RAPA (BRASSICA-CAMPESTRIS) INTO BRASSICA-NIGRA OR SINAPIS-ARVENSIS

The possibility of gene transfer between Brassica rapa and the two wee dy species B. nigra and Sinapis arvensis was evaluated with the specia l concern on transgene escape from B. rapa to these two weedy species. B. rapa cultivar Tobin was reciprocally crossed to five and four stra ins of B. nigra and S. arvensis, respectively, using controlled cross. A single interspecific hybrid was obtained from the cross B. rapa x B . nigra, but no other cross was successful. The fertility of this hybr id on open pollination, selfing and backcrosses was investigated. The data of the present study and the information available to date indica te that gene transfer between B. rapa and B. nigra is possible. The ch alice of transgene escape From B. rapa to B. nigra depends essentially on whether natural cross can occur between these two species. Gene tr ansfer between B. rapa and S. arvensis is at the most difficult, where as transgene escape directly from B. rapa to S. arvensis appears very unlikely.