AN EVALUATION OF THE POTENTIAL OF INTERGENERIC GENE-TRANSFER BETWEEN BRASSICA-NAPUS AND SINAPIS-ARVENSIS

The possibility of gene transfer between Brassica napus and Sinapis ar vensis was evaluated. Six spring-type cultivars of B. napus and four s trains of S. arvensis were reciprocally crossed through controlled cro sses. No hybrid was yielded from any cross. However, one hybrid with 2 8 chromosomes was obtained from B. napus x S. arvensis through ovule c ulture. The hybrid plant was highly sterile and set no seed on open po llination. Two F-2 plants, with 35 and 36 chromosomes respectively, we re obtained through self-pollination by hand. Backcross of B. napus pr oduced 23 plants carrying some characteristics of S. arvensis, but bac kcross to S. arvensis failed to produce a plant. The chromosome counts of the BC1F1 plants indicated that gametes with more than nine chromo somes were favoured during the meiosis. The data demonstrated that gen e transfer from S. arvensis to B. napus was very difficult under contr olled cross and backcross, while to transfer genes from B. napus to S. arvensis would be extremely remote even under the most favorable cond itions.