Intergeneric transfer of cytoplasmic male sterility between Raphanus sativus (cms line) and Brassica napus through cytoplast-protoplast fusion.

Cytoplasts isolated from hypocotyl protoplasts of Raphanus sativus cv Kosena (cms line) by ultracentrifugation through Percoll/mannitol discontinuous gradient were fused with iodoacetamide(IOA)-treated protoplasts of Brassica napus cv Westar. Seventeen randomly selected regenerated plants were characterized for morphology and chromosome numbers. All of the regenerated plants had morphology identical to B. napus and 10 of them possessed the diploid chromosome number of B. napus. The remaining plants had chimeric or aneuploid chromosome numbers. The mitochondrial genomes in the 10 fusion products possessing the diploid chromosome numbers of B. napus were examined by Southern hybridization analysis. Four of the 10 plants contained mitochondrial DNA showing novel hybridization patterns. Of these 4 plants, 1 was male sterile, and 3 were male fertile. The remaining plants showed mitochondrial DNA patterns identical to B. napus and were male fertile.