BRASSICA-CARINATA RESYNTHESIZED BY PROTOPLAST FUSION

Brassica carinata (bbcc) was resynthesized by protoplast fusion between B. nigra (bb) and B. oleracea (cc). In two fusion experiments 64 hybrid plants were obtained and identified to be true hybrids by isoenzyme analysis, nuclear DNA content, chromosome number, and intermediate morphology. Of these plants 56 % were normal amphidiploids with 2n = 34 chromosomes and a DNA content equivalent to that of natural B. carinata. The remaining plants were polyploid, morphologically abnormal, and infertile. The majority of the hybrids contained both chloroplasts and mitochondria from B. nigra, but some plants combined chloroplast and mitochondria from the different progenitors. Hybrids with a DNA content equivalent to that of B. carinata had a wide range of male fertility (4-98 %), but consistently low female fertility. Only a few selfed seed were produced, but these germinated and grew into vigorous plants.