BRASSICA-CARINATA RESYNTHESIZED BY PROTOPLAST FUSION

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