Somatic cell hybridization of 'oxy' CMS Brassica juncea (AABB) with B.oleracea (CC) for correction of chlorosis and transfer of novel organelle combinations to allotetraploid brassicas

Alloplasmic lines of cultivated Brassica species with B. oxyrrhina cytoplas m are male-sterile and suffer from severe chlorosis. We developed male-ster ile lines corrected for chlorosis by fusing protoplasts of CMS B. juncea (A ABB) with 'oxy' cytoplasm and normal B. oleracea (CC). A large number of ma le-sterile AABBCC somatic hybrids with desirable organelle combinations, i. e. chloroplasts of B. oleracea and mitochondria with recombinant genomes, w ere recovered. While no recombination was observed in the chloroplast genom e, the mitochondrial genome showed extensive recombination that resulted in the appearance of totally novel banding patterns in some of the hybrids. H ybrids with a parental-type mitochondrial genome as well as recombinant pat terns close to either of the parental types were also obtained. Using AABBC C somatic hybrids as bridging material, we transferred the desirable organe lle combinations to B. juncea (AABB), B. napus (AACC), and B. carinata (BBC C). Many of these lines are now at advanced stages of backcrossing and show stable inheritance of the CMS character and do not suffer from chlorosis.