Alloplasmic lines of cultivated
Brassica species with
B. oxyrrhina cytoplasm are male-sterile and suffer from severe chlorosis. We developed male-sterile lines corrected for chlorosis by fusing
protoplasts of CMS
B. juncea (AABB) with ’
oxy’ cytoplasm and normal
B. oleracea (CC). A large number of male-sterile AABBCC somatic hybrids with desirable organelle combinations, i.e. chloroplasts of
B. oleracea and mitochondria with recombinant genomes, were recovered. While no recombination was observed in the chloroplast genome,
the mitochondrial genome showed extensive recombination that resulted in the appearance of totally novel banding patterns
in some of the hybrids. Hybrids with a parental-type mitochondrial genome as well as recombinant patterns close to either
of the parental types were also obtained. Using AABBCC somatic hybrids as bridging material, we transferred the desirable
organelle combinations to
B. juncea (AABB),
B. napus (AACC), and
B. carinata (BBCC). 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.
Key words Brassica - CMS - Somatic hybrids - Correction of chlorosis - Mitochondrial recombination
Received: 9 August 1999 / Accepted: 14 September 1999