IMPROVED PROTOPLAST CULTURE AND STABILITY OF CYTOPLASMIC TRAITS IN PLANTS REGENERATED FROM LEAF PROTOPLASTS OF CAULIFLOWER (BRASSICA-OLERACEA SSP BOTRYTIS)

Nearly 1000 plants have been regenerated from leaf protoplasts of two cauliflower (Brassica oleracea ssp. botrytis) alloplasmic inbred lines. One line (7642A) carried the Ogura (R1) cms cytoplasm derived from radish; the other line (7642B) carried a normal Brassica cytoplasm and was the fertile maintainer for the cms line. The majority of regenerated plants displayed normal vegetative morphology; they formed normal cauliflower heads and retained the floral characteristics of seed-grown plants from which they were derived. We found no change in either male sterility or in the low temperature-induced chlorosis associated with the 7642A line. Mitochondrial DNA analysis by hybridization with five cloned mtDNA probes revealed no apparent alteration in 75 regenerated plants of both lines. These results indicate that cytoplasmic traits in Brassica oleracea are stable after one cycle of in vitro culture and regeneration. © 1990 Kluwer Academic Publishers.