Abstract: Cytoplasmic male sterility (CMS) celery is useful for hybrid seed production. Asymmetric protop last fusion of fertile celery and petaloid CMS carrot was carried out by polyethylene glycol ( PEG) 6000 treatment in order to introduce CMS from carrot to celery. Protop lasts of celerywere treated with 6 mmol·L ^{- 1}
iodoacetamide for 7 min to passivate cytoplasm, and those of carrot were continuously irradiated with UV rays(20 μmol·m^{- 2} ·s^{- 1} ) for 9 min to kill the nucleus. Low temperature (5 ℃) increased aggregation rates by 20% , and 40% PEG 6000 and 0.1 mmol·L ^{- 1} Ca²⁺ in high Ca²⁺ high pH solution were the best for fusion of two protoplasts. Twelve somatic hybrids were obtained and plants were regenerated on MS₀ medium. AFLP analysis indicated that all of them were somewhat asymmetrically fused. STS marker analysis suggested that petaloid CMS were successfully introduced into 11 regenerated plants.

Key words: celery, carrot, petaloid cytoplasmic male sterile, asymmetric somatic hybridization