Transfer of petaloid cytoplasmic male sterility (CMS) in carrot with the routine backcross method needs at least 5-6 years, while the time could be saved largely by using the asymmetric protoplast fusion method to transfer this male sterility, and breeding progress could be speeded up. Based on the study of Tanno Suenaga et al, much research work was conducted on the carrot asymmetric protoplast fusion basic systems; 61 times of asymmetric protoplast fusion in carrot had been made, callus and em...