An efficient regeneration system was established by using in vitro plantlets of germinated seedlings from different cultivars of lettuce (Lactuca sativa cv. Chongchima, Chongchuckmyun, Jeokchima, Jeokchuckmyun). Shoot formation were observed from all cultivars on MS medium supplemented with 0.1 mg/L NAA and 0.5 mg/L BA. In all cultivars, when cotyledon was cultured, the number of shoot per explant was more greater than that hypocotyl and leaf disc were cultured. Shoot formation rate (91.7%) was high in a cotyledon culture of cultivar, Chongchukmyun. The growth of multiple shoots derived from the cultivar, Chongchukmyun, was most effective on medium containing 0.5 mg/L BA and 1.0 mg/L GA3. When shoots were transferred on MS medium without plant growth regulators, roots were effectively differentiated. Rooted plantlets were acclimated on pots for further propagation.

• Young-Sook Kim
• Tea-Ho Kwon