STABLE TRANSFORMATION OF LETTUCE CULTIVAR SOUTH BAY FROM COTYLEDON EXPLANTS

Transgenic plants of lettuce cultivar (cv.) 'South Bay' were produced by using Agrobacterium tumefaciens vectors containing the beta-glucuro nidase (GUS) reporter gene and the NPT II gene for kanamycin resistanc e as a selectable marker. High frequency of transformation, based on k anamycin resistance and assays for GUS expression, was obtained with 2 4 to 72-h-old cotyledon explants cocultivated for 48 h with Agrobacter ium tumefaciens. After the cocultivation period, the explants were pla ced in selection medium containing 50 or 100 mg l-1 of kanamycin, 100 mg l-1 cefotaxime and 500 mg l-1 carbenicillin for 10 days. Surviving explants were transferred every 14 days on shoot elongation medium. Pr ogenies of R0 plants demonstrated linked monogenic segregation for kan amycin resistance and GUS activity.