The main goal of this project has been to develop genetic transformation methods for the improvement of citrus cultivars important to the California industry. The two major scion cultivars of lemon (Lisbon and Eureka) were selected to serve as the primary focus for these experiments during the initial years of the program. As a result, two functional transformation systems based on organogenic regeneration were developed. One began with three- to five-week-old nucellar seedlings, whereas the other started with flush growth from mature trees. The seedling system applied only to the Eureka cultivar due to the fact that Lisbon epicotyl tissue did not regenerate.