Important progress in the improvement of Citrus fruits rootstocks stems from the intergeneric sexed hybridization. Many hybridization projects between Citrus and Poncirus led to the selection of performing cultivars as the Citrange (Poncirus x orange) and Citrumelo (Poncirus x pomelo). In return, hybridizations with more distant genera such as Glycosmis, Murraya, Triphasia, Clausena didn't produce seeds. The somatic hybridization methods allow to bypass these incompatibility barriers