[[abstract]]為了解多胚柑桔之珠心胚與有性胚發育的情況，以提高雜交育種的效率，以雪柑為母本，分別與枳殼、晚侖夏橙 (Valencia) 鳳梨橙(Pineapple) 雜交。於授粉後80、100、120及140天採收果實，於解剖顯微鏡下調查胚數;以枳殼授粉者並播種於MS培養墓，以探討有性胚苗的獲得率。結果顯示，在調查的過程申，所增加的胚數甚少，尤其是晚侖夏橙與枳殼授粉者，且Stage I 之小胚在授粉後第80至第100天明顯減少，顯示大部份的胚應同時發育，早期胚培養以取得有性胚的方法，在本試驗之什交組合中並不適用。以枳殼授粉者，什交苗的獲得率，隨種子之成熟而增加，因此以胚培養提高什交苗之獲得機會，應以種子即將成熟時較為容易。 'Shueh-ken' orange (C. sinensis Osbeck.) was pollinated with 'Valencia', 'Pineapple' and trifoliate oranges. Fruits were harvested 80, 100, 120 and 140 days after pollination, numbers of embryos were counted with dissecting microscope, and the embryos of hybrid seeds crossed by trifoliate orange were cultured on MS medium supplemented with 7.5g/l agar and 20g/l sucrose. Average number of embryos increased slightly throughout the growing stages and that of the smallest embryos (stage I) decreased significiently from 80 to 100 days after pollination, which implied that most embryos began to develop at the same time. The percentage of zygotic seedlings crossed by trifoliate increased as seeds were more mature, so it was recommended that seeds about to mature were preferred if embryos were induced to germinate with the help of embryo culture.