(17(1):15-18)Studies On the Variation of Nucellar Seedlings upon Citrus (1) Investigation on Number and Color of Embryo upon Some Rootstock Varieties

一）本調查以育成合於吾人需要之珠心胚柑桔砧木為目的施行。 （二）柑桔砧木雖以多胚性為先決條件，但據本調查，"苦柚"雖在本省廣汎被採用作為柚子、文旦及檸檬等之砧木，但該品種仍屬於單胚種，單胚者隨時有雜交之可能，不易育成無性胚實生，似乎不宜繼續採用。 （三）廣東檬、枳殼、虎頭柑、南庄橙、小根占、柚及山蜜柑等，雖均屬於多胚性品種，但時常出現單胚種子，該等品種於播種前該先行胚分離工作。 （四）十六個調查品種中綠色系統胚及白色系統胚各佔一半，白色胚得利用Xenia現象淘汰著色有性胚，可作育成珠心胚實生之依據。 1. This investigation was made to obtain nucellar seedlings to be used as more excellent rootstock of citrus than existing varieties. 2. Kuyu-the most widely used as rootstock of shaddock and lemon in Taiwan-has only one embryo in a seed. In other word, Kuyu generally produces hybrid seedlings, thus this varieties is not worthy to recommend. 3. Although Rampur lime, Trifoliate orange, Kotokan, Nansho daidai, Konejime, Yama-mikan and Yuzu are all polyembryony varieties, the seeds contained only one embryo were also found in these varieties respectively. This fact suggests us that the separ-ation of embryo should be done prior to seeding. 4. Among sixteen varieties investigated, eight varieties have green and the others have white colored embryo. In the varieties having white colored embryo, it is possible to weed out the colored hybrid embryo when xenia phenomenon has been observed