High Ratio of Polyembryonic Seeds Was Observed in Monoembryonic Kiyomi Tangor X Ponkan and Molecular

<正> Polyembryony is a serious handicap in citrus breeding. To obtain zygotic off-springs, monoem-bryonic seed parents were usually used in breeding programs. Kiyomi, a superior monoembryonic tangor, was used as seed parent in 7 cross combinations. When pollen parents was Chandler pummelo or Tarocco blood orange, only monoembryonic seeds were observed. However, when Washington Sanguine, Li-xing orange and Bing-tang orange were used as pollen parents, no more than 7. 2% of polyembryonic seeds were observed. Interestingly, while male parents were Nucellar3 Ponkan and Oota Ponkan, high ratio of polyembryonic seeds was observed. The ratio of polyembryonic seeds was steadily at about 30 % in two consecutive years and was obviously different from other results reported. Polyembronic seeds were observed in monoembryonic varieties sometimes, but normally their ratios were no more than 7%. Polyembryonic-seedlings were got by separating the multi-embryos in seeds of Kiyomi×Nucellar3 Ponkan and then their leaves were