Ploidy Variation and Genetic Composition of Openpollinated Triploid Citrus Progenies

開放性授粉的三倍體後代的倍性變異和遺傳組成分析

朱世平(Shi-Ping Zhu) ； 宋健坤(Jian-Kun Song) ； 胡志勇(Zhi-Yong Hu) ； 譚彬(Bin Tan) ； 謝宗周(Zong-Zhou Xie) ； 伊華林(Hua-Lin Yi) ； 鄧秀新(Xiu-Xin Deng)

《Botanical Studies》 50卷3期 (2009/07) Pp. 319-324

摘要

三倍體是無核品種選育重要的候選材料。我們對開放性授粉的異源三倍體BHR（本地早橘x（哈姆林甜橙＋粗檸檬））的種子進行了離體培養和研究來證明三倍體能否在柑橘育種中作為母本進行種質的創造。通過觀察發現，後代個體在葉片形態上存在顯著的差異。流式細胞儀、SSR分子標記和染色體計數等方法對後代的倍性變異和遺傳組成進行了分析。研究發現，三倍體和二倍體在所獲得的42株後代群體中所占的比例分別為52.3%和35.7%，其次分別是非整倍體和四倍體。SSR分析結果表明三倍體後代來源於柑橘珠心細胞的無融合生殖，而二倍體個體很可能是單倍體的雌配子與外界花粉雜交後代。本研究結果表明，三倍體在柑橘的有性雜交育種中可用作母本進行新種質的創造。

關鍵字

無融合生殖 ； 流式細胞儀 ； 簡單序列重複 ； 有性雜交

並列摘要

Triploid plants are the most important candidates for the selection of seedless cultivars. In an attempt to investigate whether a triploid could be used as a maternal parent in citrus breeding for germplasm creation, seeds from an open-pollinated triploid (2n=3x=27) citrus BHR (Citrus reticulata cv. Bendizao × tetraploid HR (C. sinensis cv. Hamlin + C. jambhiri cv. Rough lemon)) were cultured. There was significant difference in leaf morphology among the seedlings. Flow cytometry, simple sequence repeats (SSR), as well and chromosome counting were carried out to determine the ploidy variation and genetic composition of the progenies. Results showed that triploid and diploid (2n=2x=18) seedlings predominated in the 42 progenies at 52.3% and 35.7%, followed by aneuploids and tetraploids. SSR analysis indicated that triploids were derived from nucellar apomixis; diploids were most probably from sexual crosses of haploid female gametes and alien pollen grains. These results revealed that triploid plants could be used as maternal parents in sexual crossing to create novel citrus germplasm.

並列關鍵字

Apomixis ； Citrus ； Flow cytometry ； Simple sequence repeats ； Sexual cross