英德
有道
百度
谷歌
图片
维基
百科
多胚生殖
polyembryony
- 文摘:通过无融合生殖方式固定水稻的杂种优势是一项具有极大诱惑力但难度颇大的探索性研究，目前还未筛选到具有实用价值的水稻无融合生殖种质.禾本科植物中已经鉴定出166个具有无融合生殖特性的物种，包括二倍体孢子生殖和无孢子生殖，尚未发现不定胚生殖现象.遗传上的异质性和染色体组的多倍性是禾本科中无融合生殖物种最基本的2个特点.由此认为，如果继续在二倍体水平筛选无融合生殖种质则难度较大，成功的可能性较小，而在多倍体水平通过适当方式先创造具有异质性的杂合群体后再进行水稻无融合生殖种质的筛选则难度较小，成功的可能性将较大.
Abstract: Heterosis fixation in rice by apomixis is an exploration with great enticement but many difficulties．Nowadays，apomictic rice with breeding significance has not yet been found though a great deal of work in this aspect was done．In Gramineae，the 166 apomictic species with diplospory and apospory have been identified，but species with adventitious embryony has not yet been discovered．The two basic characters of the apomictic species in Gramineae are heterogeneity in genetics and polyploidy in genomes．It is difficult to successfully select and breed apomictic germplasm among diploid rices，but it is easy to succeed in selecting and breeding apomictic germplasm among heterogeneous rices from cross combinations of autotetraploid rices or autotetraploid rices x diploid rices.
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中国词汇量第二的英语词典
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