小麦和无融合生殖披碱草杂交后代(BC_2F_2)的无融合生殖及胚胎发育过程中的异常现象研究

Study on the Apomixis and Some Abnormal Phenomena in the Hybrid (BC_2F_2) between Triticum aestivum and Elymus rectisetus

对小麦 (Triticumaestivum)和无融合生殖披碱草 (Elymusrectisetus)的染色体数目为 42的杂种后代(BC2 F2 )单株进行了RAPD检测和胚胎学研究。RAPD检测结果表明 :染色体数目为 42条的BC2 F2 单株的遗传组成与普通小麦的遗传组成十分接近 ,但是在部分单株中出现了披碱草的特异带。由此可以推测 ,经过回交和自交后小麦草的部分染色体片段已经整合进了小麦的染色体。在部分BC2 F2 单株胚胎学切片中发现了较高比例的 (5 %左右 )双孢原、早发胚以及多胚囊等无融合生殖现象 ,直接表明了无融合生殖基因转移。由于基因整合的多样性 ,无融合生殖基因在有些单株中并没有充分表达 ,从而造成了某些单株胚胎发育的异常。

In order to make clear if the apomixis gene has transferred into wheat (Triticum aestivum), studies were made on the cytology?RAPD technique identification and embryology in BC 2F 2 plants. Cytological research revealed that the range of chromosome number is between 29 to 69,but the number at 42 is the most with the rate up to 49.3%. The hybrids with the chromosome number of 42 were analyzed using the random amplified polymorphic DNA (RAPD), bands of apomictic wheat grass's were found, this demonstrated that some chromosome segments of Elymus rectisetus were already introduced to wheat. Studies on the development of embryo were also carried out, some apomictic phenomena were found, the apomictic degree is up to 5% or so. The results showed that the apomictic gene has transferred into wheat. Meanwhile, some abnormal embryological development was found, these phenomena might be related to the incomplete apomictic gene's expression.