【作者】 杨子贤；

【导师】 何予卿；

【作者基本信息】 华中农业大学 ， 生物化学与分子生物学， 2005， 硕士

【摘要】 93-11是我国生产上应用面积较大的两系恢复系,同时又是红莲型三系杂交水稻恢复系之一,其组配的超级杂交稻两优培九和三系杂交稻红莲优6号,具有优质高产等特性。为了进一步提高其对白叶枯病的抗性、同时增加其对水稻鳞翅目害虫（如稻纵卷叶螟、二化螟和三化螟等）抗性,我们利用常规回交育种的方法结合分子标记辅助选择将Xa21基因和Bt基因同时导入93-11中,在BC₃F₃家系中筛选到8个家系含纯合的Xa21基因和Bt基因,有两个家系与93-11比较其遗传背景的回复率很高,达到90.59%,在正常的田间条件下,改良的93-11（Bt）、93-11（Xa21）和93-11（Bt/Xa21）与93-11表现出相似的农艺性状。且带有Xa21基因的株系及其杂交种均对白叶枯病显示出很高的抗性。但在自然诱发螟虫条件下,带有Bt基因的株系及其杂交种没有受到螟虫危害。这一结果表明,通过分子标记辅助选择将多个基因同时导入某一改良亲本,结合常规育种方法选择,具有快速、良好遗传改良效果。这一遗传改良材料在农艺性状和配合力等方面基本保持了93-11及其杂交组合的主要特征特性,拓宽和增强了其对白叶枯病的抗谱和抗病能力,增加了93-11作为恢复系所配杂交水稻的抗螟虫特性,具有较好的应用前景。 另外,为了使93-11具有对野败型三系杂交稻的恢复能力,我们又将明恢63中第10染色体上的恢复基因Rf（u）通过回交育种方法结合分子标记辅助选择导入到93-11中。经3次回交,在BC₃F₁的群体中,筛选到了67个含杂合Rf（u）基因的改良型93-11,通过挑选其中3个阳性单株与珍汕97A杂交以评价改良型93-11的恢复力,同时选择20个综合农艺性状如结实率、株高、抽穗期等与93-11相似的单株自交。在与珍汕97A杂交F₁的群体中,可育单株的自然结实率处于71.4-91.6%之间,平均结实率为82.3%,而不育类单株的自然结实率处于1.4-40.4%之间,平均结实率为17.3%,不育单株与可育单株的分离比经卡方测验符合单因子1:1的孟德尔遗传分离比,这表明通过分子标记辅助选择已将Rf（u）基因导入到了93-11中,并且表现出良好的恢复力。最后,我们从BC₃F₂的群体中选到了54株恢复力良好的含纯合Rf（u）基因的改良型93-11,农艺性状和配合力的考察正在进行之中。更多还原

【Abstract】 93-11 served as an elite restorer line of two-line hybrid, which was widely used in our country’s rice production, is also a restorer line of three-line hybrid of the HL type. The super-hybrid rice, Liangyou Pei 9 and Honglianyou 6, .which was mated by 93-11, has the characteristics of high yield and good grain quality. In order to enhance its resistance to bacterial blight (BB) and lepidopteran such as leaffolder, striped stem borer and yellow stem borer etc, we intergessed Xa21 and Bt genes into the genetic background of 93-11 by backcross scheme, combining with molecular marker-assisted selection and phenotypic selection. Through three backcross and two self generations, eight-families that have homozygous Xa21 and Bt genes were obtained in the BC3F3 families. Two families show higher recovery percentage of 93-11 even up to 90.59%. In the subsequent field evaluation, 93-11 (Bt/Xa21) and its hybrid show high resistance to BB and stem borer. The agronomic performance of improved 93-11 (Bt), 93-11 (Xa21) and 93-11 (Bt/Xa21) was very similar to original 93-11 under normal condition. But on the natural stem.borer infestation condition, the improved 93-11 contained Bt gene and its hybrid was not damage by stem borer. This result shows: It has a quickly and excellent efficiency to introduce multiple genes simultaneously into a certain improved parent by MAS conjunction with conventional breeding method. The improved line persist the main agronomic trait and combining ability of 93-11, show wide spectrum to Xoo strains and enhanced resistance to BB and stem borer. Thus, this line has good prospect in future practical use.Additionally, in order to let 93-11 can restore the fertility of the WA type, we also introduce the strong restorer gene, Rf(u) that located on chromosome 10 in Minghui63, into genetic background of 93-11 by conventional backcross scheme, combining with marker-assisted selection. Through three backcross generation, 67 individuals has heterozygous Rf (u) gene were obtain in BC3F1 population and three positive individuals were selected to cross with Zhengshan97A to test their fertility restoring ability. Simultaneously, 20 positive individuals were selected according to their agronomic trait such as seed setting rate plant height heading time etc. is similar to 93-11, then were selfed to obtain homozygous individuals. In the F1 population derived from the cross between Zhenshan97A and 93-11 Rf (u) , the seed setting rate of fertile individuals vibrated from 71.4 to 91.6%, the mean of seed setting rate was 82.3%. But the seed setting rate of sterile individuals vibrated from 1.4 to 40.4%, the mean of seed setting rate was 17.3%. Chi square test show that the segregation of fertile to sterile in this population were 1:1 that is agreement with the ration of singleMendalian segregation, indicating the Rf (u) gene was introduced into genetic background of 93-11 completely and show a strong restoring ability. Finally, 54 individuals have homozygous Rf{u) gene were obtained with strong restoring ability in the BC3F2 population. The evaluation of agronomic performance and combining ability of improved 93-11 is in preceeding.更多还原