【作者】 茹岩岩；

【导师】 晏月明； 张学勇；

【作者基本信息】 首都师范大学 ， 遗传学， 2001， 硕士

【摘要】 小麦（Triticum aestivum L.）的近源种、属内含有许多与抗病、抗逆、丰产、优质等有关的优良基因，是小麦改良的巨大基因库。利用染色体工程技术，将这些基因导入到栽培小麦品种中，是当前增加小麦的遗传多样性、进行小麦遗传育种的主要手段之一。 十倍体长穗偃麦草（Thinopyrum ponticum （Host） Liu and Wang）是小麦改良中应用的较为成功的一个多年生异源十倍体种。本研究主要对两个小麦—十倍体长穗偃麦草杂交组合[（CS/87W032//小偃6号/3/40765-3）和（晋2148×BC₁-1-5（?）-2-2）]的后代进行遗传分析，以筛选出一些携带十倍体长穗偃麦草遗传物质且具有优良农艺性状的新种质。首先，根据表型性状，逐代淘汰表型差的植株，选取田间表现好的材料进行跟踪分析。1999-2000年，通过染色体计数、花粉母细胞染色体配对及GISH分析，选择出比较稳定的12份材料，对这些材料及亲本进行醇溶蛋白及谷蛋白组成分析，发现9份材料及亲本“北京837”具有黑麦1RS的醇溶蛋白标记位点GldB3，6个材料含有来自十倍体长穗偃麦草特异的HWM谷蛋白亚基。 为了得到更稳定的能为育种所利用的材料，我们对其后代材料进行了跟踪鉴定。在每个材料自交后代中随机取10粒种子分单株进行基因组原位杂交（Genomic in situ hybridization简称GISH）分析，用地高辛标记的普通小麦“中国春”（Triticum aestivum L. cv Chinese Spring，CS）基因组DNA（ABD组）作探针，20倍拟鹅观草（Pseudoroegneria stipifolia （Czern exNevski）A Love）基因组DNA（St组）为封阻对被选材料根尖细胞制片进行GISH分析，共检测出代换系2株、附加系4株、易位14株、易位-代换系6株、易位-附加系6株。用pTα71作探针，检测到在所有外源易位片段上距着丝点约2/3位置处都有一18S-5.8S-26S rDNA位点（Nor-Rl）。用基因组原位杂交的方法，分别显示出A、B、D三个基因组，证明易位发生在B组染色体上。进一步用黑麦（Secale cereale L.，R组）基因组DNA作探针，普通小麦基因组DNA作封阻进行GISH分析，结合种子醇溶蛋白电泳（A-PAGE）分析结果，最后确定所有这类易位均为1BL/1RS易位，黑麦遗传物质可能来自于亲本“北京837”。 GISH是目前鉴定杂交后代的基因组构成、染色体来源以及染色体交换的一种有效手段。但它也有一定的局限性，并可能造成一些假象。该研究提示我们：在鉴定外源染色体（质）时必须很慎重，单凭一种技术很难得出完全准确的结论，需要多种方法相互补充、印证，方为妥善。更多还原

【Abstract】 Wheat, one of the most important crops in the world, has been cultivated even longer than the civilization history of human. This domestication may have contributed to limited genetic variability in this species because of artificial selection. The introduction of genetic traits from alien species has been necessary in order to enrich the genetic diversity available for wheat improvement, and many useful traits have been introduced into wheat from alien species. Thinopyrum panticum (Host) Liu & Wang [Agropyrum elan gatum (Host) Beauv; Elytriga elan gatum (Host) Nevski], a decaploid species (2n10x70, StStEEbEX) in the tribe Triticeae, is an important source for improving the genetic variability of cultivated wheat. We aimed to gain some novel germplasms which contain the genetic materials of Th. ponticum and possess some elite agronomic traits by genetic analysis derivatives of two wheat-Thinopyrum panticum hybrid combinations [(CS/ 87W032 II Xiaoyan 6/3/40765) and (Jin2148XBC1-1-5?2- 2)]. Firstly, the undesirable individuals were eliminated through the morphological traits selection. Then, twelve relatively stable novel germplasms were selected through root-tip cells chromosome counting and the chromosome paring analysis in 1999 and 2000. The result of acid polyacrylamide gel electrophoresis (A-PAGE) of gliadin showed that 9 of the 12 and one of their parents 揃eiJing 837?have the identical IRS chromosome-specific gliadin marker GIdB3. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis ectrophoresis (SDS-PAGE) analysis of HMW glutenin subunits showed that there are 6 new lines had the specific band of Th. ponticum. In order to get more steady materials for future breeding, offspring of the 12 lines continued to be analysed cytogenetically. Ten seeds were randomly chosen in each line. Genomic in situ hybridization (GISH) was employed to identify the chromosomal constitution one by one. With digoxigenin-labelled 揅hinese Spring? (Triticum aestivum L) genomic?DNA as probe and 20-fold genomic DNA of Pseudoroegneria stipifolia (St genome) as block, GISH revealed there are 2 substitution indivaduals, 4 addition individuals, 14 transtocation individuals, 6 substition-translocation individuals and 6 addtion-translocation individuals. Using iii pTa7l as probe, locus of 18S-5.8S-26S rDNA (Nor-RI) was detected on the Robertsonian translocated chromosome found in all individuals conveyed it. Further analysis indicated that the Robertsonia translocation was concerning with B-genome chromosomes. Using genomic DNA of rye (Secale cereale L. R) as probe and wheat genomic DNA as block, GISH proved that the translocation chromosomes are 1 BU1 RS, which was inherited from one of their parents, Beijing 837. GISH is a powerful technique for identifying the genomic constitution of hybrids and initial characterization of recombination lines that contain alien segments. It is rapid, sensitive, accurate, effective and gives unique information about alien chromatin in wheat.background. But it has some limitation, false conclusion of GISH caused by cross-hybridization between genomes was discussed in this paper. The results of this study suggest us that we must be prudent in identification of alien chromosomes. It is easy to draw a false conclusion if only a single technique is adopted. Multiple methods should be used to check with each other and confirm the results.更多还原