【作者】 谭彩霞；

【导师】 潘学彪； 陈宗祥；

【作者基本信息】 扬州大学 ， 作物遗传育种， 2004， 硕士

【摘要】 构建水稻品种特青与Lemont杂交组合的F₂代无性系群体，定位了2个抗纹枯病主效基因qSB-9和qSB-11，它们分别存在于特青的第9染色体和Lemont的第11染色体上，其中在第11染色体上定位的区间与本研究组以往用Jasmine85／Lemont群体定位的QTL的区间相似，在该染色体上抗纹枯病主效QTL也是来自亲本Lemont。从该组合的F₂代无性系群体中，选择第125号无性系为回交供体亲本（双抗亲本），其在第9染色体上目标抗性主效基因（qSB-9）双侧标记带型像特青的标记带型，在第11染色体上目标抗性主效基因（qSB-11）双侧标记带型像Lemont的标记带型。第73和第86号无性系作为回交供体亲本（双感亲本），其在第9染色体上目标抗性主效QTL（qSB-9）双侧标记带型像Lemont的标记带型，在第11染色体上目标抗性主效QTL（qSB-11）双侧标记带型像特青的标记带型。它们分别与轮回亲本特青和Lemont进行回交，BC₂F₁开始每代进行标记辅助选择，并且BC₂F₁和BC₄F₁世代同步进行纹枯病病原菌人工接种鉴定，每代在每个回交组合中据标记辅助选择和抗病鉴定的结果以及综合性状与轮回亲本的相似程度来确定回交单株。在BC₃F₁世代，根据上述要求收获了部分回交组合的种子（BC₃F₂）。在BC₃F₂世代，结合于标记辅助选择和抗病鉴定的结果以及综合性状与轮回亲本的相似程度选择部分回交组合符合标准的植株，分别混合得到特青背景下的双感近等基因系，以及Lemont背景下的双感、双抗近等基因系。将这些近等基因系连同轮回亲本同时种植于扬州大学农学院试验田和江苏里下河农科所试验田，构成2个地点、每个地点2次重复的随机区组试验。人工接种试验结果表明： （1） 不同近等基因系间发病严重程度的顺序为Lemont双感系>特青双感系>Lemont>特青>Lemont双抗系； （2） Lemont双感近等基因系的病级比轮回亲本Lemont的病级高1.2级左右； 扬州人学硕士学位论又 轮回亲本Lemont的病级比Lemont双抗近等基因系的病级高0.8级左右; Lemont双感近等基因系的病级比Lemont双抗近等基因系的病级高2.0级 左右;特青双感近等基因系的病级比特青的病级高1.5级左右。由此可以 说明当qSB一9和qSB一11单独存在时，分别可减轻病级1 .0级左右，同时 存在时可减轻病级2.0级左右;（3）没有发现这两个抗纹枯病QTLS环境之间存在互作。 由此，进一步验证了水稻抗纹枯病主效QTL定位结果的可靠性:抗纹枯病主效数量基因qSB一9和qSB一11的真实存在;并初步确定了它们在染色体上的区间;为抗纹枯病QTL精细定位、进一步操作单个QTL以及QTL克隆奠定了基础。更多还原

【Abstract】 We constructed a F2 clonal population of intercross, Teqing/Lemont, and identified two quantitative trait loci (QTLs) contributing to sheath blight resistance on chromosome 9 and 11 .The two QTLs were qSB-9 and qSB-11, respectively. The located intervals were similar to those located by the two QTLs in another F2 clonal population of Jasmine85/Lemont, and the QTL ontributing to sheath blight resistance was also from Lemont. From the F2 clonal population of intercross No. 125 clone was selected as donor parent(double-resistant parent), on the chromosome 9, of which two flanking markers of the QTL(qSB-9) behaved all the same as the ones of Teqing, on the chromosome 11, of which two flanking markers of the QTL(qSB-11) behaved all the same as the ones of Lemont. No.73 and 86 clones were selected as donor parens(double-susceptible parents), on the chromosome 9, of which two flanking markers of the QTL(qSB-9) behaved all the same as the ones of Lemont, on the chromosome 11, of which two flanking markers of the QTL(qSB-11) behaved all the same as the ones of Teqing. They were separately intercrossed and backcrossed to recurrent parents, Teqing and Lemont. Beginning with BC2F1, marker-assisted selection was conducted in each proceeding generation and all backcrossed plants of BC2F1 and BC4F1 were inoculated by short toothpicks incubated with a strain, RH-9 of the fungus for identification of the resistance. In each proceeding generation, backcrossed plants were selected according to results of marker-assisted selection , disease ratings and the similarity of integrative traits between backcrossed plants and their recurrent parents. The measures ensured correctness of selected backcrossed plants. In BC3Fi, on the basis of the demands mentioned above, we gathered BC3F2 seeds of some backcrosses. AtBC3F2 generation, we selected plants of coinciding requirement of part backcrossed crosses according to the demands mentioned above and separately mixed them as homozygous lines. Thus, double-susceptible Near Isogenic Lines (NILs) in the background of Teqing, double-susceptible and double-resistant NILs in the background of Lemont were developed. The NILs and their recurrent parents were simultaneously planted on experiment fields of Agriculture Collage of Yangzhou University and Lixiahe District Institute of Agricultural Science. The inoculation was done in a random-block test with two sites and two replicates in each site. The result indicated that:(1) The order of sheath blight disease development among these NILs was: double-susceptible NILs in the background of Lemont > double-susceptible NILs in the background of Teqing > Lemont > Teqing > double-resistant NILs in the background of Lemont.(2) The disease ratings of double-susceptible NILs in the background of Lemont were higher 1.2 score than those of recurrent parent(Lemont). The disease ratings of Lemont were higher 0.8 score than those of double-resistant NILs in the background of Lemont. The disease ratings of double-susceptible NILs in the background of Lemont were higher 2.0 score than those of double-resistant NILs in the background of Lemont. The disease ratings of double-susceptible NILs in the background of Teqing were higher 1.5 score than those of Teqing. Above these it indicated that when the qSB-9 or qSB-11 solely existed in a plant, disease rating was reduced about 1.2 score. When they simultaneously existed, the rating reduced about 2.0 score.(3) No significant interaction between the two QTLs controlling sheath blight resistance and environments was found. It further confirmed the reliability of qSB-9 and qSB-11 and ascertained their exact intervals on chromosomes.It further confirmed that the results of the QTL mapping for sheath blight resistance in rice were right. For example, the QTLs(qSB-9 qSB-11) for sheath blight resistance truly lied on chromosomes and their approximate intervals on thechromosomes were located; These have laid groundwork under fine mapping ,operating single QTL and QTL’s clone.更多还原