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分子标记辅助选择技术以其对目标基因快速而精确的选择为回交育种提供了非常有效的工具。华中农业大学作物遗传改良实验室运用分子标记辅助的回交育种方法 ,将广谱高抗白叶枯病基因Xa2 1迅速导入到杂交水稻的两个优良恢复系明恢 63和 60 78之中 ,成功地完成了其抗性改良 ,并通过配组而达到了改良杂交水稻抗性的目的。本研究所运用的分子标记辅助的水稻回交育种程序是 :通过一次杂交、三次回交和一次自交的育种程序 ,将目标基因导入到待改良的杂交稻恢复系中 ;采用以PCR为基础的对目标基因片段实施选择的MAS体系检测并选择与目标基因共分离和 /或紧密连锁的分子标记基因型 ,使含有目标基因的转移片段小于 3 .8cM ;应用RFLP或AFLP标记技术对遗传背景实施选择 ,使除开目标基因区段之外 ,改良型恢复系基因组与原恢复系相同。多菌系接种鉴定试验结果表明 :改良型恢复系明恢 63 (Xa2 1 )和 60 78(Xa2 1 )及其所配杂交组合的抗性水平较原恢复系及其杂交组合均显著提高。农艺性状比较试验结果表明 :在无病害发生的自然生长区 ,改良型恢复系及其所配组合的各种农艺性状表现与原恢复系及其所配组合基本相同 ;而在严重病害条件下 ,改良型恢复系及其所配组合的农艺表现 ,包括产量及其三个构成因子 ,均较原恢复系及其
Molecular marker-assisted selection provides a very effective tool for backcross breeding with its rapid and precise selection of target genes. Huazhong Agricultural University Crop Genetic Improvement Laboratory using molecular marker-assisted backcross breeding method, the broad-spectrum high bacterial blight resistance gene Xa2 1 quickly introduced into hybrid rice two excellent restorer Ming Hui 63 and 60 78, Successfully completed the improvement of its resistance, and achieved the purpose of improving the resistance of the hybrid rice through the compounding. The molecular marker-assisted rice backcross breeding program used in this study is that the target gene is introduced into the restorer line of hybrid rice to be improved through one-hybrid, three-backcross and one self-breeding breeding programs; Of the target gene fragments of MAS system selection and detection and target gene co-isolated and / or closely linked to the molecular marker genotype, so that the target gene-containing transfer fragments less than 3. 8cM; using RFLP or AFLP markers on the genetic background The selection is made so that the modified restorer genome is identical to the original restorer except for the segment of the target gene. The results of inoculation tests showed that the resistant levels of the improved restorer lines Minghui63 (Xa2 1) and 6078 (Xa2 1) and their hybrid combinations were significantly higher than those of the original restorer and its hybrid combinations. The results of agronomic traits comparison showed that the performance of agronomic traits of improved restorer lines and their combinations was basically the same as that of the original restorer lines and the combinations thereof in the natural growth areas without disease occurrence. Under the conditions of severe diseases, The agronomic performance of the improved restorer lines and their combinations, including yield and its three constituent factors, were higher than those of the original restorer line and its