利用产量功能基因标记分析三系杂交水稻亲本的遗传多样性

【目的】利用功能基因标记分析三系杂交稻亲本的遗传多样性。【方法】利用44个根据文献共同报道的QTL位点或者已经被精细定位或已克隆的与水稻产量性状基因紧密连锁的功能基因标记，以及29个覆盖水稻12条染色体的在三系杂交水稻亲本间多态性高、带型清晰、重复性好的SSR标记分析76个三系杂交水稻亲本的遗传多样性。按POPGEN32分析软件要求将PCR扩增产物的凝胶电泳结果数字化，将数字化的矩阵数据转换为基因型数据，在POPGEN32软件下计算等位基因数（Na）、有效等位基因数（Ne）、多态性位点百分率（P）、Nei’s遗传多样性指数（He），用于评价所有亲本材料的基因多样性；计算遗传分化系数（Fst）、Nei遗传距离（D），进行遗传结构和遗传关系检测。利用NTSYS-pc2.10e软件计算品种间遗传相似系数（GS），并根据GS按非加权组平均法（UPGMA）进行聚类分析，绘制品种间遗传聚类树状图。【结果】44个功能基因标记中有37个标记具有多态性，多态性位点百分率（P）84.09%，共检测到86个等位基因位点，平均每个位点2.32个，变化范围2—4个；其中有效等位基因（Ne）62.95个，占73.2%，Nei’s遗传多样性指数（He）变幅为0.049—0.831，平均值0.585。76份材料间的遗传相似系数（GS）变幅为0.323—0.973，平均值0.650。聚类分析表明在遗传相似系数0.618处分为保持系和恢复系两类。保持系和恢复系间的遗传分化系数（Fst）为0.151，属高度遗传分化，Nei遗传距离（GD）0.185，类群内遗传距离相对较小，类群间遗传距离相对较大。29个SSR标记共检测到72个等位基因位点，平均每个位点2.48个，变化范围2—4个；聚类分析表明未能将保持系和恢复系分为两类，部分保持系聚类在了恢复系群，部分恢复系聚类在了保持系群。【结论】相对于普通分子标记，功能基因标记具有较高的DNA多态性检测效率，用于类群划分和种质资源的多样性分析等方面更具准确性和可靠性；三系杂交稻亲本在44个产量功能基因位点的亲缘关系较近，遗传基础狭窄，同源性较高。但保持系群和恢复群系间在这些功能基因位点的遗传差异较大，遗传分化程度较高，杂交水稻骨干亲本在产量性状上仍具有较高的杂种优势利用空间。

Genetic Diversity of the Main Chinese Three-Line Hybrid Rice Parents Based on Functional Genetic Markers Related to Yield

【Objective】 The objective of this study is to analyze the genetic diversity of the three-line hybrid rice parents based on functional genetic markers. 【Method】 Genetic diversity of 76 three-line hybrid rice parents was analyzed by 44 functional gene markers involved in QTL loci, or fine mapping, or been cloned which linked closely to rice yield trait, and these genes have been considerably reported by literature. At the same time, the genetic diversity of the above materials mentioned was also studied by 29 SSR markers with higher polymorphism, clear band pattern, reproducible, and covered in 12 chromosomes of three-line hybrid rice parents. According to claim of POPGEN32 analysis software, the PCR gel electrophoresis product data matrix was transformed into the genotype data, and the alleles (Na), effective number of alleles (Ne), percentage of polymorphic loci (P), and Nei’s genetic diversity index (He) were calculated. This study further evaluated the genetic diversity of all parents according to the deduced information of POPGEN32 analysis software. Besides, this study also calculated the genetic differentiation coefficient (Fst), Nei’s genetic distance (D), and further checked out the genetic structure and genetic relationship. NTSYS-pc2.10e software was used to calculate the genetic similarity coefficient (GS), and cluster analysis was made according to GS group and using the non-weighted average method (UPGMA), and the genetic dendrogram was mapped. 【Result】Of which 37 functional gene markers showed polymorphism and 86 total alleles loci were detected; the percentage of polymorphic loci (p) was 84.09%. While the number of effective alleles(ne) was 62.95, which accounted for 73.2%, Nei’s genetic diversity index(he) ranged from 0.049 to 0.831, and 0.650 in avarage. The genetic similarity (GS) of 76 varieties ranged from 0.323 to 0.973, and 0.650 in average. UPGMA cluster analysis showed that 76 accessions could be classified into two distinct classes of maintainer lines and restoring lines, at similarity coefficient of 0.618. The coefficient of genetic differentiation(gst) was 0.151, belonging to high variation level, and the Nei’s genetic distance (GD) was 0.185. The genetic distance within the groups was relatively small, relatively large among the taxa. A total of 72 alleles loci were detected by 29 SSR markers. UPGMA cluster analysis showed that the 76 accessions cannot be classified into two distinct classes of maintainer lines and restoring lines. Part maintainer lines clustered in a group of restoring lines, some restoring lines clustered in the maintainer line group. 【Conclusion】 The studies suggested that the functional gene markers had a high DNA polymorphisms detection efficiency, and can be used as a useful tool for their accuracy and reliability of measuring genetic diversity. The backbone parents in research showed nearer genetic relationship, higher homology sort of genetic basis. However, there still showed higher genetic differentiation between maintainer line and restoring line, suggesting that there was a higher space of using heterosis breeding in the yield of rice parents.