蓖麻数量性状遗传距离与杂种优势关系的研究

 【目的】摸索蓖麻种质资源的分类方法，分析蓖麻数量性状影响产量的程度，探讨数量性状遗传距离与杂种优势的关系。【方法】对46份蓖麻种质资源的11个数量性状进行了主成分分析和聚类分析，采用作图法研究21份亲本间遗传距离与杂种优势指数的关系。【结果】5个最大特征根的累积百分率为89.74%。在影响蓖麻产量的性状中，首先应考虑的性状为主穗及一二级分枝的果穗长、蒴果数，其次为单株有效穗，最后为百粒重。初步提出评选蓖麻种质资源的遗传主成分标准。46份蓖麻种质资源被分为4类，地理远缘材料在遗传上不一定远缘，而近缘材料由于选择方向不同可能成为遗传远缘。遗传距离与杂种优势指数的关系呈曲线关系。并非遗传距离越大杂种优势越强。【结论】评价资源间遗传差异时，不能仅以地理来源和亲缘关系为依据。在亲本选配时，应选择遗传距离中等较大的材料。

Study of the Relationship Between Genetic Distance and Heterosis in Castor

【Objective】To grope assoeted method in castor germplasms, and analysis degree that quantitative characters influenced yield, and realize the relationship between genetic distance and heterosis in castor. 【Method】To evaluate the factors affecting seed yield of castor and categorize castor resource, 46 castor germplasms were analyzed according to the key components analysis and cluster analysis of 11 quantitative characters. Study of the relationship between genetic distance of 21 castor inbred lines and heterosis were carried out by the graphics.【Result】The five biggest eigenvalues were chosen and their percentage of accumulative variance was 89.74%. The standard of the genetic key components had been put forward to evaluate castor germplasms. In these characters, ear length, the number of spikes and capsules of main primary and secondary branch should be selected firstly. Then the number of spike grains should be chosen and finally 100-kernel weight. 46 castor germplasms were classified into 4 groups. It was found that some varieties whose genetic distance was close were classified into geographic distant groups, and some varieties whose pedigree was close had larger genetic distance due to the different selection criteria. Genetic distance and heterosis showed a linear relationship according to F1 generation of 21 castor inbred lines. The largest genetic distance didn't mean the best heterosis. 【Conclusion】To evaluate castor germplasms' genetic difference didn't depended on geography origin and pedigree. Selecting parents with medium genetic distance may probably gain stronger heterosis.