Abstract: 【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.

Key words: Castor (Riciuns communis L.), Quantitative character, Principle components, Genetic distance, Cluster analysis, Heterosis