Abstract: Used florescence in situ hybridization（FISH）and genomic in situ hybridization（GISH）techniques to analyze the genomic organization in Narcissus tazetta var. chinensis Roem. distributed in China. Chromosome localization of 45S rDNA and 5S rDNA were studied by means of FISH on metaphase chromosomes of yellow flower narcissus and two-color flower narcissus. The results showed that NOR loci of different materials showed polymorphism. There were three 45S rDNA loci in yellow flower narcissus，while there were five loci in two-color flower narcissus. The distribution of 5S rDNA appeared similar in the two genomes. Based on GISH analysis，two-color flower narcissus（2n = 3x = 32）had two genomes of white flower narcissus（2n = 2x = 22）and a single genome of yellow flower narcissus（2n = 2x = 20）. By comparing the physical location of 45S rDNA and 5S rDNA on chromosomes and the result of GISH，it was believed that two-color flower narcissus was the result of nature hybridization between white flower narcissus and yellow flower narcissus.

Key words: Narcissus tazetta var. chinensis Roem., genomic in situ hybridization（GISH）, florescence in situ hybridization（FISH）