Abstract: To distinguish different germplasms of Coreopsis and to clarify the chromosome numbers and karyotypes characteristics of the currently widely cultivated Coreopsis,we used the conventional press slice method to identify the chromosome numbers of young root tip cells of 60 different Coreopsis germplasms,and selected 18 seedling materials for karyotype analysis. The results showed that the chromosome numbers included 12 types,ranged from 24 to 52. The materials in karyotype analysis were all diploid,existed in four chromosome basic number types of x=10,12,13,14. There was no B chromosome among these Coreopsis,but six materials had the satellites. The karyotypes of 18 conal Coreopsis were all 2A,and the karyotype asymmetry coefficients ranged from 58.56% to 64.93%,all these data indicated that Coreopsis was a more primitive genus,while the annual Coreopsis had a more evolved degree among them. The complex chromosome basic numbers and chromosome ploidies of the parents are the main reasons for the variable chromosome numbers and a large number of aneuploids in horticultural Coreopsis cultivars. This study provided a theoretical reference for the classification,identification,and breeding of Coreopsis from cytological aspects.

Key words: Coreopsis L., Cultivar, Chromosome numbers, Karyotype analysis

摘要： 为了区分不同金鸡菊的种质，明确目前广为栽培的金鸡菊的染色体数目及核型特征，采用常规压片法，以60个不同的金鸡菊种质为材料，鉴定其根尖细胞的染色体数目，并选取其中18个籽播系材料进行染色体核型分析。结果表明：60个金鸡菊的染色体数目包括12个类型，染色体数目24~52不等，18个核型分析的材料全部为二倍体，染色体基数存在x=10，12，13，14四种。在6个材料中发现了随体，未发现B染色体，染色体类型包括s，sm，st三种。核型全部为2A，核型整体上较为对称，核型不对称系数为58.56%~64.93%，一年生类型的金鸡菊普遍进化程度更高。亲本复杂的染色体基数及染色体倍性是造成栽培金鸡菊染色体数目多变且产生大量非整倍体的主要原因。本研究从细胞学方面为金鸡菊的分类鉴定和杂交育种提供了理论参考。

关键词: 金鸡菊, 栽培品种, 染色体数目, 核型分析