Abstract: The karyotype of fifteen hazelnut germplasms was studied by method of squash with the young leaves as test materials. The results showed that all the chromosomes were diploid; The karyotypes were divided into three types, i. e. 2 n = 2x = 22 = 22m type, 2n = 2x = 22 = 20m +2 sm type and 2n = 2x = 22 = 16m +6sm type. There was no satellites found in the morphological observation of chromosomes; The average of chromosome absolute length on fifteen hazelnut germplasms was 1.50 μm, so it was small in size; the karyotype of the fifteen hazelnut germplasms all belonged to 1B type except that of C. avellana L. and 7# which were 1A type and B-23 which was 2B type, respectively. There was great similarity of karyotype among the germplasms.

Key words: Hazelnut, germplasms, Chromosome, Diploid, Karyotype