Abstract: The karyological study on 11 cultivars of Chinese old garden roses such as Rosa‘Slaterps crimson China’was carried out by conventional pressed slice method. The results showed that: (1) The ploidy varied among culitvars. R. ‘Viridiflora’, R. ‘Yulinglong’, R. ‘Slaterps crimson China’and R. ‘Parsons Pink China’were diploid with 14 chromosomes (2n =2x =14). R‘ChunshuiLübo’and R. ‘Huzhongyue’were triploid with 21 chromosomes (2n = 3x = 21). R. ‘Dafugui’, R. ‘Jinfenlian’, R. ‘Juhongchao’, R. ‘Yingri Hehua’and R. ‘Sichun’were tetraploid with 28 chromosomes (2n = 4x = 28). (2) Among the cultivars, the absolute length of chromosomes ranged from 1μm to 3μm and the asymmetry index were between 56.560% and 60.376%. Except for R. ‘Sichun’and R. ‘Yingri Hehua’, no chromosome satellite was observed in the cells of other cultivars. (3) The karyotypes of R. ‘Chunshui Lübo’and R. ‘Huzhongyue’were both 1A with the same karyotype formula of 2n =3x =21 =3sm +18m. Those of R. ‘J infenlian’and R.‘Juhongchao’were both 1A and their karyotype formulas were 2n = 4x = 28 = 4 sm + 24m. With a karyotype formula of 2n = 4x = 28 = 2 sm + 26m, the karyotype of R‘Dafugui’was also 1A, while that of R. ‘Viridiflora’was 1B with 2n = 2x = 14 = 2sm + 12m being its karyotype formula. With the karyotype formula being 2n =4x =28 =4sm +22m +2m (SAT) , the karyotypes of R. ‘Sichun’and R. ‘Yingri Hehua’were both 1A. R. ‘Yulinglong’had the karytype of 1A and karyotype formula of 2n =2x =14 =2sm +12m. As far as R. ‘Parsonps Pink China’and R. ‘Slaterps crimson China’were concerned, their karyotypes were both 2A with a formula of 2n = 2x = 4 sm + 10m.

Key words: rose, chromosome, ploidy, karyotype