Abstract: The chromosomes were prepared in the backcross progenies from female hybrids of common carp and crucian carp crossed with male mirror carp and common carp by injection of PHA and colchieines. Results showed that the genome ofbackcross progenies consists of 150 chromosomes which can be divided into four groups according to the centromere site. Each chromosome subgroup is made up of three homologous chromosomes. The chromosome number of the progenies from the female hybrids of common carp and crucian carp crossed with the male common carp is 3 n = 150, the number of chromosome arms 234,and the karyotype formula 3n = 60m ＋ 24sm ＋36st ＋ 30t. The chromosome number of the backcross progenies from female hybrids of common carp and crucian carp crossed with male mirror carp is 3n = 150,the number of chromosome arms 258, and the karvotvoe formula 3n = 63m ＋ 45sm ＋12st ＋30t.

Key words: common carp, mirror carp, hybridization, backcross progeny, chromosome number