Chromosome Numbers and Karyotypes of Four Species Rubus L. from North of Iran

Karyotype study was performed across 7 populations of 4 Rubus species growing in Iran. The results showed that the chromosome numbers of R. sanctus (2n=2x=14) diploid, R. caesius, and R. discolor were (2n=4x=28) tetraploids, R. persicus (2n=8x=56) octoploid. The chromosome numbers of R. discolor, and R. persicus were reported here for the first time. Karyotypic formula also varied between the studied species, 5m+sm+t (Joybar population) & 6m+t (Babolsar population) in R. sanctus, 5m+2t in R. caesius & R. discolor, 4m+3t in R. persicus. In addition, the four studied species showed intrachromosomal (A1; range = 0.38-0.58), and inter-chromosomal (A2; range = 0.10-0.14) asymmetry and they were segregated into 3A (R. sanctus), 3B (R. caesius), 2C (R. discolor) and 3C (R. persicus) karyotypic symmetry classes. Total form percentage and the asymmetry indices, suggesting changes in the chromosome structure of Rubus species, occurred during their diversification. The chromosome number ranged from 2x to 8x in the studied species; it also confirmed that polyploidy within this genus cytogenetic phenomenon caused this variability in this genus.