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

Abstract

Karyotype study was performed across 7 populations of 4 <em>Rubus</em> species growing in Iran. The results showed that the chromosome numbers of <em>R. sanctus</em> (2n=2x=14) diploid, <em>R. caesius,</em> and <em>R. discolor</em> were (2n=4x=28) tetraploids, <em>R. persicus </em>(2n=8x=56) octoploid. The chromosome numbers of <em>R. discolor</em>, and<em> R. persicus </em>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 (<em>R. discolor</em>) and 3C (<em>R. persicus</em>) karyotypic symmetry classes. Total form percentage and the asymmetry indices, suggesting changes in the chromosome structure of <em>Rubus </em>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.