Chromosome banding patterns in the annual species of Cicer

Abstract

Somatic karyotypes of the nine annual species of Cicer (2n = 16) were analyzed using C-banding. Highly significant differences in haploid genome length and C-band positive heterochromatin content were observed. The haploid genome length ranged from 20.0 μm in the wild species C. judaicum to 28.7 μm in the cultivated species C. arietinum, and significant differences for this character were observed between accessions within several species. Based on their heterochromatin content, the species were divided into two groups: low heterochromatin content (average of 41.7%), which included C. arietinum, C. chorassanicum, C. echinospermum, C. judaicum, C. pinnatifidum, C. reticulatum, and C. yamashitae, and high heterochromatin content (average of 59.5%), which included C. bijugum and C. cuneatum. Within-group variation for heterochromatin content was insignificant, while differences between groups were highly significant. There seemed to be a trend for reduction in C-heterochromatin content in the course of evolution in Cicer. In all species studied, C-bands were located proximally around the centromere with occasional bands in intercalary and distal positions. C-banding patterns allowed for chromosome identification and matching pairs of homologues in all species analyzed.