Giemsa C Banding in Lathyrus L.

Somatic karyotypes of nine diploid species of Lathyrus (2n = 14) have been analyzed using the Giemsa C-banding technique. Distribution of heterochromatic segments is characteristic of the species Annual and perennial species could be separated into two distinct groups on the basis of their characteristic and unique C-band endowment Outbreeding perennial species are characterized by C bands distributed all over the arms of chromosomes, whereas inbreeding annual species usually exhibit centromeric and/or terminally localized C bands Species differ with respect to number and position of bands, and several species show a very reduced number. The supposedly primitive outbreeding perennials contain more bands than the diploid annuals. On the basis of previous and present data, the possibility exists of a gradual diminution in total repetitive DNA content, followed by a corresponding reduction in constitutive heterochromatin with the evolutionary specialization of the various species of this genus.