Abstract
The genetic variability based on karyotype formula was studied for 40 accessions of genus Lathyrus. All accessions have 2n = 14 chromosomes. Karyotype formula has a great uniformity among accessions of each species, suggesting interaspecific stability in Lathyrus species. Our data allowed the differentiation of several accessions among sections Lathyrus, Linearicarpus and Clymenum in number of m chromosome. The variation among section Lathyrus supports that section Lathyrus is not fully constant as has been postulated. Satellites were detected in a pair of chromosome in L. sativus (TUN and AFG). On the otherhand, B-chromosome was detected in L. sativus (USSR, BAN, CAN, and PAK) L. gorgoni (JOR) and L. annus (SYR). This finding may be due to the variation in DNA amount by increase in the non-repetitive sequence. The variation in size of chromosomes of the members of Lathyrus is associated with the evolution in the genus.