Abstract
The genus Lathyrus constitutes an important phytogenetic patrimony as a source of traditional foodstuffs in Tunisia. An Inter-Simple Sequence Repeats (ISSR) technique was employed to assess genetic diversity and relationships of seven Mediterranean species of the genus Lathyrus belonging to four sections (Lathyrus, Clymenum, Nissolia and Aphaca). The molecular characterization and fingerprint identification of 11 populations representing the Lathyrus species were conducted using 11 ISSR primers (seven 3' anchored primers and four non-anchored primers). A total of 261 polymorphic markers have been successfully generated, ranging between 400 and 3000 base pairs, with a mean of 23.72 bands/primer. The percentage of polymorphic bands for these species was 98.12%. The ISSR technique was able to characterize and differentiate between the different studied genotypes of the Lathyrus species. Genetic distance within and between populations was estimated by calculating the similarity index. The similarity indices ranged from 0.251 to 0.741, with a mean of 0.386. Our data provide evidence of high molecular polymorphism, showing that both wild and cultivated species forms constitute an important pool of diversity. Despite the large distant geographical origin site, the accessions per species issued from different geographical origins are relatively related. Moreover, the genetic similarity tree showed that the two species L. sativus and L. cicera are similar showing that L. sativus may be derived from L. cicera, whereas the principal component analysis showed a clear divergence of the L. ochrus population belonging to section Clymenum from the other populations. Furthermore, L. ochrus appears to be closer to L. aphaca and L. nissolia than to the other studied species belonging to section Lathyrus.