Karyotype Analysis of Lathyrus Species in Northwestern Iran

The Lathyrus genus is important due to forage consumption, nitrogen fixation, soil conservation, ornamentation, cultivation as green manure and its medicinal properties. Three species of Lathyrus were selected from northwestern regions of Iran and the properties of chromosomes were studied in L. cicera, L. incurvus and L. pratensis. Of these, karyotypes of L. incurvus and L. pratensis were analyzed for the first time. Five metaphysical plates were assessed in each species. The results showed that all the three species had diploid chromosome number of 2n = 2x = 14. Total lengths of haploid chromosome in L. cicera, L. incurvus and L. pratensis were respectively as 7.60, 6.16 and 6.30 micrometer. The karyotype formula of L. cicera was 5m+2sm while karyotype formula of L. incurvus and L. pratensis was 1m+6sm. All species showed relatively symmetrical karyotype and were included in 2A classification of Stebbins. Analysis of variance showed a significant difference in short arm length and total chromosome length at 1% significance level. Duncan test results showed that L. cicera had the longest total chromosome length at 5% significance level. Cluster analysis classified the species into two clusters; a) L. cicera (an annual species) and b) L. incurvus and L. pratensis (perennial species). The hybrids of these two species can be used in Lathyrus breeding programs.