cytogenetic analysis of some onobrychis species in central region of iran

genus onobrychis comprised of many cultivated as well as wild species is adapted to different regions of iran. this study was conducted to evaluate the karyotype characteristics of seven onobrychis species, employing the analysis of metaphase chromosomes of mitotic cells. results revealed that the species o. melanotricha (from semirom and feriedan)‚ o. sativa (from arak and boroujen) with 2n=28 chromosomes and o. sativa (from najafabad) with 2n=32 chromosomes were tetraploid while the other species bearing 2n=14 chromosomes were diploid. the basic chromosome number varied between x=7 and x=8. according to stebbins' classification, species o. melanotricha (semirom)‚ o. melanotricha (feriedan), and o. sativa (najafabad) were classified as symmetric class of b while the others as a. the results of anova showed significant differences among the species for most of studied traits. by cluster analysis as based upon karyotypical characters‚ the species were classified in three clusters. the lowest distance was obtained between the two species of o. melanotricha (semirom) and o. melanotricha (feriedan) while the widest between o. melanotricha (fereidan) and o. sativa (brojen). using principal component analysis, the first two components justified 85 percent of the total variance. in the first component, chromosome size while in the second one centromer position maintained the most important justification of the total variance.