Masoud Ranjbar - Department of Biology, Herbarium division, Bu-Ali Sina University, P.O.Box ۶۵۱۷۵/۴۱۶۱, Hamedan, Iran.
Roya Karamian - Department of Biology, Herbarium division, Bu-Ali Sina University, P.O.Box ۶۵۱۷۵/۴۱۶۱, Hamedan, Iran
Anahita Hadadi - Department of Biology, Herbarium division, Bu-Ali Sina University, P.O.Box ۶۵۱۷۵/۴۱۶۱, Hamedan, Iran.

Morphologic characters, meiotic chromosome number and behavior were analyzed in different wild populations of Onobrchis viciifolia Scop. and Onobrychis altissima Grossh.belonging to O. sect. Onobrychis in Iran. All Iranian populations of O. viciifolia and O. altissima studied here were tetraploid and showed ۲n = ۴x = ۲۸ chromosome number. The basic chromosome numbers (x = ۷) is consistent with the proposed base number of x = ۷ for O. viciifolia and O. altissima. For O. altissima, two ploidy levels (۲n = ۲x = ۱۴ and ۲n = ۴x = ۲۸) have been reported from Caucasus. Results support the hypothesis that Onobrchis viciifolia and O. altissima are related as a progenitor-derivative pair of species. The fact that no diploid populations of O. altissima were found in Iran, would suggest a relatively recent origin of the species, most probably in Caucasus. Almost these taxa displayed regular bivalent pairing and chromosome segregation at meiosis. Meiotic abnormalities observed included varied degree of sticky chromosomes with laggards and bridges in anaphase to telophase, asynchronous nuclei in metaphase II and desynapsis in metaphase I. Also O. viciifolia Scop. is considered as a new record from this section for Iran. These taxa of the genus are cultivated as fodder in Iran.

chromosome number, Fabaceae, meiotic behavior, Onobrychis sect. Onobrychis