Eco-geographical Distribution of Perennial Species of Onobrychis in Khorasan-e-Razavi Province

Iran is one of the most important centers of diversity for Onobrychis Mill. genus. Prennial species of Onobrychis collected from different habitates of Khorasan-e-Razavi province during 2008-2011 were evaluated and the relationship between their eco-geographical distribution, geographical and ecological characteristics were analysed by ArcGIS. Most of the perennial species of Onobrychis grow in the north and the mountainous areas of Khorassan-e-Razavi along the mountains chain of Binalood, Hezarmasjed, Kopet-dagh, Allah-o-Akbar, Chehel-Tan and Nazargah. They are also adapted to cold semi-arid, extra cold semi-arid, cold dry desert, extra cold dry desert and extra cold Mediterranean climates. The highest and lowest altitudes of the habitats are 2800 m and 780 m above sea level, respectively, indicating adaptation of this species to highlands areas. The studied species are adapted in regions with an annual mean temperature of 7.5-12.5°C and average precipitation of 250-400 mm, which implies adaptation of this species to cold and dry areas. Finally, this study showed that Onobrychis chorassanica has the greatest distribution in the province which shows its wide adaptability. It is recommended that the current varieties are crossed with O. chorasanica, if the goal of breeding of sainfoin is sustainable production in the province. The distribution of some species were also in certain habitat conditions where the soil erosion in these areas will likely lead to their extinction. On the other hand, considering the adaptation of these species to specific habitat conditions, it is recommended that the existing varieties are crossed with these species.