Karyological Study on several Populations of Tetraploid Species of Onobrychis in Natural Gene Bank of Iran

Sainfoins (Onobrychis Adans.، Fabaceae، Faboideae، Hedysareae) are Eurasian perennial herbs. This highly nutritious plant is an important forage crop with comprises approximately 342 species. The germplasm used in this study containing 19 populations from 5 species of Onobrychis genus considered by Karyotypic studies. In this study، the Video Analysis System was used for karyotype analysis. The basic chromosome number was x=7 in all of the populations but their chromosomal variations was very high. According to Stebbins'' categories، the populations number O. sativa (2399) and O. sativa (182) classified to symmetric class of B and others stand to A. The highest VRC was obtained for 6012 and the lowest was obtained for O. viciaefolia (6014) populations. Based on inter chromosomal symmetric، O. viciaefolia (3026) had the most asymmetrical and evolutionary karyotypesis and O. sativa (3396) had the most symmetrical karyotypesis. Based on intrachromosomal symmetric، O. sativa (2399) had the most asymmetrical karyotypesis. The Results of analysis of variance based on unbalanced completely randomized design showed significant differences among the populations for all traits (P<%1). Using principal component analysis، the first two components justify %99 of total variance. In the first component، the total length of chromosome and the length of the long arm، which had the highest coefficients of Eigen vectors، also had the most significant role in total variance. In the second component the feature of the arm ratio، centromer index and length of short arm had the most important part in creating of total variance. By cutting dendrogram resulted from cluster analysis (UPGMA) with Cophenetic value equall to r =0. 73 based on 5 parameters (TL، LA، SA، AR، CI،) in metric distance 2. 43، the populations classified to three classes which certainly the first and the second components had the most significant role in separated classes. The highest distance was obtaind between O. altissima (2260) and O. major (242) that indicates the least affinity between them. The lowest metric distance value was obtained between two populations of O. sativa (2985) and (3002). The diagram of the populations dispersion، based on two first components، the populations were grouped in three separated groups، which agrees with the results of cluster analysis. By cutting dendrogram produced from cluster analysis (UPGMA) with the r =0. 75 based on two parameters (A1 and A2) in metric distance 1. 56، the populations classified to three classes. The highest distance was obtained between O. altissima (2260) and O. sativa (1586) which imply the least affinity between them. There was the lowest distance between O. sativa (1586) and O. sativa (3981).