Study of karyotypic variation on six different populations in three Sophora L. species

Sophora L. (Fabaceae) is a perennial plant and its roots reportedly have antibacterial properties. In this study, we examined 6 populations, representing 3 species, including Sophora alopecuroides (S.T, S.K and 10423), S. mollis (4512) and S. pachycarpa (S.M, 3548). Mitotic chromosomes were studied in meristematic cells of root tips obtained from germinated seeds. The basic chromosome number was x=9 in all of the populations, but their ploidy level varied. According to Stebbin's categories, all of the populations placed in symmetric class of 1A, indicating a symmetric karyotype. Based on inter and intra chromosomal variations, S. pachycarpa had the most asymmetric and evolutionary karyotypes and S. mollis had the most symmetric karyotypes. Analysis of variance based on unbalanced completely randomized design showed a significant difference (P<%1) among the populations for all of the traits. Using principal components analysis, the first two components justified %99.897 of the total variance. For the first component, the length of long arm and total length of chromosome, with the highest coefficients of eigen vectors, were the most important traits. For the second component, the arm ratio, centromer index and the length of short arm had the most important role for total variation. Cluster analysis (UPGMA methods) classified the populations into three groups. The populations S.M, 3548 and S.T classified to first class and S.K and 10423 stand to second class. Also the population 4512 was grouped to third class. The diagram of the populations dispersion, based on two first components, the populations were grouped in three separated classes, which agrees with the results of cluster analysis.