Abstract

This investigation was carried out on different ten diploid populations of Silybum marianumwhich was collected from different regions of Iran. The base number of chromosomes in total studied populations were equal to x = 17. On based of two ways Stebbin's table, all of the population located in the second class of this table, that indicated which total populations are similar as evolutionary. Analysis of variance showed significant differences for the total chromosome length, sum of long arms, coefficient of variation centromic index and asymmetric index (p<0.01), the largest and the smallest length of chromosome, sum of small arms, difference of range relative length and arm ratio (p<0.05). Factor analysis introduced three factors that justify nearly 96% from total variation among data. In the first factors, the total chromosome and sum of long arms had highly load factor and named as length chromosome factor. In the second factor asymmetric index had highly load factor and named as asymmetric factor. The third factor difference of range relative length had highly load factor. Cluster analysis grouped populations in 4 groups. The least Euclidean distance observed between Ahvaz and Sary population and the highest Euclidean distance was between Ahvaz and Rasht population. Analysis of variance on parameters among of clusters showed significant differences for all parameter except difference of range relative length, among groups. Ahvaz, Sary, Esfahan populations in the first group had maximum amount of total chromosome length, the largest and smallest length of chromosome, sum of long and small arms, difference of range relative length than other investigated populations. Kordestan population located in the fourth group from asymmetric index, coefficient of variation centromic index and arm ratio were better than other investigated groups.

Key words: Silybum marianum L., cytogenetic, chromosome.