Assessment of Genetic Variation in Silybum marianum L. Using ISSR Markers

To study the genetic diversity in 77 samples of Silybum marianum (consisting 21 ecotypes) were evaluated in a randomized complete block design with three replications in Agricultural site of University of Zanjan. Using ISSR markers, the genetic diversity of some ecotypes of Silybum marianum along with their classification were studied. Out of 12 ISSR primers, 10 were amplified. Results revealed that the highest polymorphism information content (PIC) value belongs to primers UBC809 (0.492), UBC842 (0.487), and UBC826 (0.443 (, and lowest value was that of primer UBC1 (0.121). Cluster analysis using UPGMA algorithm divided the lines into 9 separate groups. For molecular analysis of variance of ecotypes a primary classification based on the geographical area used which divided them into 8 groups. Results of molecular analysis of variance revealed that within population variance was higher than between group variance due to its open pollinating nature. Regarding to principal component analysis, the first six components explained 87.5 % of the total variance and each component accounts for a small percentage of the total variance that emphasizes on good genomic distribution of selected ISSR markers. In general, the results obtained for using ISSR markers showed that this technique is a suitable one to study the genetic structure of the population Silybum marianum