Genetic Diversity Assessment of Garlic Clones with SSR Markers

Garlic (Allium sativum L.) as a clonally propagated crop has notable genetic diversity among the genotypes and cultivars growing world-wide. Simple sequence repeats (SSRs) are very valuable molecular markers for both genotyping and genetic mapping studies in plants. For the garlic genome, however, a limited number of SSR markers have been developed. In this study, 26 polymorphic SSR markers were developed from the expressed regions of the garlic genome. The genetic diversity among the 31 garlic genotypes from different parts of the world was investigated by using these novel SSR markers. A total of 130 polymorphic markers were detected with a range of 2 to13 and average of 5 alleles per SSR locus. Seven SSR loci had more than one locus in garlic genome which is not unexpected for a crop with very large genome size. While the genetic similarity was as low as %40 among the individuals, 12 garlic clones could not be distinguished from each other with 130 polymorphic SSR markers, which are most likely duplicate genotypes in the germplasm collections. Grouping of garlic clones in UPGMA dendrogram was highly similar to previously reported amplified fragment length polymorphism (AFLP), randomly amplified polymorphic DNA (RAPD) and isozymes molecular markers analyses of same garlic genotypes. This result indicates immediate utility of newly developed SSR markers in garlic genetic studies.