Genetic Diversity and Relationships of Opium Poppy Accessions Based on SSR Markers

Opium poppy is one of the most important medicinal plant species cultivated in several regions of the world for pharmaceutical and food purposes. Although it has been bred and used in many countries for centuries, taxonomical studies on the intraspecific variability are still not numerous. In the course of this study, the genetic diversity of 58 opium poppy accessions were assessed with SSR markers. Out of the 25 tested SSR markers, only 19 showed successful amplification and seven were found to reveal polymorphism. These seven markers produced 2–11 alleles within the size range of 144–280 bp. PIC value varied between 0.284 and 0.767, expected heterozygosity was between 0.136 and 1, and observed heterozygosity was between 0.344 and 0.794. Altogether, a low genetic diversity was found, and several accessions have been characterized with the same SSR allele profile. The clustering in the PCoA co-ordinate system indicates four groups, which is confirmed by the STRUCTURE analysis as well and reflects the known relationships of hybrid cultivars in several cases. The landrace taxa clearly deviate from the majority of cultivars selected for industrial purposes. The applied SSR markers were not able to distinguish the genotypes according to their geographic origin or seed color. However, in several cases, the grouping in the PCoA system reflected a diversification connected to alkaloid content and petal color of the accessions. Our results demonstrate the importance of further molecular marker studies focusing on genotypes with different alkaloid content and useful agronomical traits in order to establish more effective breeding.