Genetic diversity and identification of nerium oleander l. using CBDP and CEAP molecular markers

Nerium oleander is one of the significant plants in Türkiye, valued for ornamental and medicinal purposes. It is a source of antioxidants and anti-nematocidal properties. According to the reviewed literature, no study has been done yet to explore genetic diversity of the plant in Türkiye. The aim of this study was to assess the genetic diversity and population structure of Nerium oleander in Türkiye. In this study, 10 primers of CAAT box derived polymorphism (CBDP) and Cis element amplified polymorphism (CEAP) molecular markers were used to assess genetic diversity of 101 Nerium oleander samples collected from 3 regions of Türkiye (Eastern Mediterranean, Western Mediterranean and Aegean). The CBDP and CEAP primers generated 89 (80.91%) and 83 (80.59%) polymorphic bands with average 11 and 10 bands per primer respectively. Average PIC was higher in CBDP (0.35) than CEAP (0.30). The CBDP was more effective in discrimination of N. oleander genotypes with higher levels in polymorphism, expected heterozygosity, effective multiplex ratio, discriminating power, resolving power parameters compared to the CEAP. Neighbor-joining dendrogram obtained based on all markers revealed that genotypes were partially clustered based on location but were clustered based on the anthropogenic and natural setting. Population structure analysis based on Bayesian Structure analysis grouped genotypes into two subpopulations. SP1 mainly comprised of natural N. oleander and SP2 comprised of anthropogenic N. oleander genotypes. This was confirmed by principal component analysis (PCA) and dendrogram. This study revealed that CBDP and CEAP were effective in distinguishing N. oleander genotypes, there is high genetic diversity of N. oleander in Türkiye. Genetic diversity was higher in natural N. oleander genotypes than anthropogenic genotypes. This is the basis for future conservation efforts, mapping and identification of genes associated with different characters for breeding purposes.