Evaluation of genetic diversity in different populations of six Salvia species using R-ISSR markers analysis

Genetic diversity assessment is pivotal to comprehend the evolutionary dynamics, and conservation implications of plant species. This study used R-ISSR markers to evaluate the genetic diversity of six Salvia species (S. verticillata, S. glutinosa, S. reuteriana, S. hypoleuca, S. leriifolia, and S. limbata) across multiple populations in Iran. We sampled 28 populations (92 specimens), and conducted DNA analysis using selected R-ISSR markers to assess genetic variation. After screening 10, R-ISSR primers, four primers that produced clear and reproducible fragments were selected for further analysis. The four primers generated 93 bands ranging in the size from 100 to 2000 bp, averaging 23.25 bands per primer. Polymorphic information content (PIC) values ranged from 0.223 to 0.260, and marker index (MI) values ranged from 4.43 to 6.02 per primer. Moreover, P9 exhibited the highest PIC (0.260), and P1 displayed the highest MI (6.02). The mean coefficient of gene differentiation (Gst) was 0.7014, signifying that 48% of genetic diversity was within populations. This research yields insights into genetic differentiation, population structure, limited gene flow, marker utility, and genetic affinities. Significant differentiation between and within Salvia populations is indicated by the observed polymorphism and genetic diversity, which are most likely the result of elements like geographic isolation, environmental variations, and reproductive obstacles. Clustering analysis shows distinct genetic clusters, and subpopulations within each Salvia species. Moreover, the results from the analysis of molecular variance highlight significant genetic variation among populations, thereby suggesting limited gene flow, which was potentially affected by geographical barriers and ecological factors. Particularly, highly polymorphic P1 and P9 primers offer valuable tools for future breeding research, and germplasm management in Salvia species. Furthermore, our findings show genetic affinities, and relatedness among specific populations, thus indicating closer relationships between certain Salvia species.