1. Introduction: The genus Grammosciadium of the Apiaceae family has nine species, of which three species, G. pterocarpum, G. platycarpum, and G. scarbridu, grow in Iran which grow in most temperate or cold temperate regions and in mountain pastures. G. platycarpum is a perennial plant with a height of 40 to 100 cm, which is known as mountain parsley or mountain dill and is distributed in Iran, Turkey, Iraq, and Armenia. It is used as an infusion to reduce fat and blood sugar, and as Vegetables are, consumed raw and cooked in some regions of Iran. It has a pleasant taste and smell and is used as a vegetable and food additive in different regions in spring. Since wild and medicinal plants usually have weak and uneven germination, the use of methods to improve germination can have a positive effect on improving the production of these plants. Due to the high percentage of linalool in its essential oil, G. platycarpum is considered a valuable and promising source for the extraction and commercial purification of this compound, the demand for which is increasing across various industries. At present, industrial requirements for this plant are largely met through harvesting from natural habitats, an unsustainable practice that poses the risk of population decline and even local extinction. Consequently, the collection, identification, and characterization of native genotypes represent essential steps toward the conservation and genetic improvement of this species. In plant breeding, precise knowledge of genetic diversity provides the foundation for selecting desirable parents, while population-level studies facilitate the effective utilization of unique populations in breeding programs and support the long-term preservation of genetic resources. Therefore, assessing genetic diversity is critical for developing informed conservation and breeding strategies. In this study, the genetic diversity of several populations of this species was evaluated using ISSR markers.
2. Materials and Methods: In the initial phase of the study, potential habitats of G. platycarpum were identified using available flora references and through field surveys in surrounding regions. Fourteen populations of G. platycarpum (three individuals per population) were sampled. For each individual, a leaf sample was collected using a sterile blade, wrapped in aluminum foil, and immediately placed in liquid nitrogen. The samples were then transferred to a −80 °C freezer for storage before DNA extraction. DNA was extracted from all samples, and its quantity and quality were assessed using both a spectrophotometer and agarose gel electrophoresis. Seven primers were selected for DNA amplification. The polymerase chain reaction (PCR) was carried out in a final reaction volume of 15 µL using a thermocycler. For separation of PCR products, a 1.5% agarose gel was employed. After electrophoresis, gels were photographed for band detection. The banding patterns were scored in a binary matrix, with polymorphic bands recorded as “1” (presence) and “0” (absence). To calculate the similarity matrix, the SimQual procedure was applied. Similarity coefficients were generated using three methods: Simple Matching, Dice, and Jaccard. For clustering, the SAHN procedure with the UPGMA algorithm was employed using NTSYS software (version 2.02). The cophenetic correlation coefficient was used to evaluate the efficiency of the clustering algorithm and to determine the most appropriate similarity coefficient for analysis.
3. Results and Discussion: A considerable level of genetic diversity was observed among the individuals based on ISSR markers. In total, 34 bands were generated, of which 31 were polymorphic. The average percentage of polymorphism among the studied populations was calculated as 91.53%. The highest polymorphism percentages were obtained from primers IS4, IS13, IS15, and IS23. The mean PIC and MI values for the evaluated primers were 0.33 and 1.33, respectively. Shannon’s information index (I) ranged from 0.090 to 0.333 across populations, while Nei’s genetic diversity index (h) varied between 0.058 and 0.228. Overall, the OSH (Oshnavieh) population exhibited the lowest genetic diversity, whereas the MAH (Mahabad) population showed the highest diversity. The mean number of observed alleles and effective alleles per locus were calculated as 1.228 and 0.821, respectively. Cluster analysis using the UPGMA method and Jaccard similarity coefficient grouped the individuals from different populations into three major clusters.
4. Conclusion: The results of this study demonstrated that the high level of polymorphism observed indicates the effective performance of ISSR markers in assessing the genetic diversity of G. platycarpum populations. Therefore, these markers can serve as valuable tools for evaluating genetic variation and supporting plant breeding programs. One of the primary goals of plant breeders is the preservation of genetic resources, as higher genetic diversity enhances resistance to pests and diseases and ultimately contributes to species survival. Given that the investigation of genetic relationships is essential for plant breeding as well as for the conservation of genetic resources, the findings of this study revealed considerable genetic diversity among the examined populations, suggesting that appropriate measures can be implemented for conservation and breeding efforts in this species. Since breeding programs require substantial genetic variation among populations, the diversity identified in the studied populations can significantly support and advance future breeding initiatives.