Characterization of morphological, agronomic, chemical properties of seed-growed garden mint (Mentha spicata L.) genotypes and determination of chemical variation in vocal oils by thin layer chromatography

In this study, it was aimed to induce variation through seeds in the species Mentha spicata L., and to determine the morphological and agronomic characteristics of the resulting new genotypes, as well as the chemical variation using Thin Layer Chromatography (TLC) and GC-MS. The study was conducted between 2022 and 2023. As plant material, two different clonal parents of Mentha spicata L. were used: a local clone (Spica 1) and a foreign clone (USDA, PI 557886). Plants obtained from the seeds of these clones were grown under field conditions, and their morphological, agronomic, and chemical characteristics were determined. Yield values calculated based on grams per plant (g/plant) in the first year and grams per square meter (g/m2) in the second year. In the study, the chemical composition of the samples selected through TLC screening was identified using GC-MS and GC-FID. At the end of the experiment, the highest fresh herb yields were 2445.0 g/m2 in the Spica 1 genotypes (S-17) and 3688.0 g/m2 in the PI 557886 genotypes (P-30). In the first year of the experiment, essential oil ratios were found to be higher compared to the second year, with the highest value observed in genotype P-5 with 4.11%. As a result of the TLC screenings 13 samples from the Spica 1 genotypes and 11 samples from the PI 557886 genotypes were selected for GC-MS analysis. Chemically distinct samples from the parantel clones were identified among the genotypes. In the selected Spica 1genotypes, four different chemical groups were identified (carvone, trans-piperitone oxide, and carvone/piperitenone), while in the PI 557886 genotypes, three different groups were determined (carvone, piperitenone oxide, and carveol/pulegone). The study concluded that in cross-pollinated and fertile mint species, seed propagation can generate wide variation, including chemically distinct genotypes, and that this chemical diversity can be effectively identified using TLC prior to GC-MS analysis. TLC was found to be a useful tool in cultivar development and in assessing chemical diversity.