Investigation of genetic and phytochemical diversity of some catnip (Nepeta cataria L.) populations by RAPD molecular marker and GC/MS method

Catnip (Nepeta cataria L.), also called catmint, is a medicinal plant containing aromatic compounds and belongs to the Lamiaceae family. In this study, phytochemical and genetic variations of some Catnip germplasm were analyzed using RAPD molecular marker as well as GC/MS. The shoots of plants were collected from various habitats and dried away from direct sunlight. DNA was extracted using (CTAB) method. Eleven RAPD primers were used in PCR reaction. Based on the results of cluster analysis, 15 populations were classified into four groups. Based on the results of principal component analysis, the plant populations were clustered into five groups. Eight of 15 collected populations were analyzed phytochemically. Essential oils were extracted via water steam distillation using Clevenger apparatus. Twenty-seven components were identified from all essential oil samples. The results of GC/MS method showed that among the samples, 100% of essential oil compounds were identified in populations of Sirch, Mohammad Abad-e-Maskoon, Saqder 2, Dalfard 2, and Mijan 2. The results also showed that in samples of Dehbakri, Dalfard 1, and Saqder 1, 94.84%, 99.8% and 96.6% of essential oil compounds were identified, respectively. Three isomers of Nepetalactone constituted the major essential oils compounds. B-caryophyllene, Caryophyllene oxide, β-pinene, and α-pinene were also of main essential oil compounds. Based on the cluster analysis of GC/MS data, the populations were classified into three groups. Comparison of consisting compounds of essential oils in the eight studied populations indicated that the essential oils extracted were different quantitatively and qualitatively. This could be probably due to the different ecological conditions of habitats such as humidity, temperature, altitude above sea level, or other terrestrial, geographical and genetic factors.