Study of Genetic Diversity in some of Iranian Peppermint (Mentha piperita) Accessions Based on Morphological Traits

Medicinal plants are one of the rich sources of important compounds from ancient to the present; it has found a special place in the treatment of many diseases and has become an important reason for many studies on medicinal plants. On the other hand, the diversity of plants has led researchers to use morphological markers first and then cytogenetic markers to select the physiologically and genetically superior plant. Peppermint (Mentha piperita) from Lamiaceae family is one of the most important medicinal plants, used in food, sanitary and cosmetic industries and used as a spice and traditional herb in Iran. The purpose of the experiment is to investigate genetic diversity based on morphological diversity.

In this research, different accessions of this plant were collected from different regions of Iran. An experiment was conducted in 2021 year based on randomized complete block design to evaluate the morphological of these accessions in Meshginshahr climatic condition. The results were analyzed using spss software and univariate and multivariate statistical methods.

Analysis of variance showed that there were significant differences for the most studied traits among 12 accessions. The important traits such as plant height, branch number, leaf number traits, the internode length, in inflorescence length, the plant dry weight, plant fresh weight, bracket number, stem length, , internode number, bract number, Plant diameter, Dry weight leaf, Dry weight flower, Leaf surface and Flower number per plant were varied among accessions. The Meshginshahr, Golestan ,Ardabil and Urmia were the best in phytochemical. Maximum correlation was shown between plant height and stem length (0.97). Cluster analysis, classified the accessions into three  major claddes. Factor analysis indicated that the four factors explained 91.3 of the variability among the accessions. The results of path analysis showed that the leaf number and  plant dry weight content had highest direct and positive effect (0.75).

The results suggested that there was a considerable genetic variation among M. piperita L accessions. Indicate the presence of comparable genetic potentials in genotypes of Mentha piperita L. for cultivar development.