Morphophysiological and phytochemical properties of peppermint ecotypes: a comprehensive study in 11 provinces of Iran

In order to evaluate the quantity and quality of 11 peppermint ecotypes, rhizomes were collected from the producing provinces and tested at the Research Institute of Forests and Rangelands in 2021 and 2022. The results showed that there was a statistically significant difference, in years in the morphological traits, shoot yield, the percentage of leaves and shoot essential oil, the yield of shoot essential oil, flavonoid, chlorophyll a, b, all essential oil compounds, total nitrogen, potassium, calcium, magnesium, iron, manganese, cadmium and lead absorption. Mean comparison of years showed that the highest shoot yield (5656.88 kg/ha), leaf essential oil percentage (2.48 percent), shoot essential oil percentage (1.87 percent) was obtained in the second year. The highest shoot yield with 6559 kg/ha and shoot essential oil percentage with 2.2% was obtained from Markazi province. The most menthone with 23.7% belonged to Mazandaran. The highest amount of menthol was in Kermanshah, with 59%. The result of cluster analysis showed that 11 accessions were placed in three main clusters. The results show the difference in the quantity and quality, absorption of macro, micro and heavy metal elements of different ecotypes and it is better to do preliminary tests and choose the appropriate ecotypes for specific uses (food, medicine, cosmetics and hygiene) before planting peppermint.