Medicinal plants are plants that contain in their organs one or more of active ingredients. Among these, mint scientifically named Mentha belongs to Lamiaceae which is widely distributed throughout the world, especially in the Mediterranean region. The genus Mentha has a complex taxonomic division due to the different levels of polyploidy and frequent inter-species hybridization. Mint breeding through controlled hybridization to achieve diverse populations had many advantages in terms of economy and breeding programs. Also, phytochemical traits in plants with medicinal properties and selection of superior populations are the most important breeding goals in these plants. In this study, in addition to studying the inheritance of male sterility, the genetic improvement of various morphological and phytochemical traits in F 1 and F 2 populations derived from an intraspecific cross of mint was investigated. In this regard, four mint populations were collected from Dehbala, Lorestan, Karaj and Hamedan regions. The populations included two parental clons of Menth spicata and two parental clons of M. longifolia. This research was conducted during the years 2016-2020. In the first part, a randomized complete block design with three replications was applied to evaluate these populations at Lavark Research Field of Isfahan University of Technology. The results showed the existence of monogenic inheritance for male sterility in intraspecific cross of M. spicata . Also, the results of the present study showed that most of the measured agronomic traits showed high heredity (h 2 ). The maximum genetic advance and genetic coefficients of variation were related to fresh weight, leaf area and essential oil content and essential oil yield. Based on these traits, the total flavonoids (TFC) and total phenolic content (TPC) from the best genotypes derived from an intraspecific cross of M. spicata and M. longifolia were estimated. The results showed that some F 2 genotypes had a higher amount of phenol and flavonoids than their parents. The results of gas chromatographic analysis showed that due to intraspecific cross , the amount of piperitenone, menthon, carvon and limonene significantly increased in selected genotypes of M. longifoilia and M. spicata . This increase in the amount of essential oil compounds could be related to the transgressive segregation and heterosis. Therefore, the creation of diverse populations through controlled hybridization could be used to modify mint clones. The use of male sterility facilitates the way for higher-yielding hybrids. Also, the expression of major genes in the menthol biosynthesis pathway was evaluated along with the composition of the essential oils of two mint species under six light environments (red, blue, red-blue, white, fluorescent and greenhouse). The results showed that LED light has a significant effect on the quantitative expression of gens. The results showed that the highest expression of key genes in menthol biosynthesis pathway was affected by red light and the combination of red and blue light. However, white light and fluorescent light did not change the expression of key genes in this direction. The results of gas chromatographic analysis were slightly consistent with the results of the quantitative expression of genes. Most of the essential oil compounds were observed under the spectrum of red, blue and the combination of red and blue light. The use of artificial light can increase the expression of important genes in the biosynthesis pathway of menthol, thereby increasing the resulting compounds.