Investigation of Areal part yield and morphological traits in populations of Mentha pulegium

In order to study biomass yield in flowing stage and morphological traits, 12 populations M. pulegium were evaluated in a field experiment in the Alborz research station, Karaj Iran in 2014. Seeds of  the accessions were sown as spaced planet using complete randomized block in two replications. Each plot contains 20 spaced plants with 50×50 cm distance. The drip irrigation system was used for irrigation. In The first year, due to poor establishment no data were collrvted. In the second year, data were collected for fresh and dry matter yield, plant height, stems number, flower number per plant, the canopy diameter and infloescence length. Result showed significant differences between accessions for all of the traits (p < 0.01). Mean comparisons between populations showed that, Marivan and, 22381-Arak with values of 824 and 375.6 g/p had the highest aerial fresh and dry weight. In terms of plant height, the populations of 22381 and 22391-Arak with average values of 82.6 and 81.8 cm had the highest stem length, respectively. The highest inflorescence length with average values of 11.6 and 10.7 cm were observed in 22391-Arak and Gorgan, respectively. For flower number, Miandoab with 60 flowers per plant had the highest number. Using cluster analysis, the populations were split into two groups with 8 and 4 populations in cluster 1 and 2, respectively. The overall mean values in populations of cluster 1 were higher than cluster 2. It was concluded that the populations of Marivan and 22381-Arak had the highest aerial fresh and dry weight and can be used for improved breeding varieties.