Abstract In order to investigate diversity and explain the relationships of essential oil yield with morphological traits, 84 populations T. polycephalum, were sown in the field using randomized complete blocks design (RCBD) with three replicates in Research Institute of Forest and Rangeland, Tehran, Iran in 2013-2014. Data were collected for flowering date, growth degree days (GDD), stem number, plant height, dry matter (DM) yield, essential oil percentage, and essential oil yield. The relationships among traits were determined using correlation, regression and factor analysis. The genetic distance and genotype classification were determined using cluster analysis. DM yield was positively correlated with plant height, canopy cover, stem number and oil... |