A study on the genetic diversity of different populations of German chamomile (Matricaria chamomilla L.) using morphological traits and essential oil percentage

Despite the importance of the German chamomile (Matricaria chamomilla L.), as one of the most widely used medicinal plants in the world, there is little information about the genetic variation within and between its populations in Iran. This study was conducted to investigate the genetic diversity of 15 chamomile populations based on morphological characteristics in a randomized complete block design with three replications. Height, flower diameter, receptacle diameter, fresh flower weight, dry flower weight, wet biomass, dry biomass, flowering index, essential oil percentage and Chamazulene percentage were analyzed. The populations had a significant difference for all traits (P≤0.01). The phenotypic and genotypic variation was obtained to be more than 60% for dry weight, dry mass and Chamazulene content. Significant values were recorded for the heritability of the traits including percentage of kemazolen (94.04), the wet biomass (93.93), plant height (90.59), flower diameter (86.52), dry flower weight (84.15), and dry biomass (83.08). The highest and lowest yield (kg/ha) were related to Hamedan (9700) and Eurea (753.33) populations, respectively. The highest percentage of Chamazulene and essential oil content were obtained from Dehroud (14.10) and Jam-o-Riz (0.61), respectively. The flower diameter had the highest correlation (0.62) with the percentage of essential oil. Regression analysis for essential oil percentage as the dependent variable was performed and four traits including flower diameter, height, and fresh weight of flower were introduced into the model, explaining 59% of the variation. In the path analysis for essential oil percentage as the dependent variable, the highest direct effect was related to the fresh weight of flower (1.09) and the highest indirect effect was related to the fresh weight of flower (1.06). The cluster analysis grouped the populations into three groups that did not follow geographical distribution.