Assessment of genetic variation and grouping of licorice (Glycyrrhiza glabra L.) populations using canonical discriminant analysis

Licorice (Glycyrrhiza glabra L.) is one of the oldest and most important medicinal plants in Fabaceae, used for curing many diseases since 4000 years ago. This study was conducted to evaluate the genetic diversity of 22 different licorice populations based on morphological and yield traits at the research field of the Faculty of Agriculture, Zanjan University, during 2016 to 2018. Morphological and yield traits including plant height and width, leaf length and width, number, length and width of leaflets, number of lateral branches, main stem diameter, aerial parts fresh and dry weight, root fresh and dry weight, root to aerial parts ratio and aerial parts and root yields (per m2) were measured. Canonical discriminant (CDA) and cluster (CA) analyses were used to group the populations. In CDA, the first two canonical variables were significant. The first canonical variable included plant height and width, main stem diameter, leaf length and the number of leaflets, and the second one included aerial parts fresh and dry weight, root fresh and dry weight, root and aerial parts yields. The second canonical variable had the greatest role in population separation and grouping. Canonical variables divided populations into four main groups and confirmed CA clustering results. In general, the results indicated the good potential of canonical discriminant analysis in evaluating the genetic diversity and identifying the index traits in licorice.