Genetic structure and variation in Iranian licorice (Glycyrrhiza glabra L.) populations based on morphological, phytochemical and simple sequence repeats markers

Abstract

Licorice (Glycyrrhiza glabra L.) as a strategic and highly valuable medicinal plant in Iran with numerous beneficial pharmaceutical properties contributes substantially to Iranian herbs exports. In the present study, variation of cultivated licorice populations was assessed via morphological, phytochemical and simple sequence repeats (SSRs) markers. A remarkable variation among cultivated populations of G. glabra in terms of morphological and phytochemical characteristics was found. Maximum coefficient of variance was observed in leaf attributes such as leaf width (CV = 34.6 %) and leaf length (CV = 32.7 %) among different populations. Minimum (11.7 mg/g Dry Weight (DW)) and maximum (74.0 mg/g DW) amount of glycyrrhizic acid were observed in Haji Abad and Eghlid populations, respectively. High levels of glabridin content were allocated to Kashmar (4.0 mg/g DW), Ahar (3.0 mg/g DW) and Ilam (2.9 mg/g DW) populations. Nine EST-SSR primers were applied to analyze the genetic variation of 162 individuals of 28 licorice populations. In total 46 bands were obtained from 9 SSR markers with 24 bands being polymorphic (52.2 %). The polymorphic information content (PIC) for markers ranged from 0.32 (SSR-25053) to 0.61 (SSR-20631), with an average of 0.50. The analysis of the molecular variance (AMOVA) of the licorice populations demonstrated that 82.0 % of variability was related to the intra-population level, while the diversity among populations amounted to 18.0 %. Ultimately, the results of this investigation create guidelines such as the identification of glycyrrhizic acid/glabridin rich-clones and genetically separated clones for deliberate interbreeding and further examinations as a subset of breeding programs.