Genetic structure and variation in different Iranian myrtle (Myrtus communis L.) populations based on morphological, phytochemical and molecular markers

Myrtle is one of the most important medicinal plants because of its application in pharmaceutical and food industries. In this study, the diversity of Iranian myrtle populations was assessed through morphological, molecular markers and essential oil content. High variation in essential oil content and morphological traits was obtained among populations. Essential oil content ranged from 1.06% in Chaharmahal and Bakhtiari (sw.ch.o) to 2.28% in Lorestan (w.l.d). Eight SRAP (sequence related amplified polymorphism) primer combinations were also used to examine the genetic diversity of 86 accessions belonging to the 11 myrtle populations. Cluster analysis delineated the accessions into five groups, although such grouping could not be fitted perfectly with the geographic regions. The results of principal coordinate analysis (PcoA) were in line with those of cluster analysis. Among the populations, Fars (S.nor) and Chaharmahal and Bakhtiar (Sw.ch.m) exhibited a relatively high genetic distance (0.308), as well as higher essential oil content (1.6% and 1.85%, respectively). According to the analysis of molecular variance (AMOVA), 89.31% of the total variation was associated to the within variation, and 10.69% was observed among the populations. Relatively high genetic differentiation (Gst = 0.31) and gene flow (Nm = 1.11) were also observed among the populations. W.l.c.m population from Lorestan exhibited the highest number of observed alleles (Na), number of effective alleles (Ne), genetic variation (H), Shannon index (I), and percentage of polymorphic loci (PPL%). The results of population structure analysis also revealed the high admixture of myrtle accessions in the populations. Finally, the results of the present research could provide new insights into the conservation and breeding of the myrtle populations.