Assessment of Relationships Among and Within Helichrysum Mill. (Asteraceae) Species by Using ISSR Markers and Morphological Traits

AbstractThis study conducted to determine relationship among and within Iranian Helichrysum species (Asteraceae), using molecular analyses which are based on the inter simple sequences repeat (ISSR) technique and morphological observations of taxa which are collected in the areas of different habitats of Iran, where 20 species have been recorded within this genus. Helichrysum is a large and taxonomically difficult genus and relationships and infrageneric classification have remained largely unresolved. In this study Based on ISSR markers, ten primers generated 1145 polymorphic ISSR-PCR bands. Cluster analysis by the unweighted pair-group method (UPGMA) separated the 64 populations into two main clusters that were in agreement with the principal coordinate (PCO) analysis. Both UPGMA and the PCoA demonstrated that the highest percentage of ISSR loci polymorphism (54.7 %) occurred in populations of H. armenium. The highest gene diversity over loci (1.224), Shannon's Information Index (0.224 %) and Expected Heterozygosity (0.142 %) occurred in H. armenium (0.18) and the lowest of these parameters (0%) were observed in H. araxinum, H. graveolens, H. persicum and H. psychrophayllum. The highest genetic similarity occurred between H. armenium and H. rubicundum (0.989), while the lowest was between H.polyphyllum and H. graveolance (0.213). The analysis of molecular variance (AMOVA), showed significant genetic variation among (24%) and within (76%) species. A morphological analysis of this genus is carried out using 36 quantitative and qualitative morphological traits in 87 populations (249 individuals) of 19 species and traits such as indumentum, resting bud, achene length, achenial papillae, dimension of receptacle and form and apex of phyllaries were main diagnostic features. A high degree of similarity was revealed between H.artemisioides and H. davisianum.Results obtained from the morphological cluster were greatly consistent with the molecular data, to elucidating taxonomic relationships, as well as both attributed the higher diversity in H. armenium and H.rubicundum in comparison with other species and also indicated that H. persicum is a member of H. oocephalum species. Totally we confirmed the presence of 18 species in Iran