Assessment of Morphological and Genetic Variability in some Thymus Accessions Using Molecular Markers

Abstract

The aim of the study was to determine the morphological and genetic variability in seven accessions of Thymus: T. vulgaris, T. vilosus, T. praecox, T. serpyllum, T. × citriodorus, T. serpyllum ‘Aureum’ and T. × citriodorus ‘Silver Queen’. Morphological differences between the studied accessions were determined on the basis of morphometric measurements of some traits including: the length of the longest sprout, the width of pair leaves, length and width of leaves and essential oils content. DNA polymorphism was assessed based on the analysis in between region microsatellite sequences (ISSR-PCR) and InterGenic Spacers between copies of 5s RNA subunits genes (IGS-PCR). Amplicons were analyzed by electrophoresis on a 2% agarose gel. The 0/1 matrixes were used to calculate phylogenetic similarity and were employed to construct an UPGMA dendrograms. Morphometric studies showed that there were significant differences among Thymus accessions in all studding parameters. The ISSR reactions were carried out using 7 out of 20 microsatellite primers tested. Those amplified a total of 127 loci (309 amplicons). Specific DNA profiles were generated Only for T. vulgaris and T. serpyllum, which were different from other accessions, whereas in nested-PCR reactions (B and NSP primers) monomorphic products were amplified.