Microsatellite markers as a useful tool for species identification and assessment of genetic diversity of the Tilia species in the Czech Republic

Diagnostic morphological traits distinguishing Tilia cordata and T. platyphyllos are not always apparent. Precise species identification is crucial for conservation management and for establishing genetic resources of forest reproductive material. In this study, we employed fifteen microsatellite (SSR) markers to identify diagnostic loci for reliable species discrimination between T. cordata and T. platyphyllos species and to evaluate the genetic diversity. A total of 250 trees were sampled from eight natural autochthonous populations of T. cordata and T. platyphyllos in the Czech Republic, and additional ten individuals of T. tomentosa were included for comparison. Markers Tc8 and Tc918 were identified as diagnostic, exhibiting species-specific alleles for T. cordata and T. platyphyllos. Contrary to the previously published results, we obtained PCR amplicons at locus Tc918 with an allele size of 226 bp in T. cordata. An analysis of the fifteen SSR loci revealed a high level of genetic variability in both the T. cordata and T. platyphyllos populations. No clonally identical genotypes were detected across the eight study sites. The genetic differentiation (Fst) was higher between T. platyphyllos and T. tomentosa (0.316) than between T. platyphyllos and T. cordata (0.205). Bayesian clustering further revealed distinct genetic structures for T. cordata, T. platyphyllos, and T. tomentosa.