Genetic and morphological differentiation between Melica ciliata L. and M. transsilvanica Schur (Poaceae) in Europe reveals the non-presence of M. ciliata in the Polish flora

Abstract

A good knowledge of species delimitation is crucial for the biodiversity protection and the conservation of wild species. We studied the efficiency of AFLP markers and morphological characters to assist species determination for <em>Melica ciliata </em>L. and <em>M. transsilvanica </em>Schur within European range of distribution, including isolated and range-limit populations of "<em>M. ciliata</em>" (i.e. <em>M</em>. cf. <em>ciliata</em>) from the Polish Sudetes, where it is regarded as critically endangered. AFLP markers were found to be more effective then morphological characters (more or less continuous) in distinguishing the both studied species. AMOVA revealed very low genetic diversity within populations and high differentiation among populations of <em>M. ciliata </em>and <em>M. transsilvanica </em>(F_ST = 0.89 and 0.95, respectively). The species-diagnostic AFLP markers of <em>M. transsilvanica </em>shared with "<em>M. ciliata</em>" from the Sudetes were detected. On the other hand, no species-diagnostic genetic markers of <em>M. ciliata </em>or hybrid-diagnostic markers of <em>M</em>. × <em>thuringiaca </em>were found within "<em>M. ciliata</em>". PCoA and NJ showed an overlapping genetic diversity of "<em>M. ciliata</em>" and <em>M. transsilvanica</em>. Hierar­chical AMOVA supported the absence of a significant genotypic distinction between "<em>M. ciliata</em>" and <em>M. transsilvanica</em>. ANOVA showed that the length ratio of lower to upper glumes was the best morphological character to discriminate between <em>M. ciliata </em>and <em>M. transsilvanica</em>. Combined morphological and genetic data show that <em>M. ciliata </em>is not currently present in Poland as its putative Polish populations represent <em>M. transsilvanica</em>. A significant decrease in genetic varia­bility that could influence viability was not observed the in Sudetian populations of <em>M. transsilvanica</em>. However, the population size changes significantly as a result of plant succession. Correction of the northern limit of the continuous distribution of <em>M. ciliata</em> L. in Central Europe is presented.