Intraspecific phylogeny of a Patagonian fescue: differentiation at molecular markers and morphological traits suggests hybridization at peripheral populations

VERÓNICA GUIDALEVICH; NAGAHAMA NICOLÁS; ALDANA LÓPEZ; JUAN PABLO ANGELI; PAULA MARCHELLI; MARÍA MARTA AZPILICUETA

ANNALS OF BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2023

0305-7364

 Background and Aims: Grasses of the Festucagenus have complex phylogenetic relations due to morphological similaritiesamong species and inter-specific hybridization processes. Within Patagonianfescues, information concerning phylogenetic relationships is very scarce. In Festuca pallescens, a widely distributedspecies, the high phenotypic variability and the occurrence of interspecifichybridization preclude a clear identification of the populations. Given therelevance of natural rangelands for livestock production and their highdegradation due to climate change, conservation actions are needed andknowledge about genetic variation required. Methods: To ravel out theintraspecific phylogenetic relations and to detect genetic differences, westudied 21 populations of the species along its natural geographic distributionby coupling both molecular (ITS and trnL-Fmarkers) and morpho-anatomical analyses. Bayesian inference, maximumlikelihood, and maximum parsimony methods were applied to assemble aphylogenetic tree, including other native species. The morphological data setwas analysed by discriminant and cluster analyses.Key Results: The combined informationof the Bayesian tree (ITS marker), the geographic distribution of haplotypevariants (trnL-F marker) and themorpho-anatomical traits, distinguished populations located at the margins ofthe distribution. Some of the variants detected were shared with othersympatric species of fescues.Conclusions: These results suggestthe occurrence of hybridization processes between species of the genus atperipheral sites characterized by suboptimal conditions, which might be key tothe survival of these populations.