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

Año: 2023

0305-7364

• Background and Aims Grasses of the Festuca genus have complex phylogenetic relations due to morphological similarities among species and interspecific hybridization processes. Within Patagonian fescues, information concerning phylogenetic relationships is very scarce. In Festuca pallescens, a widely distributed species, thehigh phenotypic variability and the occurrence of interspecific hybridization preclude a clear identification of thepopulations. Given the relevance of natural rangelands for livestock production and their high degradation due toclimate change, conservation actions are needed and knowledge about genetic variation is required.• Methods To unravel the intraspecific phylogenetic relations and to detect genetic differences, we studied 21populations of the species along its natural geographical distribution by coupling both molecular [internal transcribed spacer (ITS) and trnL-F markers] and morpho-anatomical analyses. Bayesian inference, maximum likelihood and maximum parsimony methods were applied to assemble a phylogenetic tree, including other nativespecies. The morphological data set was analysed by discriminant and cluster analyses.• Key Results The combined information of the Bayesian tree (ITS marker), the geographical distribution ofhaplotype variants (trnL-F marker) and the morpho-anatomical traits, distinguished populations located at themargins of the distribution. Some of the variants detected were shared with other sympatric species of fescues.• Conclusions These results suggest the occurrence of hybridization processes between species of thegenus at peripheral sites characterized by suboptimal conditions, which might be key to the survival of thesepopulations.