Neutral and adaptive variation in the most widely distributed native tree species in Patagonia: on the way to defining provenance regions for Nothofagus pumilio.

MATTERA, GABRIELA; TORRES, ANA DELIA; SOLIANI, CAROLINA; APARICIO, ALEJANDRO G.; MARCHELLI, PAULA; PASTORINO, MARIO J.

Buenos Aires

Simposio; Simposio Frontiers in BioScience 3; 2018

IBioBa CONICET

Nothofagus pumilio (Poep. et Endl.) Krasser is a key tree species dominating the South American temperate forests, having a great relevance due to its ecological role and timber value (hardwood). Since both climate changes and anthropogenic threats may negatively affect these ecosystems, active restoration strategies have been postulated, thus fostering the ongoing domestication and low intensity breeding program for the species of the Instituto Nacional de Tecnología Agropecuaria. In our ongoing project, we aim to define Provenance Regions (PR) for the species along its distribution range in Argentina, from 36º S to 55º S. We propose the combination of neutral genetic variation with quantitative information generated from common garden provenance and progeny genetic trials. We used seven nuclear microsatellite markers to identify neutral genetic variation patterns in 34 populations. This allowed us to determine a minimum of seven Genetic Zones (GZ). A latitudinal trend for those GZ was found, probably related to the quaternary life history of the species (last glacial maximum). Our genetic field trials were installed comprising the latitudinal variation of the natural species range and three altitudinal levels (1200, 800 and 400 m asl), representing the current thermal environment of N. pumilio and two future climate scenarios; this design allow us to assess phenotypic plasticity. In these trials we evaluate several potentially adaptive traits, such as architectural, allometric, phenological, physiological and growth characters. Our first results on quantitative traits show significant variation due to the effect of population, thus highlighting the importance of considering the adaptive traits on the definition of PR. ZG and PR are operational genetic management units essential to delineate conservation, mitigation or management plans. This tool is required to avoid maladaptation of the seedlings planted in the framework of a restoration program and genetic contamination of the surrounding natural stands.