99
variation within and between populations. Such management units are pivotal for
steering the decision-making process concerning germplasm transfer within and
between areas, for example, in reforestation and/or restoration activities (Newton
et al. 1999).
Vergara (2000) defined provenance regions for the total range of N. obliqua in
Chile and Argentina based on climatic information, together with vegetation maps,
phytogeographic limits and genecological variation (Donoso 1979). Focusing on
the restricted and fragmented distribution of this species in Argentina, Azpilicueta
et al. (2013, 2016a) defined genetic zones for N. obliqua at the eastern side of the
Andes based on the available neutral genetic information, thus giving a deeper support for the identification of genetically homogeneous units (Table 4.1, Fig. 4.3).
The movement of propagation material within genetic zones minimizes the chance
of genetic structure changes. The identification of genetic zones contributes to the
definition of genetic management units thus helping in breeding and conservation
programs.
The four northernmost watersheds where N. obliqua occurs in Argentina
(Epulauquen, Ñorquinco, Quillén and Aluminé) were clustered in one unique group
(North genetic zone, Fig. 4.3a), whereas the forests at Lake Lácar were subdivided
in two different clusters, one being composed of a single population (Bandurrias
genetic zone) and the other by the rest of the populations (Lácar genetic zone)
(Fig. 4.3b).
In summary, three genetic zones were defined for N. obliqua in Argentina
(Table 4.1, Fig. 4.3). However, additional subdivisions must be recognized in two of
them according to genetic particularities: the Epulauquen subzone in the North
genetic zone and the Quila Quina subzone in the Lácar genetic zone. These subdivisions were mainly defined based on the presence of different variants at chloroplast
DNA level coexisting with the shared genetic zone haplotype (Azpilicueta et al.
2013, 2016a). Future transfers of planting material for restoration activities and
assisted natural regeneration of Argentinean N. obliqua forests have to be limited to
the same genetic zone and subzone from where seeds or plants were collected. This
information could also be used as a guiding tool for identifying the origin of seed or
other plant material.
4.3 Quantitative Genetic Variation and Phenotypic Plasticity
Genetic variation estimated through the analysis of quantitative traits is crucial to
study adaptive processes of the past and to forecast adaptive responses in case of
eventual environmental changes. Classical provenance and progeny tests are a key
tool for this purpose, and the design of multiple-site trials additionally allows studying phenotypic plasticity, which could be a decisive evolutionary strategy of the
populations to persist in situ in the face of climate change (Aitken et al. 2008).
4 Roble pellín (Nothofagus obliqua): A Southern Beech with a Restricted…
variation within and between populations. Such management units are pivotal for
steering the decision-making process concerning germplasm transfer within and
between areas, for example, in reforestation and/or restoration activities (Newton
et al. 1999).
Vergara (2000) defined provenance regions for the total range of N. obliqua in
Chile and Argentina based on climatic information, together with vegetation maps,
phytogeographic limits and genecological variation (Donoso 1979). Focusing on
the restricted and fragmented distribution of this species in Argentina, Azpilicueta
et al. (2013, 2016a) defined genetic zones for N. obliqua at the eastern side of the
Andes based on the available neutral genetic information, thus giving a deeper support for the identification of genetically homogeneous units (Table 4.1, Fig. 4.3).
The movement of propagation material within genetic zones minimizes the chance
of genetic structure changes. The identification of genetic zones contributes to the
definition of genetic management units thus helping in breeding and conservation
programs.
The four northernmost watersheds where N. obliqua occurs in Argentina
(Epulauquen, Ñorquinco, Quillén and Aluminé) were clustered in one unique group
(North genetic zone, Fig. 4.3a), whereas the forests at Lake Lácar were subdivided
in two different clusters, one being composed of a single population (Bandurrias
genetic zone) and the other by the rest of the populations (Lácar genetic zone)
(Fig. 4.3b).
In summary, three genetic zones were defined for N. obliqua in Argentina
(Table 4.1, Fig. 4.3). However, additional subdivisions must be recognized in two of
them according to genetic particularities: the Epulauquen subzone in the North
genetic zone and the Quila Quina subzone in the Lácar genetic zone. These subdivisions were mainly defined based on the presence of different variants at chloroplast
DNA level coexisting with the shared genetic zone haplotype (Azpilicueta et al.
2013, 2016a). Future transfers of planting material for restoration activities and
assisted natural regeneration of Argentinean N. obliqua forests have to be limited to
the same genetic zone and subzone from where seeds or plants were collected. This
information could also be used as a guiding tool for identifying the origin of seed or
other plant material.
4.3 Quantitative Genetic Variation and Phenotypic Plasticity
Genetic variation estimated through the analysis of quantitative traits is crucial to
study adaptive processes of the past and to forecast adaptive responses in case of
eventual environmental changes. Classical provenance and progeny tests are a key
tool for this purpose, and the design of multiple-site trials additionally allows studying phenotypic plasticity, which could be a decisive evolutionary strategy of the
populations to persist in situ in the face of climate change (Aitken et al. 2008).
4 Roble pellín (Nothofagus obliqua): A Southern Beech with a Restricted…