412
15.5.1 The Outstanding Case of a Multi-provenance
Plantation Over 70 Years Old
Given the loss of natural populations of A. angustifolia throughout its whole distribution area, plantations could be an important source of genetic diversity for the
conservation and breeding of the species (Stefenon et al. 2009), in particular those
older than 50 years, i.e., those planted when seed sources were much more diverse
than nowadays. This is the reason why the old plantation of Manuel Belgrano Forest
Station was included in the genetic diversity study performed by Inza et al. (2018).
The remaining stands of the old plantation of Manuel Belgrano Forest Station
cover an area of 448 ha and were planted in the years 1947, 1949, and 1950, with
seeds of multiple provenances. The still existing registers identify five different
provenances (Pinazo and Fassola, pers. comm.):
1. Local: probably seeds from the natural forest of the Manuel Belgrano
Forest Station
2. Regional: probably seeds from unidentified natural forests of the Province of
Misiones, excluding Manuel Belgrano Forest Station
3. Brazil: seeds from unidentified stands from Brazil, probably commercialized
for feeding
4. Barracón – Brazil: probably seeds from natural stands of the small village
Barracão, some 30 km from Manuel Belgrano Forest Station
5. Buenos Aires, 25 de Mayo Forest Station: seeds from a plantation located in the
old Forest Station of 25 de Mayo city, in the Province of Buenos Aires
This old plantation displayed higher genetic diversity indexes (He = 0.155;
PPL = 80.2; EL = 32) than all the analyzed natural populations of Argentina
(Table 15.1) and showed low genetic differentiation (3%, p ≤ 0.001) with respect to
all the natural populations taken together. This result is consistent with the multiple
provenances comprised in this plantation, potentially including uncertain localities
of the huge distribution of the species in Brazil. In contrast with these results, southern Brazilian plantations reported higher genetic diversity (Hj = 0.240, Stefenon
et al. 2008), which could be due to seeds collected from the center of the species’
distribution.
Furthermore, despite the fact that the plantation seems to contain a suitable representation of the genetic diversity of A. angustifolia from Misiones, its germplasm
could principally come from few populations (Manuel Belgrano natural forest,
Gramado, and Santa Rosa), as indicated by genetic structure and relationship evaluations (Fig. 15.10, Inza et al. 2018). However, since the admixture of seeds from
several natural populations can lead to increase the variability (Sebbenn et al. 2003;
Stefenon et al. 2008), this could explain the high genetic diversity found (Inza et al.
2018). The higher levels of genetic diversity of this plantation and its genetic similarity with the natural surrounded populations were also observed with SSRs
focused only on the Manuel Belgrano Forest Station (Sarasola et al. 2011). In this
work, the authors observed moderate to high levels of genetic diversity for this
M. E. Gauchat et al.
15.5.1 The Outstanding Case of a Multi-provenance
Plantation Over 70 Years Old
Given the loss of natural populations of A. angustifolia throughout its whole distribution area, plantations could be an important source of genetic diversity for the
conservation and breeding of the species (Stefenon et al. 2009), in particular those
older than 50 years, i.e., those planted when seed sources were much more diverse
than nowadays. This is the reason why the old plantation of Manuel Belgrano Forest
Station was included in the genetic diversity study performed by Inza et al. (2018).
The remaining stands of the old plantation of Manuel Belgrano Forest Station
cover an area of 448 ha and were planted in the years 1947, 1949, and 1950, with
seeds of multiple provenances. The still existing registers identify five different
provenances (Pinazo and Fassola, pers. comm.):
1. Local: probably seeds from the natural forest of the Manuel Belgrano
Forest Station
2. Regional: probably seeds from unidentified natural forests of the Province of
Misiones, excluding Manuel Belgrano Forest Station
3. Brazil: seeds from unidentified stands from Brazil, probably commercialized
for feeding
4. Barracón – Brazil: probably seeds from natural stands of the small village
Barracão, some 30 km from Manuel Belgrano Forest Station
5. Buenos Aires, 25 de Mayo Forest Station: seeds from a plantation located in the
old Forest Station of 25 de Mayo city, in the Province of Buenos Aires
This old plantation displayed higher genetic diversity indexes (He = 0.155;
PPL = 80.2; EL = 32) than all the analyzed natural populations of Argentina
(Table 15.1) and showed low genetic differentiation (3%, p ≤ 0.001) with respect to
all the natural populations taken together. This result is consistent with the multiple
provenances comprised in this plantation, potentially including uncertain localities
of the huge distribution of the species in Brazil. In contrast with these results, southern Brazilian plantations reported higher genetic diversity (Hj = 0.240, Stefenon
et al. 2008), which could be due to seeds collected from the center of the species’
distribution.
Furthermore, despite the fact that the plantation seems to contain a suitable representation of the genetic diversity of A. angustifolia from Misiones, its germplasm
could principally come from few populations (Manuel Belgrano natural forest,
Gramado, and Santa Rosa), as indicated by genetic structure and relationship evaluations (Fig. 15.10, Inza et al. 2018). However, since the admixture of seeds from
several natural populations can lead to increase the variability (Sebbenn et al. 2003;
Stefenon et al. 2008), this could explain the high genetic diversity found (Inza et al.
2018). The higher levels of genetic diversity of this plantation and its genetic similarity with the natural surrounded populations were also observed with SSRs
focused only on the Manuel Belgrano Forest Station (Sarasola et al. 2011). In this
work, the authors observed moderate to high levels of genetic diversity for this
M. E. Gauchat et al.