230
an important advance is the work by Mogni et al. (2016) on optimization of DNA
extraction and development of a protocol for PCR amplification for Schinopsis. In a
recent study, Mogni et al. (2018), based on nuclear and chloroplast markers, foliar
morphology and anatomy, palynology, and biogeographic features, postulated
hypotheses about phylogenetic and biogeographic patterns of the genus. There is
evidence of the possible hybrid origin of S. heterophylla (Meyer and Barkley 1973;
Hunziker 1998), but this is not confirmed yet. Moreover, there is still discussion
about the identity of S. haenkeana. According to morphological studies, no significant differences were found between this species and S. lorentzii, which could be
attributed to the altitudinal gradient (Flores et al. 2013). However, Mogni et al.
(2017) designated an epitype for S. haenkeana, thus taxonomically distinguishing it
from S. lorentzii. Notwithstanding, there are no genetic studies analyzing the relationship between the two species, which turns out to be a central issue when considering conservation and improvement programs. The difficulty in the taxonomy of
the genus (Mogni et al. 2014, describes a new species, with which there would
already be eight taxonomic species, but not necessarily biological sepecies as evolutionary units), the description of possible interspecific hybrids and the existence
of related sympatric species, difficult to differentiate morphologically, support the
hypothesis that the genus could constitute a complex of species among which there
are significant genetic flows, as in the case of algarrobo trees (Prosopis sp.). In this
context, a favorable contribution to this hypothesis is the fact that S. balansae and
S. haenkeana (La Porte, 1962; Cáceres and Ávila 1987) are diploid 2n = 28. It
remains to know the ploidy of the rest of the species that could be eventually part of
a possible homogametic complex.
The contact area between S. balansae and S. lorentzii coincides with the highest
density of clearings for agricultural use, where there are practically no natural protected areas. It is very likely that this area has an important conservation value for
quebrachos and the associated ecosystems, considering the existence of both species and the possible interspecific hybrid S. heterophylla (the three quebrachos forest). A study on the conservation status of the vegetation carried out by Torrella
et al. (2011) on remaining forest fragments of between 5 and 1000 ha in this region
stated the feasibility of constituting protected areas and biological corridors. From
the comparison of these forests with those from two existing protected areas (Copo
National Park in the semi-arid Chaco and El Bagual Reserve in the humid Chaco),
the authors concluded that the state of conservation of the remaining fragments in
the central subhumid Chaco is “surprisingly good” despite the high degree of fragmentation. They also mentioned that from the stump count in the sampling plots, it
seems that the selective extraction was not of great intensity.
Schinopsis balansae stands out against the rest of the quebrachos regarding the
needs of study, organization, and management of their genetic resources for regional
development. As we mentioned, the logging of this species in the natural forest is
mainly intended for the extraction of tannin. Thus, there would be three main
purposes for base propagation materials for the plantation of this species: (1)
A. Verga and D. López Lauenstein
an important advance is the work by Mogni et al. (2016) on optimization of DNA
extraction and development of a protocol for PCR amplification for Schinopsis. In a
recent study, Mogni et al. (2018), based on nuclear and chloroplast markers, foliar
morphology and anatomy, palynology, and biogeographic features, postulated
hypotheses about phylogenetic and biogeographic patterns of the genus. There is
evidence of the possible hybrid origin of S. heterophylla (Meyer and Barkley 1973;
Hunziker 1998), but this is not confirmed yet. Moreover, there is still discussion
about the identity of S. haenkeana. According to morphological studies, no significant differences were found between this species and S. lorentzii, which could be
attributed to the altitudinal gradient (Flores et al. 2013). However, Mogni et al.
(2017) designated an epitype for S. haenkeana, thus taxonomically distinguishing it
from S. lorentzii. Notwithstanding, there are no genetic studies analyzing the relationship between the two species, which turns out to be a central issue when considering conservation and improvement programs. The difficulty in the taxonomy of
the genus (Mogni et al. 2014, describes a new species, with which there would
already be eight taxonomic species, but not necessarily biological sepecies as evolutionary units), the description of possible interspecific hybrids and the existence
of related sympatric species, difficult to differentiate morphologically, support the
hypothesis that the genus could constitute a complex of species among which there
are significant genetic flows, as in the case of algarrobo trees (Prosopis sp.). In this
context, a favorable contribution to this hypothesis is the fact that S. balansae and
S. haenkeana (La Porte, 1962; Cáceres and Ávila 1987) are diploid 2n = 28. It
remains to know the ploidy of the rest of the species that could be eventually part of
a possible homogametic complex.
The contact area between S. balansae and S. lorentzii coincides with the highest
density of clearings for agricultural use, where there are practically no natural protected areas. It is very likely that this area has an important conservation value for
quebrachos and the associated ecosystems, considering the existence of both species and the possible interspecific hybrid S. heterophylla (the three quebrachos forest). A study on the conservation status of the vegetation carried out by Torrella
et al. (2011) on remaining forest fragments of between 5 and 1000 ha in this region
stated the feasibility of constituting protected areas and biological corridors. From
the comparison of these forests with those from two existing protected areas (Copo
National Park in the semi-arid Chaco and El Bagual Reserve in the humid Chaco),
the authors concluded that the state of conservation of the remaining fragments in
the central subhumid Chaco is “surprisingly good” despite the high degree of fragmentation. They also mentioned that from the stump count in the sampling plots, it
seems that the selective extraction was not of great intensity.
Schinopsis balansae stands out against the rest of the quebrachos regarding the
needs of study, organization, and management of their genetic resources for regional
development. As we mentioned, the logging of this species in the natural forest is
mainly intended for the extraction of tannin. Thus, there would be three main
purposes for base propagation materials for the plantation of this species: (1)
A. Verga and D. López Lauenstein