364
population was performed using 140 polymorphic AFLP markers. The genetic
diversity of C. angustifolia CSO was moderate (He = 0.204) and greater (more than
double) than the average genetic diversity of natural populations of the species in
the Yungas of NWA (He = 0,087, Inza et al. 2012). Eleven trees with exclusive loci
at individual level were identified. Genetic structure inferred by Bayesian clustering
(Structure 2.2.3, Pritchard et al. 2000) was mainly associated with latitudinal origin
of the trees, following the patterns described for the species in previous sections.
The UPGMA dendrogram (NTSYS 2.0, Rohlf 1998) showed a homogeneous general distribution of genetic relationships among trees (r = 0.84) with some trees of
northern Yungas more distant. The average similarity index (0.62) was considered
adequate to avoid inbreeding depression processes. Finally, AFLP markers allowed
the unmistakable identification of the total number of evaluated individuals.
13.2.5 Genetic Variability of Cedrela fissilis Populations
in the Alto Paraná Rainforest
Cedrela fissilis in Argentina, was subjected to intense and selective overexploitation (best phenotypes were harvested), resulting its current natural populations in
fragmented stands of small size lacking reproductive adult individuals with desirable economic characteristics. Despite the high value of C. fissilis, information on
the genetic diversity of this species is scarce. In order to assess the current levels of
genetic diversity and its distribution throughout its natural range in Argentina, we
performed a genomic analysis using SSR markers (Soldati et al. 2014b). This
knowledge will be used to sustain conservation strategies for the remnant populations and to identify future sources of genetic material for breeding programs.
We collected 107 individuals belonging to 8 natural populations of the species in
the Alto Paraná Rainforest of NEA, covering the natural distribution area of C. fissilis in the country. Total genomic DNA was extracted from dried leaf material following the procedure described by Hoisington et al. (1994) with minor modifications.
Concentration and integrity of DNA was determined by comparison with reference
standards in agarose gels. For this species, the analysis was performed with ten validated SSR markers: (i) seven SSRs transferred from C. odorata; (ii) one SSR transferred from Swietenia macrophylla; and (iii) two SSRs developed for C. fissilis
(Lemes et al. 2002; Hernandez et al. 2008; Gandara 2009; Soldati et al. 2014a).
These were amplified by PCR according to optimized protocols for other species of
the genus (Soldati et al. 2014b).
One hundred ninety-six alleles were detected, with an average number of 24.5
alleles for the 8 populations assessed. Forty-nine exclusive alleles (Ea) were found
(Table 13.5). The effective number of alleles (ENa) was variable in a range of 3.713
to 6.476, with an average value of 5.774 (SD = 0.726). Observed heterozygosity
(Ho) values ranged from 0.744 to 0.867 (mean = 0.820, SD = 0.016). Expected
heterozygosity (He – genetic diversity of Nei) levels were high, with an average
N. Zelener et al.
population was performed using 140 polymorphic AFLP markers. The genetic
diversity of C. angustifolia CSO was moderate (He = 0.204) and greater (more than
double) than the average genetic diversity of natural populations of the species in
the Yungas of NWA (He = 0,087, Inza et al. 2012). Eleven trees with exclusive loci
at individual level were identified. Genetic structure inferred by Bayesian clustering
(Structure 2.2.3, Pritchard et al. 2000) was mainly associated with latitudinal origin
of the trees, following the patterns described for the species in previous sections.
The UPGMA dendrogram (NTSYS 2.0, Rohlf 1998) showed a homogeneous general distribution of genetic relationships among trees (r = 0.84) with some trees of
northern Yungas more distant. The average similarity index (0.62) was considered
adequate to avoid inbreeding depression processes. Finally, AFLP markers allowed
the unmistakable identification of the total number of evaluated individuals.
13.2.5 Genetic Variability of Cedrela fissilis Populations
in the Alto Paraná Rainforest
Cedrela fissilis in Argentina, was subjected to intense and selective overexploitation (best phenotypes were harvested), resulting its current natural populations in
fragmented stands of small size lacking reproductive adult individuals with desirable economic characteristics. Despite the high value of C. fissilis, information on
the genetic diversity of this species is scarce. In order to assess the current levels of
genetic diversity and its distribution throughout its natural range in Argentina, we
performed a genomic analysis using SSR markers (Soldati et al. 2014b). This
knowledge will be used to sustain conservation strategies for the remnant populations and to identify future sources of genetic material for breeding programs.
We collected 107 individuals belonging to 8 natural populations of the species in
the Alto Paraná Rainforest of NEA, covering the natural distribution area of C. fissilis in the country. Total genomic DNA was extracted from dried leaf material following the procedure described by Hoisington et al. (1994) with minor modifications.
Concentration and integrity of DNA was determined by comparison with reference
standards in agarose gels. For this species, the analysis was performed with ten validated SSR markers: (i) seven SSRs transferred from C. odorata; (ii) one SSR transferred from Swietenia macrophylla; and (iii) two SSRs developed for C. fissilis
(Lemes et al. 2002; Hernandez et al. 2008; Gandara 2009; Soldati et al. 2014a).
These were amplified by PCR according to optimized protocols for other species of
the genus (Soldati et al. 2014b).
One hundred ninety-six alleles were detected, with an average number of 24.5
alleles for the 8 populations assessed. Forty-nine exclusive alleles (Ea) were found
(Table 13.5). The effective number of alleles (ENa) was variable in a range of 3.713
to 6.476, with an average value of 5.774 (SD = 0.726). Observed heterozygosity
(Ho) values ranged from 0.744 to 0.867 (mean = 0.820, SD = 0.016). Expected
heterozygosity (He – genetic diversity of Nei) levels were high, with an average
N. Zelener et al.