77
trees, good shaped and with good diametric growth. They were cut down and their
stumps resprouted profusely in the following year. Spring cuttings of semi-woody
sprouts of the current year from those resprouted stumps and also from branches of
3 and 12-year-old trees of ongoing trials were attempted to root in warm sand beds
with irrigation provided by a fogger system. The best propagation protocol resulted
from 8 cm long cuttings with half leaf and its axillary bud above the surface and two
buds under the surface, treated with rapid immersion in an IBA alcoholic solution at
7000 ppm. With this methodology and a total sampling of 1008 cuttings from 12
genotypes, rooting was achieved in only 7.9% of the cuttings assayed, with variations among genotypes from 1.2 to 23.8% (Pastorino et al. 2016). Terminal bud
grafting was also assayed, using 3-year-old saplings as rootstock. Scions were taken
from the same sources as for rooting. Grafts were mostly tested in winter time,
though a test was also performed with spring material. Success was achieved only
in 27% of the grafts, which is an insufficient proportion considering the efforts of
the technique, which was also dependent of the genotype (Pastorino et al. 2016).
The poor performance of the vegetative propagation and its dependence on the
genotype led to change the breeding strategy for raulí from clonal seed orchards to
progeny seed orchards. Additionally, a research result supports this decision. The
Chilean breeding programme of raulí established a provenance and progeny trial in
2000 near to Lake Maihue (40° 12′ S; 72° 2′ W; 180 m asl). It included the progeny
of 114 not selected open-pollinated mothers sampled in the natural forests (14 sampling points), 4 control treatments and the progeny of 8 mothers belonging to a
clonal seed orchard established in 1989 by Corporación Forestal Nacional (CONAF)
with 25 clones (Ipinza et al. 2015). At 14 years of age, this trial presented a survival
of 72.2%, with an average height of 14.7 m and a DBH of 15.4 cm. These mean
values are quite promising, but the point to highlight is that the progenies coming
from the seed orchard mothers had mean height and diameter below the average of
the trial. That is, progenies from not selected mothers were better than those coming
from crossbreeding of mass-selected trees.
According to the new strategy of installing progeny seed orchards, the already
described progeny test of the San Martín Forest Station (INTA) containing 86 openpollinated families from 8 Argentine origins was transformed in a progeny seed
orchard (0.3 ha; Table 3.2). From the original 1290 seedlings planted in 2011 at high
density (1 × 1 m) with a single-tree plot design, 622 trees remained in the seed
orchard in 2017 after mortality and a preliminary systematic thinning, with a mean
height of 272 cm (maximum: 491 cm). Seed production is expected to begin in
2023, at which time a new evaluation will be performed to prescribe a genetic
thinning.
Similarly, two trials installed in 1999 in Trevelin Forest Station (INTA) were
transformed in a selected seed stand (SSS; Table 3.2) that was registered with
INASE in 2017. Within these two trials, a study performed at 13 years of age in the
progeny test revealed significant differences in total height and basal diameter
among families (Puntieri et al. 2013). In the provenance trial, an interesting
association was found between genetic diversity and growth. The best provenance
according to DBH at 12 years of age was Hua-Hum (Lake Lácar basin; Gallo
unpublished data), which is also the population with the highest genetic diversity
3 Raulí (Nothofagus alpina = N. nervosa): The Best Quality Hardwood in Patagonia
trees, good shaped and with good diametric growth. They were cut down and their
stumps resprouted profusely in the following year. Spring cuttings of semi-woody
sprouts of the current year from those resprouted stumps and also from branches of
3 and 12-year-old trees of ongoing trials were attempted to root in warm sand beds
with irrigation provided by a fogger system. The best propagation protocol resulted
from 8 cm long cuttings with half leaf and its axillary bud above the surface and two
buds under the surface, treated with rapid immersion in an IBA alcoholic solution at
7000 ppm. With this methodology and a total sampling of 1008 cuttings from 12
genotypes, rooting was achieved in only 7.9% of the cuttings assayed, with variations among genotypes from 1.2 to 23.8% (Pastorino et al. 2016). Terminal bud
grafting was also assayed, using 3-year-old saplings as rootstock. Scions were taken
from the same sources as for rooting. Grafts were mostly tested in winter time,
though a test was also performed with spring material. Success was achieved only
in 27% of the grafts, which is an insufficient proportion considering the efforts of
the technique, which was also dependent of the genotype (Pastorino et al. 2016).
The poor performance of the vegetative propagation and its dependence on the
genotype led to change the breeding strategy for raulí from clonal seed orchards to
progeny seed orchards. Additionally, a research result supports this decision. The
Chilean breeding programme of raulí established a provenance and progeny trial in
2000 near to Lake Maihue (40° 12′ S; 72° 2′ W; 180 m asl). It included the progeny
of 114 not selected open-pollinated mothers sampled in the natural forests (14 sampling points), 4 control treatments and the progeny of 8 mothers belonging to a
clonal seed orchard established in 1989 by Corporación Forestal Nacional (CONAF)
with 25 clones (Ipinza et al. 2015). At 14 years of age, this trial presented a survival
of 72.2%, with an average height of 14.7 m and a DBH of 15.4 cm. These mean
values are quite promising, but the point to highlight is that the progenies coming
from the seed orchard mothers had mean height and diameter below the average of
the trial. That is, progenies from not selected mothers were better than those coming
from crossbreeding of mass-selected trees.
According to the new strategy of installing progeny seed orchards, the already
described progeny test of the San Martín Forest Station (INTA) containing 86 openpollinated families from 8 Argentine origins was transformed in a progeny seed
orchard (0.3 ha; Table 3.2). From the original 1290 seedlings planted in 2011 at high
density (1 × 1 m) with a single-tree plot design, 622 trees remained in the seed
orchard in 2017 after mortality and a preliminary systematic thinning, with a mean
height of 272 cm (maximum: 491 cm). Seed production is expected to begin in
2023, at which time a new evaluation will be performed to prescribe a genetic
thinning.
Similarly, two trials installed in 1999 in Trevelin Forest Station (INTA) were
transformed in a selected seed stand (SSS; Table 3.2) that was registered with
INASE in 2017. Within these two trials, a study performed at 13 years of age in the
progeny test revealed significant differences in total height and basal diameter
among families (Puntieri et al. 2013). In the provenance trial, an interesting
association was found between genetic diversity and growth. The best provenance
according to DBH at 12 years of age was Hua-Hum (Lake Lácar basin; Gallo
unpublished data), which is also the population with the highest genetic diversity
3 Raulí (Nothofagus alpina = N. nervosa): The Best Quality Hardwood in Patagonia