107
94.7% survival, mean tree height in this trial was 142 ± 44 cm, and differences
among families were found (data not published). Three years later, mean tree height
more than doubled (294 ± 65 cm); total maximum height was 5 m; and survival rate
was still high (81.3%). Differences among families continued to be significant and
even more acute, with 3.50 m of mean tree height for the tallest family and 2.47 m
for the shortest one (data not published), thus giving rise to genetic improvement.
The first trials and experiences led INTA to formally plan a low intensity breeding program for roble pellín in 2006. The main purpose was to guarantee the supply
of seeds with identified origin and a genetic quality not lower than the average.
Before that, seeds for seedling production were obtained exclusively from natural
forests which, because of their cyclical seed production, are an uncertain source. An
agreement between INTA and the National Park Administration allowed collecting
seeds from Lanín National Park where 83% of the areas with roble pellín in
Argentina are located (Sabatier et al. 2011). In the frame of this agreement, natural
stands with good seed productivity and accessibility were identified. More experience in seed collection eventually led, in 2008, to register with the National Seed
Institute (INASE) a pure 5 ha N. obliqua stand (40° 09′ 6.05″ S; 71° 30′ 41.54″ W;
870 m asl) as a Seed Production Area (SPA). Two years later a new natural stand,
this time pertaining to a provincial reserve (Epulauquen, 36° 49′ 6.20″ S; 71° 04′
14.5″ W; 1500 m asl), was also registered as a SPA. After several years of seed collection from the natural forest, it became clear that if a more regular provision of
seeds was desired, seeds had to be collected from artificial stands. Thus, INTA
decided to transform a 16-year-old plantation located in its Trevelin Forest Station
(43° 07′ 3″ S; 71° 33′ 45″ W; 420 m asl) in a 2.35 ha SPA, which was registered with
INASE in 2016 (it started to produce seeds 3 years before, in 2013). The origin of
this SPA was unknown, so a subsequent study based on chloroplast DNA markers
was performed, finally suggesting its belonging to the Lácar genetic zone
(Azpilicueta et al. accepted).
Yet, seeds collected in these SPA lack genetic improvement. In this sense, the
initial breeding strategy was to install Clonal Seed Orchards with trees selected in
the natural forest (massal selection) and in young trials (genetic selection). However,
similarly to raulí (see Chap. 3), the poor performance achieved in attempting vegetative propagation, both through rooting and through grafting, and its dependence
on the genotype (Pastorino et al. 2016), led to change the breeding strategy to the
installation of Progeny Seed Orchards. Consequently, INTA took advantage of the
high density progeny trial composed by 40 open-pollinated families and its replica
that were analysed by Barbero (2014) and Aparicio et al. (2015), to perform an early
genetic selection in order to install a progeny seed orchard. Progenies were evaluated from three out of the four populations assayed (Catritre, Pilo Lil and Yuco).
Thus, selection was carried out among 1440 trees according to 2 main criteria:
height at 3-year age and cold resistance after an episodic summer frost and the seasonal autumn cold. All saplings were cut at ground level and then potted and grown
in a nursery for 2 years. Finally, the selected trees were planted in San Martín Forest
Station of INTA (42° 0′ 22.39″ S; 71° 32′ 50.78″ W; 285 m asl) in 2016, with a
single-tree-plot design, keeping the saplings of the same family apart from each
4 Roble pellín (Nothofagus obliqua): A Southern Beech with a Restricted…
94.7% survival, mean tree height in this trial was 142 ± 44 cm, and differences
among families were found (data not published). Three years later, mean tree height
more than doubled (294 ± 65 cm); total maximum height was 5 m; and survival rate
was still high (81.3%). Differences among families continued to be significant and
even more acute, with 3.50 m of mean tree height for the tallest family and 2.47 m
for the shortest one (data not published), thus giving rise to genetic improvement.
The first trials and experiences led INTA to formally plan a low intensity breeding program for roble pellín in 2006. The main purpose was to guarantee the supply
of seeds with identified origin and a genetic quality not lower than the average.
Before that, seeds for seedling production were obtained exclusively from natural
forests which, because of their cyclical seed production, are an uncertain source. An
agreement between INTA and the National Park Administration allowed collecting
seeds from Lanín National Park where 83% of the areas with roble pellín in
Argentina are located (Sabatier et al. 2011). In the frame of this agreement, natural
stands with good seed productivity and accessibility were identified. More experience in seed collection eventually led, in 2008, to register with the National Seed
Institute (INASE) a pure 5 ha N. obliqua stand (40° 09′ 6.05″ S; 71° 30′ 41.54″ W;
870 m asl) as a Seed Production Area (SPA). Two years later a new natural stand,
this time pertaining to a provincial reserve (Epulauquen, 36° 49′ 6.20″ S; 71° 04′
14.5″ W; 1500 m asl), was also registered as a SPA. After several years of seed collection from the natural forest, it became clear that if a more regular provision of
seeds was desired, seeds had to be collected from artificial stands. Thus, INTA
decided to transform a 16-year-old plantation located in its Trevelin Forest Station
(43° 07′ 3″ S; 71° 33′ 45″ W; 420 m asl) in a 2.35 ha SPA, which was registered with
INASE in 2016 (it started to produce seeds 3 years before, in 2013). The origin of
this SPA was unknown, so a subsequent study based on chloroplast DNA markers
was performed, finally suggesting its belonging to the Lácar genetic zone
(Azpilicueta et al. accepted).
Yet, seeds collected in these SPA lack genetic improvement. In this sense, the
initial breeding strategy was to install Clonal Seed Orchards with trees selected in
the natural forest (massal selection) and in young trials (genetic selection). However,
similarly to raulí (see Chap. 3), the poor performance achieved in attempting vegetative propagation, both through rooting and through grafting, and its dependence
on the genotype (Pastorino et al. 2016), led to change the breeding strategy to the
installation of Progeny Seed Orchards. Consequently, INTA took advantage of the
high density progeny trial composed by 40 open-pollinated families and its replica
that were analysed by Barbero (2014) and Aparicio et al. (2015), to perform an early
genetic selection in order to install a progeny seed orchard. Progenies were evaluated from three out of the four populations assayed (Catritre, Pilo Lil and Yuco).
Thus, selection was carried out among 1440 trees according to 2 main criteria:
height at 3-year age and cold resistance after an episodic summer frost and the seasonal autumn cold. All saplings were cut at ground level and then potted and grown
in a nursery for 2 years. Finally, the selected trees were planted in San Martín Forest
Station of INTA (42° 0′ 22.39″ S; 71° 32′ 50.78″ W; 285 m asl) in 2016, with a
single-tree-plot design, keeping the saplings of the same family apart from each
4 Roble pellín (Nothofagus obliqua): A Southern Beech with a Restricted…