204
seeds just 3–4 years after rooting in the North Patagonian conditions, facilitate the
development of a breeding programme for the southernmost area of the species
range. On the other hand, Salix spp. breeding programmes are mainly based on
interspecific hybridization to maximize genotypic variance by combining the outstanding features of the species involved. Thus, some traits of S. humboldtiana are
interesting to consider for the general genetic programme of the genus. The higher
density and pale reddish colour of its wood stand out for use as solid wood, such as
in carpentry and openings. Its resistance against several diseases and plagues must
also be mentioned. Besides the above cited resistance to Melampsora spp. and
Marssonina spp. in Paraná River Delta, in Patagonia S. humboldtiana is rarely
attacked by the two most important plagues of willows in the region: sawfly
(Nematus desantisi) and the giant willow aphid (Tuberolachnus salignus) (Sopow
et al. 2017). In the first case, the wasp was firstly reported in Argentina in 1980 in
the Chubut River on exotic willows, and from there it has spread fast and extensively throughout the whole country (Dapoto and Giganti 1994). However, so far
only a very light attack of this very aggressive defoliator has been observed on the
native willow. Similarly, in the case of the giant aphid, the exotic willows show very
strong attacks. However, the native willow has very little or no attack of this aphid
in the wild.
7.2.4.1 Launching of a Participatory Genetic Rescue programme
As we mentioned before, S. humboldtiana is severely threatened, especially in
Patagonia (Bozzi et al. 2014), where the extinction of some populations is evident
when comparing its current absence in places where historical references mention
the presence of the species (Moreno 1876) and in some cases of thousands of trees
(Entraigas 1960). A rescue programme was consequently initiated in 2018, taking
into account some genetic principles and convening the local community to be
involved in this incipient long-lasting process. This was called Participatory Genetic
Rescue Programme of Sauce Criollo in Patagonia (Gallo et al. 2018, Fig. 7.13).
This programme was initiated by prospecting more than 2500 km of riverbanks
along seven different rivers of North Patagonia: Chubut, Limay, Collón Cura, Negro,
Futaleufú, Neuquén and Agrio. In these explorations, putatively pure S. humboldtiana individuals were identified and sampled. Branches were collected and the sampled genotypes were cloned, most of them at the Bariloche Experimental Station of
INTA. Then a set of clones were distributed to four different propagation nurseries
in Patagonia, according to their location and corresponding area of influence, for
restoration purposes: Viedma Nursery from the Province of Río Negro, Mariano
Moreno Nursery from the Province of Neuquén, Cipolletti Municipal Nursery and
the nursery of Trevelin Forest Station (INTA). Meanwhile, at the nursery of
Bariloche Experimental Station, a clonal bank with all clones (more than 300) from
all rivers was installed aiming at the ex situ conservation of the remaining genetic
diversity of the species in Patagonia. In all these nurseries, cuttings were rooted in
order to produce seedlings for restoration purposes.
P. Marchelli et al.
seeds just 3–4 years after rooting in the North Patagonian conditions, facilitate the
development of a breeding programme for the southernmost area of the species
range. On the other hand, Salix spp. breeding programmes are mainly based on
interspecific hybridization to maximize genotypic variance by combining the outstanding features of the species involved. Thus, some traits of S. humboldtiana are
interesting to consider for the general genetic programme of the genus. The higher
density and pale reddish colour of its wood stand out for use as solid wood, such as
in carpentry and openings. Its resistance against several diseases and plagues must
also be mentioned. Besides the above cited resistance to Melampsora spp. and
Marssonina spp. in Paraná River Delta, in Patagonia S. humboldtiana is rarely
attacked by the two most important plagues of willows in the region: sawfly
(Nematus desantisi) and the giant willow aphid (Tuberolachnus salignus) (Sopow
et al. 2017). In the first case, the wasp was firstly reported in Argentina in 1980 in
the Chubut River on exotic willows, and from there it has spread fast and extensively throughout the whole country (Dapoto and Giganti 1994). However, so far
only a very light attack of this very aggressive defoliator has been observed on the
native willow. Similarly, in the case of the giant aphid, the exotic willows show very
strong attacks. However, the native willow has very little or no attack of this aphid
in the wild.
7.2.4.1 Launching of a Participatory Genetic Rescue programme
As we mentioned before, S. humboldtiana is severely threatened, especially in
Patagonia (Bozzi et al. 2014), where the extinction of some populations is evident
when comparing its current absence in places where historical references mention
the presence of the species (Moreno 1876) and in some cases of thousands of trees
(Entraigas 1960). A rescue programme was consequently initiated in 2018, taking
into account some genetic principles and convening the local community to be
involved in this incipient long-lasting process. This was called Participatory Genetic
Rescue Programme of Sauce Criollo in Patagonia (Gallo et al. 2018, Fig. 7.13).
This programme was initiated by prospecting more than 2500 km of riverbanks
along seven different rivers of North Patagonia: Chubut, Limay, Collón Cura, Negro,
Futaleufú, Neuquén and Agrio. In these explorations, putatively pure S. humboldtiana individuals were identified and sampled. Branches were collected and the sampled genotypes were cloned, most of them at the Bariloche Experimental Station of
INTA. Then a set of clones were distributed to four different propagation nurseries
in Patagonia, according to their location and corresponding area of influence, for
restoration purposes: Viedma Nursery from the Province of Río Negro, Mariano
Moreno Nursery from the Province of Neuquén, Cipolletti Municipal Nursery and
the nursery of Trevelin Forest Station (INTA). Meanwhile, at the nursery of
Bariloche Experimental Station, a clonal bank with all clones (more than 300) from
all rivers was installed aiming at the ex situ conservation of the remaining genetic
diversity of the species in Patagonia. In all these nurseries, cuttings were rooted in
order to produce seedlings for restoration purposes.
P. Marchelli et al.