15
replaced by desirable characteristics for human being (i.e., high productivity of a
particular organ, outstanding yield of a certain compound, resistance to pests or
diseases inherent to monoculture) under a highly subsidized and artificial production system. The modification of the gene pool of the cultivar variety becomes so
profound that sometimes without human intervention it would not be able to persist
in successive generations.
In forest science, the concept of domestication is necessarily less strict, mainly
due to the longevity of trees. Whereas in species such as cereals, 20 years imply 20
generations, in trees they can represent only one generation or even less. For this
reason, when talking about forest species, domestication has not only genetic
aspects but also of plantation silviculture, such as the adjustment of seedling production technologies in the nursery, planting in the field, and plantation management until the conformation of an adult population. Therefore, we can define the
domestication of forest trees as the development of technologies to take this species
to plantation on an industrial scale, both for productive or conservation purposes.
From a strictly genetic point of view, tree domestication is limited to elemental
selection that rules out gene pools that are not adapted to adjusted artificial management. This selection commonly involves a single generation, and only in some species, it has reached three or four generations.
The domesticated gene pool of a forest species is not far from the wild gene pool,
so plantations maintain the ability to turning feral, and thus artificial populations
could be perpetuated without the need for recurrent human intervention. This quality is not only a restriction imposed by the long generational times but also a soughtafter characteristic due to the longevity of the trees. It is necessary to have a high
genetic diversity in the growing populations, since the trees must be adapted to the
environmental conditions at the time of planting but also need to have a high adaptability to future conditions. The environment of the future is unknown, but the longer the life cycle (or plantation rotation) of the species considered, the more likely
the environment toward the end of the cycle will be different from the current one.
This leads to sacrifice selection intensity for the sake of gaining adaptability. Only
in highly productive species with very short cycles, the intensity of selection is
maximized to the point of clonal forestry, that is, the cultivation of a few select clones.
Historically, since the beginning of civilizations, in species of food relevance and
with an annual or very short life cycle, domestication has represented a cultural
rather than a technological process. Just in the last century, domestication and
genetic improvement have resulted from a planned and directed technical process
(large-scale forest tree breeding programs began in the 1950s, White et al. 2007).
Currently, a genetic improvement program commonly begins with the generation of
information on the genetic variation patterns of the species in question, that is, its
level of genetic variation, in general, and how it is distributed among its natural
populations. This basic information is essential to outline a selection as well as a
conservation strategy.
The genetic characterization of the natural populations of a species can be
approached with genetic markers in laboratory studies or with quantitative characters in plant growth chamber, nursery, or field genetic tests. The former (e.g.,
1 Native Forests Claim for Breeding in Argentina: General Concepts and Their State
replaced by desirable characteristics for human being (i.e., high productivity of a
particular organ, outstanding yield of a certain compound, resistance to pests or
diseases inherent to monoculture) under a highly subsidized and artificial production system. The modification of the gene pool of the cultivar variety becomes so
profound that sometimes without human intervention it would not be able to persist
in successive generations.
In forest science, the concept of domestication is necessarily less strict, mainly
due to the longevity of trees. Whereas in species such as cereals, 20 years imply 20
generations, in trees they can represent only one generation or even less. For this
reason, when talking about forest species, domestication has not only genetic
aspects but also of plantation silviculture, such as the adjustment of seedling production technologies in the nursery, planting in the field, and plantation management until the conformation of an adult population. Therefore, we can define the
domestication of forest trees as the development of technologies to take this species
to plantation on an industrial scale, both for productive or conservation purposes.
From a strictly genetic point of view, tree domestication is limited to elemental
selection that rules out gene pools that are not adapted to adjusted artificial management. This selection commonly involves a single generation, and only in some species, it has reached three or four generations.
The domesticated gene pool of a forest species is not far from the wild gene pool,
so plantations maintain the ability to turning feral, and thus artificial populations
could be perpetuated without the need for recurrent human intervention. This quality is not only a restriction imposed by the long generational times but also a soughtafter characteristic due to the longevity of the trees. It is necessary to have a high
genetic diversity in the growing populations, since the trees must be adapted to the
environmental conditions at the time of planting but also need to have a high adaptability to future conditions. The environment of the future is unknown, but the longer the life cycle (or plantation rotation) of the species considered, the more likely
the environment toward the end of the cycle will be different from the current one.
This leads to sacrifice selection intensity for the sake of gaining adaptability. Only
in highly productive species with very short cycles, the intensity of selection is
maximized to the point of clonal forestry, that is, the cultivation of a few select clones.
Historically, since the beginning of civilizations, in species of food relevance and
with an annual or very short life cycle, domestication has represented a cultural
rather than a technological process. Just in the last century, domestication and
genetic improvement have resulted from a planned and directed technical process
(large-scale forest tree breeding programs began in the 1950s, White et al. 2007).
Currently, a genetic improvement program commonly begins with the generation of
information on the genetic variation patterns of the species in question, that is, its
level of genetic variation, in general, and how it is distributed among its natural
populations. This basic information is essential to outline a selection as well as a
conservation strategy.
The genetic characterization of the natural populations of a species can be
approached with genetic markers in laboratory studies or with quantitative characters in plant growth chamber, nursery, or field genetic tests. The former (e.g.,
1 Native Forests Claim for Breeding in Argentina: General Concepts and Their State