Vegetative propagation of patagonian cypress, a vulnerable species from the subantarctic forest of South America. Increasing risks of loosing forest genetic resources and the need for a sustainable quality wood supply make focusing research efforts on undomesticated tree species necessary. The study of their genetic variation in vegetative propagation ability and the development of practical methodologies to obtain genetic copies are Estaca reproduccion asexual artificial tools for conservation and breeding programs.
Its genetic diversity, mostly sheltered within unprotected populations, is seriously threatened. This work examined the ability of different genotypes of A. The influence of exogenous auxins, season of cutting collection, ontogenetic stage of the donor plants, grafting season, and type of scions, was analyzed. Only one treatment, a juvenile progeny from a xeric provenance, showed remarkable results with Grafting showed good results in early spring experiment using vigorous semi-hardwood scions, with an average of Compatibility between genotypes from different provenances used as scion and rootstock was found to be wide.
These results indicate that although A. AustrocedrusCupressaceaestem rooting, scion grafting. Estos resultados indican que aunque A. AustrocedrusCupressaceaeenraizado de tallos, injertos.
Vegetative propagation is an irreplaceable tool for tree domestication and breeding, and its advantages and implications have been widely treated in literature WrightZobel and TalbertPark et al. Although in forest research most of the efforts were traditionally focused on propagation of timber species, a scenario of rapid climate changes IPCCwith increasing land degradation and genetic diversity loss, makes it necessary to focus also on species that
Estaca reproduccion asexual artificial important for other functions, such as support of ecosystems and supply of non-timber products, or have a remarkable potential for quality wood production.
Programs involving indigenous species and impoverished communities have become important in the last decades Leakey et al. Despite the advances in tissue culture, for many conservation, domestication and breeding programs, lower cost macro-propagation methods continue to be the most convenient approaches even when human and Estaca reproduccion asexual artificial resources were not scarce e.
Only a few tree species native to the subantarctic forests of South America are included in domestication and conservation programs, being several species of Nothofagus spp.
In the Argentinean Patagonian region, patagonian cypress Austrocedrus chilensis D. It ranges through a wide variation in ecological conditions, regarding latitude, altitude, soils and pluviometric regime Gallo et al.
Its adaptation to extreme xeric conditions makes it a suitable species for commercial forestry in arid environments. Its wood has been widely used in the region during all the last century due to its good technological quality and beautiful design. Even without forest management and genetic improvement, A. The remaining total cover area of A. The total of the wood of A. In Argentina, the distribution of A. One remarkable environmental gradient given by the precipitations regime molds the physiognomy of A.
Across this strip, in a west-east direction, mean annual precipitation m. This extremely abrupt gradient determines the occurrence of drastic changes in vegetation in distances not larger than km, being five A. The most xeric populations extreme-marginal forest typeconsisting of small isolated patches located into the patagonian steppe, were found to be the most genetically diverse PastorinoPastorino et al.
Despite the evolutionary and adaptive relevance of these xeric extreme-marginal populations, they still lack of any national or international legal protection policy. Their location in private lands, the extreme environmental conditions in which they grow, their reduced number of individuals, and a context of rapid climate changes threaten the genetic diversity they shelter, as well as their dynamic evolutionary processes, being the rescue and ex situ in vivo Estaca reproduccion asexual artificial of endangered genotypes, or even entire populations, necessary.
These extreme marginal populations have to be included in research Estaca reproduccion asexual artificial oriented to study adaptive traits, such as vegetative propagation capacity. Although some isolated attempts have been made to asexually propagate A. Currently, a clear vegetative propagation protocol does not exist. Several adaptive and ecological characteristics of A.
As most conifers, it has no adaptations to asexually persist after severe disturbances, such as preformed root initials, allowing rooting of dislodged stems, or the ability of sprouting from stumps or roots. Although with fluctuations in time, A. Nevertheless, adventitious roots formation eventually occurs in natural populations.
Compact groups of apparently individual trees, more frequently observed in the xeric marginal populations, have been found to be clones multi-stemmed phenotypes formed by branch layering Pastorino and GalloGallo et al. This natural process is probably a good signal for the success of artificial vegetative propagation by stem rooting, although it could be strongly dependent on the genotype. The genetic entity at different levels i.
As an example, individual differences in the rooting capacity of Cupressus sempervirens L. Therefore, it has to be considered that the propagation protocol to be used in breeding and conservation programs could be not unique within a species.
Grafting techniques are useful when difficulties are found to propagate trees
Estaca reproduccion asexual artificial stem rooting, being also the success "Estaca reproduccion asexual artificial" grafting strongly dependent on an intrinsic genetic capacity, and on the compatibility between genotypes CopesHartmann et al.
Besides the intrinsic genetic abilities, a multiplicity of environmental factors affects the success of both rooting and grafting processes in trees e. Although general guidelines are provided in literature in relation to the most important environmental effects Hartmann et al.
As an example, stem cuttings of Chamaecyparis lawsoniana A.