Cooperative Program for Embedding and Eucalyptus Cloning

In the 1990’s, the mini- and micro-stem cutting techniques (Assis et al., 1992, 1997) were developed, making possible for commercial cloning of genotypes hard to embed. By means of the regeneration provided by micro-propagation, the embedding hormone was no longer required or started to be applied in small concentrations, as compared to the conventional micro-stem cutting process.

The major limitation of micro-stem cutting is the need for a tissue cultivation laboratory for regeneration of the vegetative material, not always existing in most of the forest companies, which leads to greater cost for seedling production (Assis, 1997). Thus, given the operation advantages and the lower cost, the mini-stem cutting has been currently adopted nearly by all forest companies. The micro-stem cutting has been used only for regeneration of clones recalcitrating to embedding, obtaining micro-plants which are conducted for obtaining mini-stems in case of vegetation, which have greater embedding potential.

In view of the evident difficulty to embed propagated stems of subtropical eucalypt uses, associated with the problems coming from deficient formation or even of apparently normal roots, but that can be the major cause due to the plant falling in the field, this project purports to assess in the morfophysiologic and anatomic manner the behavior of clones cultivated in vivo (mini-stem cutting) and in vitro (micro-stem cutting). Consequently, the following cases have been raised allowing us to guide the main goals of this project.

Starting from the protocol established for the species E. benthamii, is it possible to produce mini-and micro-plants, aimed at large-scale production of subtropical eucalyptus clones and their hybrids with difficult embedding?
May the embedding process established for the mini-and micro-stems of E. benthamii, where one can avoidformation of corns and may obtain development of the roots directly from the vascular exchange, be effected for different species and hybrids of eucalyptus?
Is falling of seedlings in the field related to the origin and induction of the radicular system in the stems?

It is worth mentioning that there are several factors influencing propagation of plants by stem cutting in the growth and differentiation of the roots, such as: species, presence of inducers and embedding inhibitors, juvenility of the sprouts, presence of bud sand/or leaves, collection period of the stems and dormancy period (Hartamann et al., 1997), nutritional status (Bellamine et al., 1998; Josten and Kutschera, 1999; Schwambach et al., 2005), sanity and variations in the climatic conditions (Corrêa, 2004), in addition to the environmental conditions and the substrate.

Planta em adaptação para introdução em laboratório

Goals

General Goal
Developing protocols for large-scale clonal production of selected subtropical eucalyptus genotypes and their hybrids by means of the mini-stem cutting and micro-stem cutting techniques, with special attention to induction and formation of a morphophysiologically functional radicular system.

Specific goals
• Assessment of the morphogenetic behavior of mini-and micro-stems of subtropical eucalyptus clones and their hybrids in response to the protocol of mini-and micro-propagation of E. benthamii;
• Morphophysiologically and anatomically assess whether the rizogenic process verified for the clones of E. benthamii, with induction of a functional radicular system shall be similarly obtained in the clones of the other species of interest;
• Assess the survival rate and production of sprouting of mini-stumpsin relation to different times of the year;
• Assess capacity of morphogenic response and embedding of mini-and micro-stems in different times of the year, to the size of vegetative propagules, regulators of growth and substrates;
• Assess whether there is a relationship between formation of roots and falling of the plants in the field;
• Anatomically assess the appropriate morphogenic stages of the mini-and micro-stems for induction of the embedding directly to the substrateavoiding damages to the radicular system;
• Assess multiplication and stretching of in vitro buds due to the BAP and ANA concentrations, clone and cultivation means;




Instituto de Pesquisas e Estudos Florestais
Via Comendador Pedro Morganti, 3500 - Bairro Monte Alegre
CEP: 13415-000 - Piracicaba, SP - Brasil
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