Genetic Transformation of Eucalyptus
The genus Eucalyptus belongs to the Myrtaceae family and has a wide distribution except in northern areas where its lack of cold resistance has limited its use in plantations. The main characteristics of Eucalyptus have already been described by McComb an
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1 Introduction 1.1 Distribution/Importance of Eucalyptus The genus Eucalyptus belongs to the Myrtaceae family and has a wide distribution except in northern areas where its lack of cold resistance has limited its use in plantations. The main characteristics of Eucalyptus have already been described by McComb and Bennett (1986) in this series and by Lakshmi Sita (1993). Currently, Eucalyptus species are becoming of increasing importance for both their timber pulp and paper production throughout the world. Eucalyptus otTers a number of major advantages over other tree species. It is a fast-growing species, has the ability to regenerate quickly through multiple shoots following harvest, it roots easily from stump sprouts, and hybrids are easily produced. Several important industrial groups have invested in Eucalyptus plantations (sometimes dosely associated with pulp mills) in Africa or South America. Such groups believe that industrial forestry has a bright future and that it will make an essential contribution to meeting the demands for many industrial wood products and, because of the intrinsically higher productivity of forest plantations (30 times that of a natural forest), it will relieve some of the pressure on natural forests. At the moment, most of these plantations result from the donal multiplication of selected trees. The rapid growth rate of Eucalyptus, together with the ability of certain species to grow in marginal soils, makes this genus ideal for "tree farming" and, in fact, it is the most extensively used genus for industrial tree plantations today. 1.2 Need for Transformation Genetic engineering is by far the most promising of current biotechnologies for adding selected gene(s) to a tree without disturbing its global genetic organization. While backcross breeding is commonly used to improve crops, it has not
ICentre de Biologie et Physiologie W:getale URA CNRS 1457, Universite Paul Sabatier, 118 route de Narbonne,3-1062 Toulouse Cedex, France
Biotechnology in Agriculture and Forestry, Vol. 29 Plant Protoplasts and Genetic Engineering V (ed. by V.P.S. Bajaj) © Springer-Verlag Berlin Heidelberg 1994
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C. Teulieres el al.
been adopted as yet in tree breeding beeause of the eonstraints imposed by long developmental eycles. Therefore, a teehnology such as genetie engineering whieh allows the transfer of se lee ted gene(s) to a chosen plant in a single generation offers promising new opportunities for tree breeding, and this is partieularly true for Eucalyptus whieh is beeoming of strategie importanee for wood and pulp produetion on the world seale. Herbicide Resistance to the Common Herbicides. Glyphosate, phosphinotriein, bromoxynil, and ehlorsulfuron would be useful in the management of young Eucalyptus plantations. It would make the manual removal of weeds unneeessary and allow the use of effieient nonseleetive herbieides for clearing plantations without any toxie effeet on the transformed Eucalyptus. Eucalyptus is highly sensitive to water and nutrient eompetition from weeds and bush and the
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