BIOTECHNOLOGY : DREAM OR REALITY ?
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CTA. 1988. BIOTECHNOLOGY : DREAM OR REALITY ?. Spore 18. CTA, Wageningen, The Netherlands.
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By diversifying the tools that researchers can use to select and reproduce both plants and animals, biotechnology offers new potential for improving agricultural production. The successful use of these sophisticated techniques for development,...
By diversifying the tools that researchers can use to select and reproduce both plants and animals, biotechnology offers new potential for improving agricultural production. The successful use of these sophisticated techniques for development, however, depends on their adaptation to local socioeconomic and biophysical conditmns. In today's changing world, no-one can remain indifferent to the development of biotechnology. Such techniques, which manipulate the properties of living material, provoke strong - if not contradictory - reactions on their future role in development programmes. The optimists claim that a 'biotechnology revolution' will end food shortages once and for all. The pessimists maintain that such complex technologies cannot be used in developing countries and will be monopolized by industrialized countries. A more balanced view sees the possibility of selecting among the many biotechnology options available, those that are best suited for developing countries. Biotechnology may be a specialized science, but it can be applied in almost any discipline. Human and animal health as well as the agrofood industry have received the most attention to date. But it is in the field of agricultural production that the most significant results are expected. While tissue culture and genetic engineering are valuable modern tools for agronomists and breeders, it should be borne in mind that they do not by any means replace traditional methods of plant multiplication. Makinq identical copies In vitro reproduction, the first biotechnology to be widely used, is based on the traditional technique of grafting cuttings. Using microscopic in vitro cuttings, thousands of identical plants can be reproduced quickly and in any season from the same mother tissue. Such plants are called 'clones', which means that they have been reproduced by vegetative -- not sexual -- means Several such techniques have now been developed by researchers who increasingly work in laboratories rather than out in the fields. Small stem or leaf fragments of the plant that is to be reproduced are incubated in test-tubes containing a precise mixture of the minerals and growth regulators needed for each plant. These pieces of plant tissue start growing from existing buds or develop 'neo-buds' before sprouting and leafing out. After several weeks, these growths are in turn microscopically divided and then replanted in the same nutritive environment so that the process is repeated. In this way, a single microcutting of a coffee plant can be used to produce more than 20.000 cuttings of the same plant in less than one year. Traditional methods normally produce only 200 plants over a two-year period. In European countries, high-value crops such as flowers and house plants, are already reproduced in this way. In vitro reproduction has also been developed for many tropical plants such as coffee, pineapple and yams. For coffee plants, however, reproduction centres using traditional techniques already exist and it is not certain that new, expensive techniques would be more cost-effective. This is especially true given the fact that these more sophisticated reproduction techniques generally demand more sophisticated planting and cultivation techniques. Thus the overwhelming importance of economic and social factors in the choice of biotechnology techniques. In vitro reproduction is particularly useful when more resistant varieties must be quickly introduced. This is currently the strategy being used in Latin America in the control of coffee rust. Another way to help control diseases is the cultivation of meristem using the terminal buds of plants that are immune to viruses and diseases. In this way healthy plants can be reproduced from sick plants. This is one of the methods used to control plant viruses in roots and tubers, such as cassava mosaic, and to make healthy plants available to farmers. More sophisticated is the 'somatic embryogenesis' technique that is currently being studied for various crops. It consists of provoking a proliferation of calluses on the plant material to be reproduced, and by transferring them to other specific host sites, to induce the appearance of plant embryos. These young shoots develop leaves and roots and so become real plants. These techniques are relatively easy to use once they have been fully developed. Because they must be customized for each strain, however, they require long and expensive research and development programmes. Miniature tree nurseries Tissue culture considerably shortens the length of time normally required to reproduce species that until now could be bred only sexually. It also reduces the time needed to breed pure lines of homogenous plants. Oil palm is an example of a tropical plant that cannot be grafted and from which cuttings cannot be taken. This meant that the spread of pure, high-performing hybrids took a long time using traditional methods. It was to overcome this problem that the Research Institute on Oils and Oleaginous Plants (IRHO) in France together with ORSTOM (the French overseas research agency), developed the in vitro micropropagation by somatic embryogenesis of this tree. In a pilot project at Me in Cote d'lvoire, thousands of different oil palm clones were produced so field tests could demonstrate their suitability and select the best ones. They will soon produce fruit for the first time. Similar work is under way on the coconut but it is less advanced. The first plants resulting from somatic embryogenesis have recently been produced. In order to restock the palms of North Africa devastated by the bayoud, the date palm has also been singled out for attention. The reproduction of resistant strains was thus able to begin. Biotechnology is particularly useful for the reproduction of forest trees, which is usually a long and delicate process. Reforestation programmes could be greatly accelerated by using more productive species. Techniques are now ready for eucalyptus and Acacia albida, and are being developed for other tropical trees. If biotechnology can considerably reduce the time required for the first phase of plant reproduction, it can do little for the indispensable field tests which cannot be shortened. Neither the rate of plant growth nor the checks made by agronomists to ensure the value of the chosen clone can be cut short In tropical countries it is of course perennial plants, particularly those destined for export, that have received the most research attention in this field. In vitro reproduction is hard to justify economically for densely planted, annual crops. Even for small farmers, however, biotechnology can be cost-effective when it is used to help control diseases that may completely destroy their crops. To control black leafspot in plantains, for example, specialists have determined that it is more effective to find resistant varieties and to spread them rapidly rather than to develop an expensive chemical pesticide programme. Simple reproduction of clones is a technique that is easily transferred to ACP countries. The installation and operation of small laboratories require relatively little investment in capital or labour and several countries, notably Cote d'lvoire and Senegal, have already established their own reproduction centres. If tissue culture is becoming commonplace, the genetic engineering of new plants still fires the imagination of the public and researchers alike. This is because it opens the way to what now seems to be almost limitless possibilities. Most of the developments, however, have yet to move beyond the test-tube and there are very few applications that have so far affected farmers even in industrialized countries. Creating new plants Using existing genetic resources to create diversity has always been the objective of researchers working on more productive varieties. Biotechnology extends the range of methods available to such researchers, and several techniques are now being developed. Isolating cells and placing them under physical or parasitic stress to induce mutants is one way. Another consists of trying to fuse together two cells (that have been separated from their cell walls or protoplasm) of two different species or varieties to create a new cell. Using this cell as the base, an entire new plant can be developed. This last phase is the most difficult and effectively blocks many research efforts. The 'pomato', created by fusing together a potato and a tomato, was the first successful application of this technique. But one can go even further in the field of genetic engineering. In the future, gene transfer seems to be the most promising direction. By isolating those fragments of DNA responsible for the synthesizing of desirable properties and implanting them in another cell, such characteristics can be transferred to another plant. Researchers in Belgium used this technique to introduce the bacterium Bacillus thuringiensis into tobacco plants which enables such plants to produce themselves the toxin well-known for its insecticidal properties. To protect cultivated plants from the side-effects of herbicides, companies have also developed cultivars that are resistant to such chemicals. For the moment, the techniques that have been developed deal mainly with the laboratory plants commonly used by researchers, such as tobacco, as well as a few plants often found in industrialized countries. It is in the area of reducing the use of chemical products that biotechnology offers the most hope for African countries. Thanks to genetic engineering, the resistance of plants to insects and diseases can be increased or (as with tobacco plants) can even be designed to produce their own insecticide For developing countries, there is also considerable interest in finding plants that make the best use of scarce water resources and poor soil conditions. Research on nitrogen-fixation is designed to decrease the need for expensive chemical fertilizers. Such work is currently concentrating on improving the symbiotic relationship between leguminous plants and Rhizobium bacteria or even to create new associations, for example with cereals. Biotechnology can also be used to improve the nutritional value of plants. Yams, which are rich in starch and water, are generally low in protein. Some varieties, however, produce flour with 11-13% protein, equal to the levels found in the best of cereals. This is an excellent opportunity for using agronomic research and development to not only produce more food but to ensure that people are better nourished For many people, therefore, the sky is the limit as far as biotechnology is concerned. But concrete results will not be achieved overnight. If the transfer of a gene capable of controlling a specific disease is now possible, the manipulation of gene complexes is still not possible. African food crops, however, need major improvements not only for disease resistance, but for other agronomic factors that have long since been improved in industrialized countries. The perfect plant, the one that grows abundantly everywhere, is resistant to everything and pleases everyone, has yet to be created! Researchers have learned through experience that performance alone is insufficient and that increases in yield are beneficial only if accompanied by improvements in storage, processing and commercialization. It is for these different reasons that ACP countries are worried about the control by industrialized countries particularly their private companies of the production of genetically improved plants. They fear that these resources will be either too expensive or inappropriate for their needs. This explains why ACP countries want to have their own biotechnology centres in order to do their own research. But such centres require highly-trained personnel and major investment. That is why most of the experts who attended the International Biotechnology Symposium held in July 1988 in Paris recommended a regional approach. The Adiopodoume Centre in Cote d'lvoire and the Dakar Centre in Senegal could thus become regional biotechnology centres that would also serve neighbouring countries. Agriculture would not be the only subject of such centres as biotechnology can be applied in many other fields. The culture of different cells is also used in the production of food and pharmaceutical substances, thereby bypassing the cultivation of plants. Third World countries are also particularly interested in fermentation processes, which can improve the value of agricultural products and by-products. Such research is all the more important as developed countries are trying to produce goods that can replace their imports of products such as cocoa butter and sugar. For Third World countries, therefore, it is essential that appropriate techniques be developed to ensure that the astonishing potential of biotechnology is used in their interest. BIBLIOGRAPHY Hobbelink H . 1988. La biotechnologie et [agriculture du tiers monde. Equilibres/ CETIM Sasson. A 1986. 'Queues biotechnologies pour les pays en developpement?~ Biofutur. UNESCO
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