
2. Description of Currently Available Biotechnologies in the Crop Sector: It is probably fair to say that the most significant breakthroughs in recent years in the area of crop biotechnologies have stemmed from research into the genetic mechanisms behind economically important traits. The rapidly progressing discipline of genomics, providing information on the identity, location, impact and function of genes affecting such traits, is producing knowledge that has driven and will increasingly drive the application of biotechnologies in crops. Here, we provide a summary of recently developed biotechnologies for the crop sector that could be used in practice for food production and agriculture in developing countries. A. Biotechnologies based on molecular markers: All living things are made up of cells that are programmed by genetic material called DNA. This molecule is made up of a long chain of nitrogen-containing bases (A, C, G and T). Only a small fraction of the sequence in plants makes up genes, i.e. that code for proteins, while the remaining and major share of the DNA represents non-coding sequences whose role is not yet clearly understood. The genetic material is organised into sets of chromosomes (e.g. 5 pairs in the much-studied mustard species Arabidopsis thaliana), and the entire set is called the genome. Molecular markers are identifiable DNA sequences, found at specific locations of the genome. They may differ between individuals of the same population. Different classes of markers exist, such as RFLPs, AFLPs, RAPDs or microsatellites. Molecular markers can be used for:
Genetically modified organisms (GMOs) are those that have been modified by the application of recombinant DNA technology (where DNA from one organism is transferred to another organism). The term ''transgenic crops'' is also used for genetically modified crops, where a foreign gene (a transgene) is incorporated into the plant genome. It may help us to distinguish between 3 distinctive types of genetically-modified crops
Transgenic plants have been the subject of much controversy, although they now cover large areas in certain parts of the world. Estimates for 1999 indicate that 39.9 million hectares of land were planted with transgenic crops. Of these, 7.1 (18%) were in developing countries, almost all in Argentina (6.7 million hectares) and China (0.3), while the US and Canada accounted for 32.7 million hectares (82%). Of the 39.9 million hectares, 28.1 million (i.e. 71%) were modified for tolerance to a specific herbicide (which could be sprayed on the field, killing weeds while leaving the crop undamaged); 8.9 million hectares (22%) were modified to include a toxin-producing gene from a soil bacterium, Bacillus thuringiensis, which poisons insects feeding on the plant, while 2.9 million hectares (7%) were planted with crops having both herbicide tolerance and insect resistance. Most of the transgenic crops planted so far have thus incorporated only a very limited number of genes. However, some transgenic crops of greater potential interest for developing countries have been developed in the research laboratories but have not yet been released commercially, such as transgenic rice of high iron content developed by transferring the ferritin gene from soybean to rice, or transgenic rice producing provitamin A.
C. Micropropagation: 3. Food and Agriculture in Developing Countries: The emphasis of the e-mail conference is on developing countries. In this context, we should keep in mind that a tremendous variety of production systems and environmental constraints are found between different developing countries and even within individual countries. Four broad agro-ecological zones (humid and peri-humid lowlands; hill and mountain areas; irrigated and naturally flooded areas; drylands and areas of uncertain rainfall) account for 90% of agricultural production in developing countries. Within each of the zones, a range of farming systems are found as well as a mixture of traditional and modern production systems. The global population size has passed the 6 billion mark and is increasing by roughly 80 million annually. Almost all population growth is in developing countries. While the number of inhabitants in the developing and developed world respectively is estimated at 4.75 and 1.31 billion respectively for the year 2000, in 20 years time it is predicted to be 6.15 and 1.36 billion respectively. Farm sizes tend to be small, as reflected by a study of 57 developing countries which showed that nearly 50% of farms were smaller than 1 hectare. The increase in food production needed to cover the increased population size cannot come from recruiting new land for agricultural purposes. Most land suitable for agriculture is already in use. When comparing the total amount of land of crop-producing potential with the amount of cultivated land, there are however noticeable differences between regions. For example, in South Asia, 191 of the potential 228 million hectares were already under cultivation in 1988-1990, whereas in Latin America and the Caribbean only 190 of the potential 1,059 million hectares were in use. However, parts of these could not be readily converted to crop production as they are already used for other purposes such as forestry, animal grazing or conservation. Degradation of land already in use, due to overgrazing, deforestation and poor farming practices, is also an increasing problem globally. The increases in food production needed to feed the world's growing population must therefore come from increasing the amount of food produced per hectare. Note, however, that the issue of world hunger may not be simply solved by increasing the world food supply. In the world today enough food is produced to feed all its inhabitants but yet it is estimated that in 1995-1997 there were roughly 790 million undernourished people in developing countries, i.e. whose food intake was insufficient to meet basic energy requirements on a continuing basis. Hunger and poverty are also influenced and determined by many different demographic, environmental, economic, social and political factors and these factors should also be considered when trying to reduce hunger in the world. Food needs to be available and accessible to the poor, wherever they may be. 4. Certain Factors that Should Be Considered in the Discussion: The key question in this e-mail conference is how appropriate each of the different biotechnologies, mentioned previously in this document, may be for the crop sector in developing countries and regions. The question of appropriateness should consider the following elements
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Last Updated on 3/13/01 Email: information@biotech-info.net |
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