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Genetic diversity and food security Geoffrey C. Hawtin, Director General of the Rome-based International Plant Genetic Resources Institute, devoted to promoting the conservation and use of plant genetic resources

Maintaining a diversity of crops and varieties is a key to survival for millions of farmers living on impoverished land The origin of some domestic animals and plant species. For thousands of years, farmers have used the genetic variation in wild and cultivated plants to develop their crops and raise new breeds of livestock. Genetic diversity gives species the ability to adapt to changing environments, including new pests and diseases and new climatic conditions. Plant genetic resources–that component of genetic diversity of actual or potential use to humanity–provide the raw material for breeding new varieties of crops. These, in turn, provide a basis for more productive and resilient production systems that are better able to cope with such stresses as drought or overgrazing and can reduce the potential for soil erosion. The use of genetic diversity–on-farm, through field experimentation or in sophisticated gene transfer procedures–remains arguably the best route to securing our food and that of our children. Although science has made enormous strides in improving the world’s ability to feed itself over the past three decades, we cannot afford to rest idle. Nearly 800 million people in the developing world do not have enough to eat.1 In these regions, the rural poor represent about 73 per cent of the people living in poverty. They often live in marginal or unsuitable farming areas, such as zones with saline soils, arid conditions, or degraded or hilly areas. Often isolated from other farms and far from urban areas, many poor farmers have barely benefited from agricultural developments elsewhere. In many cases they do not have access to commercially bred high yielding crop varieties. Diversity flourishes and remains important under such conditions. Selections and breeding To market in Peru: farmers in the Andes cultivate up to 3,000 potato varieties. Poor farmers are well aware of the relationship between the stability and sustainability of their production systems and the diversity of crops and crop varieties on their lands. Their management and use of a diverse range of plants has often helped them to survive under the most difficult conditions. By growing a range of different crops, farmers have a better chance of meeting their needs. These might be crops that mature at different times or that can be easily stored to help to ensure a stable food supply throughout the year. They may also help farmers provide a nutritionally balanced diet for their families, exploit different environmental niches that exist on their land, or diversify their income sources. Importantly, the genetic diversity contained in different varieties provides farmers with options to develop, through selection and breeding, new and more productive crops that are resistant to pests and diseases. The result may be a vast range of local varieties of crops grown by farmers in any one area. In the Andes, for example, farming communities use about 3,000 different varieties of potatoes, and in Java farmers may plant more than 600 species in a single home garden. Not respecting diversity can incur high costs: in 18th-century Ireland, where potatoes were the only significant source of food for about one third of the population, farmers came to rely almost entirely on one very fertile and productive variety, which proved susceptible to the devastating potato blight fungus. The resulting famine caused the death or emigration of more than 20 per cent of the population. The value of diversity goes well beyond its ability to support stable production systems in marginal environments. As the world’s human population rises, environmental problems (desertification, deforestation, erosion, etc.) are intensifying. Climate change, particularly global warming, could bring about drastic changes in the location of the world’s agro-ecological zones. Farmers will require new crop varieties capable of producing under diverse conditions, without adding ever-increasing amounts of fertilizers and other agro-chemicals. Because of the limited scope for growth in the world’s cultivated areas, each new generation of varieties will have to be more productive than its predecessors. Much has been written about the use of genetic engineering in plant breeding. Modern molecular techniques can be used to transfer genes from one living organism to another or to change the genetic material within to produce more desirable traits. Genetic engineering has enormous potential to help solve problems that have proved intractable using conventional breeding approaches, such as developing crop varieties with in-built resistance to key pests and diseases and tolerance to stresses such as drought. However, the possible impact of these techniques, particularly on human health and the environment, is giving rise to fierce worldwide debate. Take the case of banana and its close relative plantain, two of the developing world’s most important crops. Their improvement is hindered by the sterility of most cultivars, a problem that can be addressed through genetic engineering. It is now possible to transfer gene constructs, such as those associated with disease resistance, directly into varieties with other desirable characteristics, drastically reducing the need for pesticides. Currently, many crops are sprayed more than 40 times with fungicides to control the devastating banana and plantain disease, Black Sigatoka. The first transgenic banana and plantain plants have been produced and are now undergoing testing. Today, research on genetic engineering is focused on the development of commercial varieties of the world’s major crops of interest to industrialized farmers. Many of the staple crops of importance to poor farmers in developing countries, such as cassava, bananas, beans and yams, have received relatively little attention. This situation is likely to continue as plant breeding is increasingly privatized and biotechnology becomes the fast-growing province of private industry. Meanwhile, the high costs of the new technologies are quickly exceeding the capacity of many, if not most, public research institutions–both in developing and developed countries–to support them. Thus, for the time being, increasing agriculture’s role in the development of the world’s poor is likely to continue to depend on the identification, maintenance and use of genetic diversity. 1. See the Food and Health Organization’s 1999 Report on the State of Food Insecurity in the World. Website of the International Plant Genetic Resources Institute: www.cgiar.org/ipgri