Magazine article UNESCO Courier

Genetic Diversity and Food Security

Magazine article UNESCO Courier

Genetic Diversity and Food Security

Article excerpt

Geoffrey C. Hawtin [*]

Maintaining a diversity of crops and varieties is a key to survival for millions of farmers living on impoverished land

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

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. …

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