Agricultural biodiversity is the source of much of our food, clothing and shelter. Yet it is being lost at an alarming rate. Of the 7,098 varieties of apples that were used in the United States between 1894 and 1904, about 86 percent have been lost. The United States has also lost 95 percent of its cabbage varieties, 91 percent of its field corn varieties, 94 percent of its different peas and 81 percent of the tomato varieties that were cultivated in the last century.

Many traditional varieties have been lost and many of those that remain can now be found only in gene banks. These gene banks can also play the role of a safehouse, especially in natural disasters or time of war. They can be used to re-establish farming after disasters. That was the case in Cambodia and more recently Afghanistan.

In the last 500 years, advances in transportation made the exchange of plants among regions and continents possible. Species from the New World, such as beans, maize and rubber, were carried to Europe, Africa and Asia. Rice and soybeans from Asia travelled to the Americas where they became major crops. Maize, whose origin and primary area of diversity is Central America, has a major secondary source of diversity in Africa where many distinct types have been selected and developed over hundreds of years. New World tomatoes combined with pasta made from Near East wheat to become the basis for the traditional Italian pasta.

The principal centres of origin of cultivated plants are concentrated mainly in tropical and sub-tropical areas. Some of the poorest countries in the world are the richest in terms of the agro-diversity. But no country is self-sufficient, and each country depends on others for about 70 percent of the genetic resources for their main crops. In Brazil, for example, nearly half the population's energy from plant sources comes from the three major cereals - rice, wheat and maize - all of which originated in other parts of the world. North America is almost completely dependent for its food and industrial crops on species originally domesticated in other parts of the world. Sub-Saharan Africa depends on species domesticated elsewhere for 87 percent of its crops. It is estimated that about 70 percent of developing countries acquire more than half of their crop production from crops domesticated in other regions.

Our natural world is the result of 3 billion years of biological evolution and 10,000 years of mutual adaptation between farmers and the environment. Around 10,000 plant species have been used for human food since the origin of agriculture. Today, only about 150 plant species make up the diets of the majority of the world's population. Of these, just 12 species provide over 70 percent of food, while four -- rice, maize, wheat and potatoes -- make up over 50 percent of the food supply and only 30 crops provide 90 percent of the world's calorie intake.

The International Treaty on Plant Genetic Resources for Food and Agriculture was negotiated through the FAO Commission on Genetic Resources for Food and Agriculture (CGRFA). The conditions for access and benefit-sharing will be set out in a ÔMaterial Transfer Agreement' (MTA), to be established by the Governing Body, at its first meeting after entry into force. The multilateral system applies to a list of more than 60 plant genera, which include 35 crops and 29 forages, agreed on the basis of interdependence and food security.