In 1971, the Consultative Group on International Agricultural Research (CGIAR) was founded. An association of 41 public and private donors, including the World Bank and the Untied Nations Food and Agricultural Organization, it supports a network of international agricultural research centers located mainly in developing countries. Over 1,600 scientists of 60 nationalities work at or for these centers, with an emphasis on developing and maintaining the long-term sustainability of agriculture which preserves the natural resource base on which farming depends.

Plant breeding has always been one of the foundations of advances in global food production. The CGIAR conducts extensive breeding programs on most of the principal food crops of the Third World -- rice, wheat, maize (corn), barley, sorghum, cassava, sweet potato, and others. They also concentrate on issues which affect all agriculture: the conservation of the world's plants, both cultivated and wild, as genetic resources for future generations, the economics and politics of food production, and the strengthening of the national research capabilities of developing countries.

Recently the CGIAR focus has expanded to include additional priorities of improved productivity and sustainable production systems of livestock, fish, and forests -- and to the promise of genetic engineering. At the heart of all these efforts of CGIAR, as well as those of any other agricultural research and development efforts are the domesticated animals and crops whose evolution has been deliberately altered over many centuries. Our particular emphasis here is on the genetic modifications of plants, whose selective breeding by generations of farmers has resulted in today's major food crops, which often scarcely resemble their wild ancestors.

But productivity of these plants has plateaued. Yields per acre of wheat, corn, sorghum, soybeans, and potatoes in the United States have not increased since 1970. This stasis is also true of corn, potatoes, wheat, and cassava in Latin America. Increased food production has sometimes been achieved by planting more land, not always by planting higheryielding varieties. We must emphasize that human ingenuity in plant breeding has resulted in extraordinary improvements in crops. For example, since 1928, corn yields have increased by a factor of 5 due to the commercial breeding of hybrids (and heavy use of fertilizer).

Creating commercial hybrid seeds is a long, involved process. First, breeders seek plants with desirable traits through at least six generations of inbreeding. Some of the resulting favorable inbred lines are chosen and crossed to produce tens of thousands of different hybrids. Of these, perhaps 1 in 2,000 may be identified as a superior strain. Often, 10 to 15 years are required to come up with an improved hybrid and to prepare seed from it in commercial quantities.

Plant breeding now goes far beyond inbreeding and encompasses crossing domestic plants with wild relatives, inducing mutations in plants, or treating them chemically to make polyploids, plants with more the normal number of chromosomes in each cell. Such changes, while almost always harmful to animals, sometimes confer beneficial characteristics on plants.

Such efforts have been absolutely essential to the success of modern, large-scale agriculture. The cultivated varieties of plants that fed the two billion humans living in 1930 would not have been up to the task of supporting four billion just a few decades later without the several intervening decades of intensive efforts to produce plants with induced and selected genetic improvements.

Crops are vulnerable to many environmental stresses. Viral, fungal, and bacterial diseases and attacks of insect parasites are some of the natural enemies of plants that can be stymied, at least temporarily, by selecting plants that have gained a measure of genetic resistance to these threats through hybridization. Inexorably, through mutation and survival among these aggressors, nature matches the efforts of human ingenuity. New strains of organisms emerge which can penetrate the crops' defenses. For example, a new fungus strain appeared which managed to devastate much of the corn crop in this country in the early 1970s. Finally, resistant corn varieties were developed. Annually, hundreds of variants of seeds are created, sold, and planted to try to keep pace with these varying hazards of different localities.