Human intervention for the improvement of crops, trees, livestock and fish is nothing new. For millennia, humans have bred, crossed and selected those varieties, ecotypes and breeds that were more productive, better adapted or particularly useful.

Conventional breeding practices can now be complemented by a number of new and powerful techniques. Some of these allow, for example, the propagation of plant material in glass tubes to keep it free of diseases, and the production of more sensitive and specific reagents for diagnosing diseases in plants, livestock and fish through tissue and cell culture. Others, often referred to as molecular methods, enable scientists to see the layout of the entire genome of any organism and to select plants and animals with preferred characteristics by "reading" at the molecular level, saving precious time and resources.

Modern biotechnology also includes an array of tools for introducing or deleting a particular gene or genes to produce plants, animals and micro-organisms with novel traits. This kind of genetic manipulation is called "genetic engineering" and the product is a genetically modified organism, or GMO. Both traditional and modern biotechnologies result in plants, animals and micro-organisms with combinations of genes that would not have come about without human intervention. It has to be emphasized, however, that biotechnology includes a range of techniques and products, and GMOs are but one of them.

"With the increasingly limited amount of new land available to agriculture, modern biotechnologies could complement and improve the efficiency of traditional selection and breeding techniques to enhance agricultural productivity," says Mahmoud Solh, Director of FAO's Division of Plant Production and Protection.

So what's new?

A plant or an animal resistant to a particular disease can be produced through a "traditional" breeding programme, that is, through crosses with resistant relatives, selection and backcrossing again, or by the introduction of a gene that confers the resistance through genetic engineering. While the products of both approaches will be disease resistant, only the second one is a GMO. What is new is the ability of scientists to unravel the genome to look at the genes of an organism, and then make use of that information to change the organism, and even transfer genes to another organism very distant in the evolutionary scale. And that is where the controversy comes in.

"FAO recognizes that genetic engineering has the potential to help increase production and productivity in agriculture, forestry and fisheries," says FAO's Statement on Biotechnology. "It could lead to higher yields on marginal lands in countries that today cannot grow enough food to feed their people." But, it adds, FAO "is also aware of the concern about the potential risks posed by certain aspects of biotechnology. These risks fall into two basic categories: the effects on human and animal health and the environmental consequences."

These new tools offer new opportunities for solving agricultural problems where traditional techniques have failed. Genetically modified products are usually developed and used for large-scale commercial interests, and with a few exceptions, small-scale farmers have so far not benefited from the technology.

The articles in this focus are intended to provide background information on genetic engineering in agriculture for the non-specialist -- what it is, how it is being used, how it might be used in the future and the possible benefits and risks. If you are new to the subject, you might find it easiest to read the pages in the order shown in the column on the right. Those who would like to pursue the subject further may wish to visit FAO's Biotechnology Web site.

March 2003