Genetic Modification ~ The 'Pro' Position
Author: Professor Jennifer A Thomson ~ Department of Molecular and Cell Biology, UCT
( Article Type: Opinion )
Genetically modified (GM) crops are those in which genes from another species have been inserted to express a particular trait, which the original crop lacked. Genetic modification differs from traditional breeding in that GM crops may contain genes from a completely different organism. The major GM crops currently in commercial use worldwide are herbicide-tolerant soybean, insect-resistant maize and cotton, with smaller amounts of cotton and maize carrying both herbicide tolerance and insect resistance. Those in the development and field-testing stages include virusresistant fruits and vegetables, insect-resistant potatoes and vitamin-A-enriched rice.
The year 2005 marked the 10th anniversary of the commercialisation of GM crops. They are planted by 8.5 million farmers in 21 countries. The main countries growing GM crops are the USA, Argentina, Brazil, Canada and China. However, increasing numbers of farmers in developing countries are adopting the technologies. In 2005 38% of the global GM crops were planted in developing countries,translating into the fact that 90% of the beneficiary farmers were resource poor.
Most of the smallholder cotton farmers in South Africa are in the Makhathini Flats region of KwaZulu-Natal. In 1998/99 there were 75 adopters, growing less than 200 hectares of GM cotton. By 2000/01 this number had risen to 1 184 with about 1 900 hectares. It is now estimated that 90% of the farmers in the region are growing GM cotton and that they have reduced pesticide sprays by 60 to 70%.
Some of the ‘knock-on’ advantages of GM crops are with both herbicide-tolerant and insect-resistant plants. As spraying of herbicide can now be at the discretion of the farmer and does not have to occur before the crop is planted, there has been a marked decrease in the use of tilling. This ‘low-till’ farming practice results in a decrease in the loss of topsoil and resultant soil erosion. In addition, because insect-resistant maize does not suffer from insect damage, it is more resistant to post-harvest fungal infection. Many of these fungi produce highly toxic compounds, called mycotoxins, which can result in toxic hepatitis and oesophageal cancer.
Concerns have been raised that herbicide-tolerant crops could result in the formation of superweeds and that insects could develop resistance to the insect-resistant crops. Although to date no evidence of this has been found, it is still important to use sound agricultural practices to mitigate against this happening. For instance, farmers must plant a certain percentage of non-GM crops among their insect-resistant varieties to decrease the chances that the insects will develop resistance. Reports from the USA and China indicate that these measures are working and insects in the field are not developing resistance to the GM toxin.
Concerns have also been raised about the safety of foods derived from GM crops. No evidence of a lack of food safety has been found, despite years of rigorous testing. In fact, while conventional foods are not tested for food safety; only GM foods are. Thus we know more about the safety of foods derived from GM crops than about any other food we eat.
Another concern is that the use of GM crops will result in a decrease in biodiversity. However, the opposite may well be true. It is much easier for plant breeders to introduce a single gene, giving a desired trait, into many different crop varieties than it is with traits resulting from conventional breeding.
All countries wishing to test or commercialise GM crops are required to have in place biosafety regulations to ensure the correct use of such crops. In South Africa, the GMO (Genetically Modified Organisms) Act was passed in 1997. It is administered by the National Department of Agriculture and has on its executive committee members of all the government departments involved, e.g. Health, Environment, Trade and Industry, etc. All applications for imports, field trials and commercial releases have to be subjected to scrutiny by panels of experts before permission is given or withheld. Other countries in Africa, such as Zimbabwe, Kenya, Tanzania and Uganda, either have regulations in place or are developing them. In terms of the development of regulations, the affected countries are being assisted by the United Nations Environmental Programme and the Global Environment Facility, which aim to assist over 100 developing countries worldwide in the next few years.
Despite opposition to GM crops, most notably in Europe, developing countries are adopting the technology as part of the answer to sustainable food production. It will be important to monitor the use of GM crops on a case-by-case basis, but in most resource-poor countries the benefits are likely to outweigh any possible risks.
