The Use of GM Crops in Developing Countries
Conventional plant breeding and plant breeding using genetic modification
3.8 Conventional plant breeding is often understood as the selection of particular individuals from a great variety of naturally occurring types of plants. This activity tends to be seen as natural. Many would also view the systematic interbreeding of naturally occurring types of plants in the same vein. However, plant breeders also create plants which would not be achievable by judicious interbreeding, using techniques such as wide-crossing. This has led to completely new varieties such as Triticale (a hybrid between wheat and rye). Another technique, mutation breeding, involves the exposure of plants and seeds to radiation or chemical substances. These procedures have been, and still are being used to produce many important staple crops around the world (see paragraph 4.44).7 Thus, it is important to note that the deliberate alteration of plants as they occur in nature has been practised and accepted for several decades. In this context, genetic modification can be seen as a new means to achieve the same end; it is certainly used in that way. It differs from conventional plant breeding in that it can allow for much faster and more precise ways of producing improved crops. For this reason, we concluded in our 1999 Report that it was not helpful to classify a crop that has been arrived at by means of conventional plant breeding as ‘natural’, and to classify a crop with the same genetic complement as ‘unnatural’ if it has been produced through genetic modification.
3.9 However, there is some concern that the technique of genetic modification poses risks that differ from those implied by other forms of plant breeding. It may be the case that the intended effect of conferring a particular trait by insertion of specific gene sequences brings with it unintended effects, for example, disruptions in existing genes in the modified material.8 However, unintended effects are not specific to the use of genetic modification. They are often encountered in conventional breeding, particularly in the case of mutation breeding.9
3.10 Other concerns relate to the fact that some forms of genetic modification involve foreign genetic material. Often, viral sequences are used to facilitate the expression of a specific gene sequence in a modified organism (this function is also known as ‘switching on’ the gene). For example, a short sequence of the genetic material of the cauliflower mosaic plant virus is often used for this purpose.10 Some people regard this step as crossing a threshold which should not be breached. In their view, an organism has been created which has not previously existed in nature. We now consider the transfer of genes between species in more detail.
Footnotes7 For example, radiation in the form of gamma rays was used to alter the genes of a successful rice variety known as Calrose 76. The radiation reduced the height of the plants which resulted in increased yields of grain. The same technique was also used to develop ‘Golden Barley’, the main variety grown in Scotland until the 1980s. Chemical substances such as sodium azide and ethyl methane sulphonate are still being used, particularly in developing countries, to alter plant genes.
8 See FAO and World Health Organization (2000) Safety Aspects of Genetically Modified Foods of Plant Origin, Report of a Joint FAO/WHO Expert Consultation on Foods Derived from Biotechnology 29 May – 2 June 2000 (Geneva: WHO), Section 4.3 for a more extensive discussion of this issue. See also Royal Society (2002) Genetically Modified Plants for Food Use and Human Health – an update (London: Royal Society), p6.
9 The Royal Society notes two examples: celery and potatoes, see Royal Society (2002) Genetically Modified Plants for Food Use and Human Health – an update (London: Royal Society), p6.
10 Such sequences are used as ‘promoters’, see Royal Society (2002) Genetically Modified Plants for Food Use and Human Health – an update (London: Royal Society), p8; Independent Science Panel (2003) The Case for a GM-Free Sustainable World (London: ISP). We discuss health issues raised by these and other techniques in paragraphs 4.43-4.47.