Select Committee on European Communities Second Report



Genetic modification and traditional breeding

WHY SELECT?

17.  All current crop plants (and all domestic animals) are the result of careful selection and breeding over centuries. Selection in the case of plants has been made on the basis of taste, colour, smell, keeping qualities, nutritional value, yield and resistance to disease. The modern crops used in our fields are in most cases utterly different from the original plants from which they have been bred[26]. Most of the food we eat results from crops for which the species of origin is not native to the country in which it is grown. In Europe, more than 90 per cent. of crop plants fall into this category. Modern plant breeding has been remarkably successful in helping to raise yields, improve quality and improve resistance to pests and diseases. New cultivars are used for many reasons, including consumer demand and security of supply. It is claimed that these choices often result in a significant loss of biodiversity amongst agricultural crop varieties.

TRADITIONAL BREEDING TECHNOLOGY

18.  Traditional breeding has the same aims as genetic modification (yield, pest or disease control, hardiness and value) and much of the process is similar. Plants can be grown or stored and regenerated from single cells. The technology used is also advanced, as for example with embryo rescue[27]. It is important to remember that traditional breeding also relies on genetic transfer, but the random transfer of tens of thousands of genes at once rather than the insertion of two or three known genes, which is genetic modification. Those tens of thousands of genes often produce undesirable traits[28] that must similarly be identified and rejected. Cloning (in the form of vegetative cuttings) has been employed by plant breeders for generations.

SUBSEQUENT SELECTION

19.  The genetic modification of plants is only an initial step in the production of a commercial plant variety. With both traditionally and modern genetically modified plants, the new plants are grown through a number of generations (over several years) in order to identify those that have been successfully modified and separate out those in which any unwanted changes have occurred. In most instances this process will identify any of the deleterious effects identified in paragraph 0. Traditional breeding methods are then used to ensure that the plant variety is "distinct, uniform and stable"[29] and the initially transformed plant may be crossed with many other varieties for agricultural and economic reasons[30].

SIMILAR RISKS?

20.  The risks involved in using genetic modification are discussed in greater detail in part 3, but it should be noted here that, whatever the method of production, the quest for novel traits produces similar risks. For example, when stress tolerances[31] are altered, the risks resulting from indirect effects caused by changes in land use are potentially significant. The consequences of introducing novel species into a new environment, on their own or for breeding, can be extremely damaging[32]. Each plant introduced from a foreign country brings with it tens of thousands of genes previously unknown in the United Kingdom. Risk is particular to an ecosystem and traditionally bred crops with novel traits and weedy relatives where they are to be released may present a greater problem, in relation to out-crossing, than genetically modified crops released where they have no such relatives.

21.  While there is great similarity and overlap between the new and traditional techniques, genetic modification is also a departure as it permits the production of that which cannot be created by traditional breeding. The barriers of sexual compatibility are broken. Traits are given to a crop which it could not have acquired by any other means and from this arise new, predominantly environmental, issues. The technology allows the aims of traditional breeding to be achieved faster and with far greater accuracy and precision: only the necessary number of genes (at present in single figures) whose behaviour is known is transferred, as opposed to the essentially random process of traditional breeding with the involvement of tens of thousands of genes.


26  All modern crop plants bear little relation to their ancestral precursors. For example, today's wheats bear no visible relation to their bushy Egyptian ancestors as the crop has been bred continuously to achieve desired qualities. Back
27  The Royal Society's recent statement on "Genetically modified plants for food use" (September 1998) highlights this technique, used, for example, in sunflower breeding. If crosses are performed between sunflowers that have greatly differing genetic make-ups, the pollen will fertilise the receiving plant but the resulting embryo will abort before a seed is produced. In embryo rescue, the embryo is removed before abortion occurs and grown outside the parent plant to produce a new plant to enable crosses to be made between sunflower species which would not normally be sexually compatible.  Back
28  Many plants contain genes which, if expressed, would produce undesirable toxins. For example, the DNA of the potato is very similar to that of deadly nightshade, but the problematic genes are not expressed. Back
29  Under Article 6 of Council Regulation (EC) No. 2100/94 of 27 July 1994 on Community Plant Variety Rights (OJ L227, 1 September 1994, pp 1-30), Community plant variety rights shall only be granted for varieties that are "distinct, uniform, stable and new". A similar requirement is contained in section 4 of the Plant Varieties and Seeds Act 1997. Back
30  It is estimated that there are about two hundred varieties of soya modified to be tolerant to glyphosate on the market in the United States (American Soybean Association, p 295). Back
31  See paragraph If a crop plant is modified so that it is able to be grown in new environments (geographical locations, altitudes, soil types, conditions of excess water or drought, or even different seasonal cropping) it may become a weed or pose risks to the environment into which it is newly introduced (Professor Beringer, Q 25; Professor Williamson, Q 505). Such a risk would need to be set against the benefit of the crop's introduction.. Back
32  For example, the consequences of the introduction to the United Kingdom of the varroa mite has been devastating for bee keepers. Back

 
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