modification and traditional breeding
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.
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.
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
that must similarly be identified and rejected. Cloning (in the
form of vegetative cuttings) has been employed by plant breeders
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"
and the initially transformed plant may be crossed with many other
varieties for agricultural and economic reasons.
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
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.
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