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Farming doesn't stand still


The development of agriculture was arguably the most important step in human history. Hunting and gathering can only support relatively small groups of people, given the area needed to maintain sufficient of the animals and plants on which they depend. Essentially the whole population spends its time gathering or preparing food, eating or resting, and tribes or extended families need to move as animals migrate or fruit, nuts or grains come in and out of season.

The twin realisations that some seeds could be sown deliberately to provide a crop where it was wanted, and that some animal species were amenable to domestication meant that people could have more control over their food supplies. In some cases, this might still required a nomadic existence or subsistence farming but, in favoured places, where weather and water availability were predictable, larger settlements grew and early civilizations emerged in places such as Egypt and Mesopotamia.

For the first time larger, settled populations could be fed by smaller numbers of farmers. Other specialised trades could begin to flourish, along with architecture and the arts. This is the foundation on which modern societies have developed and which has allowed human inventiveness and creativity to flourish. This is as true today as ever; the transformative powers of modern electronics are as dependent on farming as were the Pyramids or the Roman Empire.

Farming – now seen as part and parcel of human society – is environmentally disruptive. In the sense that it can only be carried out by people, it is also deeply unnatural. Felling forests, ploughing up land and planting hedges have transformed landscapes into what we now protect and regard as part of our natural heritage. And at the same time farming has continuously evolved.

Early farmers will have selected seeds from strong, healthy plants to sow the following season, creating particular landraces well suited to the growing site. Cereals and other crops have been cross-fertilised (deliberately or not) and selected until they bear little relationship to the wild grasses or fruit from which they originated. Similarly, cattle and sheep have been selected and cross-bred for desirable qualities of meat, milk, hardiness or docility.

With each selection on the basis of appearance or other quality (the phenotype) came a selection of the genetic background (the genotype). Although this was in practice what happened, genes themselves and their role in determining traits were unknown until comparatively recently. The inheritability of genetic traits – a discovery credited to Mendel for his work on peas – first put plant and animal breeding on a more systematic basis.

Evolution proceeds both because new combinations of genes occur via cross-fertilisation and through random mutations in genomes. If the result is to give the hybrid or mutant a competitive advantage, then it out-performs other plants. At some stage, the new phenotype may be recognised as a distinct species. [As an aside, we should note that the concept of a species is to a large extent an attempt by humans to create some structure in the natural world. Clearly, there are enormous differences between many plants and animals, but the boundary between individual species is artificially drawn and, as we now know, essentially the same gene is in many cases widespread across the plant or animal kingdoms.]

Armed with some understanding of the role of genes, humans naturally used this knowledge to emulate nature. For centuries, promising parent varieties had been intentionally cross-fertilised; now breeders also began to deliberately induce mutations in plants, using chemicals or radiation. Most of the resulting progeny were useless, but from time to time useful new crop varieties emerged.

All of these efforts have produced today’s high-yielding crops, which bear little relationship to their wild ancestors and could not survive for long in the wild. Genes have been swapped, combined and altered in all sorts of ways. Bread wheat resulted from natural hybridisation, millennia ago, of three natural grass species. But the original hybrids were very tall. A century ago, wheat was still a similar height to today’s maize, but breeding has given modern ‘dwarf’ wheat, in which more of the plant’s energy goes into producing grain rather than straw.

All this happened – alongside other major changes in agricultural practice – with barely a whimper of opposition, other than the formation of the organic movement to represent the interests of the minority who want to see more ‘natural’ farming (surely a contradiction in terms). Even organic farmers have been happy to accept the results of mutation breeding, the genetic consequences of which are completely unknown.

Which makes the remaining hard core of opposition to genetically modified crops all the more surprising to those who see it as one more incremental step in the development of agricultural technology. But for many activists, a line has been drawn in the sand: GM crops are to be opposed because of hypothetical risks, whatever their benefits may be.

The latest manifestation of this unfortunate tendency is a campaign called Take the Flour back, whose short-term aim is to stop trials of aphid-resistant wheat at Rothamsted Research. The website employs the usual emotive campaigning techniques including, in this case, a loaf of bread with a cow’s head and legs. If they had any understanding of genetics, they would appreciate that there is no such thing as a ‘cow gene’ or a ‘bread gene’, but they are nevertheless implacably opposed even to such experimental crops.

They have organised a rally at the research institute on 27 May, with the original threat of destroying the crop. However, the research team, to their credit, has publicly appealed for dialogue rather than confrontation (see Sense about Science Rothamsted appeal), which has attracted considerable media attention (for example, GM wheat scientists at Rothamsted make plea to protesters).

This is an approach which seems to have worked for the John Innes Centre last year, and it is to be hoped that this time it would also weaken any public support the protesters might otherwise have had. Consumer polls continue to show that the public trusts scientists (unless, that is, they are either ‘government scientists’ or ‘industry scientists’). In any case, anyone who cares about the rights of scientists to carry out legitimate, well-regulated experiments should support the efforts at Rothamsted. People have a right to protest; they do not have a right to destroy what they don’t like.