Science and Society
It is my opinion that plant research is vital for the future of a world in which the human species has to reach a balanced and sustainable relationship with the rest of nature and its environment. We are increasing in population and this population is likely to have higher expectations in food provision and in longevity. All of this means a rapid increase in the demand for food, feed, fiber, and fuel. On the other side of the equation, we are rapidly depleting our fossil fuel reserves, and there are severe limitations on the amount of land and water available for agriculture. In addition, political problems and distribution costs suggest that we need, as far as is possible, to enable the bulk of food to be produced close to where it is needed. Eventually, if that does not happen, the hungry will move in large numbers to where there is food. The political and social consequences of a failure to meet the legitimate demands of the developing world will eventually be serious for the developed world.
There is a view that, since the West is chiefly suffering from too much rather than too little food, it can afford to put biotechnology aside and GM crops could only be used in the developing world. There are a number of dangers in this. First, there is the argument of resource efficiency: using more land, materials, and energy than we need to produce food is a misuse of resources. Second, the technology and know-how are being developed with commercial and public resources in the West, and if the technology is blocked, the flow of funds for research will inevitably diminish severely as shareholders and the public ask why money should be spent on developing this apparently unwanted technology. Third, the food supply chain is international and the decisions as to what is grown are taken by a few people in charge of the major supermarkets and commodity traders; they are more likely to support a GM-free chain for the richer customers rather than a special GM chain for the poorer customers. Finally, globalization of pressure groups is leading to universal opposition to GM crops. Thus, there is a danger that the research and development of solutions that GM crops could provide will slow or stop, despite the needs of millions of people for sufficient locally produced food. In the words of de Greef, "a food shortage caused by an empty R&D pipeline in the long-term is lethal, preventable, and immoral."
The conclusion of Braun and others is that, if scientists believe in the importance of their research and the technologies deriving from them, then they have to engage in the political process, to confront the challenges of the Green activists, to engage society in the debate, and, if necessary, take to the streets with banners. Because the outcome will most affect the young scientists, their careers, and their dependents, and because they are the ones most likely to be acceptable to society (Farmelo, 2000
), it is crucial that they are motivated to participate in the debate before it is too late. Reversing the present situation in Europe will not be easy, as supermarket chains and processed-food producers such as Gerber will need a believable case to put to the public as to why they have changed their minds on the inclusion of GM crops in their food products. However, failure to reverse the situation will jeopardize the future of plant science research and those involved in it as well as those likely to benefit from it.
Crop Improvement
The scientific goal for biotechnology and world agriculture is the improvement of the genetics of our crops. The big challenge for biological research in general, and crop improvement in particular, is how to get the most valuable knowledge the quickest from the explosion in DNA sequence information. A large-scale genomics approach is chiefly being followed in industry, but to some extent is also being tried in national and international programs. It will undoubtedly yield many benefits, but also has many limitations. It tends to be driven by data rather than hypotheses (see Duyk's comments above), which means that it may be linear and unprioritized (i.e. start with the first available sequence and work out the function of the genes one by one). It also faces difficulties in that many important crop traits depend on the interaction between a number of genes or may be encoded by multiple copies of the same gene. In addition, plants are renowned for their ability to compensate physiologically. Thus, generating large populations of plants in which single genes are either knocked out or overexpressed is unlikely to reveal the genetics of processes subject to these phenomena; generating multiple combinations will probably be numerically impossible. Even when the function of a gene sequence has been correctly identified, there remains the problem of finding the better or best alleles. For these reasons, I have argued elsewhere that the current thrust, which is largely based on a genocentric view, needs to be balanced by a matching emphasis on a phenocentric approach (Miflin, 2000).
A phenocentric view of crop improvement starts from the viewpoint that farmers cultivate phenotypes, i.e. crop performance is determined by the interaction of genotype and environment. While the farmer can do something to ameliorate the environment, crop improvement mainly depends on plant breeders assembling the best combination of alleles of the genes governing the key traits. The modified varieties are then widely tested to determine to which environments they are adapted. The development of marker technology, as exemplified in the work presented by McCouch, has now opened up the ability to identify many of the loci, genes, and alleles that are most important in crop improvement. It allows interactions between genes to be identified and it enables the mining of new favorable alleles from wild sources. Its crucial limitation is the ability to measure the phenotypic trait sufficiently reliably and accurately. It is also dependent on the existence of sufficient variation in the genetics of key traits in crossable species; where there is no difference between alleles at a locus, the importance of that locus in the process is unlikely to be revealed (e.g. the genes important in determining the rate of photosynthesis in wheat, in which there is little variation; Evans, 1993).
Physiology and biochemistry provide the third approach to identifying genes for crop improvement. In some cases, knowledge of biochemical pathways can lead to the identification of candidate genes, and the subsequent transgenic plants behave as expected (see the developments described by Herrera-Estrella and Potrykus). In contrast, most of the developments in trying to change carbohydrate metabolism (as described by Willmitzer) have led to the conclusion that we did not understand the biochemistry as well as we thought we did, or that compensation overrides the genetic changes. Nevertheless, much useful information has been gathered and, slowly, useful changes are being achieved. Sound physiological knowledge can also be highly useful in developing screens to probe the many populations of sequence-defined mutants that are being generated. An example of this in the past is the success of the screen devised by Somerville and Ogren (1979) in identifying many of the key steps in the pathway of photorespiration and determining their genetic control. Current technology will make this approach easier and more fruitful. All that remains is to devise the requisite "smart" screens to probe the physiological phenomena of interest.
ACKNOWLEDGMENTS
I am grateful to the Lawes Agricultural Trust for their support. I appreciate the large and varied inputs into this article by the speakers and the participants of the conference; because of space I have not been able to cover the talks of all of the presenters nor to attribute all of the thoughts to their originators. Also, I may have re-interpreted verbal comments in ways that the speaker would not have done. For any such sins of omission or commission, I apologize and take ultimate responsibility for the views presented.
FOOTNOTES
Received February 15, 2000; accepted February 15, 2000.
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