As the dominant species on this planet, and the only species able to investigate the enormous richness and complexity of our biosphere and to choose how we treat and exploit it, we have a responsibility to treat our biosphere with the respect it deserves.

Much more than that, our very future relies on biodiversity.

Diversity within and between species, diversity within and between habitats, ecosystems, landscapes and regions, diversity within and between cultures, diversity in space and in time - it’s all part of the diversity of life on which we rely.

Ecological, environmental and evolutionary scientists have known this for a long time. Public and political awareness have grown immensely in the latter part of the last century. Now almost every nation in the world has an environmental programme, and there are major international efforts, for example like those coordinated by the United Nations Environment Programme UNEP.

Here in the GRC we focus specifically on genetic diversity within and between cultivated and wild species of rice. Even within this somewhat narrow focus – at least narrow in the context of global biodiversity – biodiversity is nonetheless crucially important. Why?

Well, to begin with, rice is still far from being as good as we can make it. We can and we need to improve its yield potential, its grain quality (in terms of nutritional value, cooking quality and cultural preferences for flavour, appearance and texture), its tolerance of abiotic stresses such as cold, heat, drought, low pH or low nutrients, its resistance to pests and diseases, and its value for other uses such as animal feed, thatch and mushroom-growing. We don’t know what or where the genes are but we know they are there somewhere. Conserving the geneic diversity of cultivated and wild rice is a way of ensuring that we keep the genes that we need even though we don’t know what or where the genes are.

OK, now just suppose that we could produce just such a miracle rice that was perfect in every way. What then?

Well, for a start the pests and diseases would evolve new forms of virulence that would enable them to attack our miracle rice. It would no longer be a miracle rice. We know for certain this will happen. It has happened time and time again, not just in rice but also in all other crops, and indeed in farm animals, from the infamous potato famine in Ireland in the 1840s to the “mad cow disease” towards the end last century. Cereal breeders know that they must continually find and introduce new genes for disease resistance as pests and diseases evolve virulence against the old genes.

On top of that, our environment will change in many other ways. Global warming, changes in rainfall distribution, changes in the nutrient content of rainfall. Our miracle rice for the current environment will not be the best possible rice in future environments.

On top of that, agricultural technologies and agronomic practices will improve. The miracle rice under the current technologies will no longer be the best possible with new technologies.

On top of that, government policies will change how farmers farm. Governments change their minds about the relative importance of food production, other components of the rural economy, and environmental protection. Their changing policies influence all sorts of agronomic practices like the amount and nature of fertilizers, pesticides, herbicides, ploughing that farmers apply.

On top of that, public preferences change: preference for flavour, for cooking quality, for food is produced.

For all of these reasons, we know for sure that any “miracle rice” produced today will be only a temporary miracle. We don’t know exactly what the future holds, but we do know without a shadow of doubt that it will be different from today.

Yet the very success of the green revolution of the 1970s paradoxically placed at risk the very future of rice agriculture. The first new high yielding varieties of rice were so far superior to traditional varieties that farmers all over the world quickly turned from their own varieties to the new varieties. In a few years we would have lost all the biodiversity of rice that we rely on for the future sustainability of rice agriculture. Fortunately, we didn’t lose it - but only because of the foresight of our predecessors, who established the International Rice Genebank in 1977. As quickly as they possibly could, they scoured the world collecting traditional varieties that farmers were discarding. Now we have around 100,000 samples safely conserved, and available for use whenever they are required.

And that is not all – far from it. So far we have considered biodiversity only as a source of genes to be exploited by breeders to improve rice varieties, within the narrow confines of plant variety protection laws. (In order to comply with national legislation in most countries, plant breeders have no choice but to produce varieties that are genetically uniform. Before a new strain can be registered and released as a commercial variety, it must pass so-called “DUS” tests: it must be demonstrably Distinct from all other existing varieties, genetically Uniform from plant to plant, and genetically Stable from generation to generation). But that is only one part of the story, and in some ways the easiest part.

Primitive farmers knew well the value of maintaining high genetic diversity within their fields. Even today, many of the older farmers that still follow traditional methods know this. They know that a mixture of crops or a mixture of strains of one crop suffers less damage from pests and diseases. They know that a mixture of crops or a mixture of strains of one crop can produce a more reliable yield from year to year despite the vagaries of weather and rainfall. In some places they deliberately re-constitute mixtures each year. In some places they use mixtures with overlapping cropping season to reduce the length of time that soil remains bare and therefore at risk of erosion.

Yet this is an area where modern agriculture lags way behind. Modern agriculture as it developed last century was built on producing, as far as possible, a uniformly optimal environment for production regardless of environmental cost. If you can produce a uniformly optimal environment, then in the short term makes sense to seek the uniform genotype that is better than any other genotype in that environment. That was the easy part, comparatively. But at what cost environmentally? And at what cost in terms of lack of sustainability?

The great challenge now is to build on and combine the production successes of last century with the knowledge that ecological and environmental scientists now have, to produce agricultural ecosystems that are not only economically sustainable, but also environmentally sustainable and benign, and ethically desirable.

A complex, sustainable, biodiverse system is far more difficult to understand and improve. But we must address the challenge.

For further information, contact Ruaraidh Sackville Hamilton