Mi cassava es tu cassava

Friday, 2 October, 2015 - 09:40

New research shows just how much different regions of the world rely on each other for the foods they know and love – and why it’s time to share

This world is really messed up. Especially when it comes to food – and specifically the plants we eat. Take for example, a hearty British roast dinner. With close competition from fish and chips, it’s about as “traditional” as a British meal gets. But the potatoes originated in Peru, the carrots possibly in West Asia, the sweetcorn in Central America and the broccoli somewhere in the Mediterranean. It’s a hodgepodge of plants from all over the place. You can play this game for other cuisines of the world. The chilli pepper that fires-up Asian curries originated in Central or South America. The cassava that 500 million people in Africa eat everyday also first appeared thousands of years ago in South America. The tomato in your pizza topping began life in the New World too, while the wheat in the base first emerged in Asia. 

For CIAT scientist Colin Khoury, this reveals a special kind of global interconnectedness that is completely off the radar of most people.

“Usually, when we think of interdependence in food, we think of trade; we think of self-sufficiency and dependence in very narrow terms,” he says. “But there is another dimension that connects us even more deeply, one of interdependence in terms of plant genetic resources.”

Yep, you’re going to have to bear with me on this one.

The argument goes something like this: Cassava originated in South America, therefore Africa – where so much cassava is produced and consumed – needs South America. Why? Because South America has a much bigger range of cassava diversity than Africa. This diversity includes plants that might be distant cassava relatives that endure unperturbed in the wild, or the many varieties in gene banks or farmers’ fields that simply never made it to Africa. If a disease breaks out in African cassava fields, the varieties in South America might contain traits that crop breeders can use to make Africa’s cassava more resilient.

So far so good. But South America also needs South and Southeast Asia, where sugarcane comes from; Southeast Asia needs West and Central Africa for oil palm, and so on. Now enter climate change: rising temperatures could mean North America needs to track down heat-tolerant rice varieties from Asia; East Asia will need South America for more resilient peanuts, and if anything happens to coffee, the whole world is going to need Africa. Multiply this across all regions and all crops and suddenly you realize that everybody needs… everybody.

Making a mesh of it

Scientists have just published the most comprehensive effort yet to quantify this interdependence. They found that, on average, of all the plants providing calories, fat, and proteins in our diets, over two-thirds originate beyond the national borders within which they are consumed. The researchers also concluded that plants from other countries account for around two-thirds of the economic value of crop production.

Regional interdependence (calories)

This pretty kaleidoscope shows how much each region of the world depends on others for its food supply. If it looks complex, that’s because it is. But the takeaway message is simple: this world is completely messed up; we all depend on each others’ plants. For Colin, one of the scientists behind the kaleidoscope, this big, colourful mesh of interdependence translates into two simple, if far-reaching conclusions.

First, we need to conserve all plants related to our food supply; get as many different samples of domesticated crops plus their wild and weedy brethren into the world’s gene banks as quickly as possible. While I’m typing and you’re reading, cities are going up; trees are coming down; habitats are being turned into car parks. Tomorrow, some of those plants might be lost forever; many have already disappeared.

Second, those collections should be shared with whoever needs them. “The genetic diversity of crops should be considered public goods,” says Colin. “That means no-one owns them, but everyone can benefit from them.” Keeping them behind closed doors or a cumbersome application process isn’t the best way to share the love. A transparent, free and open system for sharing these collections means the plants can be more easily used in crop-breeding programs to toughen up popular varieties. It’s a form of future-proofing.

Becoming list-less

It’s also easier said than done. Establishing such a system requires unprecedented global collaboration. Nevertheless, there’s a major opportunity in Rome next week that could result in one of the most important decisions ever taken in fortifying the human food supply.

Up for discussion are amendments to the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). Unflattering both in name and acronym, it is known simply and forgivably as the Plant Treaty.

At its inception in 1998, the Treaty ring-fenced 64 food and forage crops seen as indispensable to global food security and sustainable agriculture. Since then, 130 countries have agreed to conserve and share their collections of these crops and their wild relatives. While the list of crops was never meant to be exhaustive, it was a good start.

But some major crops like peanut and soybean – and the wild relatives of maize and cassava – are conspicuous by their absence. Some important countries haven’t signed the Treaty either, for a number of reasons. Among them, perhaps, is the fact that some aren’t keen to share what they regard as the family silver. The long and short of it is that now, in late 2015, the list of 64 doesn’t represent the range of the plants we rely on – nor those that might emerge as the staples of the future.

For scientists like Colin, that means we’re vulnerable. We have a genetic safety net that is only a mere fraction of all the diversity out there. It’s too few eggs in not enough baskets.

Colin, together with scientists from the Global Crop Diversity Trust, the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) and others, will take the new data on interdependence to Plant Treaty negotiators in Rome next week.

There, they will make the case for getting rid of the list; removing it altogether from the Treaty. That way we can conserve and share all plant diversity related to agriculture. After all, it’s the best way to hedge our bets.

“The Plant Treaty is more important now than ever,” continues Colin. “But if we’re going to be prudent about protecting our food sources now and those of the future, it needs to expand its scope. Hopefully, what we now know about our interdependence on plant genetic diversity will help drive that point home.”

At the very least, it will give those responsible for influencing the new wording of the Treaty something to chew on.

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