Declarations of sovereignty and independence are not uncommon as rites of passage both for countries and teenagers. But what we typically see and what we experience is altogether different, both at home and in the world. Dependency and interdependency are the norm, whether we look at human relations, commerce, or biology. As the conservationist John Muir put it, everything is “hitched to everything else in the universe.” And perhaps this is as it must and should be. We dabble with danger when we act as if we are self-reliant and can “go it alone”, when in fact we are not and cannot. Our hubris tempts us to behave as if we are unhitched.

When it comes to the world’s food supply, dependency has five faces. Let’s look at them.


Most countries and cultures rely predominantly on foods from other regions and countries. The most important food crop in southern Africa is maize, a crop domesticated in the Americas. An FAO study quantified this degree of dependency on non-indigenous crops and found, for example, that Ghana and Italy were equal in their dietary reliance on crops originating elsewhere. Imagine Italian cuisine without pasta (made from wheat, first domesticated in the Near East) or pasta sauce (with tomatoes from Central America). Think of the impact on food security if Ghana no longer produced its top two food crops: cassava and maize (from South and Central America).


We sometimes think of developing countries as “gene rich” and developed countries as “gene poor.” This was certainly the case in the Neolithic Age, but that was 10,000 years ago. And incidentally, there were no countries then. If one considers the diversity held in genebanks – the diversity accessible for plant breeding – everyone looks poor, individually. Climate change will present growing conditions different from those ever experienced in country after country. Would any nation, rich or poor, developed or developing want to claim “independence” with so small a share of the global total of stored samples, as illustrated in Table 1?
Moreover, most countries lack genebanks capable of providing long-term storage of crop diversity. An even closer look reveals that they can’t or don’t supply the bulk of breeding materials used in their own national crop improvement efforts, meaning that many countries are effectively dependent on a handful of genebanks globally that conserve crop diversity adequately and service plant breeders everywhere.

Crop varieties
Look into President Obama’s pedigree and you will famously see ancestors from Africa, America, and Europe. Look into the pedigree of a modern crop variety and you will see something similar. Most new varieties, whether released and grown in Canada or Cambodia, will have drawn upon other varieties from multiple countries for various traits. Virtually no new crop variety anywhere has a pedigree drawn from a single country. Call that interdependency at the ground level.

The two maps show the source countries of breeding materials that went into the creation of the famous “Veery” wheat variety, and then countries in which it was released to farmers. What can we learn from the maps? That many countries contributed and many countries benefitted and continue to benefit. Over and over again, this is what one finds when examining the use of crop diversity in agricultural systems.

Trade and Food Prices
The 3000-mile Caesar salad is a feature of the modern world, at least for the time being. Food travels. Food systems and diets depend not only on local produce, but also on the success of farming systems on other continents. A country does not have to produce these crops, it only has to import and consume them, in order to be dependent on the breeders and genebanks that keep such crops afloat. This is why we should care about the genetic diversity of bananas, even if the crop isn’t grown in our country. We eat bananas, and somewhere someone is producing them for us, and relying on them as an income source for themselves.

When supply and demand become severely imbalanced, prices rise and we term the result a “food crisis.” One way of avoiding this is to ensure the stability of production, not just in one country but in all countries. This cannot be done without deploying genetic diversity in breeding programs and in the field. Viable collections of crop diversity are a prerequisite.


Finally, successful and sustainable agricultural systems are environment-friendly. Poor and unproductive agricultural systems encourage–indeed, require–people to expand cropland, cut down trees, and plough marginal lands to produce more food. How much of the world’s deforestation and subsequent loss of biodiversity is really due to unproductive farming systems and crop varieties?

The forests of Latin America depend on the productivity of crops from Asia such as soybean, and access to genetic resources to make those crops productive. The forests of Africa depend on the productivity of crops from Asia (rice) and Latin America (maize) and access to the genetic diversity of such staples. As Table 1 indicates, that diversity is not to be sourced “locally” in any one country. It must be pieced together from multiple countries and seedbanks and used to make agriculture more productive and sustainable. Again, we return to dependency and interdependency.

Our Common Future
Current food supplies and future food security, as well as our fragile environment are all dependent on crop diversity.

Take a good look at any country: the comparatively small amount of diversity held in its national genebank or its farmers’ fields is clearly inadequate by itself to ensure agricultural productivity, much less the adaptation of its agricultural system to dramatically new climates. Assertions of independence, however passionate, cannot alter this simple biological fact.

It is self-evident that our common future depends not on our particular country’s “national” collection, but on our collective success in fashioning a viable global system for conserving crop diversity for use by plant breeders everywhere.

We come full circle. Sovereignty and independence play well in certain political circles and amongst many teenagers, but are out of place in the biological sciences. In the real world of agriculture and crop diversity, we are hitched. “We are,” in the words of Martin Luther King Jr., “caught in an inescapable network of mutuality, tied in a single garment of destiny.”