All countries in the world are heavily dependent for their food supply on ‘foreign’ plants that originated from far beyond their borders. In the Netherlands, for example, 70% of the crops that we eat every day originated from other parts of the world. This was the result of a study carried out by Colin Khoury of the International Centre for Tropical Agriculture (CIAT) in cooperation with Paul Struik of Wageningen UR, the Global Crop Diversity Trust and several other universities. These researchers determined the origin of 151 crops that are part of the daily diets of 177 countries.
Potatoes appear regularly on many dinner tables in the Netherlands, but the potato was not a Dutch crop originally. The potato comes from the Andes. And wheat comes from the Middle East. Nowadays we often eat rice from Asia and drink coffee that originated in Africa.
It is not such a big surprise that people often ‘eat across the border’. But one surprising result of the study is that that no single country has a diet consisting entirely of ‘native’ crops. Khoury looked at various crops that are central to national diets (sources of carbohydrates, fats, proteins and fibre) and at the national agricultural systems (production, quality, crop areas and production quantity). All crops could be traced to 23 ‘primary diversity’ regions. In these regions, thousands of years ago, a wide range of edible plants were domesticated: farmers selected wild plants for use in local agriculture.
In his PhD research at Wageningen UR, which was supervised by Paul Struik, Khoury showed that diets worldwide have become increasingly diverse. Struik: “Due to globalisation, the diets in every country are becoming more diverse, but the differences between countries are getting smaller and smaller.”
In his subsequent research, Khoury has shown how the world is becoming increasingly interconnected by food. “It is fascinating how many crops are characteristic of ‘traditional’ diets, even though they originated many thousands of kilometres away,” Khoury explains. “We are just starting understand the dependence of national dietary patterns and local farmers on plants from other parts of the world.”
As a result, we have become increasingly dependent on other countries. For example, if Dutch plant breeders want to develop a potato that is resistant to a new disease or pest in Europe, they have to look for potato types from a region with a great diversity of potatoes. Logically, this is the region where the crop has been present for the longest, where it grows in the wild and has been grown on farms for hundreds or even thousands of years, where it was exposed to many different diseases and pests, and where it is still grown. For the potato, this is South and Central America.
Gene banks ensure that this ancient diversity is saved and made available. However, the wild varieties are often missing from these collections. We share responsibility for the preservation of traditional crops and their wild relatives. After all, we have become increasingly dependent on each other's original crops.
“To preserve and use this genetic diversity we must act in the spirit of interdependence,” says Paul Struik. “We must work together to ensure that the original varieties of our crops are effectively protected and managed. This is important because our crops are increasing threatened by factors such as climate change, and by the new pests and diseases that are associated with these factors.”
Theo van Hintum, head of Plant Genetic Resources of the Centre for Genetic Resources, the Netherlands (CGN), explains that wild plants are almost totally absent in their gene bank. “This is partly because wild plants are often difficult to propagate. The seeds can be dried and frozen, but first we need to know which types are important for breeding and will therefore be used in the future. It is impossible store all of nature in a gene bank, and why should we?”
Van Hintum says that it is very useful to provide access to these related wild species and ancient varieties by documenting them, and if they are not being saved in the gene bank, they should be monitored so they do not disappear. If wild types that are useful for breeding become endangered, they can still be saved in the gene bank.