All those veggies we will never eat

Rice, wheat, potato, maize, there is not much more on the menu today. These four crops make up for 60% of all plant-based aliments human beings eat today. And less than one hundred plant species compose 90% of the energy we consume. This is very little compare to the 12,650 edible plant species we have already identified.

Over the 20th century, modern agriculture has developed highly performant crops which can produce enough to feed the billions human beings populating the Earth. While focusing on a handful of plant species, scientists and plant breeders have neglected a large part of the agrobiodiversity that traditional farmers have taken centuries to select.

75% of the world’s food crop diversity has been lost over the 20th century. This includes the diversity within a single crop. For example, Indian rice farmers used to grow over 30 000 wild varieties of rice, now less than 50 varieties remain.

The Green Revolution of the 1960s and the rise of intensive agriculture allowed the overuse of fertilizers and pesticides as well as the selection of highly productive varieties at the expense of the natural environment and the traditional varieties.

This erosion of the agricultural biodiversity and its pool of genes puts at risk people’s food supply, especially under the unpredictable shift in weather patterns caused by climate change.

Historically, the loss of genetic diversity in a food crop has proven life threatening. In 1845 in Ireland, an epidemy of blight caused the potato production to collapse letting millions of Irish people without any food for 5 years. This was the Great Irish Famine which caused the death of over 1 million people and forced over 2 million Irish to emigrate to the United States.

Another famous example of the risk of reducing diversity within a crop, is the extinction of the Gros Michel banana. This banana variety was the most commonly grown and traded banana in the world until the 1950s. But at this date, a fungus caused banana plants to wilt and die. All the plants of the variety Gros Michel grown all around the world were clones of one single plant, therefore there were very vulnerable to pest attacks. That’s why, the world production collapsed in few months. Luckily for banana aficionados, the Cavendish banana, another suitable variety was discovered and widely commercialized.

Pests are predicted to increase with global warming. Climate change will not only make the weather unpredictable and the rainfall erratic, but it will also increase the population of pests. As pests increase, the risk of repeating the same scenarios as the Irish potato and Gros Michel banana increases as well.

Reducing the agricultural biodiversity on the field makes agroecosystems more vulnerable to pests and weather changes. When a farmer grows only one crop, he takes the risk to lose everything at once. And this is especially an issue if the farmer relies on a good harvest to feed his family and make an income to send children to schools. A series of bad harvesting seasons is even more life threatening as a farmer will not have enough money to buy seeds of modern varieties and the necessary fertilizers. A bad harvest can make farmers food insecure and push them into poverty.

The agrobiodiversity could be among crops but also within crops. On the one hand, a farmer can plant different plant species like chilli, potato, bean and corn on the same field to have a variety of crops and food sources. On the other hand, he can plant different varieties of rice, for example a mixed of traditional rice varieties with modern hybrids. In case one crop doesn’t survive a change in weather or a pest attack, the other crop can still sustain the family and ensure that everybody go to sleep with a full belly.

Promoting agricultural diversity and assisting farmers in growing traditional crops can increase community resilience. The diversity of crops and therefore food sources will allow farmers to always have one crop to eat if the main crop doesn’t produce enough.

Farmers are often very willing to grow and conserve traditional varieties. Even though modern hybrids produce more, their high needs in fertilizers and low resistance to the environment makes them a risky investment. Moreover, seed dealers often do not know the quality of their seeds and it happens that farmers buy seeds of modern varieties and realize at the harvest that these seeds were poor quality and didn’t produce as expected.

Traditional varieties are safer because seed production is completely under the control of the farmer. The low production of the traditional varieties can be a problem but it is often outweighed by reducing costs on pesticides, fertilizers and maintenance.

In addition, there is a social and cultural dimension behind the conservation of traditional varieties. Farmers have for a long time been the custodians of unique and locally adapted varieties. The knowledge to select, reproduce and take care of traditional varieties have been transmitted from generations to generations. Such varieties were often selected according to their taste, scent and colors. Traditional varieties are still used in traditions and are part of the customs of the community. The culture of the community has evolved with the tamed varieties. For example, the sticky traditional rice in Vietnam is often offered as present at wedding, funerals and significant community events. Even though it is not as productive as modern hybrids, the traditional sticky rice has a high value because of its scent and taste, and therefore plays an important role in building social bounds between members of the community. This cultural value is the main motivation for farmers to conserve these traditional varieties.

Today, many crops and traditional varieties are conserved ex-situ, in cold chambers where they are kept dormant for years. Conserving agrobiodiversity in large fridges in Norway is an easy way to keep biodiversity in a safe place. The day we will need a certain gene, it will be possible to go to these libraries of genes, regrow the necessary variety, take its gene and transfer it to another variety to give the latter a resistance to pests or drought.

However, the problem with ex-situ conservation is that it doesn’t consider the changes in environment. In gene banks, the variety is isolated and doesn’t interact and coevolve with the environment. A plant conserved ex-situ is coevolving with a changing environment and is more likely to develop an interesting genetic change to cope with harsh conditions.

Farmers around the world have a large knowledge about the traditional varieties they lived with. However, this knowledge is eroding as many farmers turn to modern productive hybrids. It’s crucial to develop programs to maintain this traditional knowledge and transfer it to other farmers and young generations so they can continue to select and breed these traditional varieties.

The development and conservation of traditional varieties is a service that smallholder farmers have given us for years. If we want them to continue to do it for free, we will need to encourage them to do so and invest in their traditional knowledge.

Traditional varieties are a good insurance against climate change. And we will need them if the main crops and varieties we are currently growing do not survive climate change.