Crop Wild Relatives, Genetic Diversity, and Food Security Concerns
An Important Announcement From the IUCN
At the end of 2017, the International Union for Conservation of Nature announced that more than twenty wild relatives of agricultural crops are in trouble. Some people may wonder why this matters. After all, cultivated crops seem to be all that we need. They have useful features, are abundant in many places, and are a major part of our food supply. Agricultural experts say that we need the wild plants for food security, however. If cultivated crops are destroyed by a widespread disaster or environmental problem and we have no wild plants to help us, humanity could be in trouble.
It's by no means certain that if a particular disaster kills cultivated crops it will also kill their wild relatives. The wild plants contain a different set of genes, which may be beneficial to them. Although specific genes are vital in order to make a plant useful to humans, genetic diversity can be important with respect to novel features and survival mechanisms. Another advantage offered by wild plants is that they sometimes grow in different areas from the cultivated ones. For these reasons, the wild plants may not be affected by a problem that kills or damages the crops.
Wild relatives of crops (often referred to as crop wild relatives or CWR) are in trouble due to human activity. Habitat for the plants is being destroyed by deforestation and land clearance for agriculture, buildings, and roads.
Wild Wheat, Rice, and Yams Are in Trouble
The IUCN has found that in the wild two types of wheat, three types of rice, and seventeen types of yams are in trouble. The idea of cultivated yams being a staple food may be strange for many North Americans, but they are an important part of the diet in some parts of the world. They feed about a hundred million people in Africa, for example. Wild yams could be important for the health of the cultivated ones.
In much of the world, the word “yam” has a different meaning from its common one in North America. In Canada and the United States, a yam is an orange-fleshed variety of the sweet potato (Ipomoea batatas), which is also available as a white-fleshed vegetable. The plant belongs to the family Convolvulaceae. True yams and their wild relatives belong to the family Dioscoreaceae. A few species of wild yams grow in North America.
True yam plants are vines with heart-shaped leaves. The part that is eaten is a tuber. A tuber (or stem tuber) is a swollen structure in an underground stem that stores starch as food for the plant. The food can also be used by us.
The Problem of Low Genetic Diversity in Crops
Cultivated plants have one feature that could become a major problem: they lack genetic diversity. In general, they have been bred for genes, gene variants, or gene combinations that make them successful crops under current conditions. Less attention has been paid to other characteristics of the plants, including ones that give them resilience to certain problems. The genes in a particular variety of a crop are so similar in different individuals that if an environmental change kills one plant it might kill them all. The stresses might include drought, flooding, fire, pest attacks, diseases, or even sabotage.
Since as a group wild plants have a wider variety of genes, it’s more likely that some members of a species would survive a disaster. These could then be bred for food. It’s also possible that if a stress weakens but doesn’t destroy cultivated plants, breeders could create hybrids between the wild and domesticated plants to provide genes and resilience. Wild plants could act as a reservoir of novel genes for crops. Marie Haga, the executive director of the Crop Trust, says that the wild relatives of crops are "an insurance policy for the world".
FAO estimates that since the beginning of this (twentieth) century about 75 percent of the genetic diversity of agricultural crops has been lost.— FAO (Food and Agriculture Organization of the UN)
A Wild and Cultivated Plant Hybrid
Some researchers are already creating hybrids between wild and domesticated crops. It might be possible for hybrids to grow in unusual habitats for cultivated crops, such as deserts or salt marshes. According to the Kew Gardens website, at least one case of hybridization with this result has already occurred.
Helianthus paradoxus is a species of wild sunflower that is classified as threatened in the United States. The plant grows near salt lakes. Researchers have created a hybrid of the wild plant with a cultivated sunflower. This has improved the growth of the cultivated plant in soil containing salt and increased the seed production by the crop growing in that environment.
More Reasons Why Crop Diversity Is Important
Genetic diversity in crops is often referred to as "crop diversity". The goal of the Crop Trust is to preserve and where possible increase crop diversity. The trust is an international nonprofit organization that was established in 2004 by FAO and Biodiversity International. It was once known as the Global Crop Diversity Trust and is sometimes still referred to by this name.
According to the Crop Trust, there are at least six reasons why genetic diversity in crops is important. I've summarized the reasons below.
- Providing Food Security: Genetic diversity may help to maintain food security, which is the provision of adequate amounts of safe and nutritious food to an entire population. The food must enable people to lead an active and healthy life.
- Adapting to Climate Change: Crops that can grow in a wide variety of climates are needed in order to provide the best chance of maintaining food security in the future.
- Decreasing Degradation of the Environment: The growth of suitable plants can reduce environmental degradation in an area. Some varieties of plants may need little or no pesticide treatment, for example, and others may have a deep or widespread root system that reduces soil erosion.
- Maintaining the Nutritional Value of Food: Genetic diversity in a crop increases the possibility that some plants will have desirable levels of vitamins, minerals, or other nutrients.
- Reducing Poverty: Fighting poverty is a complex topic. Increasing crop diversity may be helpful, however. Farmers who grow desirable crops are more likely to obtain an adequate income. When a food is widely available, it may become more affordable.
- Creating Sustainable Agriculture: Successful agricultural techniques resulting from genetic diversity in crops have an increased likelihood of being sustainable.
The Svalbard archipelago is located in the red circle shown in the map above. Norway is the country shaded in red.
The Svalbard Global Seed Vault
Protecting and preserving wild relatives of crops is important. An additional strategy is being used to help humanity recover from a crop disaster, however. The Global Seed Vault in Svalbard, Norway, is a depository for the world's crop seeds. One goal of the depository is to preserve seeds that can produce new crops if the present ones are destroyed by a problem such as climate change, a natural disaster, or a war. Another goal is to store as wide a variety of seeds as possible, thereby preserving the genetic diversity that is still present in cultivated plants.
The seed vault is meant to exist far into the future. Humanity may require specific characteristics in replacement crops at that time. The environment and the required characteristics can't be predicted. Genetic diversity is important in order to increase the likelihood of being able to grow successful and useful crops in the future.
Location and Creation of the Seed Vault
The Svalbard seed vault was opened by the government of Norway in February, 2008. The building is funded by the Norwegian government and is open to seed deposits from around the world. It's run and/or supported by three organizations: the Norwegian Ministry of Food and Agriculture, the Nordic Gene Resource Centre, and the Global Crop Diversity Trust. The depositors own the seeds and can withdraw them when they wish.
Svalbard is an archipelago located in the Arctic Ocean. It's an unincorporated area but is governed by Norway. The vault is located 1300 km beyond the Arctic Circle in an area containing permafrost. According to the seed vault's website, the vault contains "the seeds of many tens of thousands of varieties of essential food crops".
The seeds of each plant variety in the vault also exist in smaller gene banks around the world. The Svalbard vault has the advantage of being a backup depository located in an isolated area that is protected by the permafrost.
A gene bank stores genetic material. This material may be seeds or frozen cuttings from plants or frozen eggs and sperm from animals. A seed bank stores only seeds, as its name implies.
A Potentially Serious Situation
A potentially serious situation with respect to the Svalbard seed vault occurred in the winter of 2016-2017. Most of the vault is embedded in the ground, as the video above shows. The design of the vault allows the cold ambient temperature to protect the seeds from damage. The winter referred to above was unusually warm, however. Completely unexpectedly, some of the permafrost around the vault melted. As a result, meltwater entered the vault and later froze. Fortunately, the water and ice didn't reach the seeds.
Changes have been made to the vault in order to reduce the risk of damage. The situation is worrying because the Arctic is warming up as the climate changes. The seeds in the vault may one day be very important to humanity. They need to be preserved.
Seed Banks to Preserve Wild Plants
Since seeds of cultivated plants are being preserved, it might seem logical that those of wild plants should be preserved as well. Some progress has been made in this area.
In Britain, Kew Gardens has published collection guides to help people identify wild plants correctly and gather the seeds. The guides are part of their Crop Wild Relatives Project. The project is run by Kew Gardens and the Crop Trust and is funded by the Norwegian government. It concentrates on crop relatives in the grass family (such as wheat and rice) and those in the legume family (such as peas and lentils).
Collecting the seeds of wild plants could allow cultivated crops to be enhanced in the future. The seeds could also be planted in the wild so that they are exposed to different gene selection processes than the cultivated plants, which would probably be selectively bred by humans.
Crop wild relative seeds are a largely untapped resource for crop improvement, but their potential is immense.— Laura Jennings, Kew Gardens
Preparing for the Future
All sources of genetic diversity in crops could be vital in the future. The future could be nearer than we think. There has already been one withdrawal from the Svalbard seed vault. Syrian researchers have been unable to continue their research at a gene bank in their country due to the war. In 2015, they used their preserved seeds to set up research stations in other countries. In 2017, they made a new deposit to the seed vault.
We need to think about maintaining, collecting, and preserving crop diversity now. The future is unknown, but there are troubling signs in the present. Climate is changing and the world's population is increasing. Crops have already died in some parts of the world. We need to be prepared for further problems that may occur.
Wild crops listed as threatened from the BBC (British Broadcasting Corporation)
Why crop diversity matters from Croptrust.org
Information about the Svalbard global seed vault from the government of Norway
Arctic stronghold of world's seeds flooded from The Guardian newspaper
Information about the Crop Wild Relatives Project at Kew Gardens (officially known as the Royal Botanic Gardens, Kew)
© 2018 Linda Crampton