Wild relatives

Domesticated varieties of rice, wheat, maize and potatoes make up much of the world's food crops and are bred to thrive under certain conditions.

However, some experts warn that these crops could become vulnerable to global warming as optimal conditions change across the planet.

Climate change is expected to have multiple impacts on agricultural productivity, especially in areas of the developing world that are already experiencing high levels of food insecurity.

For example, in southern Africa, the yields for maize, a vital crop in a region already suffering from chronic hunger, are predicted to fall by up to 30 percent within just 20 years.

A growing population will put added pressure on the food supply. The world's population is expected to exceed 9 billion people by 2050, which will require an estimated 70 percent increase in global agricultural production, according to the United Nation's Food and Agriculture Organization (FAO).

Making use of the genetic variety contained in wild crops – the ancestors of today's food crops – could help secure the world's food supply by helping modern crops adapt to climate change, according to the Global Crop Diversity Trust.

Tough ancestors for a harsh climate

In partnership with the Millennium Seed Bank of the Royal Botanic Gardens at Kew, England, the Consultative Group on International Agricultural Research, and $50 million (38 million euros) of funding from the government of Norway, the Trust has launched a campaign to collect, save and utilize these wild plants.

The wild ancestors of today's food crops were typically very tough and able to grow in conditions that are hostile for today's agriculture, according to Cary Fowler, executive director of the Global Crop Diversity Trust.

"Some of them are extremely heat resistant or drought tolerant," he said. "If you look forward and consider the kind of projections being made in terms of climate change, these are exactly the kind of qualities agricultural crops will need in the near future."

Biodiversity: A life-saver

New climates will affect agriculture within the next 50 years, Fowler said.

Plants will have to adapt to variable temperatures, droughts, floods or different pests and diseases. He pointed to rice as an example of where wild crop varieties could benefit modern crops.

At a critical stage in the flowering process for rice, even a one-degree rise in temperature could cut yields by 10 percent.

Most high-yield varieties of rice flower during the heat of the day and a few degrees temperature change could cut yields by up to 40 percent, Fowler said.

But some wild rice relatives flower at night and if that characteristic could be incorporated into farmed rice it could save millions of tons of rice "and thousands of lives," said Fowler.

The wild relatives of today's food crops make up only a tiny fraction of the seeds currently held in the world's gene banks.

Although plant breeders have incorporated many traits from the wild versions of crops in the past, the resulting plants have never been comprehensively collected or conserved, according to the Global Crop Diversity Trust.

Many are in danger because of climate change or rapid habitat loss. The Royal Botanic Gardens, Kew, estimated that a fifth of the world's plants are threatened with extinction.

"Diversity equals resilience in the biological world, which is why this project is vital to the survival of agriculture," said Paul Smith, Director of Kew's Millennium Seed Bank.

Wild plants: A good investment

Wild crop forms annually contribute more than $100 billion to commercial agriculture, according to Fowler's estimates.

One example cited by the Global Crop Diversity Trust of how a "wild relative" can save a modern crop goes back to the 1970s, when rice harvests across Asia were hit by an outbreak of grassy stunt virus.

Scientists screened more than 10,000 samples of wild and locally cultivated rice plants for resistance to the disease and found it in a wild relative, oryza nivara, growing in India. The gene has been incorporated into most new varieties since that discovery.

Norwegian Minister of the Environment and International Development Erik Solheim said the project represented "one of the most concrete steps taken to date to ensure that agriculture and humanity, adapts to climate change. At a more fundamental level, the project also demonstrates the importance of biodiversity and genetic resources for human survival."

Solheim added that the Scandinavian country, which provided the Trust's initial funding, is committed to conserving the world's plant biodiversity and built the Svalbard Global Seed Vault on the Arctic island of Spitsbergen in 2008, to store seed samples safely for posterity.

A race against time

The international campaign will involve research centers, agricultural institutes, botanical gardens and local people around the globe, who will search out the plants and collect them.

The project is focusing on 23 crops considered to be the most important food crops, including rice, wheat, maize, potatoes, beans and peas. The time scale is 10 years, as the wild plants collected cannot be used directly in modern agriculture and because it takes seven to 10 years to breed a new crop variety.

"You have to cross the plant with a domesticated form to see what characteristics it actually has: Drought resistance, heat resistance during flowering good pest or disease resistance," explained Fowler. "You can't plant the wild plants, farmers want domesticated, higher yield varieties and so somehow traits from these wild plants have to be used in the process of making new, more modern varieties."

The results will be entered into a database and made available to plant-breeders and any other interested parties around the globe.

Ultimately, the seeds will be used to produce crop varieties that can cope with climate change.

The project is a race against time. A rapidly rising population and increased demand for meat means global agriculture production will have to double in the next 50 years, said Fowler, adding that if climate change continues in line with the most conservative estimates it would be difficult to keep up current agriculture output.

He described climate change as the biggest challenge agriculture has faced in the last 12,000 years. And the partners in the campaign believe the natural diversity in older varieties, the "wild relatives," will be the most important tool in addressing the challenge of future food security.

Author: Irene Quaile, Sean Sinico
Editor: Nathan Witkop