A bid to find wild relatives of common crops is under way to secure food supplies in the face of a growing population and climate change, experts have said.
The search for wild varieties of priority crops ranging from rice and wheat to sweet potato, millet, aubergine and apples is being led by the Crop Trust and the Royal Botanic Gardens, Kew.
The "crop wild relatives" carry traits that are not in the domestic crops, but which can used to breed more resilient plants to ensure food security.
Crop Trust executive director Marie Haga said: "These wild relatives can have traits that can help us to solve problems, in adapting plants to whatever it is, the need for plants to use less water, higher nutritional value or that they can stand higher salinity."
If, for example, a relative of wheat is found growing high on a mountain top, while it may not look much like what we think of as wheat, but its location makes it likely to be adapted to living in circumstances where water is scarce.
The need to find these plants was urgent, Ms Haga said, because of the pressure agriculture was facing, and because many of them were in areas where they were under threat from problems such as habitat loss and could be lost forever.
She warned: "Agriculture is facing probably its biggest challenge ever due to population growth and climate change.
"This dual challenge of feeding another two billion by 2050, that's a challenge in itself.
"We also know that many people will eat more meat, which will put more pressure on plant production, so it's a growing population but also a more demanding population.
"Then of course we have climate change."
She said the latest science showed that even if temperatures only increased by 1C due to climate change, the point at which the world was already at, it would lead to a 2% decrease in agricultural output worldwide each decade.
But without action to tackle greenhouse gas emissions, temperatures look likely to soar by 3C to 4C above pre-industrial levels, and the consequences would be "dramatic".
It was possible to breed plants that could absorb more carbon dioxide, have higher nutritional value or could cope with climate change, she added.
Hotspots for finding the wild species in countries and within particular regions of those countries, had been identified as part of the 10-year crop wild relatives programme, which is funded by Norway.
Scientists are spending several weeks in countries as far-flung as Azerbaijan, southern Brazil and Vietnam finding and collecting the varieties.
Work has already started on collections and will be ramped up next year.
Seeds will then be stored in gene banks in the countries where they are collected, and at the Millennium Seed Bank at Kew's Wakehurst Place, from where they will be sent out for research and to prepare genetic material for use in breeding.
They will ultimately also be backed up at Crop Trust's Global Seed Vault in Svalbard, in the Arctic in Norway.