© RBGKew

© RBGKew

Noah’s green ark

Nothing could survive without plants. They are the foundation for most of Earth’s ecosystems, help regulate the climate, and provide building materials, medicines, fuel, clean water and food, all essential for human health. But we’re losing plants fast: according to the recently published IUCN Sampled Red List Index for Plants – a study conducted by the Natural History Museum (London), the International Union for Conservation of Nature (IUCN), and the Royal Botanic Gardens, Kew (London) – one in five of the world’s 380,000 known plant species is threatened with extinction due to climate change and habitat loss.

In response, Kew’s Millennium Seed Bank project (MSB) is racing to save as much plant biodiversity as possible, giving priority to the world’s most useful and most threatened plant species. Part of the botanical research institute’s mission to learn about and conserve plant biodiversity, the MSB was launched in 2000 to collect and catalogue seeds from around the world. Working with partners in 50 countries, MSB helps identify which seeds are in most urgent need, offers conservation training and equipment, and helps develop long-term conservation programmes. The seeds are analysed for their DNA, tested for viability and, where possible, made available for non-commercial scientific research.

Search and rescue

Loss of biodiversity is particularly worrying when it comes to food security. The MSB recently joined the UN Food and Agriculture Organization’s Global Crop Diversity Trust (GCDT) on a rescue mission to save the genetic resources stored in the wild relatives of the crops we rely on. More than 30,000 plant species are edible, but we cultivate fewer than 150 for food, and only 12 species provide 80 per cent of world food. This dependence on just a few plants could spell disaster as temperatures rise, growing seasons change, the world population grows and productive arable land shrinks.

Cary Fowler, Executive Director of the GCDT, explains that we need the genetic diversity of wild relatives because they hold the solutions to such problems as drought tolerance, pests and temperature sensitivity. ‘All our crops were originally developed from wild species,’ explains Fowler, ‘and they were adapted from the plants best suited to the climates of the past. We now need to go back to the wild to find any of their relatives that can thrive in the climates of the future.’ A change of only 1ºC during rice flowering, for example, can reduce yields by a tenth, causing major shortages, says Fowler. If genes from a night-flowering wild rice variety could be bred into farmed rice, it could sustain or improve yields.

The GCDT has already collected and stored millions of seed samples in its Arctic vault in Svalbard, Norway. Its partnership with the MSB is a focused effort to gather, save, and research the useful genetic traits of wild relatives of 23 staple food crops: alfalfa, bambara groundnut, banana, barley, bean, fava bean, chickpea, cowpea, finger millet, grass pea, lentil, oat, pea, pearl millet, pigeon pea, potato, rye, rice, sorghum, sunflower, sweet potato, vetch and wheat. Over 10 years, the collected seeds will be put through a process called ‘pre-breeding’ to identify what could be incorporated into domesticated plants. Once these are identified, the material is made available to crop breeders. It takes up to 10 years to breed a new crop variety, so it’s a race against time.

Sprouting success

So far, the MSB has banked seeds from more than a tenth of the world’s flowering plants with banked seeds already being used to restore damaged habitats and help poor communities adapt to harsh conditions. Kenyan communities in the Makeuni district, for example, replanted forest degraded by overgrazing, deforestation and erosion with seedlings of indigenous trees grown from seeds collected by the MSB. The next step: to bank 25 per cent of the world’s seeds by 2020.

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This post is also available in: French, Spanish