Sarah Cody explains how gap analysis is helping our partners collect the seed of crop wild relatives (CWR) for a project called ‘Adapting Agriculture to Climate Change’, run jointly by Kew’s Millennium Seed Bank and the Global Crop Diversity Trust.
ADAPTING AGRICULTURE TO CLIMATE CHANGE
Climate change is one of the biggest challenges facing modern agriculture and the predictions for increasing temperatures and changes in rainfall pose a big threat to global food security. In response to this global threat, Kew’s Millennium Seed Bank Partnership has joined with the Global Crop Diversity Trust to launch ‘Adapting Agriculture to Climate Change: Collecting, Protecting, and Preparing Crop Wild Relatives’.
This project aims to safeguard the wild relatives of important crop species so that important characteristics are conserved and can be used to improve our crops, breeding in new characteristics to make them more suited to future climates.
Crop plants are especially vulnerable to rising temperatures and climatic change. Unlike animals, they cannot get up and walk away from a stressful environment. They are rooted to the ground and, for the most part, are dependent on humans to collect and sow their seed to complete their life cycles. Because of the domestication process many of our crops are low in genetic diversity and in great danger of being wiped out by pests, diseases and environmental stresses such as drought, flooding and higher temperatures.
Crop wild relatives (plant species that are genetically related to crop species but that have not been domesticated) can contain far greater diversity than their domestic cousins and so may hold increased potential to adapt to crop pests and diseases, adverse weather conditions and longer term changes in climate.
One way to improve the resilience of our crop plants is to harness the genetic diversity found in their wild cousins. By introducing CWR into breeding programs, the useful traits they contain, such as high yield and disease resistance, can be passed onto our crops.
Teaming up with the Global Crop Diversity Trust, Kew scientists are supporting countries around the globe in the collection of seeds from the wild relatives of 29 of the most important crop plants, including banana, apple, sunflower and sweet potato as well as crops like sorghum, cowpea and millet, which are staple foods for many people in the poorer parts of the world.
TARGETED SEED COLLECTIONS FOR PLANT BREEDING
The project focuses on collecting the seeds of plants which are not too distantly related to the crop, ie wild cousins that have retained their genetic diversity and which have a good chance of being successfully crossed with the crop to produce fertile progeny. For the 29 crops in this project the inventory of close crop wild relatives stands at ~450 species.
The first generation of a cross between a crop and its wild relative is unlikely to lead to the perfect supermarket-ready crop. The progeny may have inherited disease resistance or other valuable characteristics from its wild parent, but it will have also inherited many undesirable traits that can only be tamed though repeated back-crossing with the cultivated parent.
This can take years, which is why we need to collect these seeds as soon as possible so we can pass them onto specialist plant breeders (pre-breeders) to start the process of creating new crop varieties that are adapted to climate change.
GAP ANALYSIS AND THE IMPORTANCE OF KEW’S COLLECTIONS
In order to make quality seed collections we need to know the geographical distribution of the target species and where the gaps in our seed collections occur. To achieve this another project partner, the International Center for Tropical Agriculture (CIAT), is employing a powerful method called gap analysis. This uses location data on herbarium specimens coupled with knowledge of current seed bank holdings to help us prioritise the species and locations of crop wild relatives that are in most need of collection.
Kew’s collections include over 7 million herbarium specimens, such as the specimen of cowpea below, and 5 billion seeds collected from over 40,000 species. The data associated with these collections have been combined with data from other herbaria, genebanks and experts worldwide, and this information is vital to the gap analysis.
MAPPING AND MODELING
Herbarium specimens are a valuable record of a plant species in time and space. Fortunately for us, botanists since the 1700s have fastidiously noted down information about their specimens, such as the collection location, the soil type, the climate of the area, the altitude, and other potentially useful information, such as the local name of the plant and how the plant is used by the surrounding community. Today, with the benefit of technology we can use this information in many useful ways and gap analysis is just one of them.
The scientists at CIAT used location data from the herbarium specimens of crop wild relatives to map the places where these plants were originally collected. Then, through climate modelling they were able to extrapolate the data to make predictions of where other populations of the same species are likely to grow. This tells us the expected geographic range of the species and this is then compared with global seed collection data, including that stored in Kew’s Millennium Seed Bank, so we can identify priority locations for seed collection.
THE CROP WILD RELATIVES GLOBAL ATLAS
The map shows the gap richness of all the high priority species for all crop gene pools combined, and shows which geographic regions around the world are in the greatest need of collecting. South Africa, the Mediterranean, the Near East and Southeast Asia are areas which have high numbers of priority species that we still need to collect. The full results of the gap analysis can be found on the Crop Wild Relatives Global Atlas on the Adapting Agriculture to Climate project website.
THE TASK AHEAD
The reality is that many crop wild relatives are poorly collected, and in almost all instances the collections held in gene banks across the world do not represent the full geographic range of the species. This puts crop wild relatives, and therefore our major food crops, in a very vulnerable position, especially since many are threatened in the wild and in danger of going extinct.
The good news is we are now supporting partners across the world to collect their CWR, and thanks to the use of gap analysis we can now focus our resources on the highest priority species and where to collect them in order to fill in the gaps.
Post by Sarah Cody, Kew’s Millennium Seed Bank
Potato is one of the most important food crops in the world, particularly in Bolivia, where the crop is a primary source of nutrition and food security for a population of 10.5 million. Although not commonly served on the dinner table nor grown on farm, the wild relatives of potato are equally important – carrying an array of traits that continually adapt to changing climates.
Bolivia also has many potato wild relatives, of which 21 are endemic to the country. Out of these, at least 16 have shown to have important traits for plant breeding, such as resistance to late blight (Phytophthora infestans), one of the main diseases affecting potato cultivation in Bolivia; resistance to cyst nematodes (Globodera spp.) that attack the roots of the plant; as well as tolerance to various climatic factors such as extreme heat, drought or frost.
But crop wild relatives are increasingly threatened. After collecting new samples, and applying geographic analysis, Bioversity International and PROINPA found that more than 70% of these endemic species could be considered as vulnerable or worse according to the International Union for Conservation of Nature (IUCN) Red List criteria. Many of the locations, where these wild relatives grow, are threatened by habitat destruction, fires and livestock pressure. Threat maps developed by the International Center for Tropical Agriculture (CIAT) helped to identify which areas and which species are endangered by human disturbance.
Bioversity and PROINPA’s study found four endangered species that require special conservation efforts. Their conservation in genebanks is highly varied and some are not conserved at all or with only a few accessions. Conserving these species in genebanks might not suffice anyway – they should also be conserved in situ, in their natural habitat. These are among the species that have demonstrated resistance to several crippling pests and diseases, hence the need to prioritize their conservation.
The study also indicates several areas in the country as target areas to collect potato wild relative germplasm. This information will be of great use to the Bolivian National Institute of Agricultural and Forestry Innovation (INIAF), which currently coordinates the country’s genebanks and germplasm collections.
PROINPA will also be disseminating this information in a national biocultural program that works on the conservation of crop wild relatives. The existing national protected area network has a poor understanding of the distribution of potato wild relatives. The study therefore recommends that national parks and reserves start inventories to keep track of these endemic species, especially where ecological modeling predicts a high number of species to occur.
Read more about the conservation status of endemic wild potato in Bolivia in our recent publication: ‘Endemic wild potato (Solanum spp.) biodiversity status in Bolivia: reasons for conservation concerns’.
Bioversity International is actively involved in the research on Crop Wild Relatives. The national program that our partner PROINPA is involved in, is the ‘Programa Nacional de Biocultura’, led by Vice ministry of Environment, Biodiversity, Climate Change and Forest Development, with financial support of the Swiss Development Cooperation.
Post by Camilla Zanzanaini, Bioversity International
Earlier this month, the CIAT Crop Wild Relative (CWR) team presented oral papers as part of the American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and Soil Science Society of America (SSSA) International Annual Meetings, Nov. 3-6 in Tampa, Florida, USA.
Our first presentation reported on our research to gather and analyze data on the distributions of the wild relatives of 80 important food crops worldwide. After identifying hotspots of CWR diversity globally and comparing these against what has already been collected and preserved in gene banks, we generated a list of CWR taxa in critical need of future collection for conservation. The information generated is part of the ‘Adapting Agriculture to Climate Change: collecting, protecting, and preparing crop wild relatives’ project led by the Global Crop Diversity Trust in partnership with the Millennium Seed Bank at Kew.
We also presented on a recently completed inventory of CWR in the United States, as well as plans for protecting these plants both in gene banks and in the wild. Although North America isn’t known as a hotspot for crop plant diversity, the inventory uncovered nearly 4,600 CWR in the United States, including close relatives of globally important food crops such as sunflower, bean, sweet potato, and strawberry.
Presenting at the ASA, CSSA, and SSSA meetings was a great opportunity to meet and discuss our most recent results with colleagues from around the world. The presentations sparked questions about the next stages of the project and interest in future participation.
The Crop Science Society of America (CSSA), founded in 1955, is an international scientific society comprised of 6,000+ members with its headquarters in Madison, WI. Members advance the discipline of crop science by acquiring and disseminating information about crop breeding and genetics; crop physiology; crop ecology, management, and quality; seed physiology, production, and technology; turfgrass science; forage and grazinglands; genomics, molecular genetics, and biotechnology; and biomedical and enhanced plants.
CSSA Press Release: Protecting the weedy and wild kin of globally important crops
Blog post prepared by Vivian Bernau, Visiting Researcher (CIAT)
“A prioritized crop wild relative inventory to help underpin global food security” has just been published in Biological Conservation.
Crop wild relatives (CWR) contain a wealth of important traits for disease resistance and yield improvement, and may provide critical contributions to breeding for adaptation to climate change. Sadly, climate change itself, along with habitat modification, invasive species, and other factors are threatening CWR populations, thus jeopardizing these useful natural resources.
Why is it that despite their potential value, many CWR species are not adequately collected and conserved? The need for a systematic method for conservation has been clearly recognized by the Food and Agriculture Organization (FAO) of the United Nations and formalized in the International Treaty on Plant Genetic Resources for Food and Agriculture. The very first objectives of the Global Strategy for Plant Conservation (GSPC) of the Convention on Biological Diversity, which relate to understanding, documenting, and recognizing plant diversity, reveal a major part of the answer. If we don’t know what CWR species exist, where they live, and how threatened they are, then how can we successfully collect and conserve them?
Among wild species, an additional piece of information is vital in regard to prioritization of CWR- the degree of relatedness of the wild species to its crop cousin- as this degree determines the actual potential for successfully introducing useful traits from the wild species into the crops. Relatedness information derives from a mixture of systematics based upon traditional morphological information as well as increasingly on genotypic data, as well as information from plant breeders attempting crosses between CWR and crops.
This new paper describes the first attempt on a global scale to bring together exactly this critical primary information on CWR species identities—distributions and relatedness information—in order to inform subsequent conservation efforts. The article describes the creation of a global priority CWR inventory covering the CWR of over 150 crops, and reports on the taxonomy, geographic distribution, potential use in plant breeding for crop improvement, and seed storage behaviour of valuable CWR.
The inventory is available online at www.cwrdiversity.org/checklist/ and is searchable by crop gene pool, individual CWR species, country/region, and reported uses in breeding. Its data has provided the foundation for the global “‘Adapting Agriculture to Climate Change: collecting, protecting and preparing crop wild relatives” project, as well as activities such as an ecogeographic study of the grasspea gene pool, a national CWR inventory for the USA, and Jordan’s national strategy for plant conservation.
The cwrdiversity.org website has just released a new interactive map page displaying the results of gap analyses for the crop wild relatives of 29 important food and forage crops, with more to be added in the coming months. This Crop Wild Relative Global Atlas provides the opportunity to explore distributions and conservation concerns in geographic regions, crop gene pools, or particular CWR species of interest. The page presents occurrence data points, potential distribution maps, and maps displaying areas identified as of priority for collecting for conservation, over a Google Map interface also displaying the locations of international, national, and other protected areas.
The results displayed for the 439 CWR assessed thus far will be used by national agricultural institutes and interested conservation groups in collaboration with international organizations to help guide collecting efforts in the coming years. It is hoped that the results will also be used by other researchers and activists involved in biodiversity conservation and crop genetic resources. See the “Conservation Gaps” page for methodological resources and an overview of the results. Inputs on these results from those with experience in species distributions and conservation priorities is welcomed.
The distributions and conservation analyses for the CWR of 50 additional crops, including maize, soybean, cassava, tomato and other globally important staples will be added to the CWR Global Atlas as the results are produced and evaluated by associated researchers.
The CWR Global Atlas provides three distinct ways to visualize results:
1) CWR Taxon- view occurrence data, distribution maps, and conservation gaps maps for individual species.
2) Crop Gene Pool- view a summary of species distributions as well as conservation concerns for all assessed CWR in a particular crop gene pool.
3) Global Summary- view a summary of species distributions as well as conservation concerns for all assessed CWR in all crop gene pools combined.
To explore individual CWR species, click the “CWR Taxon” button and enter the species name in the search box. The results will first show available occurrence data points. Click on “Potential distribution map” to display the distribution model derived from occurrence data. Finally, click on “Collecting priorities map” to show areas identified as in need of further collecting. The conservation status of the species is also provided, along with a link to the associated crop gene pool.
To explore the results on the crop gene pool level, click on “Crop Gene Pool” and enter a cultivated species or its common name in the search box. The results will first display a richness map portraying the concentration of distributions of all assessed CWR species related to the crop. Clicking on “Collecting hotspots” will generate a second richness map providing concentration of distributions where species of high priority for collecting are thought to occur but have not yet been collected and conserved.
The “Global Summary” area displays richness maps of CWR species distributions, inclusive of all CWR in all crop gene pools assessed thus far. The corollary collecting priorities map reveals those geographic areas around the world with the greatest concentration of species considered of high priority for collecting.
Visit the CWR Global Atlas to explore crop wild relative distributions and conservation priorities.
Grasspea, Lathyrus sativus, is a crop with two sides to its personality. Considered both a saviour and a destroyer; in times of famine grasspea is often the only alternative to starvation. Being the hardy plant that it is, it can withstand extreme environments, from drought to flooding, and when all other crops fail grasspea will often be the last one left standing. It is easy to cultivate, and is tasty and high in nutritious protein, which makes grasspea a popular crop in south Asia and the eastern Horn of Africa where it is also grown to feed livestock. Being a member of the legume family, Lathyrus is able to fix nitrogen from the air which means that growing it keeps the soil healthy and well fertilised.
Now, before we make a saint out of the humble grasspea, let us consider some of its more sinister attributes. Eaten in small quantities, grasspea is harmless. However, eating it as a major part of the diet over a three month period can cause permanent paralysis below the knees in adults and brain damage in children, a disorder known as lathyrism. The culprit is a potent neurotoxin called ODAP. This is responsible for the drought and waterlogging tolerance of grasspea but, if taken in large quantities, it brings on the neurological disorder. For example, Ethiopia has seen several lathyrism epidemics in the past 50 years, when hunger overrules the dangers inherent in grasspea consumption. What makes matters worse is that the level of the neurotoxin increases in the crop under conditions of severe water stress which exacerbates the risk of lathyrism at a time when the poorest of the poor have no choice but to rely on the crop for their survival.
According to The Consultative Group on International Agricultural Research (CGIAR) at least 100,000 people in developing countries are believed to suffer from paralysis caused by the neurotoxin. There are a number of ways of preparing grasspea so that it is less harmful, for example, by washing and soaking the grasspeas and then discarding the water before cooking or by eating grasspea mixed in with other crops. Both strategies are effective in reducing the risk of lathyrism however in a famine where water and other food sources are scarce, detoxification of grasspea may be harder to implement.
Thanks to the Grasspea
The adverse neurological effects of eating grasspea have been known since prehistoric times. Ancient Indian texts described the disorder and even Hippocrates, the father of modern medicine himself, mentions a neurological disorder caused by eating a Lathyrus seed in 46 B.C. in Greece. Grasspea was served as a famine food during the Spanish War of Independence against Napoleon and below is one of Francisco de Goya’s famous aquatints, Gracias a la Almorta (“Thanks to the Grasspea”). It captures the hardships of the time through its depiction of the poor surviving on grasspea porridge, one of them lying on the floor, already crippled by it.
For all the effort involved in cultivating grasspea and making it safe for consumption you might think it easier to abandon the crop altogether. However, things are not as straightforward as all that. Grasspea continues to be the ultimate safety net for subsistence farmers in the poorest parts of the world and provided that consumption does not reach that critical level it is safe and nutritious to eat. Quite simply, grasspea is too important to do away with altogether.
Breeding low toxin varieties
Crop diversity is the key to overcoming this paradox and is the only thing that can put an end to the good cop/bad cop antics of grasspea. The International Centre for Agricultural Research for Dry Areas (ICARDA) is working with Ethiopian breeders to develop cultivars of grasspea with low levels of the neurotoxin ODAP. Toxins found in African and Asian grasspea plants are seven times more toxic than the Middle Eastern varieties. The new ICARDA hybrids have levels of the toxin high enough to keep up the crop’s resilience to drought and flooding, without being damaging to human health. The Centre for Legumes in Mediterranean Agriculture (CLIMA) is also conducting important research in this area and has recently produced a low toxin variety. Hope is on the horizon but much more work needs to be done to produce locally adapted, low toxin varieties and to distribute these to farmers.
Crop Wild Relatives: A source of genetic diversity
The wild relatives of grasspea are an important source of genetic diversity for the cultivation of low toxin varieties. Grasspea is one of the 29 priority crops that are the focus of the Adapting Agriculture to Climate Change project executed by Kew’s Millennium Seed Bank and the Global Crop Diversity Trust. By collecting the wild relatives of crops such as grasspea and making their seeds available to breeders, useful traits such as lower toxicity levels, in the case of grasspea, and resistance to pests, diseases and environmental stresses can be passed on to crops, making them more resilient and better equipped to deal with climate change. The development of low toxin varieties of grasspea is a matter of food security and is something that will have a direct impact on the health and livelihood of thousands of people. Grasspea takes on a special importance in the light of climate change since tolerance to drought and flooding are characteristics that give the crop an advantage in stressful conditions.
Who knows, maybe grasspea will be up for sainthood after all!
This post was written by Sarah Cody, CWR Communication Assistant for the Royal Botanical Gardens at Kew.
In this audio interview taken during the 18th International Sunflower Congress, Luigi Guarino of the Global Crop Diversity Trust asks Professor Loren Rieseberg of the Biodiversity Research Centre, University of British Columbia, about the use of the wild relatives of sunflower in research and breeding.
Most plant breeders and genetic resources scientists would agree that crop wild relatives as a rich source of exotic diversity have proved their worth in contribution to crop improvement, especially for pest and disease resistance. So it may come as a surprise that despite their long history of use in breeding major crops, many CWR species are not well collected and conserved in genebanks. Meanwhile their native habitats are increasingly threatened by development and climate change, among other factors. Why this disjunct between estimated value and adequate protection?
Though scientists appreciate the value of CWR, it appears that conservation groups, policymakers, and the general public are not as well informed about the unique potential hidden within these wild and weedy plants. How can information on the value of CWR improve? One of the most persuasive forms of communication about the issue is, of course, monetary value.
A recent analysis commissioned by Kew’s Millennium Seed Bank Partnership (MSB), and carried out by PricewaterhouseCoopers (PwC), UK, has taken the latest stab at evaluating the economic benefit of use of CWR.
By using current and forecasted gross production values from the Food and Agriculture Organization of the United Nations (FAO), the study estimated the current value of commercial crops grown today, and in the future, containing improved productivity or stress resistance traits derived from CWR.
Results based on four crops- wheat, rice, potato, and cassava- were extrapolated to a group of 29 crops prioritized by the MSB Partnership (the same crops targeted in this analysis) and assigned values based on analyses from seed development to farm-gate sales. Based on current production, the CWR of the target crops were assigned a value of $42 billion, with a potential of $120 billion in the future.
The annual GPV of the 29 priority crops was $581 billion in 2010, meaning that CWR are already valued at about 7% of annual production value.
Stephen Aherne, director, PwC adds, “While the findings in our analysis are indicative, the overall message is clear. CWRs represent a valuable tool in global crop development for many organisations related to the agriculture sector…Our research underlines the need for further investment in CWR collection and research, without which the significant potential value to global agriculture may not be realised.”
Global efforts to adapt staple foods like rice, wheat and potato to climate change have been given a major boost as new research reveals the details and whereabouts of their “wild relatives”– undomesticated plant cousins that could contain secrets to making food crops more productive and resilient.
Some of these wild and weedy species have evolved to tolerate drought, higher temperatures or pest and disease outbreaks, all of which are expected to become more frequent as a result of climate change. But according to the new research carried out by the International Center for Tropical Agriculture (CIAT) together with the UK’s University of Birmingham, as part of a project led by The Global Crop Diversity Trust in partnership with the Millennium Seed Bank, Kew, less than half of these plants are sufficiently conserved in the world’s gene banks, meaning scientists are missing out of significant opportunities for breeding more productive, climate-smart crops.
Using a technique called gap analysis, scientists studied the wild relatives of 29 important food and forage crops, including global staples such as rice, wheat, potato, and banana, as well as regionally critical crops such as pigeonpea, lentil, sunflower, and sweet potato. They found that of the 455 wild relatives identified, over half are seriously underrepresented in gene banks. Fortunately, the new findings also show where they might be found in the wild. With the new information, national agricultural institutes and interested conservation groups in collaboration with international organizations will head into the wild around the world to seek out the highest priority and most-at risk species in the largest coordinated conservation exercise for crop wild relatives ever undertaken. The study and the collecting work is part of a major 10-year project funded by the Government of Norway to help boost the resilience of staple foods crops to climate change.
The results were recently reported on in Nature News and indicate that collecting for genetic resources conservation is still an urgent concern across the globe. Jane Toll, Project Manager at the Global Crop Diversity Trust, adds, “This study has thrown up some surprises. Crop wild relatives in some areas in Australia, Europe and the USA need to be collected just as much as those in regions of Africa, Asia and South America.” This is an important finding, highlighting the important role that the wild plant resources in industrialized countries have to contribute to food security worldwide.
Adding urgency to collecting priorities, some of the regions where the wild species might be found are already at risk, with climate change itself, urbanization, invasive species, and the spread of industrial agriculture threatening unique habitats. For example, in Costa Rica, suburban expansion around the capital San Jose threatens populations of the closest wild relative of common bean – a crop grown by millions globally.
Summary results are available on the project website, with an interactive map of the results coming soon.
Plant biodiversity conservation is ideally conducted through the dual complementary strategies of collecting and storing this diversity in seedbanks (ex situ) and protecting representative populations in their natural environments (in situ). Despite its importance, there have been few major international efforts in conserving agrobiodiversity and crop wild relatives in particular in situ. The lessons learned from those projects that have occurred are therefore of great interest in terms of devising sound strategies for future work.
The recently published Crop Wild Relatives – A Manual of in situ Conservation captures practical experiences and presents good practices learned in five countries: Armenia, Bolivia, Madagascar, Sri Lanka, and Uzbekistan during the UNEP/GEF funded project “In situ conservation of CWR” . It is available online for free in English, Spanish, and French, and is complemented by a diversity of online eLearning modules that clearly describe the key issues involved with the conservation of CWR in situ.