We’re becoming more similar: trends in global diet and the consequences for food production and health

A study published today in the Proceedings of the National Academy of Sciences of the USA (PNAS) examined how national food supplies have changed over the past 50 years for 98% of the world’s population. The authors find that diets worldwide have become much more similar in composition over the past five decades, relying increasingly on a limited set of major crops for the majority of dietary calories, protein, fat, and weight.

Overall people are consuming more food, and a greater proportion of the diet is comprised of energy dense food (plant and animal sources high in fats, oils, and sugars). The crops that provide a dominant proportion of this diet are major staple cereals such as wheat, rice, and maize, as well as a suite of globally important oil crop commodities, particularly soybean, palm, rapeseed, and sunflower oil. The contribution of these oil crops in particular has risen disproportionately over the past half century.

Crops showing large relative increases or decreases in the global diet. Khoury et al. 2014

Crops showing large relative increases or decreases in the global diet. Khoury et al. 2014

As a result of these dietary changes, regionally important crops have suffered. The study shows significant decreases in the importance of cereals such as sorghum, millets, and rye and root crops such as cassava, sweet potato, and yam. Locally important crops that are not measured on the global scale have suffered the same fate. Without concerted conservation, research and advocacy efforts, the world is in danger of losing a wealth of diverse, adapted alternative crops.

Although changes in diet have occurred worldwide, the areas where food supplies have departed the most significantly from 50 years ago are in Sub-Saharan Africa and in Asia. On average, global diets have increased in similarity by an average of 36%.

The expansion of the global diet and its accompanying production systems has simultaneously increased efficiency and decreased the resiliency of the global food system. Similarities within the food system facilitate technology transfer and food production, which allow for centralized research to impact larger portions of the world. Simultaneously though, these similarities make the global food supply more susceptible to widespread problems such as pests, disease, and climate change, as a greater uniformity of crops are grown over larger areas.

While the availability of more energy dense food has improved food security in some regions in the form of both sufficient quantities and increased nutrients, the increasing homogeneity of contributing crops may contribute further to the occurrence worldwide of diseases associated with over nutrition such as diabetes, heart disease, and some forms of cancer. As over nutrition becomes as important as under nutrition for global public health, maintaining diverse diets could be a key strategy to help the fight against diet related diseases.

Change in dietary composition similarity over time. Khoury et al. 2014

Change in dietary composition similarity over time. Khoury et al. 2014

Addressing the challenges and vulnerabilities created by greater homogeneity in global food supplies will require a combination of scientific research, advocacy, political agreements, and changes in agricultural production. Key steps include: 1) ensure the genetic diversity of major crops through developing and growing a wide range of locally adapted varieties with distinct characteristics, 2) increase the conservation and utilization of diverse genetic resources- including crop wild relatives- that underpin crop diversification, 3) enhance the nutritional quality of major staples for micronutrients, and/or provide micronutrient supplements, 4) encourage a wider range of alternative crops through promotion of the benefits of such crops in the diet and via research in crop development in order to enhance competitiveness, and 5) publicly show the links between crop diversity, diet diversity, and health.

Read the article here.

Khoury CK, Bjorkman AD, Dempewolf H, Ramírez-Villegas J, Guarino L, Jarvis A, Rieseberg LH and Struik PC (2014) Increasing homogeneity in global food supplies and the implications for food security. Proceedings of the National Academy of Sciences of the USA. doi: 10.1073/pnas.1313490111. Available online at: www.pnas.org/cgi/doi/10.1073/pnas.1313490111

Project set to improve the resilience of agriculture under climate change with the help of wild genes – new paper released

Plant collectors and crop breeders from around the world have teamed up to collect, protect and prepare the wild relatives of our most important food crops in a form that can be used to create new varieties that are resilient to climate change. The project, jointly run by the Global Crop Diversity Trust and Kew’s Millennium Seed Bank with support from the Government of Norway, is called Adapting Agriculture to Climate Change and focuses on 29 crops; including globally important crops such as wheat, rice and potato as well as crops of major regional importance in the developing world, such as finger millet, sweet potato, cowpea and sorghum.

sweet potatoes. credit: Credit: Tumwegamire, S., International Potato Center (CIP)

sweet potatoes. credit: Credit: Tumwegamire, S., International Potato Center (CIP)

Scientists working on the project released a paper earlier this week emphasising the relevance of the work for food security and outlining the main phases which will lead to the development of these new varieties. Climate change is acknowledged to be one of the biggest threats to food security in the 21st century. Many decades of modern selective breeding, while greatly improving  yield in major crops,  has unfortunately left them low in genetic diversity and therefore vulnerable to stresses such as rising temperatures, drought, and diseases.  One way to introduce genetic diversity, and therefore resilience, in our crops is to include their wild relatives in breeding programs so that the useful traits they contain (e.g. higher yield, disease resistance, drought tolerance) can be passed onto our crops.

The main phases of the project are as follows

  1. identify those crop wild relatives (CWR) that are missing from existing gene bank collections, are most likely to contain diversity of value to adapting agriculture to climate change, and are most endangered;
  2. collect them from the wild and conserve them in gene banks for conservation;
  3. evaluate these and other CWR materials already in collections for useful traits and prepare them for use in crop improvement; and
  4. make the resulting products and information widely available.
bean research. credit: N. Palmer, CIAT

bean research. credit: N. Palmer, CIAT

With the first phase of the project already completed, and the second phase well underway, we will soon have a more comprehensive collection of CWR stored in seed banks as well as more active breeding programs to develop new adapted varieties.

To read the paper in full, click here.

Collecting crop wild relatives- lessons from the field in Vietnam

Elinor Breman, Species Collections Support Officer at Kew’s Millennium Seed Bank (MSB), reports on a training workshop that brought partners from across Asia together to learn about collecting, handling and banking the seeds of their crop wild relatives.

Global food security

Global food security is of growing concern in light of population expansion and climate change predictions. There are around 7,000 plant species used as food crops globally, but only 12 of these account for roughly 80% of global consumption.

Conserving the genetic diversity of the most important food plants is vital for breeding crop plants that are able to face future environmental challenges. The Millennium Seed Bank of the Royal Botanic Gardens, Kew and the Global Crop Diversity Trust have joined forces in a project to collect, conserve and make available for use the genetic diversity in the wild species related to major food crops. The Decision and Policy Analysis group at CIAT is partnering on providing information on collecting priorities.

This project – ‘Adapting Agriculture to Climate Change: Collecting, Protecting and Preparing Crop Wild Relatives’ (CWR Project)- supports national institutes around the world in collecting and safeguarding priority crop wild relatives. Seed Collecting Guides have been developed to provide collectors in the field with as much information as possible about these wild plants, so that they are able to find them and collect their seeds. The Vietnam Seed Collecting Guide contains information for 17 different Crop Wild Relatives, including distant cousins of banana, apple, pigeonpea, aubergine, rice and sweet potato. The collecting guide contains a description of what the target plants look like, when they are going to have ripe seeds, where they are found, and also has some photos to help identification.

Vietnam Seed Collecting Guide: page for banana relative Musa itinerans.
This wild relative of banana is found in evergreen forests and ravines. Unlike cultivated bananas, it has large seeds (up to 7mm) and the skin of the fruit is pink rather than yellow.

Training in Vietnam

Members of RGB Kew’s Seed Conservation Department together with representatives of the Global Crop Diversity Trust headed to Hanoi in Vietnam to lead a training course for delegates from Indonesia, Malaysia, Nepal and Vietnam.

The week-long training course on collecting, handling and long-term conservation of seeds of wild species related to crops was hosted by the Vietnamese Plant Resources Center and funded through the Sfumato Foundation. It provided a thoroughly enjoyable and educational introduction to the world of wild species seed conservation, highlighting the particular challenges that wild species pose, compared to crops, but also how crop and wild species conservation can learn from each other.

In the lecture room, the science behind long-term seed conservation was explained, enabling participants to understand how factors such as temperature, seed moisture and seed development would affect the longevity of seeds in storage. Fieldwork planning was outlined, detailing how to target species and areas for collection, the genetic basis of sampling strategies, and how to use Seed Collecting Guides.

In the field

We then moved from the lecture room to the field to put the theory into practice. In the Ba Vi Mountains National Park, to the west of Hanoi, participants were able to
• assess the quality of potential seed collections
• choose appropriate sampling strategies
• make collections of seeds, herbarium specimens and associated data
• choose appropriate post-harvest seed handling methods

Putting theory into practice – fieldwork in the Ba Vi Mountains National Park: negotiating the terrain; making a herbarium voucher; collecting target species.

The many challenges facing seed collectors in the field soon became apparent. Finding a target species when it was growing in inhospitable terrain or widely dispersed is not always that easy. When you have found it, a plant may have many fruits on it, but how many seeds are in that fruit, and how many of those seeds are fully developed and likely to germinate? The importance of checking seed viability using a seed cut test was demonstrated, together with seed number calculations which determine whether an adequate sample can be collected from the target population without impacting on the wild population’s survival.

The practical session continued the following day when the material collected in the field was cleaned and counted at the Plant Resources Center. Here a variety of species requiring different cleaning techniques were used, and different winnowing methods were shared by participants.

Seed cleaning at the Plant Resources Center, Hanoi

Local Culture

Whilst in Vietnam our hosts from the Plant Resources Center ensured that the course ran smoothly, that everyone was looked after and that we sampled Vietnamese culture. This included introducing participants to the wonders of Vietnamese cuisine and the organisation of an optional excursion after the course had finished to the World Heritage site, Halong Bay. Meal times and the excursion proved an invaluable time for networking among participants. At the end of the week, they left not only with their newly-acquired knowledge of seed collecting, handling and long-term conservation for wild species, but also with new friendships and an air of excitement about participating in the Crop Wild Relatives Project.


Participants and trainers on the training course, Hanoi, Vietnam (Photo: Plant Resources Center, Vietnam)

Agricultural Research Service develops National Inventory of Crop Wild Relatives

An estimated one of every five plant species worldwide is threatened by habitat loss, climate change, invasive species, and other threats. In the United States 30 percent of native plant species are threatened and some of these native species are closely related to crop plants we eat every day.

Through crop breeding, these crop wild relatives (CWR) can provide critical sources of genetic diversity that can provide crops with an array of economically important traits–such as resistance to emerging pests and diseases, increased yield, and better drought tolerance. The use of CWR for these purposes has been expanding in recent decades, and is thought to only continue to grow as breeders tackle the myriad challenges of future crop improvement.

Tripsacum dactyloides, CWR of maize, in Florida

Tripsacum dactyloides, CWR of maize, in Florida

In the U.S. the Agricultural Research Service and collaborating scientists have created a first-of-its-kind inventory for U.S. wild and weedy crop relatives that prioritizes the species by their breeding importance for important food and fiber crops. The Inventory lists the species and their related crops, and gives indications regarding the conservation status as well as the availability of accessions of these species in national genebanks.

Read more about the National Inventory in the January 2014 edition of Agricultural Research.

Filling in the gaps: seed collecting for the future

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.

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.

Wild sunflower, Helianthus annuus, brightening up a gloomy sky (Photo: Kasia Stepien)

Wild sunflower, Helianthus annuus, brightening up a gloomy sky (Photo: Kasia Stepien)

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.

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.

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.

Herbarium specimen of Vigna unguiculata (cowpea)

Herbarium specimen of Vigna unguiculata (cowpea)

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 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.

Global gap richness of high priority species for all crop genepools combined (Image: CIAT).

Global gap richness of high priority species for all crop gene pools combined (Image: CIAT).

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

Conservation concerns for endemic potato species in Bolivia

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

CWR gap analysis results presented at international conference

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)

Prioritized crop wild relative inventory published

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.

Crop wild relative conservation results now available through interactive map

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.

Phaseolus costaricensis, USDA Pullman, WA. photo- C. K. Khoury

Phaseolus costaricensis, USDA Pullman, WA. photo- C. K. Khoury

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.

Occurrence data and collecting priorities for Solanum candolleanum, a wild relative of potato (source: www.cwrdiversity.org/distribution-map)

Occurrence data and collecting priorities for Solanum candolleanum, a wild relative of potato (source: http://www.cwrdiversity.org/distribution-map/)

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.

Species richness of crop wild relatives of pigeonpea (Cajanus cajan) (source: www.cwrdiversity.org/distribution-map)

Species richness of crop wild relatives of pigeonpea (Cajanus cajan) (source: http://www.cwrdiversity.org/distribution-map/)

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.

Gap richness in high priority species for all crop genepools combined (source: www.cwrdiversity.org/distribution-map)

Gap richness in high priority species for all crop genepools combined (source: http://www.cwrdiversity.org/distribution-map/)

Visit the CWR Global Atlas to explore crop wild relative distributions and conservation priorities.

The curious case of the grasspea

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.

Grasspea flower Pretty Poisonous - a grasspea in flower (Photo credit: Nancy J. Ondra)

Grasspea flower
Pretty Poisonous – a grasspea in flower (Photo credit: Nancy J. Ondra)

Pretty Poisonous

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.

Bags of grasspea sold at a maket in Florence, Italy (Photo credit: Dirk Enneking, Institute for Plant Genetics and Crop Breeding)

Bags of grasspea sold at a maket in Florence, Italy (Photo credit: Dirk Enneking, Institute for Plant Genetics and Crop Breeding)

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.

Francisco de Goya's aquatint "Gracias a la almorta" translated to "Thanks to the grasspea". (Photo credit: Wikipedia Commons)

Francisco de Goya’s aquatint “Gracias a la almorta” translated to “Thanks to the grasspea”. (Photo credit: Wikipedia Commons)

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.

Grasspea seeds (Photo credit: Dirk Enneking, Centre for Legumes in Mediterranean Agriculture CLIMA 1995)

Grasspea seeds (Photo credit: Dirk Enneking, Centre for Legumes in Mediterranean Agriculture CLIMA 1995)

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.


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