Where does our food come from?

James Wong

There’s been quite a bit of discussion in the Twittersphere in recent weeks that caught my attention, about the sources and origins of our food, in which botanist, science writer, and broadcaster James Wong (@Botanygeek) has been a lively participant (expertly educating, and oftentimes correcting misinformation that surfaces all too frequently on Twitter).

So where does our food come from? No, I’m not referring to the local supermarket! Nor the countries where it’s grown and exported to the UK, to land on our supermarket shelves, such as avocados from Peru or French beans (Phaseolus spp.) from Kenya, to mention just a couple of examples.

Rather, I’m talking about the regions of the world where our food crops were first domesticated from wild species [1]. In many farmers’ fields, there is still an enormous diversity of shapes, sizes, and colors, as well as response to different growing conditions or reaction to pests and diseases. Just take the example below of potatoes from Peru, varieties that have been carefully cultivated by generations of farmers in the high Andes.

(L): Farmer varieties of potatoes from Peru; and (R): a potato farmer and her husband from the Province of Cajamarca in the north of Peru proudly holding a prized variety.

These diverse crop varieties and related wild species are the genetic resources or agrobiodiversity (perhaps a term more familiar to most through its regular use in the media) that plant breeders need to enhance agricultural productivity, transferring genes between different varieties or species to keep one step or more ahead of changing climates or increased threat of new strains of plant diseases. Without access to this valuable genetic variation, plant breeders would be challenged indeed to respond appropriately to the many threats in the agricultural environment.

There is an ongoing interdependence among countries for access to genetic resources. Take the potato, for example, with which I am quite familiar. The UK potato crop ultimately depends for its survival on plant breeders being able to access different genes and breed them into new varieties. Where do these genes come from? From from cultivated and wild potatoes in Peru and neighbouring countries. Plant breeders at the James Hutton Institute in Dundee, Scotland, regularly dip into the species conserved in the Commonwealth Potato Collection. This potato example is repeated worldwide for most other crops.

Colin Khoury

In a significant open access article (published in the Proceedings of the Royal Society B in 2016) Colin Khoury (a Birmingham MSc genetic resources graduate) and his co-authors state: Research into the origins of food plants has led to the recognition that specific geographical regions around the world have been of particular importance to the development of agricultural crops . . . We estimate the degree to which countries use crops from regions of diversity other than their own (‘foreign crops’), and quantify changes in this usage over the past 50 years. Countries are highly interconnected with regard to primary regions of diversity of the
crops they cultivate and/or consume.

Colin followed up with a piece on the blog of the Union of Concerned Scientists in 2017, discussing the interdependence of nations: The evidence on countries’ predominant use of foreign crops bolsters the rationale for strengthening international collaboration on conservation of crop diversity and for making the exchange of all agricultural seeds as easy and affordable as possible. Our interdependence also boosts the argument for considering the genetic diversity of globally important food crops as public goods which should be openly available to all, and for respecting the rights of farmers to practice their traditional methods of conservation and exchange, not only in recognition of their historical contributions to the diversity in our food, but also in active support of its further evolution.

Just take a look at this interesting graphic (click to enlarge) that was published in the 2016 paper, and republished in the 2017 blog post. I think many readers of my blog will be surprised when they discover the origins of most of the food plants they take for granted.

Origins and primary regions of diversity of major agricultural crops. Source: Khoury et al. 2016. Proc. R. Soc. B 283(1832): 20160792.

However, the concept of centers of origins and crop diversity is not a new one. It was first formulated by the great Russian geneticist (and ‘father of plant genetic resources’), Nikolai Ivanovich Vavilov (born in 1887). See how his centers coincide with the map above. Vavilov’s ideas have been reworked since his death, but still provide a fundamental foundation for the study and understanding of crop diversity. He was starved to death in one of Stalin’s prisons in 1943.

I. The Tropical Center; II. The East Asiatic Center; III. The Southwest Asiatic Center (c0ntaining [a] the Caucasian Center, [b] the Near East Centre, [c] the Northwestern Indian Center; IV. The Mediterranean Center; V. Abyssinia; VI. The Central American Center (containing [a] the mountains of southern Mexico, [b] the Central American Center, [c] the West Indian islands; and VI. The Andean Center.

One of his great works, Five Continents (a memoir of his many plant collecting expeditions) was republished in 1997 on the occasion of his 110th birthday. It had never appeared during his lifetime.

Vavilov, NI, 1997. Five Continents. International Plant Genetic Resources Institute, Rome, Italy. ISBN: 92-9043-302-7

Then, as I was thinking through these ideas about food origins, I came across the two photos below. At first I couldn’t recall where they had been taken. Then I realized they must have been taken during the drinks reception after the half-day N.I. Vavilov Centenary Symposium, jointly organized by the Linnean Society of London and the Institute of Archaeology of University College London on 26 November 1987 to commemorate Vavilov’s birth. I was one of the speakers.

Top: with Joe Smartt (University of Southampton). Bottom: Chatting with Joe Smartt, with Prof. Jacks Hawkes (University of Birmingham, to my left) with another symposium attendee.

The papers were published in a special edition of the Biological Journal of the Linnean Society in January 1990.

Sadly, all my fellow presenters have since passed away [2].

In the first paper, 1. Preface, Jack Hawkes and David Harris state the following: Vavilov laid the foundations of modern plant breeding, stressing the importance of the wide range of genetic diversity in our ancient crops and in related wild species—a diversity that before his time had barely been used or understood by breeders . . . Not only this—the whole movement of crop genetic resources conservation as a necessary prerequisite for the new more resistant and productive varieties needed now and in the future can be clearly traced back to Vavilov’s seminal ideas . . . Vavilov’s theoretical studies on crop plant origins and evolution under domestication, the areas in which crops evolved and the parallelism in their diversity in particular regions also possess clear practical implications, as well as linking into prehistory and the beginnings of agriculture.

In the second paper, Jack Hawkes discussed the impact of Vavilov’s work. He had met the great man on his visit to the Soviet Union in 1938.

Geographer David Harris discussed the origins of agriculture and how Vavilov’s studies on the centers of origin influenced the work of many other scholars. Yet he concluded that with the discovery of new evidence about the origins of agriculture, Vavilov’s concept as such had outlived its usefulness.

I was privileged to be asked to contribute to this symposium, standing alongside three colleagues: Joe Smartt, Jack Hawkes, and Trevor Williams who had encouraged me to enter the world of genetic resources and supervised my research, and mentored me at various stages of my career.

Professor Hugh Bunting had been the external examiner to the Birmingham MSc Course on genetic resources when I presented my dissertation on lentils in September 1971. There was a link to Vavilov there, because his second wife, Elena Barulina, wrote the first monograph on lentils.

My own paper discussed how homologous variation among potato species was evident when looking for resistance to pests and diseases.

I only met Gordon Hillman on one occasion at this symposium. He made very significant contributions to our understanding of early farming systems and the domestication of cereals in the Near East.

In his paper, Hugh Bunting discussed how Vavilov promoted the inclusion of physiological and biochemical features alongside descriptions of morphology to understand how plants were adapted to their environments. The examples used were groundnuts and sorghum, crops which Bunting had studied in Africa over many years.

In the final paper, Trevor Williams (who was Director of the International Board of Plant Genetic Resources, IBPGR, the forerunner of the International Plant Genetic Resources Institute, IPGRI, and Bioversity International) discussed how IBPGR’s program of collecting and conserving crop varieties and wild species worldwide had been guided by Vavilov’s ideas on centers of diversity.

As you can see, there’s more to this story of our food and its origins than perhaps meets the eye initially. It’s a story that I have followed for the past 50 years since I first set out on my career conserving and using plant genetic resources.

[1] Avocados originated in Central America, and French beans come from South America.

[2] I’ve not been able to find any further information about Stuart Davies, co-author with Gordon Hillman, since his retirement from Cardiff University.

This book (ISBN: 90-220-0785-5), by Anton Zeven and Jan de Wet, published by the Centre for Agricultural Publishing and Documentation in Wageningen in 1982 is an excellent source of information about the crop and wild species found in the centers of diversity.

It was a revised second edition of: Zeven AC and PM Zhukovsky, 1975. Dictionary of cultivated plants and their centres of diversity.

Zhukovsky was a follower of Vavilov and further developed the idea of centers of origin and diversity.

Are you plant blind?

In our 1986 book Plant Genetic Resources: An Introduction to their Conservation and Use, my former colleague and friend of almost 50 years, Professor Brian Ford-Lloyd and I wrote (on page 1):

To most people the word ‘conservation’ conjures up visions of lovable cuddly animals like giant pandas on the verge of extinction. Or it refers to the prevention of the mass slaughter of endangered whale species, under threat because of human’s greed and short-sightedness. Comparatively few  however, are moved to action or financial contribution by the idea of economically important plant genes disappearing from the face of the earth. . . . But plant genetic resources make little impression on the heart even though their disappearance could herald famine on a greater scale than ever seen before, leading to ultimate world-wide disaster.

Hyperbole? Perhaps. Through our 1986 lens that did not seem far-fetched. And while it’s fair to say that the situation today is better in some respects than Brian and I predicted, there are new threats and challenges, such as global warming.

The world needs genetic diversity to breed varieties of crops that will keep agricultural systems sustainable, allow production of crops in drought-prone regions, where temperatures are increasing, and where new races of diseases threaten even the very existence of agriculture for some crops.

That genetic diversity comes from the hundreds of thousands of crop varieties that farmers have nurtured for generations since the birth of agriculture millennia ago, or in closely related wild species. After all, all crops were once wild species before domestication.

These are the genetic resources that must be safely guarded for future generations.

The work of the International Board for Plant Genetic Resources (IBPGR), then the International Plant Genetic Resources Institute (IPGRI), was pivotal in coordinating and supporting genetic resources programs worldwide, in the 1970s, 80s and 90s.

Then a new and very important player came along. Over the past decade and half the Crop Trust, has provided long-term support to some of the world’s most important genebanks.

International mechanisms have been put in place to support collection, conservation, study, and use of plant genetic resources. Yet, much remains to be done. And ‘Joe Public’ is probably still as unaware of the importance of the crop varieties and their wild relatives (and perhaps plants in general) as we feared more than three decades ago.

Wildlife programs on TV are mostly about animals, apart from the weekly gardening programs, and some such as David Attenborough’s The Private Life of Plants (broadcast in 1995). Animal programs attract attention for precisely the reasons that Brian and I highlighted in 1986. A couple of nights ago for instance I watched a fascinating, hour-long program on the BBC about hippos in the Okavango Delta of Botswana. Wonderful footage revealing never-before-seen hippo behaviour and ecology.

When it comes to genetic resources, animals don’t do so badly either, at least here in the UK. We get an almost weekly item about the importance of rare breeds of livestock and their imperiled status during the BBC’s flagship Countryfile program on Sunday evenings presented by farmer Adam Henson, whose father Joe helped set up the Rare Breeds Survival Trust (RBST) in 1973. The RBST has been pivotal in rescuing many breeds from the brink of extinction. Just last night (28 July) Adam proudly showed an Albion calf born the day before on his farm in the Cotswolds. The Albion breed is one of the rarest in the UK.

Photo credit: the RBST

But that says very little about all the endangered livestock breeds around the world that are fortunately the focus of the work of the International Livestock Research Institute (ILRI).

Ankole cattle from southwestern Uganda (photo credit: ILRI/Stevie Mann).

However . . .

When was the last time—if ever—you watched a TV documentary about the rare (so-called ‘heritage’) varieties of the food plants on which we depend, or their closest wild species relatives, such as the barleys of Ethiopia or the potatoes of the South American Andes, for instance. And would you really care if you hadn’t?

Are you even aware that the barleys that we use for brewing originally came from Ethiopia and the Middle East? Or that the Spanish brought the potato back to Europe in the 16th century from Peru? What about your daily cups of tea or coffee?

These are just some of the myriad of fascinating histories of our food crops. Today many of these staples are often more important in agriculture in parts of the world far distant from the regions where they originated and were first domesticated.

In the UK, enthusiasts will be aware of heritage vegetable varieties, and the many varieties of fruits like apples that have disappeared from commercial orchards, but are still grown at places like Berrington Hall in Herefordshire.

Take a look at this article by freelance communicator Jeremy Cherfas about the origins of the food we eat. Jeremy has written a lot about genetic resources (and many other aspects of sustainable agriculture). As he says, you may discover a few surprises.

In centers of domestication, the diversity of the crops grown by farmers is impressive indeed. It’s wonderful. It’s BEAUTIFUL! The domestication of crops and their use by farmers worldwide is the story of civilization.

Here are just a few examples from beans, maize, cocoa, cucurbits, wheat, and lentil.

And take a look at the video below.

Who could fail to be impressed by such a range of shapes and colors of these varieties? And these varieties (and wild species) contain all the genes we need to keep crops productive.

Plant genetic resources: food for the stomach, food for the soul.

My own work since 1971 concerned the conservation and use of potatoes and rice (and some legume species as side projects).

In Peru, I came to learn just how important potatoes are for communities that live at altitude in the Andes. Could the Inca empire have grown and dominated the region had there been no potatoes (and maize)?

Machu Picchu

And there are so many wild species of potatoes that can be found from the southern USA to the south of Chile and east into the plains of Brazil. The International Potato Center (CIP) in Lima (where I worked for over eight years) has the world’s largest genebank of potato varieties. Important wild species collections are maintained there, as well as in Scotland at the Commonwealth Potato Collection (maintained by the James Hutton Institute), and the USA, at the NRSP-6 Potato Genebank in Sturgeon Bay, WI.

Rice is the food of Asia. There are thousands upon thousands of varieties that grow in standing water, or on sloping uplands, or in areas that flood and so have evolved to elongate rapidly to keep pace with rising flood waters.

Here is a selection of images of rice diversity in Laos, one of the countries that we explored during the 1990s.

Would it have been possible to build the temple complex at Angkor Wat in Cambodia in the 12th century without rice? It has been estimated that upwards of one million workers were employed in its construction. That workforce needed a constant supply of staple rice, the only crop that could be grown productively in this monsoon environment.

These potato and rice examples are the tip of the genetic resources and civilization history iceberg. Think about the origins of agriculture in Turkey and the Mideast, 10,000 years ago. Remains of wheat, barley and pulses like lentil and chickpea have been found at the earliest cities in that region. And these histories are repeated all around the world.

In 1983 and 1984, BBC2 aired two series of a program called Geoffrey Smith’s World of Flowers, in which Smith (a professional gardener and broadcaster) waxed lyrical on the history of many of his favorite garden plants, and their development in cultivation: tulips from Turkey, dahlias from Mexico, lilies from North America, and many, many more.

In these programs, he talked about where and how the plants grow in the wild, when they had been collected, and by whom, and how through decades (centuries in some cases) of hybridization and selection, there are so many varieties in our gardens today. The programs attracted an audience of over 5 million apparently. And two books were also published.

I had an idea. If programs like these could be so popular, how about a series on the food plants that we eat, where they originated, how they were domesticated, and how modern varieties have been bred using these old varieties and wild species. I envisaged these programs encompassing archaeology and crop science, the rise of civilizations, completing the stories of why and which crops we depend on.

I wrote a synopsis for the programs and sent it to the producer at the BBC of the Geoffrey Smith programs, Brian Davies. I didn’t hear back for several weeks, but out of the blue, he wrote back and asking to come up to Birmingham for a further discussion. I pitched the idea to him. I had lots of photos of crop diversity and wild species, stories about the pioneers of plant genetic resources, like Vavilov, Jack Harlan, Erna Bennett, and Jack Hawkes, to name just a few. I explained how these plant stories were also stories about the development and growth of civilizations, and how this had depended on plant domestication. Stories could be told from some of the most important archaeological sites around the world.

Well, despite my enthusiasm, and the producer warming to the idea, he eventually wrote back that the BBC could not embark on such a series due to financial limitations. And that’s all I heard. Nevertheless, I still think that a series along these lines would make fascinating television. Now who would present the series (apart from myself, that is!)?

Maybe its time has come around again. From time-to-time, interesting stories appear in the media about crops and their origins, as this recent one about cocoa and vanilla in the Smithsonian Magazine illustrates.

But we need to do more to spread the plant genetic resources ‘gospel’. The stories are not only interesting, but essential for our agricultural survival.