Tea – the elixir of life.

It was just before 6 am today. I was lying in bed, enjoying my early morning cup of tea, and waiting for the news bulletin on Radio 4 on the hour.

And I got to thinking about this photo of tea pickers in the highlands of Kenya that my friend Luigi had posted on Facebook yesterday. Tea is a very important crop in Kenya, and it now ranks as the world’s third largest producer, after China and India, with Sri Lanka and Turkey coming fourth and fifth, respectively. I’ve seen tea cultivation in Sri Lanka (above Kandy) and Indonesia (in the hills east-southeast of Bogor).

Tea is not, however, a crop that is native to Kenya, having originated in east Asia. And the same could be said for most of the plants we consume today. Just a quick survey of country of origin of fruits and vegetable on sale in supermarkets here in the UK demonstrates the global system of food production, and how far from their original regions of cultivation many of them have spread – beans from Kenya, asparagus from Peru, etc. The potato is referred to in the USA as the ‘Irish potato’ (presumably to distinguish it from the sweet potato, to which it is not related at all; or was it because of the dependence of the Irish in the 19th century on this one crop that led to mass emigration, most often to the USA, during and after the potato famine of the mid-1840s), but comes from the Andes of South America, with its greatest diversity in southern Peru and northern Bolivia. It’s now a major crop worldwide. Maize originated in the Americas but is a major staple today in many parts of Africa, although the major production area is the Corn Belt of the USA. Wheat originated in the Middle East, but major wheat-producing countries are the USA and Canada, Australia, and Russia. Rice is still the staple of Asia where it originated – probably in several centers of domestication.

In the 1980s, when I was on the faculty at the University of Birmingham, I taught a graduate course on crop evolution. I guess this interest in and research on crop origins had been instilled in me by Jack Hawkes, former head of the Department of Plant Biology at Birmingham (and my PhD supervisor), and I continued my work on potatoes for more than 20 years before moving on to rice.

One of the reasons why I find the study of crop evolution so fascinating is that it is a synthesis of so many seemingly unrelated disciplines: the biology of the wild and domesticated plants themselves, their genetics and molecular biology, ecology, and use plant breeding and farming, as well as their history and archaeology, social context, and economics over the past 10,000 years or so since the beginnings of agriculture in the Middle East, in China, and in parts of South and Central America. An interesting introductory text for anyone interested in the origins of crops is Evolution of Crop Plants (1995) edited by Joe Smartt and Norman Simmonds.

Today, the application of molecular techniques is helping to unravel further the ancestry of crop plants, showing linkages to their related wild species, and opening up many opportunities of using these genetic resources for the benefit of farmers and consumers alike, making the crops we depend on more productive, climate resilient, and pest and disease resistant.

In the 1980s the two BBC TV series of Geoffrey Smith’s World of Flowers documented the origins and history of many of the flowers that we grow in our gardens today – roses, tulips, daffodils, fuchsias, dahlias, and lilies, to name just a few. Based on the success of these programs, I did contact the series producer and sent in a prospectus for a series of programs about the origins of crop plants.

I could imagine a program on potatoes, for example, that would take the viewer to the Andes of Peru, looking at indigenous potato cultivation, linking it to the origins of Inca agriculture and the archaeology of the coastal cultures, the wealth of diversity of more than 200 wild species in the Americas, how these are conserved in major genebank collections in the USA and Europe (as well as at the International Potato Center in Lima), and how this diversity is used in potato breeding. No longer would we take these crops for granted! And the same could be done for wheat and barley – the cereal staples of the Middle east, with its wealth of archaeology in Turkey, Syria and Iraq, maize in Mexico and coastal Peru, and many other examples.

I even spent some time with a BBC producer who visited me at Birmingham – but to no avail. While they liked the idea, there was no budget to do the programs justice. I could just imagine Sir David Attenborough waxing lyrical – in his inimitable way – about our food and where it comes from. Who knows – it might happen one day (but Sir D is an unlikely presenter given his age).