Creating and Re-Creating Rice, Maize, and Chicken
We don’t just gather our food. We gather the raw materials and then we turn them into food. The skill and determination that have gone into making food inspire awe.
One way we make food is by processing it (including cooking).
Another way we make food is by domesticating and manipulating (breeding) plants and animals to get the raw materials we want. Often, though, we talk as though plants and animals were domesticated at some date in the past and that since then they have remained the same century after century.
This week three articles, one on rice, one on maize, and one on chicken, came to my attention that show how wrong this is, how domestication is not a one-time event, but something that continues.
I should say, by the way, that I am a little out of my depth here because I have no expertise whatever in plant and animal breeding. I am, however, increasingly convinced that it would be to the mutual advantage of food historians, historians of plant and animal genetics, and archaeobotanists to bridge the gap between their disciplines. So I plunge ahead, aware that I may be making all kinds of howlers. Please let me know.
The Protracted Process of Domesticating Rice in the Yangtze Valley
Rice domestication in the Yangtze Valley is the subject of a paper published by a team of Chinese researchers and the British archaeobotanist, Dorian Fuller, in Nature earlier this month.
Rice (Oryza sativa) is regarded as the only grass that was selected for cultivation and eventual domestication in the Yangtze basin of China.
Although both macro-fossils and micro-fossils of rice have been recovered from the Early Neolithic site of Shangshan, dating to more than 10,000 years before present (BP), we report evidence of phytolith and starch microfossils taken from stone tools, both for grinding and cutting, and cultural layers, that indicating barnyard grass (Echinochloa spp.) was a major subsistence resource, alongside smaller quantities of acorn starches (Lithocarpus/Quercus sensu lato) and water chestnuts (Trapa).
This evidence suggests that early managed wetland environments were initially harvested for multiple grain species including barnyard grasses as well as rice, and indicate that the emergence of rice as the favoured cultivated grass and ultimately the key domesticate of the Yangtze basin was a protracted process.
In other words, the inhabitants of the Yangtze Valley tried out the major kinds of carbohydrates useful to humans: grass seeds (including rice), nuts (acorns) and roots (water chestnuts). The only missing item is a starchy fruit, but starchy fruits (think plantains and breadfruit), although crucial in some areas, were not as globally important as seeds, nuts, and roots. Only after a long period (centuries?) of experiments, did the people of the Yangtze Valley make rice their basic food resource.
The Creation of One Maize (Corn) Landrace after Another in Different Parts of the World
The second article, published a couple of years ago in Theoretical and Applied Genetics, is Out of America: Tracing the Genetic Footprints of the Global Diffusion of Maize by French researchers, C. Mir and T. Zergel, as well as others. The authors trace the paths by which maize went from various parts of the Americas to much of the rest of the world, including parts of Asia, Africa, the Middle East, and Europe. (If you are interested in the history of corn do take a look at the fascinating maps in this article).
What struck me was that the researchers collected data about more than 700 different landraces (traditional varieties) of maize. Now if I am correct there are about 70 landraces in Mexico, the center of origin of maize.
That means that in the roughly 450 years since Europeans arrived in the New World, the number of varieties of maize has multiplied ten-fold.
Making Chickens an Appealing Color and Good Layers of Eggs
Chicken are the subject of the third article (and thanks to Adam Balic, who works on chicken genetics for a living and food history for a pastime, for passing it on to me), appeared in the Proceedings of the National Academy of Sciences in 2011.
The researchers focused on two genes known to differ between domestic chickens and their wild counterparts: a gene associated with yellow skin color, called BCDO2, and a gene involved in thyroid hormone production, called TSHR.
Though the exact function of TSHR is unknown, it may be linked to the domestic chicken’s ability to lay eggs year-round – a trait that Red Junglefowl and other wild birds don’t have.
When the team compared the ancient sequences to the DNA of modern chickens, only one of the ancient chickens had the yellow skin so common in chickens today. Similarly, less than half of the ancient chickens had the version of the TSHR gene found worldwide in modern chickens.
The results suggest that these traits only became widespread within the last 500 years — thousands of years after the first barnyard chickens came to be. “Just because a plant or animal trait is common today doesn’t mean that it was bred into them from the beginning,” Larson said.
“It demonstrates that the pets and livestock we know today — dogs, chickens, horses, cows — are probably radically different from the ones our great-great-grandparents knew,” he added.
“…They are subjected to the whim of human fancy and control, [so] radical change in the way they look can be achieved in very few generations.”
Thus it is quite possible that about 500 years ago chicken overwhelmingly had nice yellow skins and began laying more eggs for longer periods than previously.
Conclusion
Now when people were selecting rice or maize or chicken, they would have had multiple aims in mind. In the case of maize, say, they wanted some varieties that matured quickly in case of bad weather, some that withstood drought, some that withstood damp, some that were easy to “desgranar” (remove the grains), some that were auspicious colors, some that prepared into tasty dishes.
I am particularly interested in the middle categories, the culinary ones, rather than the agricultural (growing) or gastronomical (taste) categories. How did the evolution of plant processing intersect with the selection of rice? What kinds of tools and techniques go along with the relegation of most grass seeds and acorns to either famine foods or non-food status, and water chestnuts to supplementary foods?
So, again, since Mexican methods of processing maize did not travel with the plant, what is the relation between all these new landraces and ways of processing maize in different areas. What kinds of starches were good for what purposes?
And in the case of chicken, what did these new varieties of chicken have to do with the explosion of ways of cooking eggs in Europe in the sixteenth century?
There are tantalizing hints that in the ancient world, breeding and cultivating were also regarded as part of cooking. It was this that made many plants and animals better to eat: bigger grains, sweeter fruits, less stringy meat. (Of course, not all changes were culinary ones. Many were prudential. Breeding for different climates, soils, etc. Others, to repeat, were gastronomical.)
Perhaps it is time to revive the ancient idea that breeding and processing are a continuum. Instead of thinking of cooks as working with static materials (or, in the gloomy view of the present, with materials that modern breeding has made less tasty), maybe we should think of cooks and farmers as having worked in partnership over the centuries. For most of history, the farmer and the cook were one and the same or at least members of the same family.
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