Corn is the greatest success story of plant domestication. Humans and corn first went into partnership over 6000 years ago and have been ruthlessly exploiting each other ever since. In fact it is hard to know who has the upper hand in this ancient partnership – corn or humankind!
Corn is descended from a group of annual grasses collectively called teosintes. Teosintes grow wild in southern Mexico and Guatemala. They have small ears of a dozen or so kernels, each enclosed in a hard seed case. When the ears ripen, they shatter and the seeds fall to the ground. Not a very promising food crop at first glance. But the teosintes have special attributes which earmarked them for success: an astounding ability to interbreed and mutate.
Wild teosintes interbred to produce the first early corn varieties. Early corn’s ears changed from the small, hard, shattering variety into enormous cobs with hundreds of kernels that did not shatter on ripening. This made it very suitable as human food – the new strains were abundant and easier to harvest, transport and store. Giving up the ability to shed its own seed was a gamble for the corn as this made it totally dependent on humans for its propagation. The gamble paid off, and corn was traded from its heartland as far as Peru and Canada. Peru became an important centre for breeding and selection. Cold-tolerant strains were selected high in the Andes and tropical strains in the lowlands. Corn became the staff of life for the Inca, Aztec, Toltec and Maya civilisations, and gained immense ritual significance. Further north the Hopi people developed ceremonial corns with multicoloured cobs of white, yellow, red and black, as well as their famous blue corn. In North America, corn, beans and squash were revered as the ‘three sisters’ of agriculture. The three sisters were always grown together to protect and nurture each other, and also provided the basis for one of the best early agricultural diets.
The Spanish were the first Europeans to taste corn on their missions to the Americas in the late 1400s. They recorded the Arawak name for corn, mahiz, giving us the word maize. The Spanish took corn to Africa and Europe and it soon spread to Asia. Corn now had people working for it all over the world, clearing trees to make room for it, ploughing the ground, propagating its progeny and tending to its every need. By continually re-inventing itself to gratify humans, corn has made itself utterly indispensable to us.
There are hundreds of corn varieties grown by cultures around the world. There are strains suited to short northern summers, the monsoonal tropics and even semiarid regions. Corn varieties can be categorised into flour corns, dent corns and flint corns used for making flour and stock feed; and the more familiar sweetcorns, popcorns and baby corns.
Genetically, corns divide into open-pollinated heirloom strains or F1 hybrids. Open-pollinated strains come true to type if you save your own seed (with some care). They display a high degree of genetic diversity within each strain so they tend to be robust, adaptable plants. Heirloom sweet corns convert their sugars into starch rapidly, losing their sweetness within hours of harvest. This is not a problem for home gardeners. The age-old advice is to have the water on the boil before you go to pick your corn. Heirlooms have a wonderful ‘corny’ taste unmatched by hybrids. The F1 hybrid strains do not come true to type. Sugar-enhanced and super-sweet sweet corns fall into this category. The super-sweets have been developed to retain high sugar levels for up to ten days, allowing for transport to supermarket shelves. But they are not necessarily the best varieties for home gardeners. The super-sweets are finicky, highly-bred beasts. They are not as robust as the heirlooms, needing more water, food, heat and pest control. And they do not produce super-sweet kernels if they are pollinated by another strain. The sugar-enhanced strains are, in many ways, a good medium. Their sugars dissipate fairly rapidly, like heirlooms. But they will produce sugar-enhanced kernels even if pollinated by another strain and their kernels are very tender and can be eaten raw.
Today, corn is one of the most important crops in the world. It is the biggest crop of the world’s largest economy, the USA. The gift of corn from Native Americans enabled the colonisation of the USA, earning corn a special place in American culture. Ironically, the plant which has powered the US economy for centuries is now threatening to destabilise it.
The US currently grows 80 million acres of corn. You might think that this would be quite enough to give the US population a healthy, corn-fed glow. On the contrary, it is making them sick. For Americans do not consume corn as, well, corn. They consume it in processed forms such as food additives, bulking agents and in vast quantities as sweeteners.
In fact, ten percent of the calories America consumes come from high-fructose corn syrup. Not surprisingly, there is a national epidemic of Type-2 diabetes and obesity. Americans also consume corn as meat after it has been fed to chickens, pigs, cattle and even farmed fish. Corn-fed beef is higher in saturated fats than grass-fed, adding to the problem. It’s not great for the cattle, either. Cows are designed to eat grass, not corn, and corn-fed cattle need to be given more drugs to keep them healthy. And what about the environment? Modern F1 hybrid corns are farmed even in the desert states, sucking gargantuan amounts of water from far away rivers for irrigation. Corn requires more pesticide and fertiliser than any other crop. So much is used in the Midwest states that toxic runoff has found its way into the Mississippi River, killing a vast area of marine life in the Gulf of Mexico, thousands of kilometres away.
So much corn is grown in the US that there is a massive surplus of it. In 2002 it cost farmers US$3 to produce a bushel of corn, yet the selling price was only US$2. You might think that growing less corn would solve this problem by increasing its market value. Rather, the Bush government signed a bill to increase corn production, subsidising it to the tune of US$190 billion. The fact is that although it is sending farmers broke, making the population fat and ruining the environment, corn is simply indispensable. So many industries depend on this cheap raw material (agriculture, food, plastics, pharmaceuticals, etc) that the US economy would grind to a halt without it. Capitalism being what it is, supply must continue to outstrip demand for corn to remain so cheap. Thus, a humble grass has such a stranglehold on the US economy that the government is forced to do what the grass wants it to – expand its range ever further, distribute its genes ever wider, water it, feed it, protect it from pests and propagate the next generation.
Where will this megalomaniacal grass stop? World domination?
Alarmingly, this is a possibility. A number of genetically modified corn strains have been developed in the US. They have been engineered with pesticides built into their cell structure and immunity to herbicides. GM corn has not been approved for human consumption in the USA, but it can be used for stock feed. The US has also exported GM corn to Mexico, unlabelled, for stock feed. Unfortunately, some Mexican farmers have done with this GM grain what Mexicans have done with corn seed for thousands of years – sown it. Unwittingly, GM corn has been released into the ancestral home of corn. Corn uses wind for pollination, and its pollen can blow for many kilometres. GM corn has now contaminated dozens of ancient landraces of corn. And as we know, corn’s propensity to interbreed and mutate is unmatched. What happens if wind-borne GM pollen contaminates the recently discovered perennial teosinte (Zea diploperennis)? Will it give rise to a race of giant, bug-proof, herbicide-resistant perennial weeds? It is food for serious thought.
Perhaps I am naïve, but the last time I checked, corn was not an industry, nor a commodity, nor a cheap raw material for manufacturing and intensive farming. It is a uniquely simple food which needs nothing more complicated than tossing it into a pot of boiling water, and perhaps a knob of butter. You need to grow sweet corn yourself to get the best results, but what could be more pleasurable? The rustling leaves and creaking cornstalks, the smell of the silks as you husk the ears, and the yellow pearls of corn on the cob all take you back to those endless summer days of childhood. And it is hard to imagine anything more wholesome than that.