Corn has a storied and prominent place in human history.
Early farmers first domesticated it 10,000 years ago in what is now Mexico. People began planting and breeding teosinte – the ancestor of modern-day corn.
Teosinte looks nothing like modern corn. A wild grass, the cob is only 19 millimeters long, and the five to 10 kernels are tough, requiring repeated hammering with a hard object to break open. Once open the kernels are dry and taste like raw potato, according to James Kennedy, a chemistry professor in Australia who has studied the plant’s evolution.
For thousands of years farmers started selecting and saving teosinte kernels with desirable qualities: They were sweeter, more tender and grew larger. By 4000 B.C. corncobs were already an inch long.
Modern-day corn is roughly 1,000 times larger than its ancient ancestor. For years the ancestry of corn was unclear. Corn, as modern humans know it, doesn’t grow in the wild. But in the 1930s, George Beadle discovered that teosinte and modern corn’s chromosomes are compatible.
In fact, teosinte can be bred with modern corn varieties to create viable teosinte-corn hybrids.
As more corn was bred by Native American farmers, they noticed that some were sweeter than others.
Sweet corn is the result of a recessive mutation in genes that control the conversion of sugar to starch. Native American tribes introduced it to European conquerors.
More recently, super sweet corn was developed in the early 1950s by a University of Illinois botany professor named John Laughnan.
Laughnan discovered that a certain gene in corn stored less starch but held four to 10 times more sugar.
Today, sweet corn is used throughout the food processing industry and in the fresh food market. Modern super sweet varieties can be as much as 40 percent sugar.
Corn continues to change today, with new varieties being tested regularly by breeders and seed growers. Researchers hope to develop disease- and drought-resistant varieties in addition to other favorable attributes.
Corn is the No. 1 crop grown in the United States, with roughly 15.1 million bushels grown nationwide in 2016. Most of that corn is used in the production of ethanol. In fact, most corn grown in the United States is not directly consumed by people. It’s either used for industrial purposes, turned into high-fructose corn syrup or fed to cattle.
The corn used for those purposes is known as field corn. Unlike sweet corn, field corn is harvested after it’s dried. The kernels are hard and the high starch and low sugar content makes it unappetizing.
Lead photo credit: A stalk of teosinte. Each kernel has a hard case over it that has to be removed before eating. Modern sweet corn lost the ability to survive in the wild, but gained valuable agricultural traits, such as larger ears of corn, but fewer lower number of ears per plan. (Shutterstock / Shutterstock)