The National Garden Bureau (NGB) has selected sweet corn as the vegetable of honor for the year 2000 and has provided a fascinating history of the plant, as well. The origin of maize&emdash;what Americans call corn&emdash;has been traced to Mexico, with the oldest-known remains dated at 7,000 years old. The oldest corn cob found so far was dated from 5000 B.C. and was still enclosed in its husk. Maize remnants have been found in the United States dated more than 700 years old. American Indians grew many different types of maize, and Christopher Columbus is credited with bringing maize back to Spain when he returned there in 1493.
The first recorded sweet corn was collected in 1779 by the Iroquois Indians in what is now Pennsylvania. The variety Papoon, a white kerneled corn, was the first colonial sweet corn to be established in New England. The first known seed source for home gardeners was listed in a Connecticut company’s catalog in 1821 as sugar corn. Early American gardeners usually raised white sweet corn, probably because it was more available. But in 1902, the variety Golden Bantam changed the color choice to yellow. Golden Bantam is still available from many of today’s seed companies. While some changes due to natural selection and mutation may have occurred since its introduction, Golden Bantam is no doubt still very similar to its original form.
Sweet corn has received more attention from breeders than most other vegetables combined, or so it seems. The genetic knowledge of corn has advanced to a very sophisticated technology. Plant geneticists have been able to locate and single out specific genes on specific chromosomes that control specific plant characteristics. Plant breeders can now manipulate these genes to come up with an end product that has been engineered for certain desired characteristics.
Modern sweet corn cultivars have been bred to have greater sugar content and a slower conversion of that sugar to starch. This not only means sweeter produce, but also the ability to hold that quality longer, whether it is in the supermarket, in your garden or in your refrigerator. Sweet corn generally comes in one of three types. Standard sweet corn, whose sweetness gene is designated (su); supersweet, whose sweetness gene causes shrunken kernels upon drying and is designated (sh2); and sugary enhanced, designated as (se). The (sh2) types must be isolated from all other types of corn to ensure the super sweet quality. Because of their tendency to have shrunken kernels, they are most sensitive to cold soils and planting depth, and, therefore, must generally be planted a little later in the season.
The (se) types are generally more tender, and though they perform best in isolation, it is not as critical. In addition, the (se) types do not require any special handling and can be grown much like standard sweet corn. Other improvements of late include earlier days to harvest and edible ornamental corn, such as the new ‘Indian Summer’ that has yellow, white, red and purple kernels all on the same ear, yet is still sweet and tender. There’s also a solid, bright red sweet corn called ‘Ruby Queen.’
Corn is one of the four most-important agricultural crops produced in the world, so you can expect more great strides in corn breeding in the years to come.