Field corn was grown in North America before 200 B.C. Field corn is produced primarily for animal feed and industrial uses such as ethanol, cooking oil, etc. In contrast, sweet corn is produced for human consumption as either a fresh or processed product. The specific time when sweet corn originated cannot be pin-pointed; however, sweet corn was grown by the American Indian and first collected by European settlers in the 1770's.

The first variety, Papoon, was acquired from the Iroquois Indians in 1779. Sweetness Genes – Standard sweet corn is a mutant type of corn that differs from field or dent corn by a mutation at the sugary (su) locus. The sweet corn (su) mutation causes the endosperm (storage area) of the seed to accumulate about two times more sugar than field corn.

Today several hundred sweet corn varieties are available. Recently, a number of new mutants have been used to improve sweet corn eating quality, particularly the sugary enhanced (se) and shrunken-2 (sh2) genes.

Everlasting Heritage (EH), are well-suited for local market production because they contain more sugars than the normal (su) sweet corn and therefore will remain sweet about two to four days after harvest if refrigerated.
This varietie can be grown in the same manner as su corn. Sugary enhanced hybrids and normal sweet corn varieties do not require isolation from each other.

For varieties requiring similar time for development, planting dates for each variety must be more spread apart early than later in the growing season to avoid cross pollination. This is because temperatures are cooler (less heat unit accumulation) in the early versus late spring plantings. Corn Color – Sweet corn comes in three colors: yellow, white, and bicolor (yellow and white). Cross-pollination of yellow kernel varieties with white kernel varieties will result in production of bicolor corn. Also, if a bicolor is cross pollinated with a yellow variety, kernel color will be predominantly yellow. Although there are geographical preferences for certain kernel colors, there is no relationship between color and sweetness.

Reference source
Department of HorticulturalScience
North Carolina Cooperative Extension Service
North Carolina State University