When I retired, there were basically 3 types of corn: Sweet Corn (for human consumption); Feed Corn (for animal consumption); and Grain Corn (for processing into ethanol or high fructose corn syrup).

Sweet corn was further divided into 3 types: Conventional (old style corn); Sugar Enhanced (genetically improved); and SuperSweet (further genetically improved). The Conventional corn was the kind your grandfather ate: the sugar started to disappear within an hour of picking so you got the freshest corn you could and ate it all immediately. Sugar Enhanced would last a couple days before losing sweetness. SuperSweet would hold for a week, and became the primary variety that was shipped to supermarkets because it lasted. SuperSweet corn had some disadvantages: it was a little tougher (but not much), unless it was within range of a different type, in which case it was much tougher. The range was variously reported to be between a quarter mile to a mile, so you had to know what your neighbor was planting. Since it was a pollination problem, you could separate the fields by time as well as distance since the pollination of corn is only about a week long.

Further, different varieties of corn were developed to fit various markets. Fast-developing corn ripened early to please the people who wanted the first corn of the season. IMHO, the best tasting varieties had fairly long development times (70-90 days from seed to harvest) and in the mid-atlantic region ripened in August through early September.

Corn takes a large area to grow, since it's wind pollinated (primarily) and small patches of corn generally have poor kernel filling due to limited pollination. I didn't have enough available field to grow corn so I bought it from a local farmer who did. He would try different varieties every year and picked the ones that filled his needs. His needs didn't always coincide with my taste buds, and there were some varieties that I really didn't like (e.g. corn that was grown for both sweet corn and cornstalks in the fall). The field life of a block of corn is 3-5 days, after which the kernels start to get too large and lose taste. So you have to plant two blocks of corn a week, adjusting your planting for the time to harvest. And the published time to harvest for a given variety is an average, which depends on the environment (rainfall, temperature, etc.) so sometimes blocks would double up and sometimes there would be production gaps.