The first corn hybrids for farm use were produced in the 1920s, but until the 1940s most farmers still were growing open-pollinated (OP) varieties. In very short-season areas, the OPs were flints because of their tolerance to cool, wet spring conditions and requirement for fewer heat units to reach harvestable maturity. But the most corn acreage by far was planted to OPs from a new race of corn, Corn Belt Dent, that arose somewhat serendipitously during the early decades of the 1800s.
During that period, farmers in the mid-maturity areas of the U.S. favored growing OPs of the Southern Dent race because of their high-yield potential. But often, seed quality was poor because of immaturity at harvest, resulting in poor stands in the following spring. Farmers would replant gaps with early maturing OPs of the Northern Flint race.
Natural crossing between the Southern Dent and Northern Flint OPs resulted in “inter-varietal” hybrids that farmers quickly noted were superior to either of the parents. Farmer selection in Corn Belt Dent created hundreds of OP varieties, some of which became widely disseminated because of their preeminence in the popular corn shows of the late 19th and early 20th centuries. (Full Story)