Sweet corn (Zea mays var. saccharata or rugosa) is an annual VEGETABLE of the grass family. It is the result of a genetic mutation (in dent corn) which appeared in the US early in the 19th century. The genetic change prevents sugar in the kernels from being converted into starch; hence, the sweet taste. Otherwise, sweet corn is identical to field corn. In Canada and the US, sweet corn is an important vegetable, eaten fresh (on the cob) or stored canned or frozen (on or off the cob).
Sweet corn requires at least 10°C for germination; its growth is progressively better up to 35°C. Sweet corn requires 60-100 days to reach maturity, depending on cultivar and locality. The newest hybrids have been bred for additional sugar and for slower conversion of sugar into starch (to prolong the period of high quality). Hybrids make it possible to grow sweet corn in regions where the temperatures at harvest time would otherwise be too high. Harvesting is done by hand for the fresh market, by mechanical harvesters for the canning industry. Canada has about 60 000 ha of sweet corn planted annually; this represents more than 25% of the whole surface cultivated for vegetables.