The sweetness in normal sweet corn, modified sugary sweet corn, and supersweet corn comes from different genes. Supersweet types compared to normal or modified sugary types are higher in sugar, tougher skinned, lower in starch, and retain their quality longer after harvest. The seed of supersweet types may not germinate as well as normal or modified sugary types particularly in cold soils. They also have smaller, more brittle seeds, which crack easily if mishandled. Growers should make small trial plantings initially to determine performance under specific conditions.
Genes affecting sweetness are recessive.
If varieties having these sweet genes are pollinated by varieties having the dominant forms of these genes, sweetness will be lost. Table 1 summarizes isolation requirements of the various types. Sweet corn isolation chart. If isolation space is limited, plant the most affected variety on the upwind side of the field. Separate the plantings with at least four to six border rows.