Can Field Corn Pollinate With Sweet Corn?

Interbreeding

• Field corn and sweet corn are both members of the same species. Part of the definition of "species" is that members are able to interbreed. Consequently, all of the varieties of field and sweet corn are able both to cross pollinate and to produce fertile offspring. Corn interbreeds when a corn plant of one variety sheds pollen from the tassels. The wind picks up that pollen and carries it to the silk of another variety of corn. The genetic material of the two varieties intermingle in the kernels of the second plant.

What Happens

• In plants like melons or tomatoes, if two plants cross, you won't notice the effects until the next generation, when the seeds of the hybrid plant are planted and grow out. In corn, however, the effects of cross-pollination are noticeable in the corn kernels during the year the crossing took place. The gene for sweetness in sweet corn is recessive. So if sweet corn cross-pollinates with field corn, it will loose its sweetness. White sweet corn will become either yellow or bicolor. And the texture of the corn will be less tender and juicy and more like field corn.

GMOs

• According to the U.S. Food and Drug Administration, 88 percent of the corn planted in 2012 was genetically modified. So unless you live next to an organic farm, the field corn next to your garden is probably genetically modified. A study conducted at the University of Maine showed that it is possible for the genetically modified genes to appear in open-pollinated corn after cross-pollination. Taste and texture aside, if you object to GMOs in your food, you will want to take steps to keep your sweet corn from cross-pollinating with field corn.

What to do

• The best way to keep sweetcorn from cross-pollinating with field corn is to keep them apart. According to Peter Thomison of the Ohio State Department of Horticulture and Crop Science, at 12 feet, the number of outcrosses is cut in half. At 40 to 50 feet, the number is reduced by 99 percent. If you are conducting scientific research or breeding seed and if you have to be 100 percent sure that your corn doesn't cross, you need to keep it 700 feet from other corn. Another option is to isolate your corn in time. Pollen shed lasts from two to 14 days. If you can offset the tasseling time of your sweetcorn at least 14 days from the tasseling time of the field corn, the two won't cross-pollinate.