Facts About Open-Pollinated Corn

Corn Reproduction

• Corn is a monoecious plant, meaning that each corn plant has separate male and female flowers. The ears, which we eventually eat, are the female flowers. The male flower is the tassel at the very top of the corn plant.

  Corn reproduces to make seeds (the kernels we eat) by pollinating the female ears with pollen from the male tassels. Throughout most of history, this has been accomplished by open pollination: wind blows the corn pollen from each tassel over a broad area of the field, pollinating the ears of many different plants.

Open Pollination Advantages

• Corn evolved open pollination because of its advantage in creating genetic diversity. In a field of corn using open pollination, each male flower pollinates a number of other, unrelated plants. This meant that each cornfield was full of genetic diversity -- even though the plants look similar, each one was genetically unique. This makes an open-pollinated cornfield more resistant to pests, drought and disease, because the population can evolve over each generation. The seeds of open-pollinated corn reproduce true: in other words, if you plant a kernel from an open-pollinated corn plant, it will grow to be just like its parents.

The Rise of Hybrids

• If you plant the corn kernels from the corn you buy in the supermarket, chances are they won't grow at all -- or if they do, they won't create a plant with the same characteristics of the parent. That's because most corn grown today is what's called hybrid corn.

  Hybrid corn was developed in the 1930s by scientists combating one of the disadvantages of open pollination. While open pollination is good for creating genetic diversity, it also makes selective breeding very difficult. In an open-pollination cornfield, farmers have no control over which male plants pollinate which female plants.

  In the 1930s, scientists began controlled inbreeding of corn plants. They took high-producing plants and self-pollinated them with the male flowers of the same plant. This allowed the creation of pure lines, selected for specific traits such as the size of the ears, resistance to pests, or fast growth. These inbred lines were then hybridized to create the varieties of corn that dominate the market today.

Monoculture Concerns and the Return to Open Pollination

• By 1960, 96 percent of corn acreage was planted with hybrid corn varieties. These varieties are vastly more productive than traditional open-pollinated lines; productivity per acre grew fourfold from 1930 to 1980.

  Some farmers have become uncomfortable with the rise of "monoculture" agriculture, in which vast fields are planted with genetically identical plants created through genetic modification. Modern corn varieties are often owned and patented by multinational corporations and are deliberately designed to create sterile seeds. This forces the farmer to purchase seeds from the corporation year after year, rather than simply reserving part of the harvest to be planted the following year.

  Farmers also worry that the lack of genetic diversity could make the hybrid corn susceptible to devastation by disease or pests. In addition, the long-term effects of genetic modification on both corn and the animals that consume it are unknown.

  For all these reasons, open-pollinated corn has enjoyed a resurgence in use, especially among small producers.