Cross Pollination from Genetically Engineered Corn: Wind Transport and Seed Source

Organic producers, particularly dairy and sweet corn growers, fear losing their organic certification if genetically engineered (GE) proteins are found in their corn (Zea mays L.). Although corn pollen grains are among the largest and heaviest of wind-pollinated plants (Smith, 1990), transport is possible. Corn is a monoecious plant with male and female flowers borne on separate parts of the plant. Pollen shed generally occurs over the course of a week, but may last from 2 to 14 days; a majority of the pollen will be shed around the third day (Purseglove, 1972). Corn produces abundant pollen (2 – 5 million grains plant (Goss, 1968; Kiesselbach, 1948)), and environmental conditions (temperature, wind speed, and wind direction) affect the likelihood of cross-pollination. Reports of pollen viability vary. Pollen may remain viable for 24 hours (Purseglove, 1972), but could be much shorter in hot weather. Cool temperatures and relatively high relative humidity tend to increase pollen viability.