Part 1, Section 4: Corn
Corn
TYPES
High-oil corn
While normal dent corn contains 3.5 to 4.5 percent oil, commercial high-oil types contain as much as 1.5 times this amount. Commercial high-oil corn hybrids have not been widely used because their yield potential is lower than that of normal hybrids. Recently, however, an alternative system for producing high-oil corn has been developed. It involves planting a blend consisting of about 92 percent of an adapted but male-sterile hybrid and about 8 percent of a special high-oil pollinator line. The pollen shed by these pollinator plants carries a special gene that causes a kernel to produce a much larger germ or embryo. Pollen from these plants pollinates the entire field, resulting in higher oil and protein in the grain on adapted hybrid plants.
This system of producing high-oil corn was developed by DuPont and is known as the Topcross system. Because the yield of the pollinator plants is low and pollination is dependent on 8 percent of the plants, some concern exists about the yield potential of these blends compared to normal fertile hybrids. Initial testing has shown that yields of the high-oil blends are 90 to 100 percent of those of their normal counterparts. Testing these blends is difficult, since they have to be isolated from normal corn and thus cannot be tested in conventional strip tests or small plot evaluations. Grain from these blends contains about 7 to 7.5 percent oil compared to 3.5 to 4 percent for normal corn; slightly more protein, lysine, and metabolizable energy than normal corn; and less starch than normal corn.