Types
Yellow and white dent, brown midrib, waxy, high-lysine, high-oil, sweet, and pop are examples of corn types grown in Pennsylvania. Each has unique characteristics that affect its use and, in some cases, how it is grown. Of these, yellow dent and brown midrib are the most popular in Pennsylvania.
Yellow Dent Corn
Most of the corn crop in the United States is yellow dent. Its vitamin A content, high feed value, and availability of adapted superior hybrids account for its extensive use. Of the cereal grains, it contains the highest content of carotene (vitamin A). Dent corn originated from crosses of flint and floury corns. Dent hybrids vary in the proportion of hard and soft endosperm.
Brown Midrib Corn
Brown midrib plants are characterized by a brown pigmentation in the leaf midrib at the V4 to V6 stage and a light brown coloration of the pith after tasseling. Brown midrib hybrid contains a gene (bm3) that causes a lower lignin content in corn plant tissue. Lignin is a relatively indigestible compound that limits the digestibility of the fiber in the corn plant. The reduced lignin in brown midrib corn results in silage with fiber that is more digestible than normal corn.
Animal feeding trials have shown about 10 percent greater intake and increased milk production with brown midrib silage, as compared to normal silage. Brown midrib lines frequently have been low yielding, however, and have had poor standability if left for grain production. Although recently released brown midrib hybrids have improved these features, they still are lower than those of comparable normal hybrids. In our trials, brown midrib lines have yielded about 10 to 15 percent lower than conventional hybrids in fields where they are best adapted. When considering a brown midrib corn planting, growers should weigh the potential for improved milk or animal gains, which can be significant, against the higher production costs and lower yields per acre. New brown midrib hybrids can contain several bio-tech traits that are improving the stress tolerance of these lines.
