Waxy Corn Testing

Corn Services

Waxy corn kernels

Method

Waxy purity can be determined by counting two replications of 100 kernels, moistening them overnight, and then cutting off a small portion from the crown end of the kernel. The kernels are sprayed with a 0.5% iodine solution.

Waxy corn can also be examined over a light table, light passes through the dent kernels and the waxy kernels appear darker or opaque. Questionable kernels can be tested with iodine for reactions by slicing off pericarp and small amount of starch on the “crown end” of the kernel. We then touch a drop of iodine to starch and determine color (brown = waxy, purple = non waxy).

What is Reported

Waxy corn contains nearly 100% amylopectin starch which turns a brownish color temporarily after exposure to iodine. However, corn that contains amylose starch stains a blue or violet color which remains permanently.

Value of Results

Both the idodine test and the transmitted light test provide client with the waxy kernel percentage, which establishes the hybrid purity for the waxy trait.