By dough stage, four embryonic leaves have formed and about half of the mature kernel dry weight is now in place. Kernel abortion is much less likely once kernels have reached early dough stage, but severe stress can continue to affect eventual yield by reducing kernel weight. Kernel moisture content is approximately 70 percent. About 35 to 42 days after silking, all or nearly all of the kernels are denting near their crowns. A distinct horizontal line appears near the dent end of the kernel and slowly progresses to the tip end of the kernel over the next 3 weeks or so.
Severe stress can continue to limit kernel dry weight accumulation.
Kernel moisture content at the beginning of the dent stage is approximately 55 percent. Physiological maturity occurs shortly after the kernel milk line disappears and just before the kernel black layer forms at the tip of the kernels. Kernel moisture content at physiological maturity averages 30 percent, but can vary from 25 to 40 percent grain moisture. While not strictly a stage of grain development, harvest maturity is often defined as that grain moisture content where harvest can occur with minimal kernel damage and mechanical harvest loss. Harvest maturity is usually considered to be near 25 percent grain moisture.