By Andi Anderson
Corn plants produce both male and female flowers on the same plant, making them monoecious. The tassel represents the male flower, while silks on the ears serve as the female structure.
Successful pollination during tassel emergence (VT stage) and pollen shed greatly affects corn grain yield.
VT, or tasseling stage, occurs when the final tassel branch is fully visible. Interestingly, modern hybrids often begin silk emergence (R1) before tassels fully emerge, challenging traditional stage definitions.
At this point, the plant also reaches full height and becomes highly vulnerable to hail damage — 100% defoliation can cause total yield loss, even if pollination succeeds.
Each tassel contains about 1,000 spikelets, with each spikelet holding two florets and three anthers. Anthers release pollen that is carried by wind to silks for fertilization. A single tassel can produce 2 to 25 million pollen grains, though each pollen grain survives only a few minutes after release.
Pollen shed starts in the middle of the tassel and spreads up and down. Most shedding occurs mid-morning, especially under dry conditions.
Rain or heavy dew delays shedding, while extreme heat can reduce pollen viability. However, the staggered release over several days helps protect pollination against short-term stress.
In hybrid seed production, male and female inbreds are managed to control pollination. Sometimes, female lines are genetically altered using cytoplasmic male sterility (CMS) to avoid the need for detasseling.
Although CMS plants do not produce viable pollen, restorer genes or seed blending ensure proper field pollination.
Understanding tassel biology, pollen behavior, and environmental impacts on these stages is critical for maximizing corn yield and managing risk in the field.
Photo Credit: gettyimages-luc-pouliot
Categories: Indiana, Crops, Corn