Corn plants have both male and female parts on each plant. Weather and insects both have an impact on the pollination process.
The pollen shed of corn
The female part of the corn is on the ear and the male part is on the tassel. The male part sends out the pollen when the corn matures. The tassel emerges from the corn husks at this time. After it is completely emerged, the pollen is released. There are holes in the anthers that release the pollen from the tassel. The middle of the tassel in the central spike is the first place to shed pollen. This usually occurs between 9 a.m. and 11 a.m. If the weather is cloudy, cool or wet, the pollen shed will be delayed. For an entire field of corn, the pollen release process can last two weeks. The process continues and spreads to the lower branches. Pollen is shed by each anther for three minutes. The entire pollen shed starts a few days before the silk emerges. The peak period is the third day, with the shed completing in five to eight days. Each tassel contains two to five million grains of pollen.
The silk elongation of corn
The female parts on the corn plant are located in the kernel and the silk. The kernel contains the ovule and the stigma is in the silk. Silk elongation needs to occur for the plant to be pollinated. This process begins seven to ten days before the silk comes out of the husk of corn. Each kernel of corn on the ear has a piece of silk that it creates. That silk strand is then pollinated by the pollen released from the tassel. If the silk is not pollinated, the kernel of corn will not develop. Each shoot of corn has between 750 and 1,000 kernels to be fertilized. If all of the silk develops properly, they will be ready to pollinated within a three- to five-day period during the pollen shed period.
The pollen from the anthers is released as soon as the dew on the tassels dries out. Traveling up to 600 feet, the pollen is carried by the wind. Usually the pollen will spread between 20 and 50 feet from the plant of its origin. If the tassel is wet or dry or cold, the shedding stops; therefore there is no risk of the pollen being washed off the silk by rain, as no shedding happens during those times. When the pollen lands on the silk, a tube with the genes from the pollen is grown inside the silk. Sticky hairs on the silk catch the pollen. A plant's own pollen does not usually pollinate its silk. In a field of corn, it is expected that 97 percent of the kernels will pollinate.