Detect Ear-fill Problems
Corn pollination is fast approaching and it is an extremely important stage in the plant’s lifecycle. Up to this point the corn plant has been determining its yield potential. The kernels to be fertilized are set at this point and it is up to pollination to finish the process to begin seed development.
Preceeding pollination, the VT stage occurs after 1,100 Growing Degree Days have accumulated. The tassel will be fully visible from the top whorl of the plant. The tassel branches are extended and the anthers are lowered to begin to release pollen (anthesis). The length of pollination can vary in the field but normally lasts for a week or more. Peak pollen shed lasts about four days and individual plants can release over one-half million pollen grains per day at this time! That is a lot of pollen!
During the R1 stage, silks are extended outside the husks of the ear. This is a critical point in the plant’s lifecyle. The ‘magic’ of pollination and fertilization take place so any stress to the plant can negatively affect yield.
Understanding how the silks grow and pollinate can help diagnose ear-fill problems. Pollination occurs when a pollen grain actually attaches to the silk. Fertilization follows about 24 hours later, when the pollen and ovary join to produce an embryo. Silks emerge from the husks at the butt of the ear and continue growing toward the tip until they are pollinated. When ear tips do not become pollinated it may be due to a lack of pollen shed at that time. Long silks may indicate late pollination of the field.
During the R1 stage, the plant has great nutrient needs. The vegetative growth of the plant is now complete but the grainfill period is beginning and N & P uptake is at its highest level. Physical damage to the plant from hail or wind at VT or R1 can hurt yields by leaving kernels un-pollinated. Insect feeding of the silks, normally by adult corn rootworm beetles, is another way yield may be reduced by poor pollination.
Understanding the basics of pollination is important when scouting your fields at this time of year. Make notes as you scout so you’re able to better identify causes of any ear problems that may show up at harvest. And have fun while you’re scouting. Corn is a beautiful crop to scout!
