Detect ear-fill problems

Corn pollination is fast approaching, and it is an extremely important stage in the plant’s life cycle. 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 and begin seed development.

Preceding 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 it 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!

Key Points

Corn will likely soon begin its pollination process.

The peak pollen shed occurs over about four days.

Scouting now can help identify causes of ear problems that will be visible later.

During the R1 stage, silks are extended outside the husks of the ear. This is a critical point in the plant’s life cycle when the “magic” of pollination and fertilization take place. Any stress to the plant during this time can negatively affect yield.

Understanding pollination

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 grain-fill period is beginning, and nitrogen and phosphorus 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 unpollinated. 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.

Spelhaug is an agronomist with Peterson Farms Seed, Harwood, N.D. For more information, contact him at 866-481-7333, or adam@peterson

This article published in the July, 2011 edition of DAKOTA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.