By Matt Hutcheson, CCA, Soybean Lead/Field Agronomist, Seed Consultants, Inc.
One common issue observed and discussed during the 2023 growing season is poor tip fill, or tip-back in corn ears. A lack of kernel development at the tip of the ear can be cause for concern among growers. Keep in mind that any stress right before and during pollination can significantly impact kernel development. If you have scouted your corn fields late in the growing season and have noticed tip back, there are several factors that could be the cause:
• Pollination— if kernels did not develop at all near the tip of the ear, this is a sign of a pollination problem. The silks at the tip of the ear emerge last and stress at pollination can significantly impact them. Heat and drought stress can cause a lack of viable pollen as well as delayed silk emergence, resulting in no kernel development at the tip of the ear. Insect clipping of silks can also impact pollination and kernel development at the tip of the ear.
• Kernel Abortion — If it is evident that pollination was successful, but the ear developed small or shriveled kernels at the ear tip, kernels were aborted during the grain fill process. Several factors can lead to kernel abortion, such as: nutrient deficiencies, drought, severe cases of foliar disease (GLS, NCLB, tar spot, etc.), and significant plant defoliation as a result of hail damage. All these stressors ultimately impact the corn plant’s ability to carry out photosynthesis and can result in aborted kernels.
In some cases, tip back may not be a result of a problem or stress and may not indicate low yields. As discussed often by agronomists, ear size is determined early in the season during the plant’s vegetative growth period. If very favorable growing conditions exist during the V6 to V12 stage, the number of kernels per row may be unusually high. In this case, if the plant cannot fill out the entire length of the ear, some tip back may occur but there may still be high yields.