How Kernel Set Relates to Yield

  • Aug 20
    Danielle MacCallum
    How Kernel Set Relates to Yield By Danielle MacCallum on August 20, 2021
    Categories: Grain Corn

    The corn plants are at a very critical time right now in Western Canada. Most tassels have emerged (VT stage), and the pollination/silking process (R1 stage) has started.

    A corn plant drops pollen from the tassel to pollinate ear silks, and there is one silk for every kernel on a corn ear. A captured pollen grain takes about 24 hours to grow down the silk to the ovule where fertilization occurs, causing the ovule to become a kernel. Generally, 2–3 days are required for all silks on a single ear to be exposed and pollinated. Individual silks are able to receive pollen up to 10 days after the silks first emerge. The silks will continue to elongate until fertilized or will die after a prolonged period of time. The pollen tube will collapse, which restricts any further pollination; this is also what happens when a corn plant is under extreme stress, such as during very hot, dry weather.

    Pollen shed. 
    Photo: Danielle MacCallum

    It is very important to have the silks emerged at the same time that pollen is being shed. Because there is such a small window for the kernels to be pollinated, you want to see the synchronicity between these two events. If the corn experiences severe drought stress or incomplete emergence of silks, this can shorten the pollination window even more. When there is less time or silks to pollinate, fewer kernels will be set on the ear, and there will be a reduction in grain yield.

    Webinar screenshot, March 2021.
    University of Saskatchewan

    Grain yield is important for all corn growers, regardless of your end use. Grain growers want to achieve the highest kernel set on each ear possible to get the best yield/ac. Higher yield equals higher return. Silage and grazing growers want a high kernel set because the kernel accounts for almost 50% of the nutritional dry matter content. A reduction in yield will have a huge effect on the nutritional content of corn, which could lead to extra costs for supplements and a shorter length of time for feed.

    Unfortunately, there is little that can be done from the grower’s standpoint during this time except to watch. Once kernel set has completed, scouting your fields to see what the ears look like will start to give you an idea of what your end yield will be.