Wheat entering heading and flowering stage

On May 20th most wheat fields in the Fulton County area were hitting the heading stages. The wheat head is starting to pop open the sheath of the flag leaf with the wheat head emerging. The beginning of pollination or anthesis happens in 3-10 days after heading. The most mature part of the head is the center with flowering proceeding up and down the head florets until complete. For a more detailed description of wheat plant development click here.

As heads emerge farmer may note the anthers getting caught in the sheath and the head is bent or appears stuck. This phenomenon has happened over the years especially with a cool spring. Some time it is accompanied by twisted flag leaves. The picture at the left is from the spring, 2000. Often the continued emergence of the head will cause the head to break free even though it may stay bent until harvest. Pierce Paul, OSU Extension Plant Pathologist recently comment on the issue.

Wheat Heads Trapped in the Boot – Pierce Paul

Wheat in Ohio is between Feekes 9 (full flag leaf emergence) and Feekes 10.5.1 (flowering). Reports are coming in from some field going through the head emergence growth stage (Feekes 10.1-10.5) of a fairly high incidence of heads being trapped in the boot. This is not an entirely unusual occurrence in wheat fields, however, incidence as high as 20 or 50% in some cases is alarming and causing some producers to be concerned. One of the main causes of this is cold temperature. Relatively warm temperatures allow the heads to emerge quickly and easily from the leaf sheath, whereas cold temperatures slow down this process and may even prevent the heads from emerging completely, leaving them trapped by the tip. Since May 1, we have had fairly cool conditions, with an average high of 66F and low of 47F.

Fields planted with varieties that are more sensitive to cold temperatures were the ones most affected. However, this does not necessarily mean that these varieties with automatically suffer a yield reduction. Once the heads remain green and healthy and water and nutrients still travel up the stem to the spikelets, these plants will produce grain. Yield will only be affected if the heads are distorted to the point of blocking or stopping the flow of water and nutrients to the spikelets.

The last issue of the Crop Observation and Recommendation Network had a couple of good articles on head scab potential. If the weather as currently predicted for next week happens we should have a low potential for head scab. Click here for head scab articles.