1. Assessing Wheat Freeze Injury
Jeff Edwards
Oklahoma State University

2. Tools you will need
Publication C646 Spring Freeze Injury to Kansas Wheat
OR Google the phrase “spring freeze injury to kansas wheat”
Utility knife or box cutter
Magnifying glass

3. Looking at smaller wheat
Generally the head is dead or fine – no in between
Also important to look at the nodes to see if they are split or brown-colored
A damaged node now will likely mean lodging later on

4. Start by splitting stems
Select 10 – 20 tillers at random locations
Don’t just split the big tillers
Secondary tillers might still be viable even if main tillers are dead

5. - Notice white-colored glumes and awns
Damaged wheat head
- Notice white-colored glumes and awns
- This head is a complete loss
Healthy wheat head

6. - Notice white-colored glumes and awns
Healthy wheat head
Damaged wheat head
- Notice white-colored glumes and awns
- This head is a complete loss

7. Larger wheat
Large wheat/tillers can have partial head sterility or complete losses
The heads to the right are only injured on the tip and will fill grain in the remainder of the wheat head
Depending on the amount of time that has passed, you may have to look at the anthers to determine the extent of damage

8. Examining anthers
Florets in the center of the head should be the most advanced, so examine these first
Peel back the glumes until you find the anthers at the base of the floret. This can be tricky and you will likely need a hand lens.
Healthy anthers (as shown in the picture on the right) should be green in color and turgid Damaged anthers will be yellow and shriveled and will not pollinate.

9. Healthy anthers
Injured anthers

10. Healthy anthers
Injured anthers

11. Healthy anthers
Injured anthers

12. Check every field!!
Variety, planting date, and management will all affect maturity
More advanced wheat will have more damage (e.g. Overley below)
Some wheat may have only partial damage (e.g. Fuller below)
A few days difference in maturity can have a huge impact on freeze injury

13. Check every field!!
In some cases, secondary tillers may still be viable
If favorable weather occurs, these can still produce some yield