Assessing Wheat Freeze Injury

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Assessing Wheat Freeze Injury

• Jeff Edwards
• Oklahoma State University

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Tools you will need

• Publication C646 Spring Freeze Injury to Kansas
  Wheat
• http//www.oznet.ksu.edu/library/crpsl2/C646.PDF
• OR Google the phrase spring freeze injury to
  kansas wheat
• Utility knife or box cutter
• Magnifying glass

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• 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

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• Start by splitting stems
• Select 10 20 tillers at random locations
• Dont just split the big tillers
• Secondary tillers might still be viable even if
  main tillers are dead

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Damaged wheat head - Notice white-colored glumes
and awns - This head is a complete loss
Healthy wheat head
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Healthy wheat head
Damaged wheat head - Notice white-colored glumes
and awns - This head is a complete loss
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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
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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
turgidDamaged anthers will be yellow and
shriveled and will not pollinate.
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Healthy anthers
Injured anthers
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Healthy anthers
Injured anthers
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Healthy anthers
Injured anthers
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• 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

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