Early Planted Corn with "fused coleoptile or bursting on side"

 

In 2011, the U of I Plant Clinic received several corn seedling samples that appeared to have a "fused coleoptile or bursting on side".  In addition, the roots appeared to be "bottle-brushed". This corn had been planted the first week of May and unfortunately, 2 weeks later, experienced cold temperatures.

I am starting to see similar symptoms again this year in 2012:

The plants did not appear to have any disease or insect damage.  The root tissue appeared healthy, but some of the roots of the plants were sparse and appeared to have "bottle-brushed" symptoms.

There are several factors or a combination of conditions that could be causing these symptoms:

   1.)  Cold imbibhition can cause a "cork screw symptoms".  Cold injury has also been linked to ""fused coleoptile or bursting on side".  Here is a link that describes cold injury to corn in depth:

http://www.grains.cses.vt.edu/publications/Diagnosing%20Chilling%20and%20Flooding%20Injury%20to%20Corn%20Prior%20to%20Emergence.pdf

2.)  Cloroacetamide herbicide (Dual, Harness, Outlook, Surpass, Bicep) can also cause twisting of the seedling shoot. However, these herbicides are not widely used at this time and these herbicides were not known to be applied in these corn fields.

I suspected that cold temperatures and wet soils could be part of this problem, but I did not like the look of the roots of some of the corn seedlings in the sample.

Pictures of one of the corn samples (similar to those of the pictures above) were sent to Dr. Emerson Nafziger.  Here are comments from Dr. Emerson Nafziger:

"While I think cool temperatures may have contributed, seed mechanical damage and herbicide can both cause symptoms like this, and it makes sense that these factors might have worked together. Checking other fields with this same seed lot planted at the same time may indicate if seed was part of the problem.

The roots do look somewhat odd, and seem to lack the proliferation we would normally see. That could be partly due to herbicide, but I suspect that cool-then-warm soil temperatures might have contributed as well. Comparing nearby fields planted at the same time might indicate temperature effects more clearly, but I doubt that by itself this contributes much to the problem."

Could genetics along with the cold/wet temperatures play a role in this problem?