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"So it looks like resistance to high temperature may well be a
genetically controlled trait," said Steven Eckhoff, U of I
agricultural and biological engineer. This means hybrids might be
developed that can be dried at high temperatures -- a clear economic
advantage for producers.
"As a producer, I want to dry my corn at as high a temperature as
I'm allowed to use," Eckhoff said. "The higher I can dry at, the
faster my throughput is, the lower my cost.
"I call drying temperature the wild card in terms of grain
quality," he added. "You can do everything else right, but your work
can be destroyed in an instant with too high of a drying
temperature."
The goal of Eckhoff's research is to determine the magnitude of
the effect of drying temperature on starch extractability and to
determine if sensitivity to drying temperature varies by hybrid. For
his study Eckhoff chose 12 hybrids in cooperation with researchers
at Pioneer's Champaign Research Center.
Moisture content of the corn plays an equally important part in
this process, so corn harvested at 35 percent and 22 percent
moisture content was dried at temperatures of 230 F and 77 F.
"We found that the responses were different for different
hybrids," he said.
Starch yield loss was highest when corn with high moisture
content was dried at high temperatures. But the loss ranged from 4.6
percent to 12.7 percent, depending upon the hybrid.
Although drying corn with low moisture content at low
temperatures proved best for starch extractability, when certain
hybrids with low moisture content were dried at both high and low
temperatures, starch extractability was comparable.
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This research shows promise for developing hybrids that can be
dried at higher temperatures. The next step is to look at the effect
of drying at multiple (15-25) locations to determine how much this
characteristic is influenced by environment and how much is
genetics. But coordinating such a large study poses its share of
logistics problems, Eckhoff said.
"You have one shot at drying every year," he explained. "You want
to bring in samples from multiple locations, and you have to have
enough dryers to dry them all down about the same time. Coordinating
that is almost impossible."
So Eckhoff set out to make an inexpensive dryer that could be
used on location at farms and test fields. He attached a standard
funnel to the barrel of a commercial heat gun, using black pipe. A
mesh screen, stretched across the top of the funnel, holds several
layers of corn. A thermocouple is placed directly below the corn and
is attached to a data recorder, to read and record the temperature.
After trying several heat guns, he found one that had a fairly
sensitive temperature control. Researchers were able to keep the
temperature stable and use it for sample preparation.
"It still needs to be worked on, but it's not bad," said Eckhoff.
"And it gave us samples of 600 to 700 grams, which was plenty for
the starch yield testing we needed to do."
The system certainly paid off in terms of results. "We think this
research shows there is potential to produce high-yielding hybrids
that have high starch extractability at a high drying temperature,"
Eckhoff concluded. "That would be the best of all worlds."
[News release from the
University of Illinois College
of Agricultural, Consumer and Environmental Sciences]
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