Why isn’t “My Favorite Number” in the test?
Because it wasn’t selected as a widely-grown entry, and the supplier didn’t submit it as a paid entry. If you’d like to see it in the test, contact your
seed dealer or the company’s research director and ask him or her to enter it next season.
How do you select the varieties/hybrids you test?
We test a number of “widely-grown” varieties as a means of lending some continuity to tests across districts and years. Widely-grown varieties are selected
through consultation with market research and seed company personnel. Widely-grown varieties are tested without charge to the company providing the seed.
All other varieties are submitted by seed companies and genetic suppliers. If a corn hybrid or soybean variety is available for sale in Iowa, it is eligible
to be entered into our tests.
Why isn’t there a conventional herbicide test in the soybeans?
At the time of our application deadline there was only one conventional herbicide soybean entered in our tests. Therefore we had to cancel that test for
this season. If companies submit more conventional varieties in the future, we will resume testing them.
Why did you discontinue the separate test for short-stature hybrids?
Several reasons led us to drop the short hybrid test from our program. The number of hybrids entered in that test had been decreasing over the past few
years. In 2005 we had to add several filler entries just to get an entry list up to 10 or 20 hybrids. Also, there is no clearly objective way to distinguish
a short hybrid from a medium-height hybrid, since the growing season can have a substantial impact on the mature height of many genotypes. This led to
several hybrids in the test that really did not belong in a short test. Finally, the short test was initiated when the program was testing in 2-row plots.
Since that time we’ve changed to 4-row plots, but harvest only the center 2 rows for data. Our data show there are no significant yield reductions for
short hybrids among tall hybrids in this scenario.
Why the new district lines?
This was done as a way to help consolidate testing strategies between the corn and soybean tests, simplify the description and explanation of the districts,
and provide more consistent inference spaces for our data.
Why did you discontinue the protein, oil, and starch measurements in corn?
The time and expense associated with those data were too great when compared to the benefits of the information. While we still believe this information
is important for growers, we did not detect that growers were making hybrid selection decisions based on these factors. Therefore we decided to concentrate
our efforts on data that growers ARE using for selection decisions, and let other sources provide the grain quality data.
What are “phantom brands”?
Phantom brands are brand names that get entered into our test, but aren’t available for sale to growers. In most cases the brand names are legitimate,
legal entities. They just aren’t used for seed sold to growers. Because of this, we are doing are best to eliminate phantom brands from our test. If you
have knowledge of phantom brands in the test, please let us know.
Can a company overload a test with varieties or hybrids to guarantee a winner?
Companies are limited to 6 varieties or hybrids per test. It’s important to note that the number of varieties or hybrids entered by a company isn’t necessarily
related to the chances of having the top in a test. As an example, let’s say that Corn Company A has 6 hybrids in a 50-entry test, while Corn Company
B has only 1 hybrid in the same test. Who has a better chance of winning? Many people assume Corn Company A has a 6-fold greater chance of winning the
test, but this is not correct. The only way for this to be true is if ALL THE HYBRIDS IN THE TEST HAVE EQUAL YIELD POTENTIAL. This is clearly not the
case, and it’s why there is value in variety trials. So which company has a better chance of winning the test? The one with the best hybrid for the region(s)
in which we’re testing.
In what types of environments do you grow your plots?
We try to find locations that are representative of the regions in which we grow tests. Other than that, our main criterion is to find an area that is
relatively uniform in soil type, slope, and drainage. Because of manpower and monetary constraints, it is impossible for us to test on every available
soil type. Fortunately, this does not reduce the importance or the applicability of the data.
If the test isn’t grown on my farm, or on my soil type, are the data applicable to my field?
Yes! Many studies have been done to interpret the usefulness of yield trials to predict variety performance the following season. The results of nearly
all of these studies indicate that the more information you have, the more reliable the predictive values will be. This means that data collected from
multiple replications at multiple locations are more valuable than data from a single site. In fact, data from 3 locations within your region are more
reliable than data from a test plot in your own field!