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Corn+Soybean Digest

Dig Into Demo Plots

When you look at corn hybrid demonstration plots, do you only see gigantic ears or do you step beyond the seed company signs? Stepping into the plots and examining the corn could reveal some strengths or weaknesses you didn't see at the first stalk.

“A big flex ear has eye appeal but may be due to how dense the population is,” says Peter Thomison, Ohio State University extension agronomist. “The larger ears may be due to lower populations.”

Examining demo plots pays in several ways. In fact, most hybrids are only on the market for a few years and university trials don't cover all the characteristics.

“It's hard for us to get an in-depth assessment,” Thomison says. After three to four years, only about 10% of the hybrids are still in the trials.

Ohio farmer Joe Garland looks closely at grain quality and husk coverage — traits not covered in the state trials. For example, husk coverage is critical because the earliest-planted corn is some of the first birds feed on, he says.

“The first 30% of the corn planted had some damage,” Garland says about 2003. “If the tip of the ear is sticking up, you can definitely see if there's been bird damage.”

By planting plots on land he farms with his brothers, Chris and Jim, Garland can compare such things as husk coverage.

Ears that remain upright and stick out from husks are more susceptible to insects and birds, adds Thomison. He also suggests looking at husk tightness; husks that stay tight around the ear can delay drydown.

Thomison suggests that growers avoid hybrids that set ears high — 5 ft. or higher on the stalk. “Some of these hybrids will yield well, but will be more prone to lodging at high plant populations,” he says. Also, remember that later-maturing hybrids are often taller than earlier-maturing ones.

Plots can be a good place to look for stalk rot, too. Check plants in late August or about six weeks after pollination. He says to pinch the lower stalk internodes with your thumb and forefinger. Stalks that collapse easily are a sure sign of stalk rot.

Staygreen is another characteristic to examine. Staygreen is often associated with better plant health. However, hybrids that look healthiest and green may be more immature.

To find out whether corn is mature, break ears in two and look at kernel milk line development. If a hybrid is truly staygreen, stalks and some leaves will still be green but corn will generally reach black layer at the same time as non-staygreen hybrids of comparable maturity, Thomison points out.

Demo plots can also indicate localized problems. Green snap or brittle snap problems usually hit a localized area when windstorms come prior to pollination. European corn borer and western corn root-worm are other localized problems. Demonstration plots can also be used to compare Bt hybrids.

Think about the plots' soil type, drainage and weather. The variability in fields can account for a 10- to 50-bu./acre yield difference, Thomison says. Be wary of strip plots that aren't replicated and have only one check or tester inserted between every five to 10 hybrids, he warns.

Jack Walker, Syngenta Seeds' technical information manager based in West Alexandria, OH, suggests considering the odds. A hybrid with a 5-bu./acre yield advantage in one non-replicated plot with 10 entries only has a 13% probability that it was the best hybrid at that location. The probability is even lower that this winner would be the best hybrid next year with different growing conditions.

“There's no way around it, growers who base seed selection decisions solely on the results from a single plot are gambling with the future,” says Walker.

Make selections using multi-year performance on your own farm, along with wide-area, multi-year performance summaries, he suggests.

Garland compares as many plot locations as possible. “I try not to judge any hybrid on a few plots,” he says. As an Asgrow/DeKalb dealer, he studies results from a minimum of 15-20 different locations using a company's database. “If there aren't enough data points, I'll pull data from Indiana or Kentucky, where there are similar soil types.”

On his on-farm test plots, he plants 25 different hybrids from several companies. He harvests the test plots later in the season to compare standability.

Along with the plots, he also plants side-by-side comparisons running the length of the field.

“If the data from the plot is consistent with the side-by-side tests, it gives me more confidence,” says Garland. “I put a lot of faith in what the hybrid does on our own farm.”

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