Hybrids of Yesteryear Study Becomes 'How Not To' Plot

Why you need to ask questions about test plots.

When final results from the 'Hybrids of Yesteryear' plot are in, preliminary indication is that the older hybrids may do as well as the newer entries. In fact, it's possible that U.S.13, a USDA release from several decades back, and a hybrid from the '50s or '60's, may rank near the top, above stacked hybrids with '07 genetics.

Is that realistic? It's not likely. All indications are that genetic improvements, coupled with biotechnology over the past decade, have led to a sharp increase in the yield curve. There is plenty of data to back that trend up. All you have to do is compare average corn yield per acre 50 years ago with average corn yield per acre now.

The non-irrigated plots near Edinburgh, Ind., suffered a tough year. The study was on soil with three feet of loam over gravel, and consisted of 1/100th acre rows. Each entry was planted in side-by-side rows, except for a short hybrid, that was planted on the outside at three rows each time. The demonstration was replicated.

"Improvement in hybrids is obvious to me," says Jim Facemire, cooperator in the plot. When he first farmed similar land some 30 years ago, a year like this one would produce 40 -50 bushel per acre corn, tops. This year, the 38 acres surrounding the small-row plots yielded just over 80 bushels per acre..

So what happened to give the older hybrids an edge? Did stress just compress all the yields? Perhaps, but there's likely more to it. These results will underscore the need to ask questions of any plot data that you see. The key, says Dave Nanda, Corn Illustrated consultant and president of Bird Hybrids, Tiffin, Ohio, is that you understand how the tests were conducted, and evaluate anything that might have affected the plots.

Nanda would be the last to recommend returning to these ancient patriarchs. But he's also adamant about not jumping 'whole hog' into a new hybrid you've not tried on your farm before, even if it looks great in plot results. Every year is different, he says. You need to see data from multiple locations, and preferably multiple years.

Here are questions Nanda would ask about the 'Hybrids of Yesteryear' plot.

• Did the hybrids emerge uniformly? No! The four newest hybrids excelled. That's in keeping with observations last season, a totally different year, when newer hybrids dominated emergence under cool, wet May conditions.
• Was all the seed recently produced? No! That complicated the experiment from the beginning. Only 6 of 9 entries were good enough to have one row worthy of harvest. One of the older hybrids did not emerge at well. Rag doll warm germ tests confirmed that the seed just wasn't viable.
• Were both rows of each hybrid harvested? No! There was only one decent row of each older hybrid, so only one row was harvested for each plot.
• Were populations the same? No! The older hybrids were thinner, at 18-19,000, while the newer ones were thinned to about 22-23,000. They could have been much thicker, but were thinned back early to more closely match the thinnest plots. Fewer plants could have been an advantage here.
• Were both replications treated the same? No! Due to an error in planning, the second rep couldn't be sidedressed with liquid N at 145 pounds per acre, as the first rep was sidedressed. Instead, urea was hand-applied at about the same 145-pound per acre (actual N) rate. However, some leaves showed burn injury early, and then recovered.
• Did physical factors affect one rep more than the other? Yes! Due to the same error, there was physical damage to part of the second rep from tires of the applicator. Stand loss and stalk damage was severe enough that organizers elected to eliminate the second replication.
• So was this a replicated experiment? No! Damage from running over it, plus difference in nitrogen application, made the second rep unfit for use.
• Were other factors possibly involved in the rep that was used for yield? Yes! One of the hybrids fell in a spot that seemed affected by previous soil compaction. There was a recurring but not definite pattern across part of the field. One of the newer hybrids happened to be planted on both those rows.
• Was moisture content the same? No! The oldest hybrid, US 13, was wetter.

So was this plot indicative of reality? No! At least that's what Dave Nanda believes. Too many factors interfered, starting with differences in age of seed.

Sometimes there's a plot where things don't go well. This one was it for Corn Illustrated this year. The take-home message, rather than being that yields have improved with time, became: "Be leery of plot data until you know how the plot was conducted. To find that out, be open to asking questions," Nanda concludes.

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