Keeping a season-long log of how various hybrids and varieties perform and respond to stresses is always a good idea.

If your area suffered particular growth problems this year, and not many areas didn’t, jotting final notes on how your hybrids look before, or even as, the combine rolls could be helpful to your 2008 seed purchases.

“A year like 2007 may be the best for identifying weaknesses—to disease, drought, pests—that may raise red flags for the future,” said Bob Nielsen, extension corn specialist with Purdue University. “But deciding whether to cull that hybrid (for next year) depends on your assessment of the likelihood of future occurrences of that stress,” and how well the hybrid has performed in other years and in other locations this season, he said.

“Every grower does some evaluation through the growing season, but few of us have the extra time and energy to do all the evaluations we want to,” said Chris Clark, agronomy consultant and manager of Iowa F.I.R.S.T. (Farmer’s Independent Research of Seed Technologies). Iowa F.I.R.S.T. is an independent seed testing service that in 2007 had 24 locations across Iowa, in addition to cooperative programs in 10 other states.

“The point is to do at least some, compare how each of hybrids you planted performed, and to make it simple enough that you will keep a record of your thoughts.”

Clark agrees with Nielsen that farmers not make too much of a hybrid’s performance on their farm during one year. “But seeing how a hybrid responds to stress versus the others on the farm, and how that translates to yield, is part of the process,” of deciding whether a particular hybrid continues to earn a spot in the 2008 lineup.

Because of the distance between his research plots, Clark typically doesn’t get to see all plots late in the season before harvest. He makes several evaluations mid-season after pollination when kernel development is in full swing, and notes any late-season comments from plot cooperators who farm the land where plots are planted.

“Lodging is the biggest,” performance factor, besides yield, that he evaluates at harvest. “There were a lot of conditions that led to lodging this year,” Clark said. “Still, the main issue is did a particular hybrid lodge worse or better than others planted,” in various plot locations.

“I do most of final lodging and overall condition scoring from the combine cab,” Clark said.

Clark says F.I.R.S.T. agronomists use a 1-10 rating scale, with 1 noting no lodging and 10 indicating a flat field. “We relate that to percentage lodged, though the evaluation is done more by eye than by taking actual stand and lodged plant counts,” he said. “A 5 rating essentially equates to 25 percent lodging, 6 is a third of plants lodged, and so on.”

He recommends farmers in areas not prone to lodging in 2007 take the time to pinch stalks and push plants to evaluate the potential for a hybrid to lodge.

“You also can diagnose some insect problems late in the season,” Clark said. Ear tip feeding can be an indication of a number of insects, though western bean cutworm is the bug he is tracking the most.

“It has really exploded across Iowa.” He said western bean cutworm can be distinguished from other ear tip feeders, such as rootworm beetles, by looking further down the ear husk. Most tip feeders will move on to the next plant if things get too crowded on one ear, he said.

“The western bean cutworm seems to like having neighbors nearby. They’ll simply move down the husk, bore a hole to get into the center of the ear, and begin feeding again. You can still see that hole and the damage inside when you pull back the husk right through harvest.”

Farmers also can compare characteristics such as ear droop and drydown just before the combines roll, according to Daniel Davidson, DTN agronomist. For specifics on evaluating late season maturity, droop, disease issues, and how to evaluate lodging potential, check for Davidson’s articles in the Agronomy News segment on the Agronomy menu on satellite DTN products and under the Production menu on online DTN products.

Several complicating factors enter in to a final evaluation of how much of a 2007 hybrid to order for 2008, Clark said. One is the trait-shifting nature of hybrids these days.

“We rarely see particular genetics in exactly the same version more than a year or two,” Clark said. “The next year it will be stacked with an additional (insect resistance of herbicide tolerance) trait. And while the base plant genetics are the same, each new trait does change how that hybrid performs a little bit,” he said.

“Many farmers have a low tolerance level with regard to poor performance,” said Purdue’s Nielsen. “If they were burned this year, they often will cull (that hybrid) with little second thought.”

He warns against snap judgments if the hybrid has done well in the past and performed well on other farms or in a high number of test plots. “Performance at a single location should always be taken in context.”

SOURCE: DTN’s Greg Horstmeyer

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