You are here
How to simplify seed decisions
Each Christmas, many children make out a gift list. Some gifts fill a need, such as a new pair of shoes. Many, though, fill a want, such as “I want that Blume doll or a zero-gravity laser race car.”
You annually follow a similar path when you select seed corn. The plethora of choices – ranging from conventional hybrids to fully stacked hybrids – fill many wants.
“Choosing a hybrid is one of the most, if not the most, important decision to make,” says Mark Licht, Iowa State University (ISU) Extension agronomist. “But you have to narrow it down. Think about what you need vs. what you want.”
Yield potential often tops the list of what you need in a corn hybrid. At first glance, you’d think a hybrid packed with multiple herbicide-tolerant traits, above- and below-ground insect resistant traits, and excellent disease tolerance would ooze with yield potential.
Traited hybrids frequently outyield conventional hybrids in head-to-head comparisons. However, that’s due to seed companies concentrating their best genetics into traited hybrids and not into conventional hybrids, says Licht.
“It is a myth that transgenic traits (such as those that resist European corn borer or corn rootworm) increase yield potential,” says Licht.
An ISU analysis of hybrids tested from 2013 to 2017 shows that insect resistance protection via refuge in a bag and drought-
tolerant traits added little to yield. Omission of insect traits diminished yields less than 1 bushel per acre. The same minimal loss occurred when ISU researchers nixed the drought-tolerant trait.
“Year in and year out, we’re just not seeing a yield difference with them,” says Licht.
So why buy them? Heavily stacked hybrids slice risk.
Remember 2012? Up to that year, advancements in corn genetics and drought tolerance were thought to make corn bulletproof. A drought-tolerant hybrid would have better endured the yield-squelching drought that sliced U.S. average corn yields down to 123.4 bushels per acre from the previous year’s U.S. average of 147.2 bushels per acre.
Even though there have been no widespread recent outbreaks, corn rootworm can still slice corn yields 15% to 17% for each node lost to larval feeding, according to ISU entomologists. By buffering these maladies, traits can moderate risk and protect yield potential.
“Think of traits as yield protection,” says Licht.
A downside, though, is traited hybrids that tolerate nonselective herbicides and resist insects often cost more than conventional hybrids. Still, farmers who plant conventional or reduced-trait packages need to make alternative pest-protection plans.
“Your in-season management will look completely different,” says Licht.
In some cases, protecting a conventional hybrid against corn rootworm requires nothing more than rotating with a nonhost crop like soybeans. In cases where extended diapause or the western corn variant trumps crop rotation, though, alternative controls like a soil-applied insecticide is needed, says Licht.
Cutting Through Clutter
All this still leaves farmers like Ben Riensche facing an avalanche of company claims about which seed to buy. “Every seed variety is like (the school children in Garrison’s Keillor’s radio program) Lake Wobegon,” says Riensche, who farms with his son, Hans, near Jubilee, Iowa. “They all are above average. Seed catalogs do not say, ‘This hybrid is a train wreck’ or ‘Don’t plant this even if your life depends on it.’
“Seed companies are masters at getting you to think the most important decision you need to make is the variety of seed,” adds Riensche. Seed is part of his recipe for growing a successful corn crop. Yet, so are other factors.
“I make 99 decisions to grow a good crop,” he says. “One of them is picking seed. But there are just so many things to know other than just picking seed.”
They include the following:
- Timely field operations
- Dependable machinery
- Optimal drainage
- High fertility
- Reduced or improved tillage
Weather also complicates seed selection. “You tell me if it’s going to be hot or cold, early or late, or wet or dry,” he says.
If you could know that, it would be possible to pick the perfect seed. “Otherwise, you can only select for average conditions.”
Instead, Riensche aims for consistently performing hybrids across several companies.
“It’s like picking blue-chip stocks,” he says. “You don’t know if every one will hit, but most cylinders will fire. You can do the same thing with corn hybrids.
“I concede there are traits you need to watch,” he adds. “You need better drought-tolerant varieties on lighter soils. You also need to pick wisely for an early harvest or a delayed harvest. But if you take the top handful of hybrids, you can do just as good as micromanaging seed decisions.”
Multiple Locations, Multiple Years
One way to boost the odds of making a correct seed decision is to assess a hybrid’s performance across multiple locations and years, says Licht.
One example was the 2013-2017 Iowa Crop Performance Test that analyzed 9,400 trials. Researchers grouped hybrids into yield quartiles. Averaged across location, the hybrids in the top two quartiles – the top one half – had a 60% chance of being in the top half of the trial the next year. Meanwhile, hybrids ranking in the bottom one half of the trial just had a 30% chance of surfacing in the top half of hybrids the following year.
“It’s not about choosing hybrids that were high yielding last year,” says Licht. “It’s about choosing a hybrid that’s going to be high yielding next year.”
Match Hybrids to Fields
Matching hybrids to specific field conditions is also key. “Everyone has good products to sell, but there are differences as to which hybrids are better adapted to a field,” says Lance Tarochione, an Asgrow and DeKalb technical agronomist.
For example, some fields are more prone to harboring certain diseases than others. Hybrid selection is particularly important for fields with a history of Goss’s wilt, since foliar fungicides have no impact on this bacterial disease, says Licht.
“With northern corn leaf blight or gray leaf spot, you may be able to select a susceptible high-yielding hybrid knowing you will have to pay attention to in-season scouting and potential fungicide application,” says Licht.