• Balance yield potential and consistency.It’s common for one soybean variety to out-yield another by as much as 25% in the same field, with the same inputs and the same management, says Shaun Casteel, Purdue University Extension soybean agronomist. In Purdue’s 2009 variety trials, for example, the difference between high- and low-yielding varieties ranged from 6 to 12 bu.
But yield potential is only half of the equation, Casteel says. “High yield is the foundation of variety selection, but high-yield potential doesn’t do you much good if the variety only performs well half the time. Yield stability is the other part.”
• Match seed agronomics to field history.Variety selection plays a key role in managing weeds, diseases and pests, says Seth Naeve, University of Minnesota Extension soybean agronomist.
Many soybean varieties offer excellent tolerance to major yield robbers, such as brown stem rot, iron deficiency chlorosis, Phytophthora root and stem rot, white mold, soybean cyst nematode, soybean mosaic virus, and sudden death syndrome, which was widespread in the Midwest in 2010. New varieties with soybean aphid resistance will be available in 2011.
On the horizon: 2,4-D and dicamba-tolerant varieties. As glyphosate-resistant weeds loom, “weed control may re-enter the seed selection process,” says Vince Davis, University of Illinois soybean agronomist.
• Select for oilseed traits.Don’t overlook opportunities to earn a premium for qualities such as oil and protein content, says Bob Klein, University of Nebraska Extension agronomist. Oil and protein are influenced by weather and management, but also by genetics. “U S. growers need to try to get those up” to remain competitive in world markets, Klein says.
• Ensure diversity.“Genetic diversity spreads out risk. But we don’t do as good a job on this as we could,” Davis says.
One reason is co-branding of seed genetics. To avoid buying the same variety or resistance package under different names, ask questions. “Seed salesmen have a good handle on which varieties are genetically related,” Davis says. You can also obtain genetic diversity by selecting varieties that differ in maturity, disease and insect resistance, plant height and other characteristics, Klein adds.
• Keep good records.“Record keeping is one of the weakest management areas I see on farms,” says independent crop consultant Curt Burns of CB Agronomics, Stewart, MN. When you’re selecting defensive seed traits, “You need to remember exactly what happened two or three years ago, or diseases can pop up on you.”
The pathogens survive a long time in the soil, Purdue’s Casteel says, and if weather conditions are favorable, they’ll come roaring back, so “you need to be out scouting your fields to make future seed selections.”