- Soybean variety selection should focus on yield (and yield consistency) as well as maturity selection and disease tolerance.
- Choose multiple varieties from different company umbrellas to spread genetic risk.
- Use multi-year, multi-location yield trial information that matches your environment (crop rotation, tillage system, soil, and drainage).
- Balance seed cost with yield potential and costs that can be influenced by varietal characteristics.
Soybean variety selection should have the same amount of consideration as is given to corn hybrid selection. Many characteristics can be used that can affect in-season management. And in some cases, soybean variety characteristics need to be matched up with the equipment and cropping systems management being used.
Characteristics to consider
- Yield and yield consistency: select soybean varieties that are high yielding in public and private variety trials. Poor yielding genetics rarely produce high yields. Evaluate varieties for yield consistency from location to location and year to year to ensure for robust, high performance. Do your homework to understand which seed brands fall underneath the same company umbrella. While it is recommended to plant several different genetic lineups, the easiest way to ensure you do not plant the same variety with a different number is to use brands from multiple company umbrellas.
- Maturity: plant a wide range of soybean maturities, up to a full maturity group difference, to spread out the harvest window and weather associated risk. Using a wide range of variety maturity can increase the chances of favorable weather conditions during grain fill. A wide harvest window can minimize harvesting soybean below 13% moisture. While not always true, longer season varieties tend to have slightly higher yield potential.
- Disease tolerance: knowing field disease history is key for finding the right variety for the field. Couple disease history with how problem diseases can be managed will help determine what variety ‘must-haves’ include. Some diseases have to be managed through variety selection, such as soybean cyst nematodes, iron chlorosis, and white mold. Other diseases have non-variety selection management options that can be balanced with cost.
- Transgenic traits: this option is pretty much limited to herbicide traits in soybean varieties. There is a tendency to use conventional soybean to lower seed and production costs, however, this strategy must reflect a change in the herbicide program as well as increased herbicide costs. When selecting herbicide traits, understand what herbicide traits were contained in the previous corn hybrid to allow flexibility in controlling volunteer corn. Also, be aware of which herbicides weeds have developed resistance to make the most out of the herbicide traits.
- Standability and lodging: soybean planted at higher seeding rates or in high fertility fields are more susceptible to lodging due to taller plant growth. If lodging becomes a significant factor in your fields, it could reduce yield and slow harvest progress.
- Pod shattering: pod shattering is typically associated with harvest delays where seed moisture falls below 13% and then goes through rehydration and drying cycles. Shattering can be minimized by paying attention to variety scores as well as selecting a range of soybean maturity groups.
- Seed costs: the highest yielding variety may not be the most profitable variety. Balance the cost of the seed with the yield potential. Understand how the variety selected will influence in-season management costs that need to be offset by the cost of seed.
Where to find public yield trial information
- Iowa State University / Iowa Crop Improvement Association
- University of Illinois
- University of Nebraska – Lincoln
- University of Minnesota
- University of Missouri
- South Dakota State University
- University of Wisconsin
It may be valuable to look at university trials in neighboring states with similar growing environments. Consider other public and private strip trials from FFA clubs, FIRST Seed Tests, cooperatives, and seed companies. These sources may or may not have entries from multiple brands and often are not replicated.
Interpreting yield trial information
The objective of variety selection is to predict how well a variety will do next year, not evaluate past performance. The difference here is that selecting a variety requires having enough information from many yield trials to predict future performance. To make predictive decisions, use yield trials that have single location as well as multi-location averages. Multi-location averages are required because they can account for a range of environmental conditions such as weather, nutrients, insects, and diseases. When choosing which yield trials to use, consider tillage, soil type, and drainage similar to your fields. These factors interact with yield potential in ways that affect how well the yield trial will predict variety performance specific to your field and management.
To use yield trial data confidently, do not rely on the yield value itself. Use information like least significant difference (LSD) to tell if a variety is statistically different than another. Even using simple quartiles can be useful when combined across multiple yield trials. For example, a variety that is in the top quartile for every yield trial has consistent performance, whereas a variety that lands in a top quartile at one location and a middle location at another location is not a consistent variety with predictive performance. Looking for high-performing varieties that perform consistently across many locations and yield trials will lead to making variety selection decisions that are predictive for the next growing season.