In the last two installments of “Production Notes,” I discussed the importance of selecting varieties for high yields and SCN resistance. This week, I will touch on a few of the many other important factors when selecting varieties.
While selecting the variety with the highest yield potential will get you 80 percent of the way there, the key to maximizing overall profits is identifying the best variety for each field. While the genetic base for soybean is quite narrow, each variety has its strengths and weaknesses. A proper positioning of the best lines across your acres will certainly increase yields by several bushels per acre. Many will promise that they can help choose these varieties for each field, but unless you work with a crop consultant that has spent time scouting your fields, most will not have enough information to help position varieties.
The key is a detailed and well-organized inventory of all of your acres. The essential ingredient for variety selection is a clear understanding of the diseases that impact soybean yields on each farm, so knowledge of where and when diseases have been present will help in your task.
For this reason, I always remind producers to walk fields throughout the season and take note of any troublesome issues. Plants with diseases that can’t be readily identified in the field should be sent to the Plant Disease Clinic at the University of Minnesota. Areas should be mapped and notes should be made to identify associations between disease and environmental factors or management decisions. For instance, “Disease X was present in the south half of the Y 80. Planting conditions were excellent and variety Z was treated with A+B+C.” Paired with soils and yield maps, these observations can be quite powerful.
Without a real understanding of what organisms impact your soybean yields, it is difficult to select among the hundreds of available varieties. Just keep in mind that there is genetic resistance available for only a small number of diseases, and additional soybean management will be required to reduce risk from all diseases.
When choosing among varieties it is also important to keep seed quality in mind. Although it is unlikely that you will be penalized directly for low protein or oil content of your soybeans, all of your crop will be marketed at a small discount for historical low protein levels typically found in this region. This penalty is embedded within the basis. Choosing high quality soybean genetics will allow Minnesota soybeans to remain competitive in local and international markets.
The most practical selection criterion among varieties is maturity. Selecting soybeans across a range of maturities will help hedge against some extreme weather events, but can lead to overlap with corn harvest. In general, select the longest season varieties that fit with the logistics of your operation.
Some final tips:
- Select six or more unique varieties
- If possible, purchase from different companies with different genetic backgrounds to ensure that you are really utilizing unique genetics.
- All varieties are rated good to excellent for most traits, so carefully identify any potential weaknesses and keep these varieties off of acres where those weaknesses may show.
- Ignore red-herrings like “hypoctyl length, bushy vs thin-line, leaf shape, seeds per pod, seed size, standability and shattering.” These measures rarely differentiate varieties in the real world.
- And, most importantly, be sure to use multiple sources of information when choosing varieties. Look for independent support for each of the varieties that you choose. Use the Minnesota Variety trials and the FIRST test results in addition to local strip trial data.
Seth L. Naeve is a University of Minnesota Extension Soybean Agronomist and Associate Professor of Agronomy and Plant Genetics. Reach Seth at 612-625-4298 or email him at firstname.lastname@example.org.