In an unscientific survey taken by yours truly, 88% of farmers say their number-one factor in choosing a soybean variety for their farm is yield. I’m going to argue today that it’s not actually yield that’s driving the majority of decisions. Don’t get me wrong. You do need yield to make money and continue to farm each year. Looking at which variety won some yield trial is not the best way to get the most yield on your farm, though. SO WHAT IS THE BEST WAY TO PICK A SOYBEAN VARIETY? Finding the “must-have” defensive traits that prevent losses in your fields. But which of these traits do YOU need in 2024?
NEMATODE RESISTANCE
Root Knot Nematodes (RKN): Found primarily in soybeans grown in southern states, RKN is a big problem and there are few varieties with resistance. Crop rotation, excellent weed control, nematicides, seed treatments (like Saltro and ILeVO), and picking one of the resistant varieties are all important to protect your yields.
Soybean Cyst Nematodes (SCN): One new tool that is very promising and should be considered if you have even moderate levels of SCN is choosing a variety with the Peking (PI 548402) source of resistance. Peking varieties are really showing up well in yield trials this year for two reasons. First, there are some really good top-end-yielding Peking beans in both XtendFlex and Enlist varieties. Second, they are doing a better job protecting beans from SCN that have built tolerance up to PI 88788 soybeans.
PHYTOPHTORA RESISTANCE FIELD TOLERANCE
Similar to what you just read about resistance or tolerance building to the widely used SCN source in soybeans, we’re seeing the same thing with the Rps 1K & Rps 1A sources of resistance to phytophthora root rot. Each resistance source works on some different phytophthora strains, and other sources like Rps 1C, Rps 3A, and especially stacked gene soybeans with multiple Rps sources are working better.
Seed treatments can definitely help hold off phytophthora, especially early in the season. However, for the later-season protection you will need, there is no substitute for having a source of resistance in the soybean variety itself.
IRON DEFIECIENCY CHLOROSIS TOLERANCE
If you have high pH soils, IDC is a potential problem for you. Iron converts from the plant-available ferrous form to the unavailable ferric form in the soil. Plants show yellowing between leaf veins and yields go down, sometimes WAY down. Picking an IDC-tolerant variety certainly helps, but be careful in doing so because the rating scales from one company to another can vary. Do your own research and work with a trusted agronomist.
One other thing to look for is the Excluder trait. Often called chloride excluder beans, these varieties have the ability to block out chloride compounds in the soil that are often found in poorly-drained fields, in fields that are irrigated, or in fields where IDC regularly shows up.
There are a number of things that can cause similar plant appearances to IDC. Look for what’s causing yellow beans in your area and pick better varieties that can help defend against it. Oh, and improve your soil’s internal drainage for the long-term fix to most of them.
FROGEYE LEAF SPOT TOLERANCE
In some parts of the U.S., if you don’t have good frogeye tolerance, your soybeans don’t have a chance. Here are two things about fungicides to keep in mind, as well. First, frogeye is usually resistant to the strobilurin family (Headline, Quadris, Evito, Gem, etc.), so pick other modes of action for foliar treatments and spray before the disease shows up. Second, Xyway fungicide got labeled last year for use in soybeans at planting time and is showing a high level of protection from frogeye. If you use Xyway, either put it in a 2 X 2 or use the 3Rive 3D system that turns the liquid into a foam, providing 50 times greater coverage in the furrow, making it much safer to be close to the seed.
STANDABILITY
While you may not think of this as a defensive trait, standability helps so much through the season. It lessens the chance of getting diseases like sclerotinia white mold; it makes it much easier to drive through the field with a sprayer; it makes it easier to get spray coverage on all the little weeds out there; and it allows you to catch more of the pods with the combine. Standability is always a must-have for me.