Herbicide-tolerant and conventional (non-GM) soybean varieties are tested at several locations across Manitoba each year. In MPSG’s annual soybean variety guide and in Seed Manitoba, the results are reported by eastern and western sites, as well as first-year soybean entries.
Criteria to help you select the best variety for your farm:
- Maturity zone – Soybeans require anywhere from 105 to 125 frost-free days from planting to maturity. Narrow down your list of possible soybean varieties to only those suitable to your location using the maturity zones map and days to maturity. This is your key for what will mature before a fall frost in your region.
- Yields – Find long-term yields in the variety description tables and 2020 yields in the yields by location tables. Use the highlighter test to compare statistical differences among varieties (see example below).
- Type – For the herbicide-resistant varieties, type indicates if it is an Xtend (glyphosate + dicamba tolerant), Enlist (glyphosate + glufosinate + 2,4-D choline tolerant) or Roundup-Ready (glyphosate tolerant) variety.
- IDC, PRR, SCN – Based on what’s most important for your farm or specific fields, next consider IDC ratings, Phytophthora root rot (PRR) resistance genes and soybean cyst nematode (SCN) resistance of varieties.
- Protein – Find protein values for each variety at seedmb.ca. Genetics play a role in soybean protein levels and the environment influences what protein level will be expressed. However, more research is needed to understand soybean protein in Manitoba. It is likely that agronomic management has less of an impact on protein levels than genetics and environment.
The highlighter test is the best way to make statistical yield comparisons among varieties. We can be confident that yield differences outlined by the LSD are due to the genetics of the variety and not from environmental or experimental error.
Highlighter test example: S007-y4 selected as the check variety (highlighted in yellow) for herbicide-tolerant soybeans in the very early- to mid-season maturity zones. Values highlighted in green yielded significantly more at that site-year, while those highlighted in red yielded less. No highlight means no difference.
To be sure you are selecting a registered variety for next year, look it up in the CFIA database. Note that some varieties have already been de-registered and more are designated for de-registration over the next few years.