FI = (# of cysts on entry/# of cysts on Williams 82) x100
If the FI was <10%, an entry was considered resistant (R). If the FI was 10 – 30%, it was considered moderately resistant (MR). If the FI was 30-60%, it was considered moderately susceptible (MS), and greater than 60% susceptible (S).
Results
The following table includes only those varieties that exhibited resistance or moderate resistance to Race 1 in our test. A specific variety may not be listed because either the seed provider did not consent to testing, or it did not exhibit resistance. Resistance to SCN is a product of large-effect single genes donated by certain resistance sources, in addition to many small-effects genes that may or may not be present in the variety, making resistance a complex genetic phenomenon. A variety with a resistance source in its ancestry does not necessarily make it completely resistant, and thus results from bioassays such as this one are helpful to ensure resistance is present. These results will assist producers in selecting varieties with independently verified resistance. If you are a seed provider and want your varieties to appear in this table, please inquire with Aaron Lorenz (lore0149@umn.edu).
Table 1. Soybean varieties in trial that exhibited resistance or moderate resistance to SCN Race 1.
Year entered | Provider | Variety | Source of resistance | Relative maturity | Herbicide trait | Female index | Rating |
---|
| Control* | Peking | | | | 0.3 | R |
| | | | | | | |
| | | | | | | |
| Control* | PI 88788 | | | | 35.8 | MS |
2021 | Syngenta / NK | S23-G5X | PI 89772 | 2.3 | Xtend | 27.1 | MR |
2021 | Syngenta / NK | S26-E3 | Peking | 2.6 | Enlist E3 | 18.3 | MR |
2021 | Mustang Seeds | C-220N | Peking | 2.2 | Conv. | 2.5 | R |
2021 | Albert Lea Seed | 2340KN | Peking | 2.3 | Conv. | 2.0 | R |
2021 | Legend Seed | LGS1452RX | Peking | 1.4 | Xtend | 1.5 | R |
2021 | Cornelius Seed | CB26X78 | Peking | 2.6 | Xtend | 9.0 | R |
2021 | Federal Hybrids | F2290N R2X | Peking | 2.2 | Xtend | 0.2 | R |
2021 | Stine | 25EB62 | Peking | 2.5 | Enlist E3 | 15.1 | MR |
2022 | Channel | 2020R2X | Peking | 2.0 | Xtend | 0.1 | R |
2022 | Stine | 21EE62 | Peking | 2.1 | Enlist E3 | 0.8 | R |
2022 | Federal | F1720N RXF | Peking | 1.7 | Xtend Flex | 0.6 | R |
* Control varieties Peking and PI 88788 are two sources of SCN resistance, which were included in SCN race determination. The Female Indexes on these two varieties indicate that the SCN population can overcome the resistance in the varieties derived from PI 88788 but not the varieties with good level of Peking resistance. Seed is not available for these non-commercial varieties.
Source : umn.edu