Table 2.
Samples of Conyza canadensis from Ohio, Iowa, and Canada exhibiting either proline or serine at position 106 of EPSPS2.
| Region | Amino acid at p106 | First base at p106 | Sample ID | Resistance rank | Amino acid at p106 | First base at p106 | Sample ID | Resistance rank |
|---|---|---|---|---|---|---|---|---|
| Ohio | Proline | C | N64 | S | Serine | T | N89 | R3 |
| C | N28 | S | T | N11 | R4 | |||
| C | N50 | S | T | S15 | R4 | |||
| C | N53 | S | T | S18 | R4 | |||
| C | N58 | S | T | S23 | R4 | |||
| C | N66 | S | T | N26 | R4 | |||
| C | N90 | S | T | S3 | R4 | |||
| C | N42 | R1 | T | S38 | R4 | |||
| C | N83 | R1 | T | S60 | R4 | |||
| C | N52 | R2 | T | N65 | R4 | |||
| T | S74 | R4 | ||||||
| T | N76 | R4 | ||||||
| T | S78 | R4 | ||||||
| T | N9 | R4 | ||||||
| Iowa | Proline | C | N17 | S | Serine | T | N10 | R3 |
| C | N2 | S | T | S12 | R3 | |||
| C | N9 | S | T | S9 | R3 | |||
| C | N12 | R1 | T | N28 | R4 | |||
| C | N19 | R1 | T | S11 | R4 | |||
| C | S16 | R1 | T | S14 | R4 | |||
| C | S4 | R1 | T | S15 | R4 | |||
| C | S8 | R1 | T | S25 | R4 | |||
| C | S37 | R2 | T | S27 | R4 | |||
| T | S41 | R4 | ||||||
| T | S45 | R4 | ||||||
| Canada* | Proline | C | 59 | S | Serine | T | 20 | R3 |
| C | 67 | S | T | 10 | R4 | |||
| C | 75 | S | T | 13 | R4 | |||
| C | 79 | S | T | 15 | R4 | |||
| C | 80 | R11 |
Biotypes or accessions were grouped into resistance categories based on <80% survival at 1×(S) or ≥80% survival at 1×(R1), 8×(R2), 20×(R3), and 40×(R4); see Beres et al.32 for details. “S” and “N” in sample IDs designate samples collected from “Soybean fields” or “Non-agricultural sites,” respectively. All R1 and R2 plants are presumed to have non-target site resistance, which could also occur in R3 and R4.
1Scored as susceptible by Page et al.23; this accession may represent multiple individuals and may have non-target resistance.
*One accession (CA 27; R4) is not shown because it respresented multiple individuals, some with the p106 mutation and others lacking it.