Table 6.
Log-logistic model parameter estimates, standard errors, dose to 90% biomass reduction (GR90), and resistance ratio (R/S) for each P2 population of Palmer amarantha.
| Population | Herbicide | Progeny | b | e | GR90 | R/S |
|---|---|---|---|---|---|---|
| Perkins | Glyphosate | Unselected | −1.7 ± 0.4 | 11.2 ± 0.4 | 24.6 ± 2.3 | — |
| Air inclusion | −2.8 ± 0.3 | 376.0 ± 45.4 | 1346.0 ± 376.5 | 54.7 | ||
| 2,4-D | Unselected | −1.4 ± 0.3 | 128.8 ± 20.0 | 603.8 ± 143.4 | — | |
| Air inclusion | −1.1 ± 0.2 | 190.0 ± 24.2 | 1506.6 ± 440.1 | 2.5 | ||
| Flat Fan | −0.8 ± 0.2 | 67.3 ± 25.5 | 1073.3 ± 372.1 | 1.8 | ||
| Dicamba | Unselected | −0.7 ± 0.1 | 25.0 ± 2.9 | 558.9 ± 154.2 | — | |
| Air inclusion | −0.7 ± 0.1 | 19.4 ± 2.1 | 393.9 ± 117.0 | 0.7 | ||
| Flat Fan | −0.6 ± 0.1 | 12.4 ± 1.5 | 427.2 ± 126.7 | 0.8 | ||
| Chase | 2,4-D | Unselected | −1.2 ± 0.2 | 131.5 ± 16.4 | 781.0 ± 150.1 | — |
| Air inclusion | −1.3 ± 0.2 | 126.8 ± 16.9 | 657.2 ± 140.0 | 0.8 | ||
| Flat Fan | −1.1 ± 0.2 | 135.9 ± 17.2 | 932.1 ± 189.8 | 1.2 | ||
| Dicamba | Unselected | −0.6 ± 0.1 | 12.1 ± 1.4 | 470.4 ± 139.8 | — | |
| Air inclusion | −0.7 ± 0.1 | 17.8 ± 2.0 | 394.8 ± 112.7 | 0.8 | ||
| Flat Fan | −0.7 ± 0.1 | 18.4 ± 2.0 | 457.6 ± 124.4 | 1.0 |
ab parameter corresponds to the slope at the inflection point; e parameter corresponds to the inflection point; GR90 corresponds to the effective dose to reduce plant biomass by 90%; resistance ratios (R/S) were calculated as the ratio of the GR90 for each P2 population to the respective P2 unselected population.