Table 3. Level and stability of pyrimorph resistance for the parental wild-type isolates and the resistant mutants of Phytophthora capsici.
| EC50 b (µg/ml) | RFc | |||||
| Isolate | Origina | 1st | 10th | 1st | 10th | FSCd |
| Hd3 | Parent | 1.282 | 1.200 | – | – | – |
| R3-1 | Mutant | 28.366 | 20.841 | 22.13 | 17.37 | 0.78 |
| R3-2 | Mutant | 65.350 | 65.250 | 50.98 | 54.37 | 1.07 |
| R3-3 | Mutant | 67.470 | 65.448 | 52.63 | 54.54 | 1.03 |
| Hd11 | Parent | 1.226 | 1.220 | – | – | – |
| R11-1 | Mutant | 68.677 | 64.729 | 56.02 | 53.06 | 0.95 |
| R11-2 | Mutant | 28.979 | 20.393 | 23.64 | 16.72 | 0.71 |
| Hx18 | Parent | 1.003 | 1.005 | – | – | – |
| R18-1 | Mutant | 10.697 | 10.960 | 10.67 | 10.91 | 1.02 |
| R18-2 | Mutant | 31.369 | 32.099 | 31.28 | 31.94 | 1.02 |
| R18-3 | Mutant | 45.712 | 27.359 | 45.28 | 27.22 | 0.60 |
| R18-4 | Mutant | 46.599 | 29.265 | 46.46 | 29.12 | 0.63 |
| R18-5 | Mutant | 41.594 | 30.968 | 41.47 | 30.81 | 0.74 |
| R18-6 | Mutant | 16.518 | 19.856 | 16.47 | 19.75 | 1.20 |
| Dz21 | Parent | 0.907 | 0.906 | – | – | – |
| R-21 | Mutant | 23.191 | 22.095 | 25.57 | 24.39 | 0.95 |
a
Parent isolates were collected from the field locations. Mutants were obtained by mass selection on pyrimorph-amended medium.
b
EC50 = effective concentration for 50% inhibition of mycelial growth at the 1st transfer and the 10th transfer.
c
RF = resistance factor, a ratio of EC50 for a fungicide-resistant mutant relative to the EC50 for the parental isolate.
d
FSC = the ratio of RF values at the 1st and 10th transfers.