Table 2.
Origin of Plasmodiophora brassicae field isolates, the related field information, and the results of pathotype classification. Isolates were collected from 41 clubroot-infested fields in seven federal states in Germany from 2016 to 2020.
| Pathotype Classification 3 | |||||||
|---|---|---|---|---|---|---|---|
| Isolate | Federal State 1 | Soil pH | Frequency of OSR in a Rotation (Years) |
Mean Value of DI per Region in Clubroot-Infested Field (%) 2 |
ECD Code | Somé 1996 | DSI on OSR cv. Mendel |
| 1 | HE | 6.39 | 5 | 36.9 ± 15.1 | 17/31/31 | P1 | 9 |
| 2 | HE | 5.89 | 4 | 19/31/31 | P1 (+) | 100 | |
| 3 | HE | 6.44 | 3 | 16/31/31 | P1 (+) | 100 | |
| 4 | HE | 5.48 | 2 | 24/31/27 | P1 (+) | 95 | |
| 5 | HE | 5.73 | 4 | 16/31/31 | P1 (+) | 100 | |
| 6 | HE | 6.96 | 4 | 16/28/30 | P5 | 0 | |
| 7 | HE | 6.19 | 3 | 16/03/31 | P2 | 12 | |
| 8 | HE | 5.11 | 3 | 17/22/31 | P5 | 17 | |
| 9 | NI | 5.20 | 2 | 40.5 ± 18.7 | 16/23/30 | P1 (+) | 65 |
| 10 | NI | 5.72 | 4 | 16/31/31 | P1 (+) | 75 | |
| 11 | NI | 6.30 | 3 | 16/14/21 | P3 | 0 | |
| 12 | NI | 6.02 | 4 | 16/012/31 | P3 | 5 | |
| 13 | NI | 6.39 | 2 | 16/31/31 | P1 | 10 | |
| 14 | NI | 6.23 | 3 | 17/31/31 | P1 (+) | 90 | |
| 15 | NI | 5.76 | 5 | 16/31/31 | P1 | 10 | |
| 16 | NI | 5.78 | 5 | 16/31/31 | P1 | 0 | |
| 17 | NI | 6.90 | 5 | 16/30/31 | P3 | 22 | |
| 18 | NI | 6.20 | 3 | 17/31/31 | P1 (+) | 60 | |
| 19 | NI | 6.60 | 3 | 16/06/12 | P3 | 12 | |
| 20 | MV | 6.73 | 2 | 51.1 ± 24.7 | 16/31/12 | P1 | 87 |
| 21 | MV | 6.25 | 3 | 16/14/30 | P3 | 0 | |
| 22 | MV | 5.90 | 3 | 16/31/30 | P1 | 25 | |
| 23 | MV | 6.30 | 5 | 16/31/12 | P1 | 5 | |
| 24 | MV | 5.80 | 3 | 16/31/30 | P1 | 15 | |
| 25 | MV | 6.70 | 3 | 16/31/31 | P1 | 10 | |
| 26 | MV | 6.20 | 3 | 16/31/30 | P1 | 15 | |
| 27 | MV | 5.86 | 3 | 16/31/31 | P1 | 8 | |
| 28 | MV | 6.40 | 4 | 16/31/30 | P1 | 12 | |
| 29 | NW | 5.51 | 4 | 22.5 ± 3.5 | 17/31/31 | P1 | 8 |
| 30 | NW | 6.45 | 4 | 16/15/31 | P3 (+) | 80 | |
| 31 | RP | 6.50 | 5 | 10.0 ± 0.0 | 16/06/30 | P3 | 0 |
| 32 | SN | 5.71 | 4 | 55.0 ± 14.1 | 16/02/30 | P3 | 15 |
| 33 | SN | 6.30 | 3 | 16/31/31 | P1 | 25 | |
| 34 | SH | 5.27 | 3 | 41.3 ± 13.6 | 16/31/31 | P1 (+) | 100 |
| 35 | SH | 6.80 | 4 | 16/31/30 | P1 | 18 | |
| 36 | SH | 6.50 | 3 | 16/31/30 | P1 | 12 | |
| 37 | SH | 6.15 | 3 | 16/14/31 | P3 | 0 | |
| 38 | SH | 6.25 | 3 | 16/31/30 | P1 | 35 | |
| 39 | SH | 6.36 | 3 | 16/31/31 | P1 | 25 | |
| 40 | SH | 5.72 | 3 | 16/31/30 | P1 (+) | 100 | |
| 41 | SH | 6.75 | 3 | 16/02/30 | P3 (+) | 45 | |
1 Federal States in Germany: HE: Hesse; NI: Lower Saxony; MV: Mecklenburg-Vorpommern; NW: North Rhine-Westphalia; RP: Rhineland-Palatinate; SN: Saxony; SH: Schleswig-Holstein. 2 Mean value of disease incidence (DI) in clubroot-infested fields in each federal state. The incidence of disease in each clubroot-infested field was estimated by randomly choosing 50 plants. The presence of any swelling or gall formation on the root was assumed as proof of P. brassicae infection. 3 Classification was done according to the differential systems of the European Clubroot Differential set (ECD; [19]) and Somé et al. [20]. A cut-off point of the disease severity index (DSI) of 25% was used to classify plant reactions as resistant or susceptible [20].