Table 2.
Incidence of black scurf in selected potato cv. Russet Burbank variants in glasshouse (GH1—2010; GH2 and GH3—2011) trials. Rhizoctonia solani AG3 isolates R299, R422, and TAS1 were tested separately in each trial.
| Variants | Relative tuber disease incidencea | Disease incidence (infected tubers (%))b | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GH1 | GH2 | GH3 | ||||||||||
| Common scab | Powdery scab | Black scurf | R299 | R422 | TAS1 | R299 | R422 | TAS1 | R299 | R422 | TAS1 c | |
| A380 | 0.27 | 0.53 | 0.65 | 71.3 (1.09) | 100 (1.57) | 64.2 (0.85) | 66.7 (0.87) | 61.1 (0.66) | 66.7 (0.88) | 77.8 (1.16) | 44.4 (0.64) | 36.7 (0.39)a |
| A168a | 0.32 | 0.49 | 0.89 | 100 (1.57) | 100 (1.57) | 67.5 (0.97) | — | — | — | — | — | — |
| TC-RB8 | 0.66 | 0.99 | 0.86 | 98.6 (1.48) | 100 (1.57) | 61.7 (0.82) | 83.3 (1.22) | 69.4 (0.92) | 72.2 (0.94) | 100 (1.57) | 100 (1.57) | 86.7 (1.26)ab |
| A362 | 0.78 | 0.80 | 0.86 | 100 (1.57) | 91.4 (1.32) | 66.1 (0.90) | — | — | — | — | — | — |
| Russet Burbank (parent) | 1.00 | 1.00 | 1.00 | 100 (1.57) | 100 (1.57) | 100 (1.57) | 100 (1.57) | 100 (1.57) | 100 (1.57) | 100 (1.57) | 100 (1.57) | 100.0 (1.57)b |
| P | 0.12 | 0.06 | 0.17 | 0.44 | 0.07 | 0.34 | 0.44 | 0.12 | 0.04 | |||
| LSD (0.05) | ns | ns | ns | ns | ns | ns | ns | ns | 0.89 | |||
—: lines not tested within the specified trial.
aMean relative disease incidence for common scab, powdery scab, and black scurf was generated for each variant by dividing the mean disease score of each variant by the mean disease score of the parent cultivar in each trial in which they appeared and averaging the result. Common scab data are from [3] and powdery scab data are from [2].
bData are mean percentage of tubers with any black scurf symptoms and transformed arcsine means (in parentheses).
cTransformed means followed by the same letter within the same column are not significantly different at P = 0.05 using Fisher's LSD test; ns: non-significant.