ISHS Acta Horticulturae 273: V International Workshop on Fireblight
ENVIRONMENTAL AND STRAIN EFFECTS ON SCREENING FOR FIRE BLIGHT RESISTANCE |
| Authors: | R.L. Bell, T. van der Zwet, B. Thibault, W.G. Bonn, P. Lecomte |
| Abstract:
Eleven genotypes of pear (Pyrus communis L.) and 5 strains of Erwinia amylovora Burr. (Winsl. et al.) were used in various combinations at three locations for two years in order to assess the degree of variability in disease expression due to random strain and environmental effects. For hosts and strains common to all locations and years, considerable variability among shoots in percent lesion length and in percentage of successful inoculation precluded detection of significant main effects in the full linear model, but sequential elimination of non-significant higher order interactions clarified interpretation of the data. Location, strain and year main effects, and all interactions were not significant. Although differences among host genotypes were significant, the choice of standard susceptible and resistant host plant genotypes in multi-location trials can be arbitrary. Strain E2002A, the Canadian standard bacterial strain, was highly aggressive, but not statistically superior. Increasing the number of replicated inoculations per experimental unit to at least 20, will increase the sensitivity of the future experiments, especially if substituted for yearly repetitions of identical experiments. | |
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