Summary
Race specific resistance to red core (red stele) root rot, caused by Phytophthora fragariae var. fragariae, is known to occur in the cultivated strawberry (Fragaria × ananassa Duch.), but frequently this resistance does not completely prevent infection. We therefore developed a classification method which distinguishes partial and complete resistance. It accounts for differences in the aggressiveness of isolates and in the appropriateness of experimental conditions for infection. This method is based on the microscopically assessed disease severity of a tested strawberry genotype relative to that of an universally susceptible reference cultivar. If the tested genotype is significantly (P≤0.01) less diseased, it is considered to possess resistance. Data from 18 genotype-isolate combinations, including five genotypes (‘Blakemore’, ‘Md683’, ‘Redgauntlet’, ‘Del Norte’, ‘Yaquina A’) and four North American isolates (A2, A4, A6 and A10) demonstrated the validity of our classification scheme.
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Abbreviations
- PIRT:
-
Percentage of Invaded Root Tissue
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van de Weg, W.E., Giezen, S., Henken, B. et al. A quantitative classification method for assessing resistance to Phytophthora fragariae var. fragariae in strawberry. Euphytica 91, 119–125 (1996). https://doi.org/10.1007/BF00035282
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DOI: https://doi.org/10.1007/BF00035282