Host-pathogen interactions in witches's broom disease of cocoa
data, including unpublished work, from a research programme at Imperial College which focused on the variability of Crinipellis perniciosa have been re-analysed and are presented as host-pathogen matrices to examine interactions between different cacao types and (usually) five isolates in the context of three processes basic to Witches's Broom disease: brooms grow, brooms die and basidiocarps are produced. In respect of broom growth, hypocotyl inoculations provide valuable data on the extent of hypertrophy either expressed as mean percentage increase in hypocotyl diameter relative to uninoculated seedlings or as mean weekly increase in hypocotyl which, with successive measurements, can show when broom growth is slowed. Broom growth from cotyledon bud inoculations is less conveniently characterised, though patterns within matrices based on percentage increase in maximum broom diameter relative to uninoculated seedlings were similar to those observed with infected hypocotyls. Mean weekly increase in broom diameter was not a useful parameter but the degree of branching was useful in characterising particular pathogen-host reactions, especially those involving an isolate from Bolivia. With hypocotyl inoculations on Amelonado cacao, there was no significant relationship between "days to death" and "seedlings dry weight", but seedlings infected by some isolates died more quickly. Basidiocarp production in cabinets from seedlings infected at the hypocotyl and from brooms produced by inoculating cotyledon buds also differed with the isolate used. The data indicate that generally there is a fairly constant ranking of isolates of C. perniciosa in relation to the limited range of cacao types tested. The results are related to the international context of testing for resistance
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| Format: | biblioteca |
| Published: |
Reading (RU) INGENIC
1999
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| Subjects: | THEOBROMA CACAO, CRINIPELLIS PERNICIOSA, ENFERMEDADES FUNGOSAS, RESISTENCIA A LA ENFERMEDAD, ESPORAS FUNGICAS, RELACIONES HUESPED PATOGENO, |
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