Pathogenic Variability among Isolates of Phytophthora Capsicl Causing Black Pod Disease of Cocoa in India

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dc.contributor.authorChowdappa, P.
dc.contributor.authorChandra Mohanan, R.
dc.date.accessioned2014-07-11T05:27:39Z
dc.date.available2014-07-11T05:27:39Z
dc.date.issued2007-02
dc.description.abstractPathogenic variability among five isolates of Phytophthora capsici viz.. I-CP/23.1-CP/25.I-CP/27.1-CP/76 and I-CP89 collected from five localities of Kerala state of India was studied using wounded and unwounded detached pods of 20 cocoa accessions. .Mycelial discs of 5 mm diameter, cut from the periphery of seven-day-old sporulating cultures of P. cupsici grown on carrot agar medium, were used to inoculate fully developed but unripe detached cocoa pods. Lesion size (cm), mycelial growth and sporulation on lesion surface were recorded after seven days of inoculation. All the five isolates of P. capsici were pathogenic to wound-inoculated cocoa pods of 20 accessions. Interactions between isolate and accessions for lesion size and mycelial growth were highly significant, suggesting differential host-pathogen interactions. In general, the isolates produced less aerial mycelium on lesion surface. Studies on lesion sporulation indicated that isolates I-CP/23 and I-CP/76 produced few sporangia on Landas 356 and 365 respectively. Similarity among isolates of P. capsici was determined by cluster analysis based on their lesion size on 20 cocoa accessions. Two phenotypic clusters were identified. Similarly among cocoa accessions was also determined based on their reaction (lesion area) to five isolates of P. capsici. The cocoa accessions were grouped into five clusters. Isolates induced low levels of infection or no infection on unwounded pods of 20 cocoa accessions tested. When cocoa pods of 20 accessions were inoculated without wounds, isolates I-CP/27. I-CP/23. I-CP/76.1-CP/25 and I-CP/89 caused infection only on 12. nine, eight, seven and four accessions respectively. Thus, for cocoa breeding purposes, screening cocoa genotypes with two isolates of P. capsici may suffice in selection for resistance to P. capsici.en_US
dc.identifier.citation11th international cocoa research conference p 21-22en_US
dc.identifier.urihttp://hdl.handle.net/123456789/4019
dc.language.isoenen_US
dc.titlePathogenic Variability among Isolates of Phytophthora Capsicl Causing Black Pod Disease of Cocoa in Indiaen_US
dc.typeArticleen_US

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