Oospores of Phytophthora palmivora were harvested from pairings of isolates of A1and A2mating types. The oospores were subjected to sonication and treatment with hemicellulase and cellulase before plating onto agar medium. After incubation at 20 deg;C, germination of the oospores was observed as the emergence of germ tubes which terminated in germ sporangia. The number of oospores that germinated from any pairing was raised by exposing the oospores to a temperature of 40 deg;C during the enzyme treatment and allowing a maturation period of the oospores of at least 4 weeks. Oospore germination was depressed by chilling to minus;12 deg;C during the enzyme treatment. The addition of an extract from papaya foliage did not significantly affect the frequency of oospore germination. Following the techniques described in this study, sexual progeny, freed from contamination by alien organisms or vegetative hyphae of the parent isolates, can be reliably obtained.Key words:Phytophthora palmivora, oospore, germination.
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