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PHYTOPHTHORA INFESTANS IN ECUADOR: EVIDENCE FOR POPULATION SEGREGATION ON DIFFERENT HOSTS.
PHYTOPHTHORA INFESTANS IN ECUADOR: EVIDENCE FOR POPULATION SEGREGATION ON DIFFERENT HOSTS. L.J.Erselius, M-E.Ordofiez, P. Ramon, P. Oyarzun, and G.A. Forbes International Potato Centre, Casilla 17 -16-129 - C.E.Q., Quito, Ecuador. P. infestans was isolated from sporulating leaf lesions of potato, tomato, pepino dulce (Solanum.muricatuin), tree tomato (Cyphomandra betacea), S phureja and the wild plants S. caripense, S. colombianum, S. ochrantum, S. brevifolium and S. tetrapetalum. Isolates were characterised for compatibility type, Gpi and Pep alloenzymes, mtDNA tfpe, and, for some isolates, RFLP pattern. The A2 compatibility type was only found on S brevifolium and S. tetrapetalum. These isolates differed from those from all other hosts, although isolates from tree tomato had the same unusual Pep phenotype 85/100. Isolates from S. tuberosum, S. phureja and S co.lombiaum were very similar. Another group consisted of isolates from Lycopersicon esculentum, S.muricatum and S caripense. These groups are distinct, suggesting that there is little or no recombination taking place.