ABSTRACT
When electrophoretic profiles of native proteins from vegetative mycelia of Phytophthora palmivora, Phytophthora capsici and Phytophthora citrophthora causing black pod disease of cocoa in India were compared on a single Polyacrylamide gel, the isolates of same species were readily distinguished both qualitatively by visual similarity in banding patterns and quantitatively by calculating similarity coefficients. Similarity coefficients were generally much higher between isolates within a species than between isolates of different species. The dendrograms obtained after unweighted pair grouping with arithmetic averaging cluster analysis, revealed that all the isolates of Phytophthora capsici were highly homogenous and formed a single cluster. The isolates of Phytophthora citrophthora were resolved into two electrophoretic types which were clustered into two distinct sub groups. Phytophthora palmivora formed a separate group. Thus, the results reveal that polyacrylamide gel electrophoresis can be used successfully in distinguishing species and sub groups within a species of Phytophthora encountered on cocoa.