Variation Within and Between Phytophthora Species from Rubber and Citrus Trees in China, Determined by Polymerase Chain Reaction Using RAPDs

Variation among 39 isolates of Phytophthora of six morphological species {P. citrophthora. P. parasitka, P. capsici, P. palmivora and P. meadii. from rubber and citrus trees, and P. colocasiae frotn taro) was studied using random amplified polynnorphic DNA (RAPD) analysis. Ten randomly-chosen 10-mer primers were used. Generally, the banding patterns were similar within species and diflFerent between species, but no one primer was able to distinguish all six species from one another. Cluster analysis on pooled data from all the primers gave six groups of isolates corresponding to the six morphological species. The group corresponding to P. citrophthora was divided further into sitbgroups that were related to host species and geographical location. This work confirmed the existing morphological classification of Phytophthora isolates from rubber and citrus trees in tropical China and showed the validity of using RAPDs to study the taxonomy of Phytophthora.