VARIABILITY AMONG ISOLATES OF XYLARIA-CUBENSIS AS DETERMINED BY ISOZYME ANALYSIS AND SOMATIC INCOMPATIBILITY TESTS

Thirty strains of Xylaria cubensis isolated from leaves of the Brazili an rainforest palm Euterpe oleracea were compared by means of somatic incompatibility tests and gel electrophoretic analysis in order to gai n further insights into their population dynamics. Five enzyme systems were used to assess genetic variability. Isozyme results showed that somatically compatible isolates do not necessarily have the same pheno type. Comparison of isozyme banding patterns revealed a relatively hig h degree of genetic diversity within populations of X. cubensis, sugge sting that E. oleracea leaves are subjected to a constant immigration of fungal inoculum. This genetic diversity is presumably the result of sexual reproduction and consequently development of new genotypes of X. cubensis in the forest surrounding the palms.