DNA ANALYSIS OF CYLINDROCLADIUM-FLORIDANUM ISOLATES FROM SELECTED FOREST NURSERIES

Isolates of Cylindrocladium floridanum obtained from diseased roots of white and black spruce seedlings and surrounding soil in bareroot nur series in Ontario, Minnesota and Wisconsin area were compared by mitoc hondrial DNA (mtDNA) and ribosomal DNA (rDNA) restriction fragment len gth polymorphisms (RFLPs), human minisatellite DNA fingerprints and po lymerase chain reaction. Nucleotide sequences of rDNA ITS regions of s elected isolates were also performed. Based on the nuclear DNA fingerp rinting patterns, these isolates could be divided into three groups, n amely S1, S2 and S3. Isolates of S1 and S2 showed the same mtDNA RFLPs which were slightly different from that of S3. Isolates representing each of the three groups showed an identical nucleotide sequence of rD NA ITS regions. These data suggest that all the isolates tested belong to the same species which may be divided into three biotypes or popul ations.