ISOZYME SUBGROUPS IN TRICHODERMA SECTION LONGIBRACHIATUM

Seventy-eight representatives of Trichoderma sect. Longibrachiatum, Hy pocrea jecorina, and H. schweinitzii were compared using ten enzyme sy stems. The results essentially supported Bissett's morphologically bas ed taxonomy of Trichoderma sect. Longibrachiatum, in that the species ?: longibrachiatum, ?: citrinoviride, ?: parceramosum, and TT: pseudok oningii could be distinguished. Trichoderma reesei was closely related to H. jecorina and more distantly linked to I longibrachiatum, thus t he synonymy of T. reesei with T. longibrachiatum was not supported. Th e possibility that I: reesei is a clonal derivative of H. jecorina is discussed. Strains of Trichoderma citrinoviride were intermingled with Northern Hemisphere strains of H. schweinitzii, suggesting it is the anamorph of that holomorph. Trichoderma pseudokoningii, the type of wh ich was originally derived from ascospores of an Australian collection of H. schweinitzii, clustered with some New Zealand collections of H. schweinitzii, but independently of Northern Hemisphere H. schweinitzi i. Trichoderma pseudokoningii may be rare outside of Australasia. No t eleomorph could be linked either to I: longibrachiatum or I parceramos um. Four collections of H. schweinitzii from New Zealand (3) and the A ndean region of Venezuela formed a discrete group within the cluster t hat included H. jecorina and H. schweinitzii. There was great homogene ity among strains of H. jecorina from a narrow equatorial band, sugges ting continuing gene flow over disjunct regions.