Recombination in Calonectria morganii and phylogeny with other heterothallic small-spored Calonectria species

The Calonectria morganii cultures studied were isolated from several hosts in the USA. Isolates were mated in all combinations, and one successful mat ing was selected to establish whether recombination occurred. RAPD and mati ng type data of parental isolates and progeny confirmed C. morganii to have a heterothallic mating system. Furthermore, to infer the phylogenetic rela tionships of C. morganii with morphologically similar Calonectria spp., DNA sequences of the ribosomal 5.8S RNA gene and the flanking internal transcr ibed (ITS) spacers, as well as part of the high mobility group (HMG) box (f orming part of the MAT2 mating type gene) and the P-tubulin gene, were anal yzed. Maximum parsimony yielded concordant trees for all three data sets. T hese data supported the morphological and biological species concepts propo sed for C. morganii and other Calonectria species with, similar, small-spor ed Cylindrocladium anamorphs.