RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM ANALYSIS OF VARIATION IN FUSARIUM SPECIES CAUSING EAR BLIGHT OF CEREALS

Genetic variation in Fusarium species on wheat was investigated using restriction fragment length polymorphism (RFLP) analysis. Single-spore lines (76) of Fusarium were recovered from 24 ears of wheat in a field plot exhibiting severe symptoms of Fusarium ear blight and identified using classical taxonomic criteria. Four Fusarium species were present, of which F. avenaceum and F. culmorum were predominant with F. lateritium and F. poae present in two ears and one ear, respectively. RFLP analysis using rDNA (pTA71) or total genomic DNA from an F. culmorum isolate clearly distinguished the four species. Genetic fingerprints of the isolates generated using DNA of bacteriophage M13 (which contains a mini-satellite repeat sequence) revealed considerable variation within three of the four species (except F. poae). Generally, only a single clone was recovered from each ear and in all but one case only a single species was obtained from each spikelet. However, in several instances it appeared that more than one clone of a species was present within a single spikelet.