Isozyme Studies on the Origin and Evolution of Puccinia Graminis F. SP. Tritici in Australia

Isozyme phenotypes for eight enzyme systems were used to assess the origins and evolution of P. graminis f. sp. tritici (the wheat stem rust pathogen) in Australia. The results obtained by this approach agreed with pathways postulated on the basis of virulence studies, confirming the suggestion that most of the major changes in the wheat stem rust pathogen flora of Australia have resulted from overseas introductions. Moreover, they suggest that, although the more recent of these were from Africa, the first major change detected occurred as a result of an introduction from elsewhere.