Figure 33. Diagrammatic representation of the origin and structure of the Australian Puccinia graminis f. sp. tritici population. I, II, II, and IV refer to separate lineages within the population. The details are discussed in the text. Pathotypes 126-5,6,7,11; 21-0; and 34-2,11 are the founders of lineages I, II, and III, respectively. Pathotypes 194-1,2,3,5,6, and 326-1,2,3,5,6 appeared within 9 months of each other and are assumed to have a common, although unexplained origin. The historical duration of each lineage is represented diagrammatically by the shaded areas, the size of which provides a general guide to the relative importance of each. Solid arrows indicate the origin of lineages, dashed arrows indicate the associations between pathogenicity and molecule markers. 

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