Puccinia striiformis f.sp. tritici in Australasia: pathogenic changes during the first 10 years

Pathogenic attributes of the wheat stripe rust pathogen were monitored in annual surveys from the first recording of this disease in Australia in 1979. During the 10‐year period to 1988,15 different pathotypes were detected in Australia and New Zealand. The pathotypes included some of economic importance to commercial wheat cultivars and others with no obvious selective advantage to aid their survival. Single‐gene mutations were the most likely causes of variation. The implications of these results on pathogenicity surveys and breeding for resistance are discussed.