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Leaf rust, caused by the fungus Puccinia triticina, is the most common rust disease of wheat in wheat‐producing areas worldwide. The Israeli population of P. triticina has been consistently monitored since 1993. A total of 784 single urediniospore isolates from Triticum aestivum were analysed during 2000–15. The structure of the pathogen population has changed to a large extent since 2000. The annual populations of P. triticina were separated into two distinct groups, 2000–11 and 2012–15, while populations of 2000–5 and 2006–12 were differentiated to a lesser extent. The change in the population originating from T. aestivum during the period 2000–15 is less significant compared to changes in the 1990s described previously. Diversity within the annual populations of P. triticina was rather stable during the period studied. Three new pathotypes, characterized by virulences on Lr3ka and Lr30 genes, became dominant between 2012 and 2015, while all but one prevailing pathotypes in 2000–11 were avirulent on these two genes. Significant changes in virulence frequencies on a number of Lr genes (Lr2c, Lr3ka, Lr15, Lr21, Lr23, Lr26, Lr30) and pairwise associations of virulences (mainly with Lr2c and Lr26) were registered in 2012–15 or earlier. It is postulated that the composition and pathotype structure of the P. triticina population in Israel is determined by wind‐disseminated urediniospores from neighbouring regions, where the migration of P. triticina from the eastern part of the Mediterranean Sea and from the Horn of Africa seem to have the greatest influence. [ABSTRACT FROM AUTHOR]

Leaf rust, caused by the fungus Puccinia triticina, is the most common rust disease of wheat in wheat-producing areas worldwide. The Israeli population of wheat leaf rust has been consistently monitored since 1993. A total of 840 single urediniospore isolates from Triticum aestivum (567), T. dicoccoides (119) and T. durum (154) were analysed during 1993-2008. The structure of the pathogen population has changed to a large extent since 1993. The annual populations of P. triticina were separated into two distinct groups: 1993-1999 and 2000-2008. Differentiation among the annual pathogen populations, as well as between the overall populations of the 1990s and 2000s, could be mainly attributed to the following forces: (i) migration of leaf rust urediniospores from neighbouring regions; and (ii) selection pressure of new yellow rust-resistant wheat cultivars that have been introduced into Israel since 1997. Genetic multiplicity of wild emmer contributes to P. triticina variability in Israel. Leaf rust populations collected from common wheat, wild emmer and durum wheat differed. The population that originated from T. durum was rather stable during the years of the survey, whereas that from T. aestivum changed significantly from the 1990s to the 2000s. Diversity within the annual populations of P. triticina was highest in 1994 when many new pathotypes and associations between virulences were observed. Single-step derivatives of the new pathotypes became dominant after 2000. Significant changes in virulence frequency to a number of Lr genes (e.g. Lr2a, Lr15, Lr17, Lr21, Lr26) were also registered in 2000-2008. [ABSTRACT FROM AUTHOR]