Virulence characterization of <i>Puccinia striiformis</i> f. sp. <i>tritici</i> collections from six countries in 2013 to 2020

Puccinia striiformis f. sp. tritici (Pst) causes wheat stripe rust (also called yellow rust, Yr), one of the most important diseases worldwide. Characterization virulence in Pst populations is essential for developing cultivars with effective and durable resistance to control disease. A total 138 races, including 120 races that were not previously reported, identified from collections made Canada, China, Ecuador, Egypt, Italy Mexico 2013–2020 using a set 18 Yr single-gene differentials. Virulence gene Yr5 or Yr15 was found isolates any countries, indicating their effectiveness against populations. 16 genes detected, but frequencies varied greatly among countries. On average, Yr6, Yr7, Yr9, Yr43, Yr44 YrExp2 high (81.7–90.6%), those Yr1, Yr8, Yr17, Yr27, YrSP Yr76 moderate (34.0–56.8%), Yr10, Yr24, Yr32 YrTr1 low very (0.4–18.5%). The same detected different countries clustered into groups, migration especially between eastern Asia Mediterranean region. These results should be useful breeding these as well globally.