Is virulence phenotype evolution driven exclusively by <i>Lr</i> gene deployment in French <i>Puccinia triticina</i> populations?

Puccinia triticina is a highly damaging wheat pathogen. The efficacy of leaf rust control by genetic resistance mitigated the adaptive capacity pathogen, expressed as changes in its virulence combinations (pathotypes). An extensive P. population survey has been carried out France over last 30 years, describing evolutionary dynamics this pathogen response to cultivar deployment. We analysed data set for 2006–2016 period determine relationship between Lr genes cultivars and pathotypes. Rust populations were dominated small number pathotypes, with variations most frequencies related corresponding gene cultivated landscape. Furthermore, emergence spread new matched introduction use (Lr28), confirming that deployment qualitative an essential driver evolution populations. However, principal component analysis (PCA) revealed certain pathotype–cultivar associations cannot be explained solely distribution This conclusion supported predominance few pathotypes on some cultivars, persistence several other compatible at low frequencies. Specific interactions are not, therefore, sufficient explain hypothesis quantitative bread cultivars—based differences aggressiveness—is also pathotype deserves further investigation.