ABSTRACT Triticale (× Triticosecale ), a wheat–rye hybrid first cropped in the 1960s, was initially renowned for its high resistance to biotic stresses such as leaf rust ( Puccinia triticina ) and has contributed to improving wheat cultivars from the 1980s onward. However, since the 1990s, with the rise in large‐scale cultivation in some regions of Europe favouring pathogen adaptation, susceptibility of triticale to leaf rust has increased and it has become a significant threat in major production areas like France. The mechanisms behind this pathogen adaptation being unclear, we conducted a comparative assessment of the virulence spectrum and race structure of P. triticina populations collected from triticale and bread wheat. Comparative infection assays on wheat and triticale differential lines and genotyping assays to determine whether current epidemics are due to specialized races originating from wheat, revealed significant differences in population and race structure and a notably high level of triticale resistance to P. triticina . Thus, triticale continues to be a valuable asset for breeding wheat disease resistance, provided newly identified resistances are used carefully to ensure their sustainability. Despite the relatively marked genetic isolation between wheat and triticale populations, we detected a few isolates sampled on triticale with interaction profiles typical of bread wheat isolates, advocating for joint sustainable management of disease resistance in bread wheat and triticale.
Delestre et al. (Fri,) studied this question.