Black rust is a very old and globally feared wheat disease that can lead to crop losses of up to 70 %. The pathogen, Puccinia graminis f. sp tritici, is heteroecious and requires the infection of Berberis vulgaris for the pathogen to overwinter before infecting the wheat. Therefore, the systematic removal of B. vulgaris has prevented the spread of black rust epidemics in temperate areas for decades. In the past, black rust was restricted to warm areas (e.g. East Africa, southern USA) where winters are very mild or even absent.

In the last decade, global warming and long-distance transportation of uredospores have contributed to the arrival of black rust in Europe, leading to spectacular outbreaks (e.g. Germany 2013, Ireland 2020). Initial studies found that 80% of cultivated wheat varieties are susceptible to black rust, making the identification and crossbreeding of resistance genes urgently necessary. Currently, black rust resistance in Europe is based on only three genes, Sr24, Sr31 and Sr38, for which resistance-breaking isolates have already been reported.

The risk posed by black rust will be mitigated by (1) analyzing a spelt collection (n=300) as a promising gene pool for black rust resistance (2) introducing two new resistance genes (Sr26, Sr61) with high black rust resistance into Central European/Swiss wheat material.