Abstract
Key message A non-durable adult plant stripe rust resistance gene in wheat was mapped to the distal region of chromosome 2DS and designated Yr88 . Abstract Wheat stripe (yellow) rust, caused by Puccinia striiformis f. sp. tritici ( Pst ), is one of the most damaging fungal pathogens of wheat globally. Efforts to breed improved wheat cultivars have placed high priority on incorporating resistance to Pst . The resistances used are expressed at either all growth stages (all stage resistance; ASR) or at post-seedling growth stages (aka adult plant resistance; APR). Although APR has a reputation for being more durable than ASR examples have been documented of virulence for this type of resistance in the UK, Europe and in North America. Incursions of two genetically and pathogenically distinct pathotypes of Pst into Australia in 2017 and 2018 changed adult plant field stripe rust responses of many wheat cultivars grown in eastern Australia at that time. In some cases, changes in response could not be accounted for based on virulence on ASR genes, suggesting that the protective value of APR may have changed. This study reports the discovery of a new gene conferring race-specific APR to Pst pathotype 198 E16 A- J+ T+ 17+, a member of the internationally accepted multi-locus genotype (MLG) PstS13. The gene was mapped to the distal region of chromosome 2DS and designated Yr88 . Evidence is provided for the presence of Yr88 in near isogenic genes carrying selected ASR and APR Yr genes, four Australian wheat cultivars (LRPB Hellfire, Sherriff CL Plus, Vixen, Wyalkatchem) plus the Mexican green revolution wheat cultivar Lerma Rojo 64 and the Pakistani wheat cultivar Moomal 2000.