Detection of Puccinia graminis f. sp. tritici Race RRTTF in Ecuador in 2016

Wheat stem rust is a devastating disease that has incited severe epidemics resulting in extreme yield losses over the past century. Stem rust infection in plots of wheat line UC11075, known to carry the Sr38 resistance gene, was unusual and severe in February 2016 in a nursery at the Instituto Nacional de Investigaciones Agropecuarias Austro station near Cuenca, Ecuador. Stems with heavy infection by Puccinia graminis f. sp. tritici (Pgt) were sent for genotyping in labs at Ottawa, ON and St. Paul, MN, and for phenotyping at Morden, MB. None of the samples received directly from the field had viable spores, but genotyping was done in Ottawa and St. Paul using DNA extracted from spores or infected plant materials killed in ethanol. DNA was extracted using the OmniPrep™ kit (G-Biosciences, St. Louis, MO). Results from the Ottawa genotyping lab using 11 of 20 SSR markers (Stoxen, 2012) indicated that all February 2016 samples from the Austro station were genotypically identical, and nine of 11 markers matche...