Soybean production has rapidly increased over the past decade and is now the third most important crop in Canada. This rapid expansion has been accompanied by an increase in Phytophthora root rot, a disease caused by Phytophthora sojae, which causes revenue losses of over $50 million annually in Canada. The most effective control method currently available relies on the use of soybean cultivars carrying resistance genes against specific pathotypes of P. sojae present in soybean fields. A diagnostic tool will be developed and offered to growers, allowing them to choose soybeans lines with the appropriate P. sojae resistance genes, and to breeders to deploy new soybean varieties resistant to the various pathotypes of P. sojae in Canadian fields. The implementation of this technology could save Canadian soybean growers over $20 million annually through the accurate exploitation of disease resistance. It is also expected to reduce the number of fungicide applications for the management of soybean diseases.