Disease Resistance Terminology

Monsanto Vegetable Seeds Division is transitioning to one approach for describing disease resistance and pathogen abbreviations in line with the current guidelines published by the International Seed Federation (ISF) system.

With regard to disease resistance descriptions, Monsanto Vegetable Seeds will use the term “High Resistance” (HR) and will no longer use the term “Resistance” (R). This is only a change in terminology and does not reflect a change in product performance.

Use of the “Intermediate Resistance” disease performance description remain unchanged.

Click here to view the updated Disease Resistance Abbreviations List.   

IR = Intermediate Resistance — The ability of a plant variety to restrict the growth and development of the specified pest or pathogen, but may exhibit a greater range of symptoms compared to highly resistant varieties. Intermediate resistant plant varieties will still show less severe symptoms or damage than susceptible plant varieties when grown under similar environmental conditions and/or pest or pathogen pressure.

HR = High Resistance — The ability of a plant variety to highly restrict the activities of a specific pathogen or insect pest and/or to restrict the symptoms and signs of a disease, when compared to susceptible varieties. Highly Resistant varieties may exhibit some symptoms when specified pathogen or pest pressure is severe. New and/ or atypical strains of the specific pathogen or pest may overcome the resistance, sometimes completely.