Rootstock Disease Resistance Abbreviation Guide

Definitions

(as outlined by the International Seed Federation)

Susceptibility is the inability of a plant variety to restrict the growth and development of a specified pest.

Resistance is the ability of a plant variety to restrict the growth and development of a specified pest and/or the damage they cause when compared to susceptible plant varieties under similar environmental conditions and pest pressure.

Resistant varieties may exhibit some disease symptoms or damage under heavy pest pressure. Two levels of resistance are defined.

High resistance (HR): plant varieties that highly restrict the growth and development of the specified pest under normal pest pressure when compared to susceptible varieties. These plant varieties may, however, exhibit some symptoms or damage under heavy pest pressure.

Intermediate resistance (IR): plant varieties that restrict the growth and development of the specified pest but may exhibit a greater range of symptoms or damage compared to high resistant varieties. Intermediately resistant plant varieties will still show less severe symptoms or damage than susceptible plant varieties when grown under similar environmental conditions and/or pest pressure.

Resistance Coding is based on Pathogen Codes of the International Seed Federation.

The order of the resistance claim coding is according to alphabetical order within the pathogen groups, which have the following order;  Virus/Bacteria/Fungus/Nematodes/Insect.

Monsanto follows commonly used strain denomination and ISF guidelines.  As there is still some difference of strain nomenclature, the commonly used strain nomenclature of the region is used.

For example:

  • Fusarium:   Fol:0,1,2 (EU)  =  Fol:1,2,3 (US)   is same as Fol:0-2 (EU) = Fol:1-3 (US)
  • Verticillium:   Va:0/Vd:0 (EU)  =  Va:1/Vd:1 (US)

For more information on resistance definitions, visit the International Seed Federation.

ROOTSTOCK

         

PATHOGEN: SCIENTIFIC NAME

ENGLISH COMMON NAME

CODE

RACES / STRAINS

RESISTANCE LEVEL

CODES (US / CANADA)

VIRUS

         

Tomato mosaic virus

Tomato mosaic

ToMV

0,1,2

HR

ToMV:0-2

FUNGI

         

Fusarium oxysporum f. sp. lycopersici

Fusarium wilt

Fol

1-3 (US)

HR

Fol:1-3 (US)

Fusarium oxysporum f. sp. radicis-lycopersici

Fusarium crown and root rot

For

 

HR

For

Pyrenochaeta lycopersici

Corky root rot

Pl

 

HR / IR

Pl

Verticillium albo-atrum

Verticillium wilt

Va

 1 (US)

HR

Va:1 (US)

Verticillium dahliae

Verticillium wilt

Vd

1 (US)

HR

Vd:1 (US)

NEMATODE

         

Meloidogyne arenaria

Root-knot

Ma

 

IR

Ma

Meloidogyne incognita

Root-knot

Mi

 

IR

Mi

Meloidogyne javanica

Root-knot

Mj

 

IR

Mj

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