Differential Sets

Photo Credit: Yue Jin, USDA

Differential sets are a vital component of race analysis. The aim is to have a set of differential varieties, ideally each with a different single resistance gene, which can distinguish races by their qualitative differences in reactions to different pathogen strains. Numerous different differential sets are in use by rust labs undertaking race analysis on a routine basis.

This current lack of consistency in differential sets between rust labs makes international comparison of results extremely difficult. As a result of the recognition of the emerging threat posed by new races of stem rust like Ug99 and the clear need for global collaboration and consistency, a new international set of differentials has been agreed upon by a panel of global rust experts. Partners in the BGRI are now using the following international core set of differentials to ensure global consistency for race analysis. Optional additions to the international core set can be made by individual labs to cover local needs.

For more information about obtaining seed of the International core diferential set. Please contact:

Dr. K. Nazari, ICARDA, P.O. Box 5466, Aleppo, Syrian Arab Republic. Email: K.Nazari@cgiar.org

Dr. T. Fetch, AAFC, Cereal Research Centre, 195 Dafoe Road, Winnipeg, Canada R3T 2M9. Email: Tom.Fetch@AGR.GC.CA

BGRI International Core Differential Set – Stem Rust (ordered by sets used in North American nomenclature system)

Set Gene LIT Diff line for world distribution, April 2009 Origin/Pedigree Source
1 Sr5 0 ISr5-Ra CI 14159 Thatcher/Chinese Spring Jin, USDA
Sr21 1- T monococcum/8*LMPG-6 DK13 Einkorn CI 2433 Fetch, AAFC
Sr9e 1- to 2- Vernstein PI 442914 Little Club //3* Gabo /2* Charter /3/3* Steinwedel / CI 7778 Jin, USDA
Sr7b 2 ISr7b-Ra CI 14165 Hope/Chinese Spring Jin, USDA
2 Sr11 ; to 2- Yalta PI 155433 Kenya C6402/Pusa4//Dundee Park, Australia
Sr6 0; ISr6-Ra CI 14163 Red Egyptian/Chinese Spring Jin, USDA
Sr8a 2- to 2 Mentana W1124 PI 221154 Rieti / Wilhelmina // Akagomughi Park, Australia
Sr9g 2- Acme CI 5284 Selection from Kubanka (CI 1516) Pretorius, SA
3 Sr36 0; W2691SrTt-1 CI 17385 CI 12632 T. timopheevii Jin, USDA
Sr9b 2 Prelude*4/2/Marquis*6/Kenya 117A Kenya 117A Fetch, AAFC
Sr30 1+ to 2 Festiguay W2706 PI 330957 Festival / Uruguay C10837 Park, Australia
Sr17 ;1 Prelude/8*Marquis*2/2/Esp 518/9 Esp 518/9 Fetch, AAFC
4 Sr9a 1- to 2- ISr9a-Ra CI 14169 Red Egyptian/Chinese Spring Jin, USDA
Sr9d 1- to 1 ISr9d-Ra CI 14177 Hope/Chinese Spring Jin, USDA
Sr10 ;1N to 3C W2691Sr10 CI 17388 Marquis*4/Egypt NA95/2/2*W2691 Jin, USDA
SrTmp 2- CnsSrTmp Triumph 64 (CI 13679)/Chinese Spring Jin, USDA
5 Sr24 1- to 2- LcSr24Ag Little Club/Agent (CI 13523) Jin, USDA
Sr31 1- to 2 Kavkaz/Federation4 Kavkaz Pretorius, SA
Sr38 X= Trident Spear*4/VPM (PI 519303) Park, Australia
SrMcN 2- McNair 701 (CI 15288) Jin, USDA

Source: Prof. Z.A. Pretorius, University of the Free State, South Africa