RACE DIFFERENTIATION IN CEREAL RUSTS 



c -l 



additional differentials only in the case the corresponding main differ- 

 ential is susceptible. This approach is illustrated in Table 12. 



New (good!) differentials can be added without difficulties with race 

 numbers or additional figures. No longer useful differentials of former 

 investigators can be missed without confusing the historical race key. 

 I am rather convinced that only in the beginning it looks uncomfortable, 

 and I hope that it provides more honest information. Isolating "V23.StD" 

 from Spain and from Chile means that similar pathogenicities are valid in 

 both places as far as we know. But indicating that race 3/55 was found 

 in countries on different continents is dangerous because races which 

 look identical on internationally used differential sets may very well be 

 geneticially different (Guthrie, 1966; Hassebrauk, 1967). 



Table 12. Proposed method of naming races of stripe rust based 

 on differential variety abbreviation and specific reaction 





Id) 





Differential variet 



y and 



abbreviation 





Races (c 



Chinese 

 166 



(Ch) 



Heines Vilmorin 

 Kolben . 23 

 (HK) (V23) 



Lee 

 (Lee) 



Strubes 

 Dickkopf 



(StD) 



Spaldings 

 prolific 

 (Spa) 



60A 





ch a 



HK 



Lee 



StD 



(Spa) b 



60 





Ch 



HK 





StD 



(Spa) 



27/53 





Ch 







StD 





54 







HK 





StD 





3/55 







V23 





StD 





32A 







(V23) 



Lee 





Spa 



20A 







(HK) 



Lee 







Abbreviation written = the reaction of this differential is 

 susceptibility and the race is virulent for this variety. 



Abbreviation in parentheses = the reaction of this differential 

 is mesothetic and no clear cut resistance/susceptibility behavior is 

 possible. 



c 



Abbreviation absent - the reaction of this variety is resistance 

 to the race. 



CONCLUSION 



To summarize, allow me to quote some scientists who are masters in 

 their fields and who write much better English than I ever could. 



There is the statement of Johnson, Green and Samborski (1967), 

 "...ravages of the rusts are still not under control...." "It is a 

 tribute to the enormous plasticity and adaptability of these pathogens, 

 which have in one way or another circumvented the control measures that 

 have been devised." 



