DISEASE RESISTANCE IN ANNUAL CROPS 



53 



RESISTANCE 



HEINES VI 



A. 



1 2 3 6 5 6 7 8 9 10 11 12 13 U 15 16 17 18 RACES 



RESISTANCE 



PROBUS 



B. 



11 12 13 U 15 16 17 RACES 



Figure 10. Interactions between winter wheat cultivars 

 Heines VII (A) and Probus (B) and races of Puooinia striiformis, 

 Heines VII displays high differential resistance apparently 

 combined with moderate but quite irregular uniform resistance. 

 With Probus, however, the resistance spectrum is difficult to 

 interpret in terms of differential and uniform resistance 

 (calculated from data of Stubbs , Vecht, and Fuchs , 1968). 



