76 EVA FUCHS 



Table 8. Seedling reaction of wheat variety Spalding's 

 prolific to races of stripe rust under differing environ- 

 mental conditions 









Conditions 







Race 



Lit. E 



22/16 b 

 3000 



22/16 b 

 1000 



17/13 b 

 3000 



Green- 

 house 



60 



0-IV 



II- 



0-IV 







0+ 



1 



i 



i-0 



0+ 



i 



i 



54 



0+ 



0-IV 



0-IV 







0+ 



42A 



i 



i-0 



i-0 



i-0 



i 



20A 



i-0 



i-0 



i-0 



i 



i 



27/53 



0+ 



1 1 -IV 



II-IV 











2 



IV 



IV 



IV 



IV- 



IV- 



3/55 



i-0+ 







i-0 



i-0 



i 



32A 



0-IV 



ii-IV 



IV- 



O-II 



0-IV 



32 



0-IV 



IV 



IV 



IV 



IV 



26 



IV 



IV 



IV 



IV 



IV 



7 



0+ 



11 + 



0-IV 



0-IV 







15 



IV 



IV 



IV 



IV 



IV 



Indicates the combined results of thousands of greenhouse tests. 



Temperature in degrees C/photoperiod in hours; light intensity in 

 lux. 



C Temperature 17°C±2°; light intensity 4000 up to 14,000 lux. 



Besides the standard factors of the environment, other elementary 

 factors are of influence, too. In the case of stripe rust Schroder and 

 Hassebrauk (1964) found in Braunschweig that the spores germinated more 

 slowly and less intensely if the sporulation happened in spells of 

 cyclonic weather. They germinated relatively fast and more completely 

 if they were produced during a change from cyclonic to anticyclonic 

 weather. Sharp (1967) found in Montana and Alaska that the concentra- 

 tion of ions in the air influenced the germination of spores. 



We know from our practical inoculations through the entire year that 

 the culture of stripe rust in a climate greenhouse is not always guaran- 

 teed. Some days we inoculated wheat seedlings with poor rust material 

 but obtained good success; other days (under the same conditions) we 



