In the case of teliospore production by urediospore cultui'es, tlie cool chamber produced a 

 higher percentage of telial supporting cultures regardless of the temperature at which the 

 urediospores were produced (tables 5 and 6) . A feature of importance to us was culture age at 

 teliospore appearance. The cool chamber produced teliospores more quickly than the warm 

 chamber (tables 7 and 8) , but a statistical test could not be performed because of tlie low 

 level of teliospore production in the warm chamber. Tlie temperature of the chamber that 

 produced the urediospores had no apparent influence (table 9) . 



Table S. --Percent of Cronartium ribicola urediospore cultures derived from population 

 of single aeciospore cultures grown in warm chamber on Ribes hudsonianum 

 var . petiolare INT Clone-1 that produced teliosgores by 49 days after 

 inoculation when grown on Clone-1 at 55°F+2 (13 C+1 ) and 70°F+2 (21 C+1) 

 and 16 hr days 



Tel iospores 



Treatment Yes No Total Percent 



Aeciospore Urediospore 

 culture to subculture 



Warm to cool 22 1 23 96 



Warm to warm 2 12 14 14 



Total 24 n 37 65 



- 25.27 P of larger = 0.0005 



d.f. = 1 



Table 6. --Percent of Cronartium ribicola urediospore cultures derived from population 

 of single aeciospore cultures grown in cool chamber on Ribes hudsonianum 

 var. petiolare Clone INT-1 that produced teliospores by 49 days after 

 inoculation when grown on Clone-1 at 55"f+_2 (13 C+1) and 70 F+2 (21 C+1) 

 and 16 hr days 



Teliospores 



Treatment Yes No Total Percent 



Aeciospore Urediospore 

 culture to subculture 



Cool to cool 41 9 50 82 



Cool to warm 5 24 29 17 



Total 46 33 79 58 



X^ = 31.67 Probability of larger = 0.0005 



d.f. = 1 



5 



