RELATIVE BLISTER RUST RESISTANCE OF NATIVE AND 



INTRODUCED KHITE PINE SPECIES IN EUROPE 



Bent F. S0egaard 

 Royal Veterinary and Agricultural University Arboretum 

 Htfrs ho lm 3 Denmark 



ABSTRACT 



Native European white pines, and those introduced from Asia and 

 North America are considered in three groups. Native European 

 white pines include Pinus cembra 3 P. sibirica (possibly one of 

 the original hosts of white pine blister rust, Cronartium 

 ribicold) , and P. pence. P. cembra and P. sibirioa seem to be 

 moderately to highly resistant under natural exposure to the 

 rust in the Italian and Swiss Alps, in Germany, Denmark, 

 Belgium, Finland, France, Great Britain, Norway, Poland, and 

 Sweden. Occurrence of the rust in natural stands of P. peuce 

 is little known, but under introduction into more northerly 

 European localities it is seen to range from almost as suscep- 

 tible as P. strobus , to highly resistant. Performance of 

 hybrid seedlings from Danish crosses between P. peuce and P. 

 strobus has demonstrated the ability of P. peuce to transmit 

 its resistance to offspring. Often the hybrid seedlings were 

 heavily infected, but--unlike P. strobus seedlings--they 

 survived. 



Asiatic introductions include P. armandii , showing a high degree 

 of resistance; P. griffithii (syn. P. w alii chi ana) , ranging from 

 moderately to highly resistant; P. koraiensis , found to be 

 moderately to highly resistant in both Europe and North America, 

 and P. parviflora, resistance of which is largely unknown. 



North American white pine introductions include P. albicaulis 

 (rare but always heavily attacked) , P. flexilis (generally 

 found highly susceptible) , P. strobus (moderately to highly 

 susceptible) , P. lambertiana (more susceptible than P. strobus) , 

 and P. monticola (fairly rare but always highly susceptible) . 



Emphasis is given to the need for further investigation of 

 variation in resistance within white pine species—especially 

 P. amandii s P. peuce 3 P. griffithii, P. cembra 3 and P. sibiricc. 

 To make full, yet judicious and economical use of resistant 

 germ plasm now, or soon available, international cooperation 

 will be a necessity. 



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