The leader of the site group presented a paper at the Fifth World 

 Forestry Congress entitled "The Classification of Forest Productivity Systems". 

 At various formal and informal meetings he was able to present the advantages of 

 the Ontario approach over those used in the United States and Europe. 



TREE BREEDING 



Since the inception of the tree breeding program in 1946 there have 

 been two main projects: the selection and propagation of superior strains of 

 white pine resistant to blister rust and weevil » and rapidly growing poplars of 

 good form for southern Ontario. A sizeable program has developed since 1954 in 

 the breeding of two needled pines. Smaller projects on chestnuts and white cedar 

 have continued since 1955 and 1956 respectively. 



White Pine 



New materials included scions of Idaho white pine (Pinus monticola ) 

 showing high heritability of blister rust resistance, several P. cembra materials 

 from Switzerland and a few plus trees of northern Ontario white pine (P. strobus ). 

 Hybridization was centered on interracial work with native white pine (P. strobus ), 

 using pollen from one tree at Pointe Platon, Quebec on grafts of the same origin 

 at Maple. Pollen of a promising P. griffithii was received from Rochester and 

 much of our own pollen was used to determine the breeding value of our own mate- 

 rials. An abundant crop of cones, containing hybrid seeds, was harvested. These 

 include the first seeds of interracial hybridization-. A fairly large seed collec- 

 tion from resistant trees in Germany yielded seedlings that, thus far, do not seem 

 to be more resistant to blister rust than the average native white pine. 



Propagation of white pine by juvenile cuttings was started; also an 

 experiment in bench grafting of white pine in the greenhouse to obviate the use 

 of potted stock. Irradiation of white pine seed, to induce mutations of possible 

 value, was carried out at Chalk River, Ontario. Seeds from several plus trees 

 at Petawawa have yielded seedlings for progeny tests. 



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