The selection for resistance to weeviling, in co-operation with the Forest 

 Insect Laboratory in Sault Ste. Marie, was continued. A plantation of white pine 

 (P. strobus) in the Kirkwood Management Unit was top-grafted for this purpose 

 with 1,050 scions of 21 clones of various native and hybrid white pine materials 

 selected for resistance to blister rust. 



Some white pine seeds were irradiated with thermal neutrons at the plant 

 of Atomic Energy of Canada Limited in the fall of 1960. Two hours in the 

 pile with a total dose of about 6,000 rem reduced germination to 36% of 

 untreated controls, i.e. the L 50 dose is somewhat lower than this treatment. The 

 surviving seedlings have thus far not shown abnormal growth peculiarities. Their 

 resistance to blister rust in comparison with seedlings raised from untreated seeds 

 of the same origin is being studied. 



Poplars 



The production of aspen-like hybrids, suitable for growing in southern 

 Ontario continued to be the chief aim of this project. This project was started 

 by the Research Branch in 1946. 



Interspecific hybridization resulted in 16 successful crosses between various 

 aspen hybrids. 



A good method for testing the rooting ability of stem cuttings was developed 

 and applied to numerous new aspen materials. Several promising clones of silver 

 poplar (Populus alba L.) and aspen hybrids raised at the Southern Research 

 Station, Maple, were selected on the basis of this new test. 



Hybrids of P. trichocarpa with various forms of P. alba are beginning to 

 show promising possibilities of introducing the very high rooting ability of P. 

 trochocarpa into aspen hybrids. Two new test plantations were established, one 

 comprising 15 clones and 12 populations in Wainfleet Township, and another 

 comprising one clone and 1 1 populations in the Fort Frances area. 



Hard Pines 



The development of new types, resistant to the European shoot moth and 

 superior in growth form and growth rate, continued to be the aim of this project. 

 This project was started by the Research Branch in 1954. 



A seed collection from red pine (P. resinosa Ait) plus trees was made 

 in northern Ontario, and 17 seedling populations were obtained. 



The breeding work was centered on a study of the efforts of inbreeding 

 on red pine, and 150 different pollinations on 2,068 flowers were made for this 

 purpose at Kane, Pa., and in Ontario in the Lake Abitibi area. Swastika and Chalk 

 River. Red pine of 12 origins were selfed, pollinated with mixed local pollen and 

 top-crossed with red pine pollen of one origin. 



The extensive interspecific hybridization of 1959 yielded 2,051 full seeds in 

 1960 and 667 seedlings in 1961 from 14 crosses involving Pinus densiflora, 

 P. nigra, P. resinosa and P. silvestris in different combinations. 



A selfing study of five red pine in Vivian Forest yielded seedlings that 

 indicate that at least these five trees are self-fertile and sihow no inbreeding 

 depression. 



The results of the grafting experiment of 1960 show that early winter 

 grafting — ^before January 1st — in the greenhouse is significantly superior to late 

 winter grafting. 



Much new material was set out this year at Turkey Point for provenance 

 tests, progeny tests and observation plots, study resistance to shoot moth under 

 conditions of severe attack. 



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