for the grafting of breeding materials, five new hybrid populations were ob- 

 tained. In breeding for rooting ability from stem cuttings, it was found possible 

 to cross silver poplar with western Cottonwood and to produce a second generation 

 progeny of silver poplar-aspen hybrids. The new method of aspen seedling pro- 

 duction developed in the nursery in 1954 was modified and considerably improved. 

 A successful method of bench -grafting of aspen hybrids was worked out. TTie 

 establishment of poplar test plantations in co-operation with several wood-using 

 industries was continued and considerably expanded. Attempts at pollen 

 fractionation of aspens, with the aim of separating giant pollen grains for the 

 production of extremely vigorous hybrids, were started in co-operation with the 

 National Research Council. 



Two-needled Pines 

 The aim is the production of new types of hard pine, resistant to the 

 European shoot moth and suitable for planting in southern Ontario, in areas where 

 attacks by this insect make the growing of hard pines extremely difficult. To 

 this end, four crosses with Asiatic pine species were made in 1953 which pro- 

 duced hybrid seedlings, and six crosses were made in 1954 yielding seemingly 

 viable seeds. Nine new crosses were made in 1955. Crosses of Japanese red 

 pine with species of the Austrian pine group have thus far yielded the most 

 promising hybrids. Pollen of Japanese black pine, a species showing high 

 resistance to the shoot moth, was obtained for further hybridization work. An 

 experiment in partial girdling of young planted red pine, to induce early flowering 

 was started in 1947 and is now yielding results of significance to this breeding 

 project. An experiment in phloem inversion, also with the aim of early flower 

 production in hard pines, was started in 1955. 



Chestnut 

 A sweet chestnut breeding project was started in 1955. The aim is 

 to produce hardy dwarf chestnuts resistant to blight. Such materials could be 



