VEGETATIVE PROPAGATION EXPERIMENTS IN WHITE PINE 



L. Zufa 



Research Branch, Ontario Department of Lands and Forests 

 Maple, Ontario, Canada 



ABSTRACT 



Vegetative propagation is a vital tool for defining genetics 

 of resistance and pathogenicity. Rooting of white pine cuttings 

 and needle fascicles was attempted. Results showed that (1) 

 cuttings and needle fascicles of P. griffithii x strobus rooted 

 better than those of P. strobus, (2) rooting ability of P. 

 strobus did not decrease significantly up to the age of 10 years, 

 (3) no significant differences were found in the rooting between 

 cuttings and needle fascicles, (4) cuttings and needle fascicles 

 rooted either in plastic tubes or in flats, (5) cuttings planted 

 in tubes developed an evenly distributed and balanced root system 

 in contrast to the unilateral roots developed on cuttings in 

 flats, (6) cuttings planted in tubes showed a better survival 

 than those planted in flats, and (7) coarse sand with a bottom 

 layer of white pine humus was a superior rooting medium to a 

 mixture of sand and humus . 



The experiments also gave indications that (1) differences in 

 rooting ability existed between different white pine species 

 and their hybrids, (2) differences in rooting ability existed 

 among populations of the same species or hybrid, (3) within 

 population variation in rooting ability existed, and (4) within 

 population variation in rooting ability was more pronounced 

 with age. 



INTRODUCTION 



The white pine vegetative propagation trials were initiated to 

 exploit more accurate means of blister rust resistance testing and to 

 prevent the loss of genetic gain achieved in the selection of blister 

 rust-resistant trees. Vegetative propagation provides full utilization 

 of the resistant trees and a shortcut in white pine improvement work. 



Farrar and Grace (1940, 1942) made observations on the influence of 

 time of cutting collection on rooting. They obtained better results 

 with Pinus strobus L. cuttings collected and planted in late August than 

 with those taken in the spring. 



Thimann and Delisle (1939) studied rooting differences of cuttings 

 taken from various parts of the crown. They found that cuttings taken 

 from lateral branches rooted consistently better than those taken from 



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