MULTIPLE TRAIT SELECTION IN WHITE PINE 593 



Table 1. Two hypothetical schemes for evaluating resistance to 

 white pine blister rust and to white pine weevil in a breeding 

 program, indicating procedures and percentages of healthy and 

 unweeviled survivors at various ages 













Scheme 2, Nursery and 





Scheme 1, Forest 

 Survivors after 



exposure 

 attack bv: 



forest exposure 





Survivors after attack by: 



Age 



Rust 



Weevil 



Eith 



er 



Rust 



Weevil Either 



2-5 





outplant 







expose 





5-4 



100 



100 



100 







expose 



4 











50 

 evaluat 



50 15 

 e resistance 



5 



95 



98 



93 







outplant 15 



10 



60 



45 



27 





8 



7 0.56 



15 



20 



5 



1 





3 



2 0.06 



20 



4 



2 



0. 



08 







7 



eva 



luate resistance 







evaluate growth 







and grov, 



th 









Table 2. Genetic parameters of traits correlated with yield 

 of white pine 



Additive 

 Phenotypic genetic Genetic Herita- 

 Phenotypes correlations values correlations bilities 



g r h 



s gy g 



r bg 

 b r by h b 



bw 



w r h 



wy w 



y r h 



gw y 



G, 



growth rate 



R GY 

 R BG 



B, 



blister rust 



R BY 





resistance 







R BW 



w, 



weevil 



R WY 





resistance 



Y, 



yield 



R GW 



