406 W. A. BECKER AND M. A. MARSDEN 



The gains for stage A were much larger than given previously for 

 the 1960, 1962, and 1963 progeny tests (Bingham et al. , 1969). Within 

 an elevational zone stage A gains were larger than either stage B or C 

 gains . 



The total gains for all three methods of selection varied from 

 14.9% to 30.5%. 



DISCUSSION 



The results from the quantitative genetic analysis showed that the 

 gains from selection for healthy trees in the forest (stage A) were 

 greater than previously reported. This difference is probably due to 

 the fact that inoculation of seedlings in the 1964 test occurred during 

 the second rather than during the first growing season. 



Also the heritabilities were in general lower for the selection unit 

 method of selection than had been estimated previously. One factor 

 affecting the heritability was the high estimate of dominance and 

 epistatic variance as compared with the estimate of the additive genetic 

 variance in each elevational zone. The high estimate of dominance and 

 epistatic variance could be a result of a few dominant major genes for 

 resistance or susceptibility segregating in the population. 1 



REFERENCES 



Anderson, R. L., and T. A. Bancroft. 1952. Statistical theory in 



research. McGraw-Hill Book Co., New York. 399 p. 

 Bartlett, M. S. 1936. The square root transformation in analysis of 



variance. J. Royal Statis. Soc . Suppl . 3: 68-78. 

 Bartlett, M. S. 1947. The use of transformations. Biometrics 3: 39-52, 

 Becker, W. A. 1967. Manual of procedures in quantitative genetics. 



2nd ed. Program in Genetics, Wash. State Univ., Pullman, Wash. 130 p. 

 Bingham, R. T., R. J. Olson, W. A. Becker and M. A. Marsden. 1969. 



Breeding blister rust resistant western white pine. V. Estimates of 



heritability, combining ability, and genetic advance based on tester 



matings. Silvae Genet. 18: 28-38. 

 Fisher, R. A. and F. Yates. 1948. Statistical tables for biological, 



agricultural and medical research. 3rd ed . Hafner Publ. Co., New 



York. 112 p. 

 Kendall, M. G. , and A. Stuart. 1963. The advanced theory of statistics, 



Vol. 1. Hafner Publ. Co., New York. 433 p. 

 Scheffe\ H. 1959. The analysis of variance. John Wiley $ Sons, New 



York. 477 p. 



1 Editor's note: The reader is directed to Hoff and McDonald's 

 paper in these proceedings } where dominance (single mac or 9^ ne effects 

 controlling resistance) is brought out. 



