Quantitative Genetics 



All mean squares associated with the main effects of families at each planting site 

 (table 5) were statistically significant at the 1 percent level of probability. As a percent 

 of the sum of variance components, the family variance accounted for about 4 percent of the 

 total variance and slightly more variance than effects of populations. Still, the use of 

 these results to estimate genetic components of variance (table 6) needs explanation. 



Because of the methods of calculation, bias is introduced at four levels into estimates 

 of the additive genetic variance, phenotypic variance, and, consequently, heritabilities . 

 First, the assumption is implied that families were composed of half-sibs. But, progenies of 

 wind -pollinated trees are slightly more closely related than actual half-sibs (Namkoong 1966); 

 thus, additive genetic variances (table 6) are slightly overestimated. 



Table S . --Results of analyses of variance of 16-year height for each location 



Source of 

 variance 



Hoi comb 



Mean 

 d.f. square 



Idaho City 



Mean 

 d.f. square 



Boulder Creek 



d.f. 



Mean 

 square 



Jack's Creek 



d.f. 



Mean 

 square 



Blocks 7 



Populations 36 



Families/ 



Populations 198 



Experimental 



error-^ 1186 



Within 2041 



544,147 1604 9 

 19,786 127 36 



10,350 



249 



207 



7,527 2002 1826 

 3,762 3762 2948 



213,488 1037 9 154,743 363 5 178,051 945 



21,302 97 36 30,265 128 36 22,499 315 



10,689 



218 207 16.171 340 193 12,907 464 



7,198 1924 1852 10,632 3804 470 10,726 2338 

 3,542 3542 2095 3,442 3442 710 7,078 7078 



^Contains sources of variance involving interactions of blocks. 



Table 6. --Genetic components of variance for each location. 

 Calculations follow Namkoong (1979) 



Holcomb Idaho City Boulder Creek Jack's Creek 



^2 = o2 + a2 + o2,„ 6013 5684 7586 9880 



Additive genetic variance: 



o? = 4o2 „ ' 996 872 " 1360 1856 



A F/P 



Total phenotypic variance: 



4 = °W ' ' 4/P 



Family phenotypic variance: 



°TP = °W ^ °E ^ °F/P ^^^^ 



lleritability of families: 



hi = °l 0.27 0.33 ' 0.34 0.17 



r 



4p 



Heritability of individuals: 



h2 = °A 0.17 0.15 0.18 0.19 



4 



6 



