NOTE 14B: This standard calculation gives the broad-sense heritability. Note that it applies only to this backcross population: The heritability in the F2, for example, would be higher and would include dominance components (because three genotypes would be present at each gene, not two as in a backcross). The assumption that the environmental variance in the F1 is the same as that in the backcross is dubious because the genotypes are different and, in particular, because the trait mean in the F1 is lower than in the backcross (2.25 g vs. 5.30 g). We would expect the variance to be higher if the mean is higher.