Suppose a flower color follows this additive model and depends on 5 loci. You have 2 pure breeding plant lines (red and white), cross them to produce F1s, and cross F1s to produce F2s. Among the F2s, What proportion do you expect to be pure red?
1) 1/4
2) 1/4³
3) 1/4⁵
4) 5^(1/4)