Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) x aabbcc (light colour), in $F_2$ generation what proportion of the progeny is likely to resemble either parent?

In polygenic inheritance involving 3 pairs of genes, the number of phenotypes in $F_2$ follows the ratio of coefficients in $(a+b{)}^6$, which is $1:6:15:20:15:6:1$. The total number of possible combinations is $2^6=64$. Only 1 offspring will resemble the dark parent (AABBCC) and 1 will resemble the light parent (aabbcc). Proportion = $2/64=1/32\approx 3.12\%$, which is less than 5 percent.