Question

Grain colour is determined by 3 pairs of polygenes. Following cross AABBCC(dark colour) $\times$ aabbcc (light colour), in $F_2$ gen what proportion of the progeny is likely to resemble either parent?

Answer 1

Answer is "less than 5%"
Polygene results in quantitative inheritance which is characterized by occurrence of intermediate forms between the parental type. In case of crossing between AABBCC (dark color) and aabbcc (light color), in F2 generation seven phenotypes will obtain with ratio of 1 : 6 : 15 : 20 : 15 : 6 : 1. The total number of progeny is 64, out of which only two will be likely resemble with either parents. Hence, their proportion in F2 generation would be 3.12 i. e. less than 5%