Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) x aabbcc (light colour), in F2 generation what proportion of the progeny is likely to resemble either parent?

Question

Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) x aabbcc (light colour), in F2 generation what proportion of the progeny is likely to resemble either parent? (A) Half (B) Less than 5 percent (C) One third (D) None of these

Tardigrade Admin · Accepted Answer

Polygene results in quantitative inheritance which is characterised by occurrence of intermediate forms between the parental type. In case of crossing between AABBCC (dark colour) and aabbcc (light colour) in F 2 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 F 2 generation would be 3.12 i.e., less than 5 %.

Q. Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) x aabbcc (light colour), in F2​ generation what proportion of the progeny is likely to resemble either parent?

Half

Less than 5 percent

One third

None of these

Q. 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?