Question

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

• A. Half
• B. Less than 5%
• C. One third
• D. More than 10%

Answer 1

The correct option is B Less than 5%

AABBCC (dark grains) x aabbcc (light grains)
$\downarrow$
$F_1$: AaBbCc
$\downarrow$
$F_2$: (selfing) AaBbCc x AaBbCc



Since, the trait is a polygene, only 2 progenies (AABBCC and aabbcc) out of 64 progenies will resemble either parent. Hence, the percentage of progeny which is likely to resemble either parent = $\frac{2}{64}\times 100$ = 3.125% which is less than 5%.