Question

When a pure bred, red flower producing plant of genotype RR is crossed with a pure bred, white flower producing plant of genotype $rr$, all the plants produced pink flowers. If all the plants in each generation from $F_1$ to $F_6$ are selfed, what will be the percentage of plants with red and white flowers in the final population consisting of a large number of individuals?
(Consider that flower colour as no effect on reproduction and survival.)

• A. 3-4
• B. 12-13
• C. 49-51
• D. 97-100

Answer 1

Answer: (D)

A cross between red flower producing plant and white flower producing plant is shown below

When $F_{1}$ to $F_{6}$ individuals during each generation are sefed, i.e.

This shows that $50\%$ plants are homozygous with red and white flowers.
We know that homozygous plants will produce homozygous off springs.
Thus during each generation the heterozygous progeny will give further $50\%$ heterozygous and $50\%$ homozygous progeny. This will reduce the number of heterozygous successively.
$\therefore $ The final population will have $97-100\%$ of homozygous progenies, i.e. red and white flowers plants.