Question

Two homozygous parents harbouring two different alleles of a gene, exhibiting incomplete dominance for flower colour were used for a genetic experiment. Which one of the following statements is incorrect?

• A. The $F2$ generation will consist of plants of three different flower colours.
• B. The genotypic and phenotypic ratios obtained in the $F2$ generation will be different.
• C. The $F1$ generation will be of a different flower colour compared to both the parents.
• D. The genotypic ratio obtained in the $F2$ generation will be the same irrespective of whether it is complete dominance or incomplete dominance.

Answer 1

Answer: (B)

The genotypic and phenotypic ratios obtained in the $F2$ generation will be different.

Incomplete dominance is a type of dominance in which the phenotype of a heterozygote is intermediate between the two homozygous parents having contracting phenotypes. When two homozygous parents having two different alleles of gene for flower colour are crossed, the F${}_1$ generation will be of a different flower colour compared to both the parents. The F${}_2$ generation will have plants with all the three different flower colours. The genotypic ratio obtained in the F${}_2$ generation will be the same irrespective of whether it is complete dominance or incomplete dominance. The phenotypic ratio however will be same as genotypic ratio, that is 1:2:1 where 1 part will be homozygous dominant, 2 part will be heterozygous showing new flower colour and 1 part will be homozygous recessive.

Thus, the correct answer is option B.