Question

The F${}_2$ generation offspring in a plant showing incomplete dominance, exhibit ?

• A. Variable genotypic and phenotypic ratios
• B. A genotypic ratio of 1 : 1
• C. A phenotypic ratio of 3 : 1
• D. Similar phenotypic and genotypic ratios of 1 : 2 : 1

Answer 1

Answer: (D)

Similar phenotypic and genotypic ratios of 1 : 2 : 1

• In incomplete dominance, $F_1$ hybrids exhibit a mixture of characters of two parents.
  
• The genotypic and phenotypic ratio remains the same in case of incomplete dominance and it is 1:2:1.
  
• For example, in snapdragon (Antirrhinum), one parent is homozygous for red flowers (AA) and the other is homozygous for white flowers (aa). No dominance is present and the heterozygous $F_1$ flowers are pink.

• The ratio is 1:2:1 of red, pink and white flowers in the $F_2$ progeny.

So, the correct answer is 'Similar phenotypic and genotypic ratios of 1: 2: 1'.