question_answer

The \[{{F}_{2}}\]generation offspring in a plant showing incomplete dominance, exhibit:

A)  variable genotypic and phenotypic ratio

B)  a genotypic ratio of 1 : 1

C)  a phenotypic ratio of 3 : 1

D)  similar phenotypic and genotypic ratio of 1 : 2 : 1

Correct Answer: D

Solution :

In incomplete (partial or intermediate) dominance the effect of dominant allele is diluted or modified, so that the phenotypic expression of the concerned trait in a hybrid is distinguishable from both parental type. Consequently both phenotypic and genotypic ratios in \[{{F}_{2}}\]generation are 1:2 :1. For example when Red and white flowered plants of Mirabilis jalapa has crossed, the \[{{F}_{1}}\] progenies show pink flower.