Question

In a pea plant (Pisum sativum) inflated pod shape is dominant over constricted pod shape. The expected ratio of phenotypes of the offspring in a cross between both the parents with heterozygous inflated pod shape will be:

• A. 1:0
• B. 1:1
• C. 2:1
• D. 3:1

Hint:

In a monohybrid cross between two heterozygotes, the phenotypic ratio is always 3:1 (dominant:recessive).

Answer 1

The Correct Option is D

Let the allele for inflated pod shape be \( I \) and for constricted pod shape be \( i \). The genotype of heterozygous inflated pod shape is \( Ii \). A cross between two heterozygous parents results in: \[ Ii \times Ii \Rightarrow II,\ Ii,\ iI,\ ii \] Phenotypic ratio = 3 Inflated : 1 Constricted.