Question

In Mendel's monohybrid cross, the phenotypic ratio of long and dwarf pea is

• A. 3 : 1
• B. 1 : 3
• C. 1 : 2 : 1
• D. 1 : 1 : 2

Hint:

The phenotypic ratio of long to dwarf in a monohybrid cross is always 3 : 1.

Answer 1

The Correct Option is A

Step 1: Recall Mendel's monohybrid cross.
In a monohybrid cross between two heterozygous pea plants (Tt × Tt), where T represents the dominant allele for long and t represents the recessive allele for dwarf, Mendel observed the inheritance of these traits.
Step 2: Determine the genotypic and phenotypic ratios.
The genotypic ratio for this cross is 1 TT : 2 Tt : 1 tt. Since both TT and Tt plants express the long phenotype (dominant), and tt expresses the dwarf phenotype (recessive), the phenotypic ratio is 3 long : 1 dwarf.
Step 3: Conclusion.
Thus, the phenotypic ratio is 3 : 1.
Final Answer: \[ \boxed{3 : 1} \]