Question

A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because

• A. tallness is the dominant trait
• B. shortness is the dominant trait
• C. tallness is the recessive trait
• D. height of pea plant is not governed by gene ‘T’ or ‘t’

Answer 1

The correct option is A

tallness is the dominant trait

The correct option is : A

Explanation of the correct option:

1. According to the Mendel's first law of inheritance or law of dominance, the hybrid offspring produced will only inherit the dominant trait in the phenotype.
2. The alleles that are suppressed are known as recessive traits while that determines the trait are known as dominant traits.
3. A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because tallness is the dominant trait.
4. Thus, tallness is the dominant trait.

Explanation of the incorrect option:

Option B :

As the progeny does not show any characteristic short pea plant, it means the shortness (tt) is a recessive trait.

Option C :

As the progeny shows all phenotypically tall plants, it means that tallness is a dominant trait.

Option D :

The height of the pea plant is governed by two alleles : “T” for tallness and "t" for shortness.

Final answer: A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because tallness is the dominant trait.