Question

In a Mendelian cross between two heterozygous pea plants (Tt x Tt), where "T" is the dominant allele for tall plants and "t" is the recessive allele for short plants, what is the probability of obtaining a short plant?

• A. \( 0 \)
• B. \( \frac{1}{4} \)
• C. \( \frac{1}{2} \)
• D. \( 1 \)

Hint:

In a Mendelian monohybrid cross, the possible genotypes and phenotypes can be predicted using a Punnett square. For a recessive trait to be expressed, the individual must be homozygous recessive (tt).

Answer 1

The Correct Option is B

This problem concerns Mendelian inheritance of plant height, controlled by alleles T (dominant for tall) and t (recessive for short). Crossing two heterozygous plants (Tt) yields the following offspring genotypes:

1. Parental cross: \( Tt \times Tt \).

2. Punnett square analysis reveals possible offspring genotypes: \( TT \) (homozygous dominant, tall), \( Tt \) (heterozygous, tall), and \( tt \) (homozygous recessive, short).

3. The genotype \( tt \) is required for a short plant. The probability of obtaining this genotype is \( \frac{1}{4} \).