Question

When a pure-tall pea plant is crossed with a pure-dwarf pea plant, the percentage of tall pea plants in F1 and F2 generation pea plants will be respectively:

• A. 100%; 25%
• B. 100%; 50%
• C. 100%; 75%
• D. 100%; 100%

Hint:

In a simple Mendelian cross, dominant traits like tall (T) mask the recessive dwarf trait (t). The F1 generation is all heterozygous (Tt), and the F2 generation follows a 3:1 ratio.

Answer 1

The Correct Option is A

A Mendelian monohybrid cross is performed between a pure tall pea plant (TT) and a pure dwarf pea plant (tt). The F1 generation, resulting from this cross, consists of all tall plants (Tt), as the tall allele is dominant.The F2 generation results from crossing two F1 plants (Tt x Tt):\[\text{Gametes from } Tt \rightarrow T, t\]The Punnett square demonstrates the following genotypes:\[\begin{array}{c|cc} & T & t \\\hlineT & TT & Tt \\t & Tt & tt \\\end{array}\]The genotype ratio for the F2 generation is:\[\text{Tall (TT or Tt)} : \text{Dwarf (tt)} = 3 : 1\]Consequently, 75% will be tall and 25% will be dwarf. The correct answer is option (1).