Question

Explain Mendel’s monohybrid progeny with the help of any one cross.

Answer 1

• Mendel brought about a cross between two pea plants with only pair of contrasting characters. This type of cross is called a monohybrid cross. 
• Tall pea plants and dwarf pea plants were used in this cross. Hence this is parent generation (P₁).

• All the plants produced in F₁ generation are tall, having genotype Tt. This indicates that the gene responsible for tallness in pea plants is dominant over the gene responsible for dwarfness.
• When F₁ plants are self pollinated they produce second filial generation (F₂).
• In F₂ generation both tall and dwarf plants appeared in the ratio 3:1.
• Thus, the genotypic ratio of F₂ generation is 3 (Tall) : 1 (Dwarf) and the genotypic ratio is 1 TT : 2 Tt: 1 tt.