Question

How do Mendel’s experiments show that the traits may be dominant or recessive? 

Answer 1

Mendel crossed purebred tall pea plants with purebred dwarf pea plants and found that only tall pea plants were produced in the first generation, and there were no dwarf pea plants. He concluded that the first generation showed the traits of only one of the parent plants tallness. The trait of the other parent plant dwarfness did not show up in the progeny of the first generation.

He then crossed the tall pea plants obtained in the first generation (F₁ generation) and found that both tall plants and dwarf plants were obtained in the second generation (F₂ generation) in the ratio of 3 : 1. Mendel noted that the dwarf trait of the parent pea plant which disappeared in the first generation progeny reappeared in the second generation. In this way, Mendel’s experiments with tall and dwarf pea plants showed that the traits may be dominant and recessive.