How do Mendel’s experiments show that traits may be dominant or recessive?
Mendel performed a monohybrid cross experiment with pea plants, and he observed that one of the contrasting characters disappears in F1 generator. This character reappears in F2 generation (obtained by selfing F1) in just 25% of progeny.
Mendel concluded that:
The character which expresses itself in F1 is the dominant character while the other one which is not able to express through present in F1 individuals is recessive.
This recessive character is able to express only in its pure form i.e., in 25% of F2 individuals.