Mendel conducted breeding experiments on pea plants :
He selected pure breed tall and dwarf plants. He cross pollinated these plants. In the F1 generation obtained only tall plants, tallness is the dominant trait.
Then, he produced F2 generation by selfing of hybrids of F1 generation. He found that 3∕4 th of the plants were tall and 1/4 th were dwarf. The trait which remains hidden in F1 generation plants is the recessive trait.