Mendel conducted a monohybrid cross with pea plants and he observed that one of the contrasting character disappear in f1 generation . This characteristics reappears in f2 generation.Fronm this he concluded that the character which expresses itself is dominant which is not able to express is recessive

Mendel selected true breeding tall (TT) and dwarf (tt) pea plants.When a tall pea plant is crossed with a short (dwarf) pea plant, all the F1 hybrids are tall. (i.e., in this case, the gene causing tallness is dominant while the gene causing dwarfness is recessive.).The trait expressing itself in the hybrid is the dominant one.\xa0(Mendel’s first law of inheritance states that when a pair of contrasting factors is brought in a hybrid, one factor inhibits the appearance of the other. The one which inhibits is the dominant one and which is inhibited is recessive.)\xa0
Mendel conducted the experiments using\xa0Pisum sativum\xa0or pea plant.He\xa0selected homozygous tall (TT) and dwarf (tt) pea plants.He crossed the tall pea plant with the dwarf pea plant.It was observed that the F1\u200b\xa0generation are all tall plants.Thus, it was concluded that the gene causing tallness is dominant while the gene causing dwarfness is recessive.The trait expressing itself in the hybrid is the dominant one.\xa0This experiment proves Mendel’s first law of inheritance.