How do mendel's experiment show that traits may be dominant or recessive ?
Mendel crossed tall pea plants with dwarf pea plants. He obtained tall plants in the first generation and when first generation was self crossed tall and dwarf pea plants were obtained in a ratio of 3 tall and 1 dwarf pea plants. This shows that the tall trait was dominant over the dwarf trait as in first generation no dwarf plant was obtained and in second generation tall plants was 75% as compared to 25% of dwarf plants.
Mendel selected true breeding tall (TT) and dwarf (tt) pea plants. Then, he crossed these two plants. The seeds formed after fertilization were grown and these plants that were formed represent the first filial or F1generation. All the F1plants obtained were tall.Then, Mendel self-pollinated the F1plants and observed that all plants obtained in the F2generation were not tall. Instead, one-fourth of the F2plants were short.From this experiment, Mendel concluded that the F1tall plants were not true breeding. They were carrying traits of both short height and tall height. They appeared tall only because the tall trait is dominant over the dwarf trait.