how do Mendel find out dominant and recessive traits ?

Dear Student,

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.

Regards