Q11 of 33 Page 1

How do Mendel’s experiments show that traits may be dominant or recessive?

When Mendel crossed pure tall (TT) pea plants with a pure dwarf (tt) pea plants, in the F1 generation he found that all pea plants were tall (Tt). There were no dwarf plants produced in an F1 generation. When he self-pollinated these F1 plants, in the F2 generation he obtained tall and dwarf plants in the ratio 3:1. Thus as three-fourths of the plant in an F2 generation are tall and one-fourth is dwarf so tall is a dominant trait whereas dwarf is a recessive trait [ which expressed itself only in homozygous condition]. So he concluded that for a particular trait [here in this example height of the plant] it may be dominant or recessive.


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