A tall plant (TT) is crossed with a short plant (tt). If the F1 pea plants are allowed to pollinate, A. the offspring will be of medium height B. all of the offspring will be tall C. all of the offspring will be short D. the offspring can be tall or short

Question

A tall plant (TT) is crossed with a short plant (tt). If the F1 pea plants are allowed to pollinate,                                                   A. the offspring will be of medium height     B. all of the offspring will be tall                  C. all of the offspring will be short                  D. the offspring can be tall or short

matt101 · Answer

If you cross a homozygous tall plant (TT) with a homozygous short plant (tt), all the F1 offspring will be heterozygous (Tt). If the F1 are then crossed themselves, THEIR offspring will have genotypes 1 TT : 2 Tt : 1 tt which corresponds to phenotypes 3 tall : 1 short (assuming T is dominant to t). That makes D your answer.

F1 Punnett square for reference:

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