HEREDITY
MONOHYBRID CROSS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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100% Tt
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50% Tt, 50% tt
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75%Tt, 25%tt
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25%TT, 50%Tt, 25%tt
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Detailed explanation-1: -A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because tallness is the dominant trait. Thus, tallness is the dominant trait.
Detailed explanation-2: -When a heterozygous plant is self crossed with itself in a monohybrid cross, the genotypic ratio obtained is TT:Tt:tt = 1:2:1.
Detailed explanation-3: -When a pure tall plant (TT) is crossed with the pure short plant (tt), then the progeny in the F1 generation will be hybrid (Tt). When the F1 generation is self-crossed (Tt), then in the F2 generation, the progeny produced will be tall homozygous (TT), Tall heterozygous (Tt), and dwarf homozygous in the ratio of 1:2:1.
Detailed explanation-4: -So, the correct option is ‘50%’.
Detailed explanation-5: -Since a Tt heterozygous, tall plant produce with equal probabilities the gametes T and t, and the tt homozygous, short plant only t gametes, when they are crossed (Tt x tt) the progeny will be 50% tall (all genotypically Tt) and 50% short (all genotypically tt).