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NDA 2021 GAT · General Knowledge · Genetics and Heredity · hard

When pure tall pea plants (TT) are crossed with pure dwarf plants (tt), the F2 generation shows the phenotypic ratio of tall to dwarf as

Single correct option

When pure tall pea plants (TT) are crossed with pure dwarf plants (tt), the F2 generation shows the phenotypic ratio of tall to dwarf as
  1. A. 1 : 1
  2. B. 1 : 2 : 1
  3. C. 9 : 3 : 3 : 1
  4. D. 3 : 1
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Answer: (D) 3 : 1

The F1 plants are all tall (Tt). On selfing, F2 has genotypes TT, Tt and tt in the ratio 1 : 2 : 1, giving 3 tall to 1 dwarf phenotypically. 1 : 2 : 1 is the genotypic ratio, and 9 : 3 : 3 : 1 is the dihybrid ratio.
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Original question written in the NDA 2021 GAT pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake