​In Mendel’s cross. a pure tall plant (TT) is crossed with a dwarf plant (t t) The Phenotypic ratio in generation is:​

Correct option is B

The correct answer is (B) 3 : 1.

In Mendel's cross of a pure tall plant (TT) with a dwarf plant (tt), the phenotypic ratio in the F1 generation is 3:1.

Here's why:

1. Parental Generation:
• Pure tall plant (TT)
• Dwarf plant (tt)
2. Gametes:
• Tall plant (TT) produces gametes with the T allele.
• Dwarf plant (tt) produces gametes with the t allele.
3. F1 Generation:
• All offspring in the F1 generation will be Tt (heterozygous).
• Phenotypically, all F1 plants will be tall because the T allele (tall) is dominant over the t allele (dwarf).
4. F2 Generation:
• When F1 plants (Tt) are self-crossed, the following phenotypic ratio is observed in the F2 generation:
• 3 Tall plants (TT, Tt, Tt)
• 1 Dwarf plant (tt)

Therefore, the phenotypic ratio in the F2 generation is 3:1 (tall:dwarf).