If the F1 generation allows for self-pollination, what will be the genotypic ratio of the offspring?

Analyze the question: The question asks about the F1 generation self-pollinating and the genotypic ratio of the offspring (F2). The question is about a monohybrid cross, where the F1 plants are hybrids (heterozygous, e.g., Tt). Note that it asks for the genotypic ratio, not the phenotypic ratio.

Concept: In Mendel's monohybrid cross, pure-breeding parents (TT × tt) produce an F1 generation in which all plants are heterozygous (Tt). When the F1 self-pollinates (Tt × Tt), the gametes from each parent are T and t.

Solution: Punnett square for Tt × Tt:

| | T | t | |---|---|---| | T | TT | Tt | | t | Tt | tt |

Offspring genotypes:

• 1 TT (homozygous dominant)
• 2 Tt (heterozygous)
• 1 tt (homozygous recessive)

Genotypic ratio = 1 TT : 2 Tt : 1 tt = 1 : 2 : 1

(The phenotypic ratio would be 3 : 1, which is option C. This is the usual trap, because the question asks for the genotypic ratio.)

Answer: Option A, 1 : 2 : 1.

Tip: Remember "Genotype = 1 : 2 : 1, Phenotype = 3 : 1" for a monohybrid cross with complete dominance. Always check whether the question asks for genotypic or phenotypic ratio before choosing.