MP Board · Class 10 · Science · HeredityIn a pea plant, a homozygous tall plant (TT) is crossed with a homozygous dwarf plant (tt). Find the phenotypic and genotypic ratio of the F2 generation. Show complete step-by-step working.
Step-by-Step Solution
Step 1: Identify parental genotypes and phenotypes.\nParent 1 (Homozygous Tall) = TT\nParent 2 (Homozygous Dwarf) = tt \nStep 2: Determine gametes produced by parents.\nParent TT produces gametes with allele: T\nParent tt produces gametes with allele: t \nStep 3: Cross parents to find F1 generation.\nOffspring of F1 generation = Tt (All heterozygous tall) \nStep 4: Self-pollinate the F1 generation (Tt × Tt) to find F2 generation.\nGametes from F1 plants: T and t (from both male and female parents) \nStep 5: Draw Punnett Square for F2 generation:
| T | t | |
|---|---|---|
| T | TT | Tt |
| t | Tt | tt |
| \nStep 6: Determine Genotypes and Phenotypes of F2 generation. |
- TT (Homozygous Tall) = 1
- Tt (Heterozygous Tall) = 2
- tt (Homozygous Dwarf) = 1 \nStep 7: Calculate final ratios.
- Genotypic Ratio: 1 (TT) : 2 (Tt) : 1 (tt)
- Phenotypic Ratio: 3 Tall : 1 Dwarf
💡 Study Guide: This question tests core syllabus concepts from Heredity. For formulas, key summaries, and mock exam reference guides, read the full Heredity Revision Notes.