NCERT · Class 10 · Science · HeredityIf a pure tall pea plant with round seeds (TTRR) is crossed with a pure dwarf pea plant with wrinkled seeds (ttrr), what will be the phenotype of the F1 generation? Explain the reasoning behind your answer.
Step-by-Step Solution
Step 1: Identify parental genotypes and phenotypes.\nParent 1 (Homozygous Tall, Homozygous Round Seeds) = TTRR\nParent 2 (Homozygous Dwarf, Homozygous Wrinkled Seeds) = ttrr \nStep 2: Determine gametes produced by each parent.\nParent TTRR produces gametes carrying: TR\nParent ttrr produces gametes carrying: tr \nStep 3: Combine gametes to form the F1 generation.\nFertilization of TR gametes with tr gametes results in offspring with the genotype: TrRr (or conventionally written as TrRr -> Let's use standard notation: TrRr is TtRr).\nSo, F1 genotype = TtRr. \nStep 4: Analyze the phenotype of the F1 generation.
- The allele 'T' is dominant over 't', so the plant is tall.
- The allele 'R' is dominant over 'r', so the seeds are round. \nStep 5: Final Conclusion.\nTherefore, the phenotype of all individuals in the F1 generation will be Tall with Round seeds, because dominant alleles mask the expression of recessive alleles.
💡 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.