What is the expected ratio of tall and dwarf plants when a heterozygous tall pea plant is crossed with a dwarf plant?
Answer and explanation
Correct answer: One to one
Use T for the dominant tall allele and t for the recessive dwarf allele. The heterozygous tall parent is Tt, while the dwarf parent is tt. The first parent produces T or t gametes, and the second produces only t gametes. The offspring are Tt and tt in equal expected numbers, so the phenotype ratio is one tall to one dwarf. Hence A is correct; 3:1 applies to a heterozygote × heterozygote cross.
Frequently asked questions
What is the correct answer to this question?
One to one
Why is this the correct answer?
Use T for the dominant tall allele and t for the recessive dwarf allele. The heterozygous tall parent is Tt, while the dwarf parent is tt. The first parent produces T or t gametes, and the second produces only t gametes. The offspring are Tt and tt in equal expected numbers, so the phenotype ratio is one tall to one dwarf. Hence A is correct; 3:1 applies to a heterozygote × heterozygote cross.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: World of Living. Topic: Heredity and Evolution.
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