If a dwarf plant is treated with gibberllins it becomes tall and plant now crosses with pure tall plant then progeny of first generation (F1) is

Options

A. All dwarf
B. All tall
C. 75% tall and 25% dwarf
D. 75% dwarf and 25% tall

Answer

To solve the question, we need to analyze the genetic implications of the dwarf plant being treated with gibberellins and then crossed with a pure tall plant. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Genotypes
- The dwarf plant has a genotype of **tt** (homozygous recessive) because it expresses the dwarf phenotype.
- The pure tall plant has a genotype of **TT** (homozygous dominant) because it expresses the tall phenotype.

**Hint:** Remember that dominant alleles mask the expression of recessive alleles.

### Step 2: Treatment with Gibberellins
- Gibberellins are plant hormones that promote growth and can make the dwarf plant appear tall temporarily.
- However, gibberellins do not change the genetic makeup of the plant. The dwarf plant remains genetically **tt** despite its increased height.

**Hint:** Consider how hormones affect phenotype without altering genotype.

### Step 3: Crossing the Plants
- When the dwarf plant (tt) is crossed with the pure tall plant (TT), we can set up a Punnett square to determine the genotypes of the offspring (F1 generation).
- The possible gametes from the dwarf plant are **t** and from the tall plant are **T**.

**Hint:** Use a Punnett square to visualize the genetic combinations from the parents.

### Step 4: Determine the F1 Generation
- The offspring (F1 generation) will receive one allele from each parent:
- From the tall parent (TT), all offspring will receive a **T**.
- From the dwarf parent (tt), all offspring will receive a **t**.
- Therefore, all F1 progeny will have the genotype **Tt** (heterozygous).

**Hint:** Remember that heterozygous genotypes will express the dominant phenotype.

### Step 5: Phenotype of the F1 Generation
- Since **T** is dominant over **t**, all F1 plants will exhibit the tall phenotype, even though they are genetically heterozygous (Tt).

**Hint:** Dominance determines the observable traits in the offspring.

### Conclusion
- The F1 generation will consist entirely of tall plants with the genotype **Tt**.

### Final Answer
The progeny of the first generation (F1) will be tall plants with the genotype **Tt**.

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