Question

14. Cross a homozygous dominant plant with a heterozygous plant.
What is the genotypic ratio

Answer 1

To determine the genotypic ratio from crossing a homozygous dominant plant (let's denote its genotype as **AA**) with a heterozygous plant (genotype **Aa**), we can use a Punnett square.

Here’s how the cross looks:

- **Parent 1 (homozygous dominant):** AA
- **Parent 2 (heterozygous):** Aa

The possible gametes from each parent are:

- Parent 1 can only produce gametes: **A**
- Parent 2 can produce gametes: **A** and **a**

Setting up the Punnett square:

```
A | A
------------------
A | AA | AA
------------------
a | Aa | Aa
```

Now, we can see the resulting genotypes from this cross:

- **AA**: 2 times (from A and A)
- **Aa**: 2 times (from A and a)

So the resulting genotypes from this cross are:

- 2 **AA**
- 2 **Aa**

Now, to find the genotypic ratio, we summarize our findings:

- **AA**: 2
- **Aa**: 2

Thus, the genotypic ratio is:

**2 AA : 2 Aa**

This can also be simplified to:

**1 AA : 1 Aa**