When red flowered plants are crossed with white flowered plants the `F_(2)` generation gives a ration of 3:1. What do you conclude?

Options

A. That there are lethal genes
B. That three is independent assortment
C. That white colour is dominant
D. That red colour is dominant.

Answer

To solve the question regarding the inheritance of flower color in plants, we can follow these steps:

### Step 1: Understand the Cross
When red-flowered plants are crossed with white-flowered plants, we need to determine the inheritance pattern of flower color. Let's denote the allele for red flowers as "R" and the allele for white flowers as "r".

### Step 2: Analyze the F1 Generation
In the F1 generation, all offspring will inherit one allele from each parent. Since red (R) is dominant over white (r), all F1 plants will have the genotype "Rr" and will display the red flower phenotype.

### Step 3: Determine the F2 Generation
When the F1 generation (Rr) is self-crossed (Rr x Rr), we can use a Punnett square to predict the genotypes of the F2 generation.

- Possible gametes from each parent: R and r
- Punnett Square results:
- RR (homozygous red)
- Rr (heterozygous red)
- Rr (heterozygous red)
- rr (homozygous white)

### Step 4: Calculate the Ratio
From the Punnett square, we can see the following genotypic ratio:
- 1 RR: 2 Rr: 1 rr

This translates to a phenotypic ratio of:
- 3 red (RR + Rr) : 1 white (rr)

### Step 5: Conclusion
The observed ratio of 3:1 in the F2 generation indicates that the red flower color is dominant over the white flower color. Therefore, we conclude that red color is dominant.

### Final Answer
The conclusion is that red color is dominant.

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