When blue flower with long pollen plant (BBLL) was crossed with red flowered with round pollen plant (bbll) in Lathyrus and their `F_(1)` was red round parent, then what is the ratio of blue long and red round obtained in this cross ?

Options

A. `1//16 : 1//16`
B. `7 // 16 : 7 //16`
C. `7 // 16 : 1 // 16`
D. `9 // 16 : 3 //16`

Answer

To solve the problem, we will follow these steps:

### Step 1: Identify the Genotypes of the Parents
The genotypes of the parents are given as:
- Blue flower with long pollen: **BBLL** (homozygous dominant)
- Red flower with round pollen: **bbll** (homozygous recessive)

### Step 2: Determine the F1 Generation
When we cross the two parents (BBLL x bbll), all offspring in the F1 generation will be heterozygous for both traits:
- F1 genotype: **BbLl**
- F1 phenotype: Blue flower and long pollen (since blue and long are dominant traits).

### Step 3: Cross the F1 Generation with the Recessive Parent
Now, we need to cross the F1 generation (BbLl) with the red round parent (bbll):
- F1 genotype: **BbLl**
- Recessive parent genotype: **bbll**

### Step 4: Determine the Gametes
The gametes produced by each parent are:
- F1 (BbLl) can produce four types of gametes: **BL, Bl, bL, bl**
- Recessive parent (bbll) can only produce one type of gamete: **bl**

### Step 5: Create a Punnett Square
We can set up a Punnett square to visualize the combinations:
```
bl
__________
BL | BbLl (Blue, Long)
Bl | Bbll (Blue, Round)
bL | bbLl (Red, Long)
bl | bbll (Red, Round)
```

### Step 6: Identify the Phenotypes
From the Punnett square, we can identify the phenotypes:
1. BbLl: Blue flower, Long pollen
2. Bbll: Blue flower, Round pollen
3. bbLl: Red flower, Long pollen
4. bbll: Red flower, Round pollen

### Step 7: Count the Parental Combinations
The parental combinations are:
- Blue flower with long pollen (BbLl)
- Red flower with round pollen (bbll)

### Step 8: Calculate the Ratio
From the combinations, we see:
- Blue Long (BbLl): 1
- Red Round (bbll): 1

Thus, the ratio of blue long to red round is **1:1**.

### Final Answer
The ratio of blue long to red round obtained in this cross is **1:1**.

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