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In a plant , tallness is dominant over d...

In a plant , tallness is dominant over dwarfness and red flowers are incompletely dominant over white flowers, the hybrid being pink. How many offsprings will be of tall height with pink flowers from a cross involved two plants each of which is hybrid tall and has pink flowers ?

A

`4/16`

B

`6/16`

C

`10/16`

D

`2/16`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to determine the number of offspring that will be tall with pink flowers from a cross between two hybrid plants. Here's a step-by-step breakdown of the solution: ### Step 1: Define the Traits - **Height**: Tallness (T) is dominant over dwarfness (t). - **Flower Color**: Red (R) is incompletely dominant over white (r), resulting in pink (Rr) when heterozygous. ### Step 2: Determine the Genotypes of the Parents Both parent plants are hybrids for both traits: - **Height**: Tt (tall) - **Flower Color**: Rr (pink) Thus, the genotype of each parent plant is **TtRr**. ### Step 3: Set Up the Punnett Square We will use a fork-line method to analyze the inheritance of the two traits separately. #### Height Cross (Tt x Tt) 1. Possible gametes: T, t 2. Punnett Square for height: ``` T | t ---------------- T | TT | Tt ---------------- t | Tt | tt ``` 3. Resulting genotypes: - TT: 1 (tall) - Tt: 2 (tall) - tt: 1 (dwarf) Thus, the probability of tall offspring (TT or Tt) is: - Probability of TT = 1/4 - Probability of Tt = 2/4 - Total probability of tall = 3/4 #### Flower Color Cross (Rr x Rr) 1. Possible gametes: R, r 2. Punnett Square for flower color: ``` R | r ---------------- R | RR | Rr ---------------- r | Rr | rr ``` 3. Resulting genotypes: - RR: 1 (red) - Rr: 2 (pink) - rr: 1 (white) Thus, the probability of pink flowers (Rr) is: - Probability of Rr = 2/4 = 1/2 ### Step 4: Combine Probabilities Now, we need to find the combined probability of getting tall offspring with pink flowers: - Probability of tall (T) = 3/4 - Probability of pink (Rr) = 1/2 To find the combined probability: \[ \text{Combined Probability} = \left(\frac{3}{4}\right) \times \left(\frac{1}{2}\right) = \frac{3}{8} \] ### Step 5: Determine the Total Offspring If we assume we are looking at a total of 16 offspring (as commonly used in genetic problems), we calculate the expected number of tall pink offspring: \[ \text{Number of tall pink offspring} = \frac{3}{8} \times 16 = 6 \] Thus, the final answer is that **6 offspring will be tall with pink flowers**.
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