1:1:1:1 ratio of progenies can be obtained if the plants for crossing are :
A. TTRR x ttRR
B. TtRr x ttrr
C. TERR x ttrr
D. Ttrr x ttRr

Options

A. A,B,C
B. A,B,C,D
C. B,D
D. A,B,C

Answer

To solve the problem of determining which crossing will yield a 1:1:1:1 ratio of progenies, we need to analyze the given options based on the principles of inheritance, specifically focusing on the genotypes of the parents and the expected phenotypic ratios.

### Step-by-Step Solution:

1. **Understanding the 1:1:1:1 Ratio**:
- A 1:1:1:1 ratio indicates that we are looking for a dihybrid cross where two traits are segregating independently, resulting in four different combinations of alleles in the offspring.

2. **Analyzing Each Option**:
- **Option A: TTRR x ttRR**
- This cross will produce offspring that are all TtRR (100% TtRR). This does not yield a 1:1:1:1 ratio.
- **Option B: TtRr x ttrr**
- This cross can be analyzed using a Punnett square:
- TtRr can produce gametes: TR, Tr, tR, tr
- ttrr can produce gametes: tr
- The combinations will be: TtRr, Ttrr, ttRr, ttrr (resulting in a 1:1:1:1 ratio).
- **Option C: TERR x ttrr**
- This cross will produce offspring that are all TtRr (100% TtRr). This does not yield a 1:1:1:1 ratio.
- **Option D: Ttrr x ttRr**
- This cross can also be analyzed using a Punnett square:
- Ttrr can produce gametes: Tr, tr
- ttRr can produce gametes: tR, tr
- The combinations will be: TtRr, Ttrr, ttRr, ttrr (resulting in a 1:1:1:1 ratio).

3. **Conclusion**:
- The correct options that yield a 1:1:1:1 ratio are **Option B (TtRr x ttrr)** and **Option D (Ttrr x ttRr)**.

### Final Answer:
- The plants for crossing that can yield a 1:1:1:1 ratio of progenies are **B. TtRr x ttrr** and **D. Ttrr x ttRr**.