In pea plants, yellow seed color is dominant and green seed color is recessive. Let's analyze the generational outcomes following Mendel's method, where two true breeding parents with opposite traits are crossed.
### Generational Analysis
1. Parent (P) Generation:
- P Generation has all yellow seeds: This statement is correct. When true-breeding yellow-seeded plants (YY) are crossed with true-breeding green-seeded plants (yy), the resultant P generation plants each have yellow seeds because yellow is dominant.
- P Generation has all green seeds: This statement is incorrect. As we mentioned, the P generation plants have yellow seeds.
- P Generation has yellow and green seeds: This statement is incorrect. The P generation is composed of true-breeding yellow or green-seeded plants separately, not a mix within a single plant.
2. First Filial (F1) Generation:
- F1 Generation has yellow and green seeds: This statement is incorrect. All the F1 plants exhibit the dominant trait. Since yellow is dominant over green, all F1 plants will have yellow seeds.
- F1 Generation has all yellow seeds: This statement is correct. The F1 generation comes from crossing YY with yy, resulting in all heterozygous Yy plants, which display yellow seeds.
3. Second Filial (F2) Generation:
- F2 Generation has all green seeds: This statement is incorrect. The F2 generation results from crossing two heterozygous F1 plants (Yy x Yy). This creates a 3:1 phenotypic ratio (3 yellow-seeded plants to 1 green-seeded plant).
- F2 Generation has yellow and green seeds: This statement is correct. The genetic cross Yy x Yy in the F2 generation produces plants that could have either yellow seeds (YY or Yy) or green seeds (yy), so the F2 generation will display both yellow and green seeds.
### Conclusion
From the options provided:
- The P generation has all yellow seeds. (Correct)
- The F1 generation has all yellow seeds. (Correct)
- The F2 generation has yellow and green seeds. (Correct)
Thus, the valid statements are the first, the fifth, and the seventh options:
1. The P generation has all yellow seeds.
5. The F1 generation has all yellow seeds.
7. The F2 generation has yellow and green seeds.
