Answer:
F1) 100% bbRr, red flowered plants.
Explanation:
<u>Available data:</u>
- flowers may be yellow, blue, red, or mauve
- colors may be true-breeding
- the cross of blue-flowered plants with red-flowered plants, produce plants that have yellow flowers
- F2 generation: 9/16 yellow, 3/16 blue, 3/16 red, and 1/16 mauve.
Knowing that the phenotypic ratio is 9:3:3:1, we can assume that there are two genes involved in the flower color expression. We can name these genes B and R with a dominant and a recessive allele each (B, b and R, r respectively).
According to the first cross, we might establish the following genotypes:
1st Cross: blue-flowered plant x red-flowered plant
Parentals) BBrr x bbRR
Gametes) Br, Br, Br, Br bR, bR, bR, bR
F1) 100% BbRr, yellow plants
Parentals) BbRr x BbRr
Gametes) BR, Br, bR, br
BR, Br, bR, br
Punnett square) BR Br bR br
BR BBRR BBRr BbRR BbRr
Br BBRr BBrr BbRr Bbrr
bR BbRR BbRr bbRR bbRr
br BbRr Bbrr bbRr bbrr
F2) 9/16 yellow ---> 1/16 BBRR + 2/16 BBRr + 4/16 BbRr + 2/16 BbRR
3/16 blue ------> 1/16 BBrr + 2/16 Bbrr
3/16 red---------> 1/16 bbRR + 2/16 bbRr
1/16 mauve ----> 1/16 bbrr
So,
- Yellow-flowered plants: BBRR, BBRr, BbRR, BbRr
- Red-flowered plants: bbRR, bbRr
- Blue-flowered plants: BBrr, Bbrr
- Mauve-flowered plants: bbrr
According to these genotypes, the second cross would be like following,
2nd Cross: true-breeding red-flowered plants with true-breeding mauve flowered plants.
Parentals) bbRR x bbrr
Phenotype) Red Mauve
Gametes) bR, bR, bR, bR br, br, br, br
Punnett square) bR bR bR bR
br bbRr bbRr bbRr bbRr
br bbRr bbRr bbRr bbRr
br bbRr bbRr bbRr bbRr
br bbRr bbRr bbRr bbRr
F1) 100% bbRr, red flowered plants.
