Passage II

Plants from Species X can be tall or short, and they can have red, pink, or white flowers. Height in Species X plants is controlled by Gene T, which has 2 alleles, T and t. Flower color in Species X plants is controlled by Gene R, which also has 2 alleles, R and r. To determine how height and flower color are inherited in Species X, a student conducted the following crosses.

Cross 1

Two tall Species X plants, each with the genotype Tt, were crossed. The numbers and phenotypes of the resulting offspring are shown in Table 1.

Cross 2

Two pink-flowered Species X plants, each with the genotype Rr, were crossed, and the numbers and phenotypes of the resulting offspring are shown in Table 2.

Cross 3

Two Species X plants, each with the genotype TtRr, were crossed. The numbers, genotypes, and phenotypes of the resulting offspring are shown in Table 3.

9. Suppose a gardener wants to produce tall pink-flowered Species X plants. Based on the results of Cross 3, which of the following pairs of plants, if crossed, would produce offspring with this phenotype?

Answer and Explanation

Your Answer is

Correct Answer is A

Explanation

From table 3, it can be seen that genotype TT and Tt correspond to tall, and genotype Rr corresponds to pink, so offspring can only be TTRr and TtRr.

The TTRR and TTrr parents in option A can produce TTRr offspring, which meets the requirements of the question