In tomatoes, red fruit is dominant to yellow fruit color. A farmer has plants that produce either red or yellow tomatoes. he has signed a contract with a large seed company to provide pure red dees and pure yellow seeds. the do not want hybrids. How can the farmer determine if his red tomatoes are pure or hybrid. The farmer can't see the genotype except for one phenotype.

To determine whether the red tomatoes are pure or hybrid, the farmer can perform a test cross. A test cross involves crossing the unknown tomato plants with a known genotype that exhibits the recessive trait (in this case, yellow tomatoes).

Here's how the farmer can conduct a test cross to determine if the red tomatoes are pure or hybrid:

Step 1: Select a yellow tomato plant with a known pure genotype. This plant should only produce yellow tomatoes.

Step 2: Take this selected yellow tomato plant and cross-pollinate it with the red tomato plant. This can be done by transferring the pollen from the yellow tomato's flowers to the red tomato's flowers using a small brush or by physically transferring the pollen-bearing parts of the yellow tomato to the red tomato's flowers.

Step 3: Allow the fruits resulting from this cross-pollination to develop and mature.

Step 4: After the fruits have ripened, observe the phenotype of the offspring (the tomatoes). If all the tomatoes are red, it suggests that the red tomato parent was pure breeding (homozygous) for the red fruit color. This means that the red tomatoes are also pure breeding.

Step 5: Conversely, if any of the tomatoes are yellow instead of red, it indicates that the red tomato parent was a hybrid (heterozygous) and carries a recessive yellow allele. This means that the red tomatoes are hybrid (heterozygous) for fruit color.

By performing this test cross, the farmer can determine whether the red tomatoes are pure or hybrid based on the observed phenotypes of the offspring.