Question

PLEASE HELP!
A major seed company wants seeds that will produce only red tomatoes, not yellow. Red tomatoes are dominant over yellow tomatoes.

Explain how the farmer could use a test cross to determine if his red tomatoes are homozygous or heterozygous. (Make sure you thoroughly explain what a test cross is.)

Answer 1

He would take the genetic makeup of two red tomatoes and cross them with each other. By crossing, you obtain data on weather the tomato is homozygous or heterozygous. Heterozygous genes could possible turn the tomato yellow. A test cross is basically a small cross with 4 squares where you write the phenotype of your tomato plant on the top and on the left side, then you multiply one phenotype with another, and write the answer in one of the four boxes..You will run a F1 cross with both red tomato seeds, to see what the outcome is out of 4 crosses. Just to make sure that the tomatoes will be 100% red, take two of the children from the F1 cross and cross them again in a F2 cross, once again verifying that all of the tomatoes will be red. If you get all your population to be red tomatoes, have verified that you will only produce red tomatoes.

Answer 2

@shanti33k , Thank you!! soo much, i appreciate it:)