Question

You have two families of true-breeding diploid Zea mays(maize, corn) plants.

1. Late flowering, with tall stalks
2. Early flowering, with short stalks

A cross between these two plants yields F1 hybrids that are late flowering, with tall stalks.

1. Given this information, which alleles are dominant? Explain your reasoning.

2. Using the letters F or f for flowering and T or t for stalk height, indicate the genotypes of the two plants.

Plant 1 ______________                           Plant 2 ___________________

3. What is the genotype of the F1 hybrid? ______

4. A maize breeding company wants to generate a stock of maize plants that are true-breeding for early flowering with tall stalks.  Indicate the genotype of these desired plants.

5. In this next question, you can use Plant 1, Plant 2 and the F1 hybrid to generate the desired maize plant.

It will take two generations of crossing to get the desired plants indicated in (d). In the space below use Punnett squares to draw out the two crosses AND include a description of which specific individuals (genotypes) in your first cross that you will use in your second cross. Additionally, which individuals in your second cross will have your correct genotype. REMEMBER: your breeding is based on phenotype only, if a plant has a dominant phenotype, you cannot distinguish homozygous and heterozygous plants.