Radish genetics part 3

[Note to instructors: See Week 10 and Week 11 laboratory exercises for first two parts of radish genetics study]

Two weeks ago, you germinated seeds from two lines of radish, one with purplish hypocotyls and one with yellow-green hypocotyls.

Last week, you germinated seeds from the F1 generation formed by making crosses between the two parental lines with different colored stems.

Today, you will accomplish two tasks:

1. After your seedlings have been growing for at least 6 days, count the number of purplish hypocotyls and yellow-green hypocotyls in your F1 dish. Enter your data into a class spreadsheet so we can analyze all data together as a class.
2. Start your F2 dish by wetting the paper and placing it in a bright location partially submersed in water, just as you did for the other dishes.

Counting seedlings

For the F1 dish, for each germinated seed, decide whether the hypocotyl ("stem") between the two small cotyledons ("leaves") and radical ("root") looks more purple or yellow-green.

• If the stem is light in color but the root end is distinctly bright reddish-purple in color, count that plant in the purple category.
• If the stem is pale yellowish green throughout, count it in the yellow-green category.

Count the number in each category.

Open the linked Excel spreadsheet linked in Blackboard. On the spreadsheet scroll down below the yellow box. Find your name in the large data table. Enter the number of each color of hypocotyl for the F1 dish in row 15 of the spreadsheet.

Starting F2 seedlings

You know how to start seedlings by wetting the filter paper with embedded seeds, placing it in its petri dish, and placing the petri dish standing on its edge partly submersed in a dish with about an inch of water. Complete this process for the F2 dish.