Six Crops, Two Radish Lines and a Glowing Gene

The Greenhouse Club's Year

1The greenhouse club at Cedar Hollow Middle School planted one long bed with six crops: wild cabbage, kale, cabbage, broccoli, Brussels sprouts and kohlrabi. Club member Mirela Sandoval read the seed packets and found that all six belong to the same species. Plants of the different crops can pollinate each other, and the seeds grow into healthy plants that make seeds of their own. Wild cabbage still grows on seaside cliffs in parts of western Europe.

2By midwinter, the plants in the bed looked very different from one another, even though they shared the same soil, water and light. The wild cabbage had loose leaves on a thin stem. Each crop had one part that was far larger than the same part on wild cabbage, as Table 1 shows.

3In the fall, the club also started its own experiment with radishes, a plant from the same plant family. From one packet of seeds, the club grew 60 radishes. Their roots ranged from about 8 g to 20 g, with an average of 14 g. The club then made two lines. For the big-root line, they replanted the 6 heaviest roots, let them flower and moved pollen between their flowers with a small brush. For the small-root line, they did the same with the 6 lightest roots. Seeds from each line's chosen parents grew the next 60 plants of that line.

4Both lines grew side by side in the same greenhouse, in the same pots and soil, with the same water and light. The club teacher, Mr. Obinna Fairweather, had students weigh each root after rinsing off the soil, so the roots could still be replanted. Table 2 shows the average root mass in each generation.