Photoperiodism was first characterized in

Options

A. Cotton
B. Tobacco
C. Potato
D. Tomato

Answer

**Step-by-Step Text Solution:**

1. **Understanding Photoperiodism**: Photoperiodism is the physiological reaction of organisms, particularly plants, to the length of day and night. It involves how plants respond to the relative lengths of light and dark periods, influencing their growth and developmental processes, such as flowering.

2. **Historical Context**: The concept of photoperiodism was first characterized in the 1920s. Researchers were investigating how the length of daylight affects flowering in plants.

3. **Key Experiment**: The phenomenon was notably studied in tobacco plants. During experiments, it was observed that the flowering of tobacco was linked to the length of the day and night.

4. **Discovery of a Mutant**: In the course of these studies, a mutant variety of tobacco known as "Maryland Mammoth" was discovered. This variety had large leaves and grew tall but did not flower under normal conditions, indicating a unique response to photoperiod.

5. **Conclusion**: Based on the historical studies and experiments conducted, it can be concluded that photoperiodism was first characterized in the tobacco plant.

**Final Answer**: The correct answer is **B) Tobacco**.

---