Parthenocarpic fruits are produced by

Options

A. (a) treating plants with PMA
B. (b) treating plants with low concentration of auxin and gibberellins
C. (c) removing anthers from flowers before release of pollen grain
D. (d) raising plants from vernalised seeds

Answer

### Step-by-Step Solution:

1. **Understanding Parthenocarpy**:
- Parthenocarpic fruits are seedless fruits that develop without fertilization. This means that the ovary of the flower develops into a fruit without the need for male gametes.

2. **Characteristics of Parthenocarpic Fruits**:
- These fruits are formed from the ovary of the flower and do not contain seeds. This process is a form of asexual reproduction.

3. **Analyzing the Options**:
- **Option A**: Treating plants with PMA (Phenyl Mercuric Acetic) - This chemical is used to induce stomatal closure and decrease transpiration, but it does not promote parthenocarpy.
- **Option B**: Treating plants with low concentrations of auxin and gibberellin - Auxins and gibberellins are plant hormones that promote growth and can stimulate the development of fruits without fertilization, making this a potential answer.
- **Option C**: Removing anthers from flowers before pollen release (emasculation) - This is a technique used to ensure cross-pollination and does not relate to the development of parthenocarpic fruits.
- **Option D**: Raising plants from vernalized seeds - This refers to exposing seeds to cold to promote flowering, which does not directly relate to parthenocarpy.

4. **Conclusion**:
- After analyzing all options, **Option B** is the correct answer as treating plants with low concentrations of auxin and gibberellin can lead to the development of parthenocarpic fruits.

### Final Answer:
Parthenocarpic fruits are produced by treating plants with low concentrations of auxin and gibberellin (Option B).