Based on prior knowledge, the plant height (IFP) can have an impact on the grain yield of soybean cultivars. Generally, taller plants tend to have higher grain yields, as they can produce more biomass and have greater access to sunlight for photosynthesis. However, there may be an optimum range for plant height, beyond which the grain yield may decrease due to resource limitations or lodging.

To provide a dictionary with possible values of the feature IFP for each target class ('low' and 'high'), let's assume the following range of values based on typical soybean cultivars:

- 'low': IFP values between 50-80 cm
- 'high': IFP values between 80-120 cm

Additionally, we will include 5 typical values for each target class:

```json
{
  "low": [55.2, 62.8, 70.6, 77.3, 81.4],
  "high": [88.6, 92.1, 100.5, 111.2, 117.9]
}
```