Based on the information provided, it seems that the Repetition feature is a numeric variable and should have a range of values associated with it. Unfortunately, the specific range is not provided, so we will need to use our prior knowledge to determine appropriate ranges of values for the Repetition feature.

To analyze the relationship between the Repetition feature and the grain yield of the soybean cultivar, we can make several assumptions:

1. Repetition values might represent the number of times a specific cultivar has been repeated or tested in the experiment.
2. Higher Repetition values could indicate that a particular cultivar has been tested multiple times, suggesting a higher level of confidence in the grain yield results.
3. Lower Repetition values might indicate that a cultivar has been tested fewer times or is relatively new, leading to less certainty in predicting its grain yield.

Based on these assumptions, we can generate a dictionary with typical Repetition values for each target class ('low' and 'high').

Here's the generated dictionary:

```json
{
    "low": [1.0, 2.0, 3.0, 4.0, 5.0],
    "high": [10.0, 12.0, 15.0, 20.0, 25.0]
}
```

Please note that the specific values provided in the dictionary are solely based on assumptions and may not accurately represent the actual relationship between the Repetition feature and the grain yield of the soybean cultivar.