Based on the given feature and task, it seems like we are trying to determine the relationship between the repetition of a soybean cultivar and the grain yield. 

To analyze this relationship, we can use our prior knowledge and experience to determine potential ranges of repetition values. Since the feature "Repetition" is not clearly defined, we will assume it represents the number of times each soybean cultivar has been repeated in the experiment.

Here is an example dictionary showcasing the relationship between the Repetition feature and the target task (grain yield):

```json
{
    "low": [1.0, 2.0, 3.0, 4.0, 5.0],
    "high": [8.0, 9.0, 10.0, 11.0, 12.0]
}
```

This dictionary suggests that for the "low" grain yield class, typical repetition values range from 1.0 to 5.0. Conversely, for the "high" grain yield class, repetition values typically range from 8.0 to 12.0.

Please note that these values are just examples and may not accurately reflect the actual relationship between repetition and grain yield. To provide a more accurate analysis, additional information and data would be required.