Based on prior knowledge and assuming that higher seed weight generally leads to higher grain yield, we can analyze the relationship between the MHG (Thousand seed weight) feature and the grain yield target variable.

Analysis:
- Since grain yield is the target variable, we need to determine the appropriate ranges of values for MHG to classify it as "low" or "high". Without specific domain knowledge, we can't provide exact thresholds for this classification.
- However, we can assume that seed weights below a certain value (e.g., 100g) may result in a lower grain yield, while seed weights above that value may lead to a higher grain yield.
- It's important to note that the classification thresholds may vary depending on the specific dataset and domain knowledge.

Based on this analysis, we can create the dictionary with the MHG values for each target class:

```json
{
	"low": [80.0, 90.0, 95.0, 95.5, 98.0],
	"high": [105.0, 110.0, 115.0, 120.0, 125.0]
}
```

Please note that the MHG values provided here are just examples and should be adjusted based on specific domain knowledge, dataset characteristics, and experimental contexts.