Based on prior knowledge, the Thousand Seed Weight (MHG) is a feature that can potentially be related to the grain yield of a soybean cultivar. Typically, a higher seed weight is associated with a higher grain yield.

Here is a dictionary that represents the relationship between the feature MHG and the target variable (grain yield):

```json
{
	"low": [200.5, 205.0, 210.1, 190.3, 215.2], 
	"high": [220.6, 225.8, 230.4, 235.1, 227.9]
}
```

In this dictionary, the "low" key represents the target class "low" and the corresponding values are typical MHG values that are associated with a low grain yield. Similarly, the "high" key represents the target class "high" and the corresponding values are the typical MHG values associated with a high grain yield.

Please note that the provided MHG values are just examples and should be replaced with actual data or values that are appropriate for the specific soybean cultivar being analyzed.