Based on prior knowledge, the Thousand Seed Weight (MHG) can be a strong indicator of grain yield in soybean cultivars. A higher value of MHG indicates a heavier weight per seed, which often leads to higher grain yield.

To analyze the relationship between the MHG feature and the grain yield target, we can consider the following:

1. Low Grain Yield:
   - In soybean cultivars with low grain yield, the MHG values are generally lower.
   - As per prior knowledge, typical MHG values for low grain yield could range from 11.5 to 16.5 grams.
   - We can select 5 typical MHG values for low grain yield: [11.5, 12.2, 13.1, 15.4, 16.2]

2. High Grain Yield:
   - In soybean cultivars with high grain yield, the MHG values tend to be higher.
   - As per prior knowledge, typical MHG values for high grain yield could range from 18.5 to 22.5 grams.
   - We can select 5 typical MHG values for high grain yield: [18.5, 19.8, 20.3, 21.6, 22.2]

Based on this analysis, we can create the following dictionary:

```json
{
	"low": [11.5, 12.2, 13.1, 15.4, 16.2],
	"high": [18.5, 19.8, 20.3, 21.6, 22.2]
}
```