Based on the limited information provided, it is difficult to determine the exact relationship between the feature "Repetition" and the target variable "grain yield of soybean cultivar". However, we can make a few assumptions and create the dictionary based on those assumptions.

Assumption 1: Higher values of "Repetition" may indicate higher grain yield.
Assumption 2: The target variable "grain yield" has two classes - "low" and "high".

Based on these assumptions, we can create the required dictionary as follows:

```json
{
	"low": [1.0, 2.0, 3.0, 4.0, 5.0], 
	"high": [6.0, 7.0, 8.0, 9.0, 10.0]
}
```

Please note that the list of values provided in the dictionary are purely based on assumptions and do not represent actual data. For accurate analysis, more information and data about the relationship between "Repetition" and "grain yield" would be required.