Based on prior knowledge about soybean cultivar, it is important to consider the appropriate ranges for the feature "Season" and how it relates to the grain yield.

Analyzing the relationship:

1. Low Grain Yield:
   - In general, soybean cultivars with low grain yield are often associated with seasons that have unfavorable growing conditions, such as extreme temperatures, drought, or heavy rainfall.
   - Possible values of the "Season" feature for low grain yield could range from 1.0 to 1.5.

2. High Grain Yield:
   - Soybean cultivars with high grain yield usually thrive in seasons with optimal growing conditions, including moderate temperatures, adequate rainfall, and good sunlight.
   - Possible values of the "Season" feature for high grain yield could range from 1.6 to 2.0.

Based on this analysis, let's create the dictionary:

```json
{
	"low": [1.0, 1.1, 1.2, 1.3, 1.4],
	"high": [1.6, 1.7, 1.8, 1.9, 2.0]
}
```