Based on prior knowledge, the number of grains per pod (NS) can be used as a measure of grain yield for soybean cultivars. Generally, a higher number of grains per pod indicates a higher grain yield, while a lower number indicates a lower grain yield.

To analyze the relationship between NS and the grain yield of the soybean cultivar, we can consider the following ranges:

- Low grain yield: NS values ranging from 1 to 2 grains per pod.
- High grain yield: NS values ranging from 3 to 5 grains per pod.

Based on this analysis, the dictionary can be generated as follows:

```json
{
	"low": [1.0, 1.5, 1.8, 1.2, 2.0],
	"high": [3.5, 4.0, 4.5, 3.2, 5.0]
}
```

These values represent typical NS values for each target class ('low' and 'high') in relation to grain yield.