A germination test is used to determine the maximum germination potential, or viability, of the grain. Grain vigor is the concept used to explain this performance difference between germination test and actual field emergence.
Grain with high vigor gives rapid, uniform emergence, and normal seedling development under a great range of environmental conditions. High vigor grain also tend to retain its ability to germinate after prolonged storage.
Impurities are presence of fusarium infected kernels or kernels of foreign species.
Low grain quality carries a discount and could have a negative marketing impact. Carryover stocks of grain are also difficult to market unless the grain vigor was high.
Seed with fusarium infected kernels should not be planted as this will spread and also introduce the fungi to new areas.