The Germination Test
The object of the germination test is to the determine the maximum germination potential of a seed lot. This information can be used to compare the quality of different lots and also estimate the field planting value of a seed lot.
Laboratory tests aim to control the environment in order to give the most regular, rapid and complete germination for the majority of samples of a particular species. Germination of a seed in a laboratory test is defined as the emergence and development of the seedling to a stage where the aspect of its essential structures indicates whether or not it is able to develop further into a satisfactory plant under favourable conditions in the field.
Test times vary according to species. The test times for the more commonly tested species is as follows:
- Barley 7 days + chilling time (see below)
- Wheat 7days + chilling time (see below)
- Oats 10 days + chilling time (see below)
- Maize 7 days
- Perennial ryegrass 14 days
- Italian ryegrass 14 days
- White clover 10 days
Chilling may be required for certain species in order to break dormancy. The number of days chilling will generally depend on the time elapsed since harvesting of the seed. Typically a current harvest barley sample will be chilled for an additional 3 to 5 days from August through to December. From January onwards chilling can vary from 1 to 5 days.
EU legislation prescribes various standards which seed lots must conform to if they are to be offered for sale within the EU. Germination standards for the most commonly tested species are as follows:
- Barley 85%
- Wheat 85%
- Oats 85%
- Maize 90%
- Perennial Ryegrass 80%
- Italian Ryegrass 75%
- White Clover 80%
Germination test reports
Results are posted to the address provided by the customer. The germination report states the percentage of seeds which produced normal seedlings. The report will also state what pre-treatment (if any) has been used. This may include:
- The number of days chilling in order to break dormancy
- Chemicals used such as KNO3 (potassium nitrate) & GA3 (gibberellic acid)
In certain species, e.g. clovers, the number of hard seeds may also be stated. Hard seeds are seeds which have failed to imbibe water during the germination test and may retain the ability to germinate.