Vigor

cold-test-cornCold Test (CT): A vigor test that indicates the potential emergence of seeds under early spring field conditions where cold and wet soils are prevalent. Used for corn, beans, peas, and vegetables that are planted in the early spring in cold-wet soil.

Accelerated Aging (AAT): A vigor test, where seeds are stressed with high temperature and relative humidity for a period of time prior to the germination test. High quality seeds tolerate such stress conditions and retain their capabilities to produce normal seedlings when germinated.

Conductivity Test (CT): A test to measure the integrity of the cell membranes. Low vigor seeds have leaky membrane structure and release electrolytes into the soak-water. The level of electrolytes is reflected in high electric conductivity of the soak-water.

Seedling Growth Rate (SGR): At the end of the standard germination test, the dry matter of the seedlings is determined using the oven method. Seedling dry matter was found to correlate closely with vigor (AOSA Seed Vigor Testing Handbook).

Speed of Germination (SG): high quality seeds germinate faster than poor quality seeds.  The number of normal seedlings recorded in the first count represents the population of fast germinating seeds and thus functions as a vigor measurement (AOSA Seed Vigor Testing Handbook). The following formula is used to calculate the speed of germination (SG):

speed-germination-equation