Accelerated Ageing (AA) was initially developed as a test to estimate the longevity of seed in commercial storage (Delouche and Baskin, 1973) and has been used to predict the life span of a number of different species. The test has subsequently been evaluated as an indicator of seed vigour in a wide range of crop species and has been successfully related to field emergence and stand establishment. Surveys of Seed Testing Laboratories in North America have shown that the AA test is one of the most frequently used vigour tests (TeKrony 1983). Source: International Seed Testing Association, Handbook of Vigour Test Methods, 3rd Edition 1995.
Since then this test has been accepted for addition into the ISTA rules for seed testing and is one of two ISTA recommended vigour tests. Accelerated Ageing is also a recommended Vigour test of the Association of Official Seed Analysts, Seed Vigor Testing Handbook, Contribution No. 32.
The Accelerated Ageing test subjects seed to conditions of high moisture and humidity. These variables are known to cause rapid seed deterioration. Seed lots with high vigour should be able to withstand these stress conditions and deteriorate at a slower rate than lots with poorer vigour.
After the ageing period, which may be different for different crop species, the seed is planted in germination test conditions. The result is reported as a percentage. The closer the AA number is to the germination the better the vigour. Results are expressed as a percentage normal germination after ageing (vigorous seedlings).
Remember it is important to support all vigour tests with a germination result. Adequate germination is the first requirement in choosing seed lots.
Crop species that have had accelerated ageing research conducted includes: Soybean, Brassica spp., Sunflower, Beans, Clovers/Alfalfa, Corn, wheat, and grasses. Seed Check Technologies has recently conducted its own in house research using the accelerated ageing test on Barley. Results in many cases predicted a drop in germination extremely accurately.
Seed Check Technologies Inc. has seed technologists who have recent training in Conductivity testing from Dennis TeKrony at the ISTA Vigour workshop in South Dakota June 2002.