Accelerated aging test: principles and procedures

The accelerated aging (AA) test exposes seeds for short periods to two environmental variables, high temperature and high relative humidity, which cause rapid seed deterioration. High vigor seed lots will withstand these stressful conditions, deteriorate at a slower rate and have high germination following aging, compared to low vigor seed lots. This paper reviews the major factors influencing the AA test results and provides a stepwise procedure for conducting the test. The essential equipment needed for the AA test is outlined and the primary questions relating to standardization of this test are answered. The results of the AA test have been shown to provide an accurate estimate of seed vigor in soybean, corn and many other crop species. Several studies have reported that AA results more accurately predict field emergence under stressful soil conditions than do standard germination results. The AA test for soybean is recommended by the Seed Vigor Testing committees of both the Association of Official Seed Analysts and International Seed Testing Association (ISTA). The AA test has met the ISTA requirements for repeatability and standardization and was approved in 2001 for the International Rules for Seed Testing as an accepted vigor test for soybean seed.