Precision is an essential component in seed vigour testing

A vigour test assesses, either directly or indirectly, the physiological and physical basis of potential seed lot performance and provides a more sensitive differentiation among seed lots than does the standard germination test. Although seed vigour tests are widely used by the seed industry and are now offered by two-thirds of ISTA seed testing laboratories, vigour testing was only recently (2001 ISTA Congress) approved for inclusion in the ISTA Rules for Seed Testing. The primary reason for this long delay in official recognition has been the lack of uniformity in vigour test results among seed testing laboratories. It is now recognized that greater precision is required for vigour testing than is required for standard germination testing. This recognition has led to improved standardization and uniformity in comparative tests. The objective of this paper is to describe why it has been much more difficult to achieve standardization in vigour testing. It will also outline the procedures, equipment and training needed for seed analysts to achieve and maintain the precision needed in vigour test methods. Finally, it will define the role of seed testing laboratories and the seed industry in the acceptance of seed vigour as a valuable test of physiological seed quality.