Seed Health Testing: Doing Things Right

Abstract

Since seeds can be a route for pathogen introduction, they are routinely inspected and tested to prevent pest outbreaks and introduction into new territories. The need for high throughput, short lead times, and cost reduction has played an important role in the development and application of techniques in seed health testing. Examples are molecular and serological techniques, such as ELISA and PCR assays, which are commonly called indirect tests. After signal detection in ELISA or PCR assay a seed lot is a suspect lot that requires further investigation for a final conclusion about the health status of the seed lot, since these tests do not provide any information about pathogen viability or pathogenicity. The seed industry uses them as a prescreen to identify healthy seed lots and in combination with classical methods, commonly called direct tests, to confirm viability of the target pathogen and demonstrate its pathogenicity. However, outside industry, indirect tests are increasingly used to make a final decision on the health status of a seed lot. This has led to a growing number of seed lots being rejected when the risk of introducing a pathogen to importing countries may have been negligible. We propose that investments continue to be made in the development of high-throughput prescreening detection methods like HTS and PCR assays, but together with direct tests that enable accurate assessment of the risks involved when target pathogens are detected using indirect tests. Close collaboration between molecular scientists and classical phytopathologists is essential. [Figure: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Keywords

• biological relevance
• direct test
• indirect test
• seed movement