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International Seed Testing Association
International Seed Testing Association
Richtiarkade 18
8304 Wallisellen, CH
+41 44 838 60 00
International Seed Testing Association

Purity Committee

According to the Historical Papers by Hans Arne Jensen, purity work has a long history. From the first approval of the ISTA rules in 1931 to the purity test according to the quicker method in 1950, to the first pure seed descriptions in 1976, to the current rules.
There are now Pure Seed Definitions for 438 Genus in the rules and an explanation of the PSD’s in the handbook.


  • To maintain and update the ISTA rules on purity testing 
  • To update and clarify these rules whenever needed. This can be a request from a member laboratory, the industry, and others 
  • To provide tools and information as an aid in seed identification 
  • To look into possibilities of e.g. image analysis and other tools to be implemented in daily routine analysis in a laboratory 

The work of the committee is responsible for:

  • Chapter 3  The purity analysis
  • Chapter 4  Determination of other seeds by number 
  • Chapter 10 Thousand-seed weight (TWS) determination
  • Chapter 11 Testing coated seeds
  • Chapter 14 X-ray test
  • Chapter 16 Rules for size and grading of seeds
  • Chapter 18 Seed mixture analysis 


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