Summary
 
This paper reviews the development of the ISTA purity analysis and determination of other seeds by number from the foundation of ISTA in 1924 to 2006. Focus is on publications and reports which, before the formal validation of Rules proposals, served as the scientific background for changes of the ISTA Rules.
 
Important steps in the development of the ISTA Rules were: approval of the first ISTA Rules and international certificate (1931); purity tests according to the quicker method (1950); introduction of the three component rule (1974); pure seed descriptions (1976); blowing of grass samples (1966, 1976, 1992); testing of grasses containing multiple seed units (1984); working samples for purity and determination of other seeds by number based on the mass (weights) corresponding to 2500 seeds (1966) and 25000 seeds (1990), respectively, and formulation of specific Rules for testing of coated and pelleted seeds (1976, 1985). In the period 1931 to 2006 the number of genera or species included in the Rules has been increased from 41 to 898.
 
The ongoing Rule changes have improved the uniformity within and between ISTA laboratories and saved time for the analysts. Proficiency (referee) testing, workshops and other training activities as well as use of other supplementary publications have also improved the quality of the analytical work. A large number of colleagues have contributed to the substantial progress in the development and implementation of the purity chapters of the ISTA Rules.
 


  Historical Paper - Volume 2 2008