(ISTA News Bulletin) No. 136, October 2008 - International Seed ...

Rules Development
ISTA Method Validation 2007: a historical
retrospect
Prof. Dr. Dr. h.c. A.M. Steiner 1 , Prof. Dr. M. Kruse 2 and Prof. Dr. N. Leist 3
1
ISTA Alumnus, 2 ISTA Personal Member and 3 ISTA past President and Honorary Life Member
University of Hohenheim and LTZ Augustenberg
Karlsruhe, Germany
steiner@pz.uni-hohenheim.de
mkruse@uni-hohenheim.de
norbert.leist@botanik1.uni-karlsruhe.de
In 2000, Sheppard and Cockerell published
the “ISTA Handbook of Method
Validation for the Detection of Seed-borne
Pathogens”, and in 2007 ISTA published
the document “ISTA Method Validation
in Seed Testing”. Neither contains references
referring to the role of method
validation in the past. In 2005 Hampton
wrote: “Method validation was introduced
to ISTA by the Seed Health Committee …
in 2000.” In a paper from 2007 he repeated
this statement, adding inter alia “the process
is new to most other TCOMs.” Again
no references are given. Seed scientists recognizing
the value of ISTA’s work, and that
of the five decades before ISTA’s inception
in 1924, are surprised at words such as “introduced”
and “new”, because there is a
long and commendably well-documented
history of method validation in seed testing
which is much older than ISTA.
Definition of validation
The ISO definition of validation
[8402:1994] is: “Confirmation by examination
and provision of objective evidence
that the particular requirements for a specified
use are fulfilled.” The term “method
validation” is new in seed testing; it was
previously called “method standardization”
or “method elaboration”. Likewise,
“objective evidence” is new; it was previously
called “scientific evidence” or “supporting
evidence”.
Development of method validation
1869–1924
In 1869, Prof. Dr. J.C.F. Nobbe published
his Statute, with recommendations
for sampling and sample sizes, and
a review of germination determination.
He did this to the best of his knowledge
and experience. There was no validation
(Steiner and Kruse 2007).
In preparation for the “1st Meeting of
the Heads of Seed Testing Stations and
other interested Persons in Graz 1875”,
each of the 31 participants from Central
Europe received in advance rules proposals
from Nobbe, to allow in-house verification
and discussion. The proposals were
then seriously discussed at the meeting and
finally voted on by the heads of the seed
testing stations for “unanimous application”.
Consequently, the description of
methods, in-house verification and discussion,
discussion at the meeting and voting
by the responsible persons became the first
step of validation.
In 1876, at the 2nd Meeting of the Heads
of Seed Testing Stations in Hamburg, with
Nobbe presiding, the main topic discussed
was “uniformity in seed testing”, now
the motto of ISTA. In 1877, at the 3rd
Meeting in Munich, the first comparative
test was initiated by Nobbe for improving
and standardizing germination testing
in Kentucky bluegrass. In 1878, at the 4th
Meeting in Cassel, the results of the comparative
test were presented and discussed,
and the method approved for general
application. Accordingly, discussion of
method development, formulation of a test
plan, comparative testing, evaluation of
test results and discussion and voting at a
meeting by the test participants became the
second step of validation. In subsequent
years, seed testing methods were standardized
on this basis. Incidentally, the minutes
of the meetings, including the discussions,
have been published.
In 1888, the Association of Agricultural
Experiment Stations in the German Empire
(LVS) was founded, today the Association
of German Agricultural Experimental and
Research Stations (VDLUFA). Nobbe was
elected President. In 1893 in Würzburg, at
the General Assembly of this association,
a Permanent Committee for Seed Testing
was established “mainly for the elaboration
of standardized seed testing methods”
(Steiner 2000). Thus, monitoring by
a committee, preparation of a test plan,
comparative testing, evaluation of the test
results, formulation of a proposal and discussion
and voting by the test participants
became the third step of validation. At the
same time, similar developments along
with mutual information exchange were
taking place in other countries, resulting
in national seed testing rules, as communicated
at the 1st International Conference
for Seed Testing in Hamburg 1906 (Steiner
and Kruse 2006).
A landmark example of method
validation in 1901–1905
At the end of the 19th century, the
German Agricultural Society (DLG) contemplated
introducing quality standards
for the trade of seed. In this connection,
in order to randomly monitor standardization
in seed testing, sampling, influence
of transport and germination testing in red
clover, and thousand-seed mass determination
in orchard grass, were reassessed. The
DLG and the LVS formed a committee
of three experts, all renowned pioneers in
seed testing: Wilhelm Edler (1855–1936),
from Jena; Oskar von Kirchner (1851–
1925), from Hohen heim; and Hermann
Rodewald (1856–1938), from Kiel (Fig.
1; Steiner 1998). Their task was to organize
the reassessment and standardization
in four independent test runs from 1901
to 1905. Altogether, 23 seed testing stations
cooperated under the leadership
of the DLG. The original documents are
in the archives of the Division of Seed
Science and Technology at the University
of Hohenheim. The letters and draft test
plans of the committee are handwritten in
German or Latin script; the minutes of the
meetings of the committee and of the meetings
of the heads of the seed testing stations
are typed; the test plans for distribution
to the participants are calligraphically
handwritten in German script or typed.
The standardization procedure was, as approved
at that time:
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Seed Testing International No. 136 October 2008