Agriculture Reference
In-Depth Information
case, the integrity of the tests must not be compromised when performing such tests. In some cases, a third
party testing laboratory may be used for labeling or certiication purposes for that company.
Private Laboratories
Private laboratories operate on a fee basis only, and therefore must be completely self-supporting.
Consequently, their fees may be higher than some oficial laboratories which are publicly supported. As
with any business, these laboratories must operate on a sound inancial basis and operate at a proit. In many
cases, competition among private labs at one area may drive the testing prices down for the beneit of the
customers. Quality assurance programs and accreditation systems can be advantageous for competing labs
in such cases.
QuALITy ASSurAnCE
Quality assurance in seed testing laboratories refers to the group of documented processes and actions
that ensure quality performance and testing results to meet speciied quality standards. It is speciically
addressed to their credibility in producing accurate, repeatable results that are consistent with good labora-
tory practices. This credibility is essential if the tests are to be meaningful and provide the kind of services
needed by the seed industry. Seed producers must have accurate test results to determine if the seed they
produce meets contract requirements or that provide information which enables them to label seed cor-
rectly. Certiication agencies rely on laboratory tests to determine if the seed meets the required quality
standards. Seed traders rely on seed tests to determine the monetary value of seed. Government oficials
apply test results to determine if the seed meets the legal requirements for sale. Most countries require
import standards, and the seed test determines if the seed meets those requirements. Finally, the consumer
who buys the seed must have conidence that the seed test is valid and can be trusted.
Although quality assurance has always been a concern of seed analysts and the seed testing commu-
nity, it has come more into focus in recent years with the increasing quality consciousness of today's seed
consumers. Although considerable government involvement still exists, more often the burden and respon-
sibility for quality assurance is being placed on individual laboratories and seed testing organizations. Thus,
it is essential that conscious programs of quality assurance be available and carefully followed.
Why Test results May Vary
Although seed testing laboratories generally obtain reasonably uniform test results, differences occasion-
ally occur. According to Grabe (1993) the most common reasons why test results vary are as follows:
1. Non-uniform seed lots. If improper sampling procedures are used, the sub-samples drawn from
the same seed lot may not be representative of the lot and the samples received by laboratories
may not be equivalent. Consequently, this can result in signiicant variation among test results.
2. Different test methods. The germination testing Rules of ISTA and AOSA allow the use of optional
substrates, temperatures and dormancy-breaking treatments for many species. The choice of con-
ditions is determined locally in experiments for each species in order to identify the optimal condi-
tions. The use of various optional methods may lead to different results, particularly if the seed
lots are freshly harvested and partially dormant. The general idea is that each laboratory should
identify the germination temperature(s) and substrates that give the maximum germination; the
optimal conditions may depend on the equipment and the varieties used. The philosophy is that
this will give smaller differences overall than if every laboratory should use the same speciied
settings.
