Agriculture Reference
In-Depth Information
analysts with advanced training. Where possible, all operations must be simple so that they can be
competently conducted in seed laboratories with current staff at a reasonable cost.
4. Objective
. For a vigor test to be easily standardized, a quantitative, numerical assessment of seed
vigor should be employed. This eliminates subjective interpretation by analysts, which is one of
the major sources of variation in results among laboratories. Since such tests give a more sensitive
measure of seed viability than the germination test, the objective interpretation of vigor results
becomes even more critical.
5. Reproducible
. The success of any test depends on its reproducibility. If test results cannot be
repeated due to intricate procedures, dificulty in interpretations, etc., then a comparison of results
among laboratories for the same seed lot becomes meaningless. Thus, before adopting any vigor
test for routine testing, the results must be reproducible.
6. Correlated with ield performance
. The deinition of seed vigor emphasizes the relationship
between seed vigor and anticipated ield performance. Many studies have demonstrated that this
association exists. Consequently, the ultimate value of any vigor test will be determined by its
ability to produce results that are related to ield performance.
recommended and Suggested Seed Vigor Tests
Both AOSA and ISTA have developed handbooks on seed vigor testing. These provide backgrounds on vigor
testing and speciic vigor testing protocols. Both handbooks should be consulted whenever conducting vigor
tests. Each handbook covers vigor tests that are recommended and suggested. Recommended vigor tests
include only those that have been critically evaluated over several years for the relationship of test results
with ield performance and repeatability of results among various testing laboratories. Recommended vigor
tests are considered standardized. Suggested vigor tests are those showing promise in assessing seed vigor
and continue to be the subject of standardization efforts among seed testing laboratories or those which are
used more for research purposes such as ATP and GADA tests. Tables 8.3, 8.4, and 8.5 demonstrate the
relative popularity of these tests for speciic crops in 1976 1982, 1990, 1998, and 2007.
Table 8.3. Survey results of seed vigor tests offered by U.S. laboratories from 1976 to 2007.
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Year 1976 1982 1990 1998 2007
Vigor test No. Labs (52) (59) (84) (77) (28)
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Accelerated Aging 70 130 108 50 10
Saturated Salt AA -- -- -- -- 4
Controlled Deterioration -- -- -- -- 1
Cold Test 119 144 129 52 14
Saturated Cold Test -- -- -- 9 4
Cool Germination 12 62 49 23 6
Electrical Conductivity -- 62 28 14 3
Seedling Growth Rate 30 64 26 -- 2
Seedling Vigor Classiication -- 52 35 -- 5
Tetrazolium (TZ)* 57 132 176 23 8
Speed of Germination 20 -- 6 0 0
Other tests -- -- -- -- 6
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The surveys included AOSA (Oficial/state) and SCST (commercial/private) laboratories in the United States.
Many of the laboratories from 1990 and 1992 surveys were using tetrazolium tests for viability and germination infor-
mation rather than as a vigor test.
