Agriculture Reference
In-Depth Information
ence between results is declared signiicant, i.e., due to random sampling variation and possible
error in the evaluation and/or other step in the test procedure.
ToLErAnCES for ELECTrIC ConduCTIVITy And ACCELErATEd AGInG TESTS
The International Seed Testing Association (ISTA) has tolerance tables for two vigor tests: the conductivity
test and the accelerated aging test. The tolerance tables for the conductivity test are: Table 15B, maximum
tolerated range between four replicates within a conductivity test (5% signiicance level); Table 15C, toler-
ances for two conductivity tests on the same submitted sample when tests are made in the same laboratory
(two-way test at 5% signiicance level); and Table 15D, tolerances for conductivity test on different submit-
ted samples when tests are made in different laboratories (two-way test 5% signiicance level). The toler-
ance tables for the accelerated aging test are: Table 15E, maximum tolerated range between two replicates
of 100 seeds in one accelerated aging germination test (two-way test at 2.5% signiicance level)[tolerances
are extracted from Table G1, Column L, in Miles (1963)]; Table 15F, tolerances for two accelerated aging
tests on the same submitted sample when tests are made in the same laboratory each on 200 seeds (two-way
test at 5% signiicance level); and Table 15G, tolerances for accelerated aging tests on different submitted
samples when tests are made in different laboratories each on 200 seeds (two-way test at 5% signiicance
level).
ISTA Tables 15B, 15C, 15D, 15E, 15F, and 15G are listed as Tables 13.10, 13.11, 13.12, 13.13, 13.14
and 13.15, respectively. For more details, refer to the ISTA rules.
ToLErAnCES for SEEd MoISTurE dETErMInATIon
Both AOSA and ISTA rules include tolerances for seed moisture determination. An example of the AOSA
seed moisture determination tolerance table is shown in Table 13.16.
AoSA ToLErAnCES for fLuorESCEnCE TESTS of LOLiuM And 400 - 1,000-SEEd SEPArATIonS In
PurITy AnALySES
Table 13.4 (Table 13H, 2010 AOSA rules) shows AOSA tolerances for luorescence tests of Lolium and
400- to 1,000-seed separations in purity analysis. The latter application includes: (1) separations to deter-
mine the percentage of different kinds of sweetclover seed in sweetclover samples or (2) variety determina-
tions in sorghum, oats, or other species.
These tolerances based on studies by Leggatt (1939) are used when two independent trials or tests
have been made on the same properly mixed bulk lot. Unlike germination and purity tolerances, these toler-
ances recognize only random sampling variation and do not account for variation due to other sources of
experimental error (systematic errors). These tolerances recognize the error in tolerances by using small
numbers of seeds in the test. One-half the regular pure seed tolerances shall be added to compensate for the
small number of seeds used in the tests.
The tolerance is found by entering the percentage to which it is to be applied in the left-hand column
of Table 13.4. Next, ind in the top horizontal row the number of seeds used in the test to which the toler-
ance is to be applied and, in the second row, the number of seeds used in the test with which the results are
to be compared. If the number of seeds is not known, 400 should be assumed. The tolerance, plus one-half
the pure seed tolerance, should be added to the percentage for which tolerance is required. Tolerances for
fractions of percentages entered in column 1 should be interpolated. Thus, the tolerance in the 400/400 seed
column for 94.5% is 2.75.
The application of the luorescence tolerance is illustrated by a ryegrass seed lot having 98.40% pure
seed and 10% luorescence for a seed lot of a variety with an established luorescence level of 0%. The
tolerance for 10% luorescence level in a 400/400-seed comparison is 4.6%. One-half of the pure seed
 
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