25
SEED TESTING INTERNATIONAL APRIL 2026
• RULES DEVELOPMENT
temperature. The seeds are drained, poured onto 
absorbent paper and wiped dry. The germination 
test must start promptly after drying.
For this study, the commercial product 
‘Etheverse’ (Bayer ©) was used, with an ethephon 
concentration of 480 g/l. The solution was 
prepared by dilution: 0.6 ml Etheverse in 1 l of 
water.
All four methods were tested on two replicates 
of 100 seeds per laboratory participant. Given 
the number of samples tested, the ISTA Statistics 
Committee were asked to validate the relevance 
of testing the lots on 200 seeds and not 400 as 
usual. Each participant laboratory was free to use 
their own germination method, provided it was 
the same used with no dormancy treatment and 
with dormancy treatment.
Statistical Analyses
Statistical analyses were performed using 
‘ISTAgermMV’, the tool developed by the 
ISTA Statistics Committee. Boxplots (per 
lot, per method, per method × lot and per 
laboratory), data checking and the repeatability/
reproducibility results were generated from this 
statistical tool. Analysis of variance (ANOVA) and 
the Student Newman-Keuls (SNK) test were also 
carried out.
Results and Discussion
Table 1 shows the details of the germination 
results in percentage obtained by each 
participant laboratory and by method. 
Laboratory E was the only laboratory to obtain 
a strong increase in the percentage of abnormal 
seedlings (24%) with the ethephon method.
Laboratory E was also the only one to use a 
pleated paper (PP) method, so we decided to 
carry out a few tests to evaluate the impact of the 
substrate on the development of seedlings after 
ethephon application. The results showed that 
with a PP substrate, the percentage of abnormal 
seedlings was much higher, demonstrating a 
toxic effect observed with PP, but not with sand or 
between paper (BP).
Figure 1 shows the percentages of normal 
seedlings obtained with the different methods 
used on the ten seed lots by laboratories, without 
laboratory E. The figure shows that the results 
with ethephon are better compared to the 
preheating method, and therefore better than the 
prechilling method.
Figure 2 shows the percentages of fresh seeds 
obtained with the different methods for each 
lot. Lots H7 and H10 present seed dormancy, 
in particularly for laboratories A and B, as 
previously mentioned.
Figure 3 shows the percentages of fresh seeds 
obtained with the different methods used by 
laboratories A and B for two seed lots. Lot H7 
ETHREL
PRECHILLING
PREHEATING
SD
Lab
NS
ANS
FS
DS
NS
ANS
FS
DS
NS
ANS
FS
DS
NS
ANS
FS
DS
A
92
4
2
2
87
7
3
3
91
6
1
3
86
5
6
3
B
95
3
1
1
91
4
2
3
93
4
1
2
85
5
7
3
C
93
5
0
3
91
6
0
3
–
–
–
–
89
5
1
4
D
93
4
0
3
90
5
2
3
92
5
0
3
89
6
3
3
E
74
24
0
2
93
4
0
3
90
6
0
4
92
4
0
4
F
94
2
0
5
93
2
0
6
93
2
0
5
92
3
0
5
G
89
5
1
5
89
2
0
9
90
2
0
8
86
3
0
11
Mean
90
7
1
3
90
4
1
4
91
4
0
4
88
4
2
5
Table 1. Germination results (%) obtained by each participant laboratory and by method (NS = normal 
seedling, ANS = abnormal seedling, FS = fresh seed, DS = dead seed)
Figure 1. Boxplots for the four methods grouped across seed lots on the normal seedling, for all the 
laboratories except laboratory E
Figure 2. Boxplots for the four methods per seed lot and grouped by laboratory on fresh seed

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