Response Surface
Analysis of Seed
Germination
Percentage and MTG
of 6 Basil Cultivars
By Emily Zhou
Department of Horticulture
STAT 5606 Spring 2013
2
Sweet Basil (Ocimum basilicum L.)
o A frost sensitive low-growing herb in
family Lamiaceae (mint family)
o A summer and annual crop in North
America and native to southern Asia
o Grows a lot in Mediterranean area
and South Asia
o More than 60 cultivars
Seed Germination Testing

Very important to assess quality

6 Sweet Basil Cultivars
1.
2.
3.
4.
5.
6.
‘Italian Large Leaf’ (‘ILL’): higher yields
‘Italian Large Leaf’ 35X (‘ILL’ 35X): 5+ years old seeds
‘Nufar’: disease (Fusarium) resistant ‘Italian Large
Leaf’ type
‘Genovese’: traditional Italian basil
‘Genovese Compact Improved’ (‘GCI’): for
containers and pack sales
‘Aroma 2’: disease (Fusarium) resistant ‘Genovese’
type
Thermo-gradient Table



Creating different temperatures at same time using
the principles of thermodynamics.
Wide temperature range from -10 to 85ºC (±1.1ºC ) .
Often used to test seed germination.
Germination Testing




4 × 25 seeds of cultivar 1 and 2 at each
temperature
2 × 50 seeds of cultivar 3 to 6 at each
temperature
Seeds were placed in 11×11×4 cm transparent
covered plastic boxes, on top of two thicknesses
of germination blotter paper, the blotters were
saturated with 15 ml distilled water
Standard AOSA (The Association of Official Seed
Analysts) germination testing procedure, grow in
dark in one dimensional thermo-gradient table
Germination Data Analysis
 Germination
 MTG
percentages
(mean time to germination):
∑(NiTi)/∑(Ni), where Ni is the number of new
germinated seeds at time Ti after imbibition
calculated from four replications of 25 seeds
each (Nerson and Paris, 1988)
Analysis of Covariance of Germination%
Analysis of Covariance of Germination%
Analysis of Covariance of Germination%
Response Surface
Germ% Response Surface Effect by Cultivar
Germ% Response Surface Effect by Cultivar
Cultivars
Max Germ
(%)
Optimal
Temp (°C)
R2
P
1-ILL 35X
84.1
32.2
0.821
<0.0001*
2-Nufar
100
26.4
0.502
<0.0001*
3-Genovese
89.2
28.4
0.632
<0.0001*
4-GCI
100
27.1
0.547
<0.0001*
5-Aroma 2
94.3
31.3
0.757
<0.0001*
6-ILL
99.3
31.5
0.649
<0.0001*
Analysis of Covariance of MTG(days)
Analysis of Covariance of MTG(days)
Analysis of Covariance of MTG(days)
Response Surface
MTG(days)Response Surface Effect by
Cultivar
MTG(days)Response Surface Effect by
Cultivar
Cultivars
Max MTG
(days)
Optimal
Temp (°C)
R2
P
1-ILL 35X
-1.4
30.6
0.934
<0.0001*
2-Nufar
-1.0
32.1
0.860
<0.0001*
3-Genovese
-1.6
31.6
0.844
<0.0001*
4-GCI
-0.3
32.1
0.828
<0.0001*
5-Aroma 2
-0.9
32.2
0.894
<0.0001*
6-ILL
-1.4
31.7
0.839
<0.0001*
Future Research
Find out the optimal germination temp(°C)
for each cultivar


High germ%
Low MTG(days)
Thank you!