M. Vos´atka, M. Gryndler Applied Soil Ecology 15 2000 145–152 147
inoculum of six isolates of AMF 0.2 g per plant, seven levels of the second experimental factor: G. fis-
tulosum isolate BEG23, Glomus manihotis BEG112, Glomus geosporum BEG11, Glomus deserticola
BEG73, Glomus mosseae BEG25, Scutellospora het- erogama BEG35. Latter five isolates were obtained
from The International Institute of Biotechnology, MIRCEN, Canterbury, Kent. As the third experimen-
tal factor, the plants were either left non-inoculated or they were inoculated with two bacteria three
levels of the experimental factor: isolate B1 and iso- late M30 the latter was isolated from hyphosphere
under mycorrhizal culture of maize. Bacteria were propagated and applied the same way as in previous
experiment. This factorial experiment thus involved 42 treatments 2×7×3 with eight replicates. All the
336 pots were placed randomly on a cultivation table in temperature-controlled greenhouse and the plants
were irrigated daily with tap water as needed. Plants were harvested after 11 weeks, and dry biomass of
the shoots, numbers and weight of minitubers were measured, and MC was evaluated as in experiment 1.
2.4. Experiment 4 Potato plants of Karin variety were either left
non-inoculated or they were preinoculated in multi- ple trays in the same way as in experiment 1 with
four isolates of AMF. All the inoculated treatments also received 1 ml of a mixture 1:1 of cultures of
bacterial strains M30 and B1. AMF isolates used were G. manihotis BEG112, G. mosseae BEG25, G.
deserticola BEG73, and G. etunicatum S329. The plants were transplanted to the shadowhouse beds
100 cm×40 cm. Each bed contained 30 plants. Each treatment involved nine replicates beds. The plants
were cultivated for 14 weeks and, after the harvest, the mean number of minitubers NT, total weight of
minitubers and number and weight of marketable size minitubers per plant were estimated, and the MC in
each treatment was evaluated.
2.5. Statistical evaluation of the data Data sets were checked for normal distribution and
logarithmically transformed when necessary. One-, two- or three-way ANOVA was used for evaluation
of effect of different factors and their interaction. Duncan multiple range test was used to analyze sig-
nificant differences between means. The statistical evaluation was performed using SOLO statistical
package BMDP Software, Los Angeles, CA, 1991. Control non-inoculated treatments were excluded in
all experiments from statistical analysis of MC.
3. Results
3.1. Experiment 1 In the pot experiment, significant effects of exper-
imental factors and significant interaction between both inoculations were observed for the Krista variety
only, while no effects were found for Karin variety Table 1. For the Krista variety, a significant de-
crease in minitubers number per pot was observed as a response to inoculation with bacterial strain M11
compared to unbacterized treatment, and with AMF G. fasciculatum compared to uninoculated controls or
to plants inoculated with G. fistulosum Table 2. The opposite trend was observed for the mean weight of
minituber. It was significantly increased in treatments
Table 1 F-values and significance of two-way ANOVA of number of mini-
tubers NT, total fresh weight of minitubers TFW, fresh weight of one minituber FWO and mycorrhizal colonization MC of
potato plants of two varieties transplanted post-vitro to the pots and inoculated with two bacteria and three arbuscular mycorrhizal
fungi AMF experiment 1, d.f. represents degrees of freedom for the given factor
Factor d.f. NT
TFW g FWO g MC Variety Karin
Bacteria A 2
0.33 ns
a
1.04 ns 0.04 ns
0.51 ns
b
AMF B 3
2.32 ns 0.57 ns
1.05 ns 0.12 ns
A×B 6
0.53 ns 2.12 ns
0.63 ns 0.43 ns
Error mean square 60 1.12 60 8.11 60 0.387 58 0.67
Variety Krista Bacteria A
2 17.32
a ,∗∗∗
2.10 ns 17.05
∗∗∗
1.97 ns
b
AMF B 3
6.36
∗
0.89 ns 6.30
∗∗∗
0.96 ns A×B
6 2.08
∗∗∗
2.16 ns 1.52 ns
0.38 ns Error mean square
60 2.48 60 9.61 60 0.419 58 3.13
a
ns — nonsignificant effect of the factor.
b
Non-mycorrhizal treatments were not included into the sta- tistical treatment of MC.
∗
Significant effect at p0.05.
∗∗∗
Significant effect at p0.001.
148 M. Vos´atka, M. Gryndler Applied Soil Ecology 15 2000 145–152
Table 2 The effect of inoculation with three AMF and two bacteria on NT,
TFW, FWO and MC of potato plants of two varieties transplanted post-vitro to the pots experiment 1
Factor NT
TFW g FWO g MC Variety Karin
Bacteria None
6.95 a
a
24.22 a 3.52 a
12.3 a
b
Bacterial isolate B1 6.71 a
23.12 a 3.54 a
14.5 a Bacterial isolate M11 6.79 a
23.30 a 3.49 a
16.9 a AMF
None 6.39 a
a
22.95 a 3.63 a
b
G. fistulosum 6.69 ab 23.87 a
3.65 a 15.7 a
G. fasciculatum 6.89 ab 23.30 a
3.43 a 10.4 a
G. etunicatum 7.30 b
24.05 b 3.35 a
18.9 a Variety Krista
Bacteria None
9.70 b
a
31.23 a 3.36 a
9.7 a
b
Bacterial isolate B1 9.22 b
32.88 a 3.71 a
11.9 a Bacterial isolate M11 7.18 a
31.35 a 4.42 b
8.9 a AMF
None 9.17 b
a
31.00 a 3.51 a
b
G. fistulosum 9.79 b
32.68 b 3.49 a
10.7 a G. fasciculatum
7.80 a 31.86 ab 4.21 b
12.5 a G. etunicatum
8.06 ab 31.76 ab 4.11 ab 8.1 a
a
Means of six replicates each replicate as a mean from eight plants within one parameter and one factor are not significantly
different according to Duncan multiple range test, p0.05.
b
Non-mycorrhizal treatments were not included into the sta- tistical treatment of MC.
inoculated with all the three mentioned microorgan- isms. One-way ANOVA showed significant increase
in minituber number in treatment inoculated with G. fistulosum together with bacteria B1, increase of
mean weight of minituber in the treatments inocu- lated with bacteria B1 and all three AMF according
to AMF species the increase was 40, 57 and 60 compared to control uninoculated plants data of
one-way ANOVA not shown.
3.2. Experiment 2 In greenhouse beds, bacterial inoculation signif-
icantly affected the NT and the mean fresh weight of minitubers of both potato varieties Table 3. The
NT of Krista variety was further affected by AMF inoculation. MC of roots of both plant varieties was
significantly affected by inoculation with different
Table 3 F-values and significance of two-way ANOVA of NT, TFW, FWO
and MC of potatoes of two varieties post-vitro transplanted to the greenhouse beds, as influenced by inoculation with two bacteria
and three AMF experiment 2, d.f. represents degrees of freedom for the given factor
Factor d.f. NT
TFW g FWO g MC
Variety Karin Bacteria A
2 6.08
a ,∗∗
0.77 ns 4.54
∗
1.15 ns
b
AMF B 3
0.82 ns 0.55 ns
0.22 ns 3.11
∗
A×B 6
1.71 ns 0.73 ns
1.34 ns 0.33 ns
Error mean square 36 1.76 36 109.5 36 1.09 32 0.94
Variety Krista Bacteria A
2 6.34
a ,∗∗
0.19 ns 3.51
∗
0.78 ns
b
AMF B 3
4.22
∗∗
1.13 ns 2.19 ns
4.53
∗∗
A×B 6
5.18
∗∗∗
0.55 ns 0.31 ns
0.74 ns Error mean square
36 1.68 36 115.0 36 2.84 32 0.67
a
ns — nonsignificant effect of the factor.
b
Non-mycorrhizal treatments were not included into the sta- tistical treatment of MC.
∗
Significant effect at p0.05.
∗∗
Significant effect at p0.01.
∗∗∗
Significant effect at p0.001.
AMF species. Significant interaction between AMF and bacteria inoculation treatments was found for va-
riety Krista for the NT. Inoculation of plants of variety Karin with bacterial isolate B1 significantly increased
the NT, compared to non-bacterized treatments Table 4. For Krista variety, the bacterial inocula-
tion increased only the mean weight of minituber. G. etunicatum caused the highest level of MC in roots
of both plant varieties. The best combination of in- oculants was G. fistulosum and bacteria B1 but only
for Krista variety. For this variety, an increased total yield of minitubers up to 24 was found compared
to uninoculated control, whereas G. etunicatum itself without bacteria increased total NT up to 55 data
of one-way ANOVA not shown.
3.3. Experiment 3 The results of three-way ANOVA Table 5 showed
that Zeolite amendment of the substrate for Karin va- riety significantly affected shoot dry weight SDW,
TFW and the mean fresh weight of minituber FWO. Bacterial treatments affected MC of roots. AMF in-
oculation significantly affected SDW, TFW and MC. Significant interaction was found only between the
M. Vos´atka, M. Gryndler Applied Soil Ecology 15 2000 145–152 149
Table 4 The effect of inoculation with three AMF and two bacteria on
NT, TFW, FWO and MC of potatoes of two varieties post-vitro transplanted to the greenhouse beds experiment 2
Factor NT
TFW g FWO g MC Variety Karin
Bacteria None
8.95 a
a
50.78 a 5.72 a
16.9 a
b
Bacterial isolate B1 10.29 b
47.13 a 4.62 a
17.8 a Bacterial isolate M30
8.80 a 46.52 a
5.31 a 20.6 a
AMF None
9.63 a
a
48.10 a 5.16 a
b
G. fistulosum 9.37 a
50.36 a 5.41 a
16.1 ab G. fasciculatum
9.53 a 49.01 a
5.21 a 11.8 a
G. etunicatum 8.85 a
49.10 a 5.08 a
22.4 b Variety Krista
Bacteria None
9.19 a
a
64.45 a 7.37 a
9.7 a
b
Bacterial isolate B1 7.63 a
66.25 a 8.92 b
11.9 a Bacterial isolate M30
8.00 a 66.64 a
8.43 ab 8.9 a
AMF None
7.63 a
a
62.08 a 8.45 a
b
G. fistulosum 8.04 a
70.00 b 8.95 a
11.9 a G. fasciculatum
8.03 a 66.15 ab 8.33 a
17.7 ab G. etunicatum
9.39 b 64.90 ab 7.24 a
19.4 b
a
Means of 12 replicates each replicate as a mean from eight plants within one parameter and one factor are not significantly
different according to Duncan multiple range test, p0.05.
b
Non-mycorrhizal treatments were not included into the sta- tistical treatment of MC.
Table 5 F-values and significance of three-way ANOVA for shoot dry weight SDW, NT, TFW, FWO and MC of potato plants of Karin variety
inoculated with six AMF and two bacteria and grown in pots with peat-based substrate amended with Zeolite experiment 3, d.f. represents degrees of freedom for the given factor
Factor d.f.
SDW g NT
TFW g FWO g
MC Zeolite A
1 126.4
a ,∗∗∗
0.7 ns 9.5
∗∗
7.6
∗∗
0.4 ns
b
Bacteria B 2
1.0 ns 1.3 ns
1.4 ns 0.5 ns
7.7
∗∗∗
AMF C 6
4.3
∗∗∗
1.3 ns 2.3
∗
2.2 ns 69.6
∗∗∗
A×B 2
0.2 ns 0.5 ns
0.1 ns 7.1
∗∗
4.2
∗
A×C 6
1.1 ns 0.5 ns
0.9 ns 1.1 ns
1.5 ns B×C
12 1.8 ns
1.4 ns 1.0 ns
0.8 ns 1.6 ns
A×B×C 12
0.8 ns 0.7 ns
1.1 ns 1.7 ns
1.7 ns Error mean square
292 0.03 292 0.6
292 17.5 292 20.5
252 101.9
a
ns — nonsignificant effect of the factor.
b
Non-mycorrhizal treatments were not included into the statistical treatment of MC.
∗
Significant effect at p0.05.
∗∗
Significant effect at p0.01.
∗∗∗
Significant effect at p0.001.
type of substrate Zeolite amendment and bacte- rial inoculation for the mean weight of minitubers
and for the MC. Inoculation with G. manihotis in- creased growth of shoots, total yield of minitubers
and the mean FWO, compared to uninoculated plants Table 6. At the same time, this fungus caused the
highest colonization of potato roots. Inoculation with G. geosporum increased weight of minituber but
no effect was found on the minitubers number. The only significant effect of bacterial inoculation was
a decrease of MC in the treatments inoculated with bacteria B1. Amendment by Zeolite had negative
effect on the growth of aboveground parts of the plants, nevertheless, it increased significantly the to-
tal yield of minitubers and the mean fresh weight of minitubers.
3.4. Experiment 4 In shadowhouse, the dual inoculation of Karin va-
riety affected significantly only the NT and MC of potato roots Table 7. Total NT was increased by inoc-
ulation with two AMF: G. mosseae and G. deserticola Table 8. Similarly as in the previous experiment,
G. manihotis was the inoculant causing the most extensive MC of potato. The number of marketable
minitubers NMT and their fresh weight remained unaffected by the inoculation.
150 M. Vos´atka, M. Gryndler Applied Soil Ecology 15 2000 145–152
Table 6 F-values and significance of ANOVA for SDW, NT, TFW, FWO and MC of potato plants of Karin variety inoculated with six AMF and
two bacteria and grown in pots with peat-based substrate amended with Zeolite experiment 3 Factor
SDW g NT
TFW g FWO g
MC Zeolite
Not added 0.91 b
a
2.04 a 20.12 a
13.95 a 10.5 a
b
Added 0.70 a
1.96 a 21.53 b
15.32 b 11.2 a
Bacteria None
0.78 a
a
1.93 a 20.3 a
14.4 a 12.6 b
b
Bacterial isolate B1 0.81 a
2.10 a 21.1 a
14.3 a 7.6 a
Bacterial isolate M30 0.81 a
1.96 a 21.1 a
15.2 a 12.5 b
AMF None
0.79 ab
a
2.02 a 20.22 a
13.64 a
b
G. fistulosum 0.74 a
1.90 a 19.86 a
15.04 ab 5.4 a
G. manihotis 0.90 c
2.14 a 22.46 b
16.13 b 35.6 b
G. geosporum 0.83 bc
1.83 a 21.29 ab
16.08 b 6.5 a
G. deserticola 0.81 b
2.08 a 21.33 ab
14.01 a 4.3 a
G. mosseae 0.78 ab
1.87 a 20.14 a
13.89 a 8.0 a
S. heterogama 0.76 ab
2.14 a 20.46 a
13.66 a 5.6 a
a
Means of 12 replicates within one parameter and one factor are not significantly different according to Duncan multiple range test, p0.05.
b
Non-mycorrhizal treatments were not included into the statistical treatment of MC.
4. Discussion
