الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Rhizoctonia solani, Fusarium solani and· Macrophomina
phaseolina are considered the most common destructive pathogens
that cause root- rot and damping- off disease of beans.
Objectives:
The research aims at
(a) Studying the effect of inoculation with mycorrhizal fungi which
symbiosis with bean root.
(b) Estimating the effectiveness of some systemic and non-systemic
fungicides on mycorrhizal fungi.
(c) Studying the effect of biological control from both pathogenic
and mycorrhizal fungi.
The obtained results could be summarized as follows:
1- R. solani, F. solani and 11,1. phaseolina were isolated from
diseased bean, faba bean, peas, chick pea and lupines plants roots
collected from the fann of the Faculty of Agric.at Moshtohor,
Zagazig Univ., A.R.E.
2- M ph aseo lina was the most destructive fungus causing the
higlrest percentage of pre- or post- emergence damping- off in
sterilized and unsterilized soils. On the other hand, R. solani
caused the highest percentage ofroo - rot severity in both soils.
- The compound infection of the three pathogens caused a
significant increase in the percentage of pre-emergence damping
off and root-rot. It also caused a significant decrease in the height,
number of leaves for each plant and a decrease in both dry and
fresh weights of roots and shoots in both soil types .
. 4- The Glomus mosseae was isolated from the studied soil samples.
By examined of mycorrhizae symbiosis root, it was found that VAmycorrhizal
fungi have an extensive hypha! net work that extends
from the root. External hyphae are thick walled, variable and
irregular in shape. Vesicles and arbuscles are produced in the soil.
The shape of spores generally in Egyptian soils are gloubose,
ellipsoid their longest dimension ranging form 30- 40 urn.
s. For ilil;~e under the local environment, the study succeeded in
developing the mycorrhizal fungi, after Murashing and Skoog
(1962) medium was modified to urge the spores to germinate after
2 - 3 weeks incubation period at 40 ± l°e, VAM- fungi begun to
grow on the modified medium of Murashing and skoog (1962)
after 2 - 3 weeks at 40 ± I’’C. At the beginning a few hyphae
were formed after one week more, spores were fanned with uge
amount, these spores gernrinated after one week and formed more
- hyphae. After 3 months a large net work of hyphae were formed
in the plates with a few n bers of spores.
6- Addition of VA- mycorrhiza to the soil in the presence of the three
pathogens caused a decrease in the percentage of pre- emergence
~130-
damping- off. This trend was found ill both unsterilizedand
sterilized soils.
7- Addition of VA-mycorrhiza increased plant height, root length,
number of leaves number of pods, fresh matter of shoots and roots
and the dry matter of shoots and root in both soils compared with
the control. Also, addition of VA- mycorrhiza in the presence of
any of M phaseolina, R. so/ani and F. so/ani improved the
previously mentioned growth characters compared with each
pathogen alone.
8- VA- mycorrhiza colonized the roots of bean plants in sterilized
and unsterilized soils. All treatments of the pathogenic fungi with
G1 or G2 showed root colonization with VAM. Root colonization
with VAM was higher in the sterilized soil than in the unsterilized
soil.
9- Addition of VAM- fungi to Gland G2 in sterilized or unsterilized
soils decreased the percentage of root- rot and increased all
growth characters under study.
10- Addition of VAM- fungi to GI and G2 in the s erilized and
natural soils increased root colonization with VAM compared with
the control.
11- Seed dressing with the ftmgicide Benlate combined with soil
inoculated with G1 + G2 was effective in reducing the percentage
of the per-emergence damping- off. Soil inoculated with G1 + G2
successfully prevented from infection with the root- rot of bean
plants. Almost all combinations of systemic fungicides and
VAM increased plant height, root length, shoot fresh and dry
matter and root fresh and dry matter.
12- Addition of any of Gland G2 and their combinations to sterilized
and unsterilized soils showed high colonization of bean roots with
VAM- fungi. Seed dressing with any of the two systemic
fungicides inhibited root colonization.
13- Seed dressing with the non- systemic fungicide Dithane-M 45
combined with soil inoculated with G2 was effective in reducing
the percentage of the per-emergence damping- off. Seed dressed
with Mancoper showed the lowest percentage of root- rot.
Almost all combinations of the non- systemic fungicides and
VAM increased the number of leaves, plant height, fresh and dry
matter of shoots and the fresh matter of the roots.
14- Addition of any of G1, G2 and their combinations to sterilized and
unsterilized soils showed high colonization of bean roots with
VAM- fungi. Seed dress’ g with the two non- systemic fungicides
inhibited root colonization.
15- Addition of any of G. macrocarpum, T. harizianum, B. subtilis
and their combinations to the sterilized soil in presence of R
solani, F. so/ani and M. phaseolina separatel increased the
percentage of the per - emergence- damping- off. All treatments
included M phaseolina showed higher percentage of damping-
off than other treatments. On the contrary, addition of mycorrhiza
and the two antagonists to the soil decreased the percentage of
root- rot.
16- Plant height was increased with the addition of any of G.
macrocarpum, T harizianum, B. subtilis and their combinations to
the soil in most treatments. Root length was decreased with the
addition of the pathogenic and the antagonistic fungi separately or
in combinations. All treatments included the mycorrhiza and the
antagonistic fungi separately or in combination increased number
of leaves. Treatments included G. macrocarpum, the autagnistic
fungi or their combinations increased shoot fresh matter in some
cases and decreased in the others. Shoot dry matter, root fresh and
dry matter were increased in treatments included G.
macrocarpum, the antagonistic fungi and their combinations.
17- Bean plants grown in sterilized and unsterilized soils inoculated
with mycorrhiza, T. harizianurn, B. subtilis and their combinations
showed high percentages of root colonization. On the other hand,
addition of the pathogenic fungi to soil inoculated with the
mycorrhiza decreased the percentage of root colonization.
Generally, the percentage of root colonization was higher in the
unsterilized soil than the sterilized one.
18- Bean plants grown in sterilized soil inoculated with G.
macrocarpum had high contents of chlorophyll A and B in their
leaves compared with the control. The combinations of
mycorrhiza + R. solani or F. solani showed higher contents of
chlorophyll A and B than each pathogen separately which were,
however, less than the control. The same trend was also found
with the caroteinoids. All combinations of the mycorrhiza and
the pathogenic fungi showed higher contents of caroteinoids than
each pathogen separately.
19- Addition of G. macrocarpum to the soil increased the levels of
gibberellin in bean plants than the other treatments and the control.
Also, plants grown in soil infested with R. solani showed high
percentage of gibberellin than the other two pathogens. Addition
of mycorrhiza to soil infested with each pathogen decreased the
level of gibberellin except in case of R. solani + the rnycorrhiza
whereas, the level of gibberellin was deceased.
20- Transverse sections in roots of bean plants infected with VAM
showed an increase in number and diameter of zylem vessels
which occupied the zylem parenchyma.