الفهرس 
EVALUATION OF RHIZOCTONIA STEM CANKER DISEASE RESISTANCE OF FABA BEAN GROWN IN SOIL AMENDED WITH BIOCHAROnly 14 pages are availabe for public view
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Abstract
This study was performed to investigate the efficacy of biochar rates, as a soil amendment, in suppressing plant diseases such as Rhizoctonia solani. Rhizoctonia solani is one of the soilborne
fungi, causing serious diseases to faba bean plants. This work was achieved to study the effect biochar and biofertilizer addition on plant growth parameters and productivity, as well as its role in reducing fungal activity.
The main obtained results of the present study could be summarized as follows:
1- Isolation of the fungus from the diseased faba bean plants, suffering from stem canker symptoms that diagnosed and collected from different locations of El-Beheira governorate.
2- By morphological and microscopic investigation, the culture was confirmed to belong to the
fungus (Rhizoctonia solani).
3- Molecular identification of Rhizoctonia solani was performed by PCR technique using pair of specific primers (ITS1 and ITS4) used for amplification of internal transcribed spacer region
of rDNA and showed specific bands approximately between (600-700bp). The result illustrated that the isolate belongs to the fungus Rhizoctonia solani.
4- Two types of biochar were produced from sugarcane bagasse feedstock (SCBF) and corncob feedstock (CCF). The main characterizations of biomass and biochar were determined. The results indicated that the biochar content includes sodium, potassium, zinc, and manganese,
while the biomass had a higher content of phosphorous and copper than biochar, and iron had a fixed concentration in both. pH measurements showed that the processed biochar has higher
pH values than that of agricultural residues before processing.
5- Two laboratory experiments were conducted to evaluate the effect of different concs. (0, 0.5, 1, 2, and 3%) of two the tested types of biochar (CCB and SCBB) on fungal growth by measuring the growth rate and estimating both wet and dry weight of the fungus. Obtained
results showed that biochar did not inhibit the fungal growth, but slowed down the growth of the fungus at cocs. 0.5 and 1%, which. Obtained results showed that reduction of fungal growth
was higher in corncob biochar, compared to sugarcane bagasse biochar.
6- A laboratory experiment was performed to evaluate the effect of different concs. (0, 0.5, 1, 2, and 3%) on the two tested types of biochar (CCB and SCBB) on the number of bacterial
colonies. The results showed direct proportion between the concentration of biochar and the number of colonies. Number of colonies for both types was higher at conc. 2%, however,
colony numbers were more in corncob biochar, compared with sugarcane bagasse biochar.94
7- Pathogenicity test of the identified fungal isolate was examined by using four treatments in soil amended with corncob biochar at four different concentrations (0, 0.5, 1, and 2%). as
following:
a. Control (biochar treatments only),
b. Fungus (Rhizoctonia solani) addition,
c. Biofertilizer (Microbin) addition, and
d. fungus and biofertilizer
The results showed that the highest effect on the seedlings pre-emergence and post-emergence above the surface of the soil was obtained by the fungus alone. Better plant growth was attained
by microbial fertilizer alone, compared to the previous treatment. Addition of fungus and biofertilizer showed a medium plant growth between the two previous treatments, compared to the control.