Document Details
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Document Type |
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Thesis |
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Document Title |
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MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION AND MANAGEMENT STUDIES OF (ALTERNARIA SOLANI ) ON TOMATO( LYCOPERSICON ESCULENTUM) MILL دراسات على التعرف المورفولجى والجزيئى والمكافحة للفطر المسبب لمرض الندوة المبكرة Alternaria solani فى الطماطم Mill Lycopersicon esculentum |
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Subject |
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Faculty of Meteorology, Environment and Arid Land Agriculture |
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Document Language |
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Arabic |
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Abstract |
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The aims of this study were to isolate, characterize, and differentiate between two Alternaria solani isolates causing early blight on tomato fields in Hada Al-Sham, Province of Al-Jamoum, Saudi Arabia and to evaluate fungicides, biocontrol agents and botanical products against A. solani . Experiments were carried out in the Lab of Plant protection, Department of Arid land Agriculture, and in the Hada Al Sham Agricultural Research Station, King Abdulaziz University, Saudi Arabia. Tomato leaves samples with typical early blight symptoms were collected from two different tomato fields and then brought to the lab of plant protection. The causal agent (A. solani) was isolated and pure culture of the pathogen was obtained by Hyphal Tip Isolation Method (HTIM). The pathogen was identified based on morphological characteristics of the conidia and characterized as two isolates AS1 and AS2 for further investigations. Study on morphological characteristics of the tested isolates of A. solani showed diversity based on their mycelial width, conidial size, beak length and septations. Result of the pathogenicity test for the isolates of A. solani revealed that the isolates exhibited differences in their pathogenic potential, where the isolate AS1 recorded maximum level of disease incidence and disease severity compared to AS2. The results of cultural characteristics revealed significant differences between A. solani isolates As1 and AS1 with regard linear mycelial growth, mycelial growth patterns, and pigmentation on various solid culture media. The highest radial growth was observed in Sabouraud’s Agar Medium for isolate AS1 and AS2 on Richard’s Agar (9.0 cm). The lowest mycelial growth (3.3 cm) was recorded for AS2 on Host Extract Agar. AS1 and AS2 isolates illustrated significant differences in pigment production, growth margins and growth surface. Regarding effects of pH, temperature and light on AS1 and AS2 growth the results showed that the optimum pH level for both isolates was 6.5, temperature of 30 °C and light regime of 12 h light and 12 h dark for AS1 and continues light for AS2.
Molecular characterization of AS1 and AS2 isolates of A. solani was conducted using RAPD markers. A. solani isolate AS1 was identified by 9 different RAPD loci with a molecular weight ranged from 170bp for OPD-09 and 700pb for OPD-13. Moreover, A. solani isolate AS2 was identified by 3 RAPD loci with a molecular weight ranged from 170bp for OPC-01 to 700bp for OPC-01. Materix similarity for estimating genetic relationships between the A. solani isolates AS1 and AS2 was calculated. The sum of similar patterns between AS1 and AS2 was 0.133. The results of in vitro control of A. solani using botanical extracts revealed that the plant extracts from Azadirachta indica recorded the maximum radial growth inhibition (58.3%) of the pathogen, followed by Lantana camara (50%) and Allium sativum (41.6%). Chemical control treatments indicated that Hexaconazole 5 EC caused the highest radial growth inhibition (90.2 %) followed by Mancozeb 80 WP (71.7%), Benomyl 50%WP (68.1%) and Carbendazim 50%WP (55.8%). In dual culture assay, Trichoderma harzianum found to be the most effective biocontrol agent by recording highest percent inhibition of the pathogen growth (54.6%) followed by Trichoderma viride (48.4%), Pseudomonas flourocsens (27.8 %) and Bacillus subtilus (21.6%). In vitro control of A. solani using botanical oils indicated that lemon oil at 3% significantly inhibited mycelial growth (31.6%), followed by ginger oil. Results of field control of A. solani using botanical oils revealed that garlic oil reduced disease severity by 34.2 %, followed by clove oil (34.1%). |
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Supervisor |
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Dr. Magdy Ali Mousa |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1438 AH
2017 AD |
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Co-Supervisor |
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Dr.. Mohammed Hussein Madkour |
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Added Date |
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Tuesday, May 30, 2017 |
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Researchers
| نجيب الله نجيب الله رحمتزي | Rahmatzi, Najibullah Najibullah | Researcher | Doctorate | |
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