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العنوان
MANAGEMENT OF POTATO BACTERIAL WILT DISEASE USING BIOTIC AND ABIOTIC TREATMENTS \
المؤلف
MOSTAFA, HANAN SALEH ABD RABBO.
هيئة الاعداد
باحث / حنان صالح عبد ربه مصطفى
مشرف / ناجي يسين عبد الغفار
مناقش / إبراهيم حسن طلبه
مشرف / وداد التهامى السيد عويضه
تاريخ النشر
2020.
عدد الصفحات
121 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
علوم النبات
تاريخ الإجازة
19/1/2020
مكان الإجازة
جامعة عين شمس - كلية الزراعة - أمراض نبات
الفهرس
Only 14 pages are availabe for public view

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from 121

Abstract

Bacterial wilt disease caused by Ralstonia solanacearum is one of the most important and widespread bacterial diseases of solanaceous crops in tropical, subtropical areas and some temperate regions. The bacterium has a quarantine status in Egypt and in Europe. Current official controls aim to ensure that potatoes for export are produced in pathogen-free areas (PFAs) and that these areas remain free for future production. Meanwhile where it is endemic, to maintain production of this main food crop, there is also need for improved control of the pathogen in many areas of Egypt. Study plan including isolation and identification of the causal organism using conventional and modern techniques. Also, this study disease control using chemical factors, resistance inducers and bio-agents individually or in combination by effecting on the disease severity and the yield of potato, under artificial inoculation conditions. The results could be summarized as follows: -
1- Typical syndromes of potato brown rot disease were observed on tubers, cutting the diseased tubers revealed a browning and necrosis of the vascular ring and immediately surrounding tissues side of the ring. A creamy fluidal exudate usually appears on the vascular ring of the cut surface.
2- Isolation of the pathogen was made from samples of infected potato tubers on the modified SMSA medium selective for the pathogen. These samples were collected from different locations, during growing seasons 2016 – 2017.
3- Pathogenicity test was carried out on tomato seedlings (3-leaves). the symptoms on tomato seedlings were recorded wilting, stunting and yellowing of foliage compared with non-inoculated seedlings as control treatment. While hypersensitive reaction (HR) the symptoms on tobacco plants were water soaking spots, yellowing and brown died spots.
4- Five pathogenic isolates were selected to their identification according to cultural and morphological characteristics. All isolates were short-rod, negative staining and non-sporulating. Developed colonies on nutrient agar (NA) medium were irregularly-round, convex, smooth surface, entire margin, translucent and yellowish brown in color. Meantime, these colonies were whitish-gray in color on King s B (KB) medium. Colonies on tetrazolium chloride (TTC) medium and semi-selective medium of South Africa (SMSA) were fluidal white with red or pink center.
5- Physiological and biochemical characteristics of five pathogenic isolates showed positive results with oxidase, catalase enzyme, nitrate reduction, growth at 1% NaCl. However, these isolates were negative with starch hydrolysis, arginine hydrolysis, Produced indole, gelatin liquefaction, Levan production, and growth at 5% NaCl.
6- Serological (IFAs) and molecular (PCR) tests were applied to confirm the identification of the pathogen. The serological test shown positive result where the cells of Ralstonia solanacearum were watched coated with conjugate staining which give apple green color under florescent microscope. But PCR is more sensitive test to detect the lower concentration of R. solanacearum and consider a confirmation test in detection methodology. All isolates give a positive result in PCR.
7- All isolates were identified R. solanacearum according to cultural morphological, physiological, biochemical, serological (IFAS) and molecular (PCR) tests.
8- Bactericides (cefalexin, gentamycin) and copper sulphate were examined against the growth of R. solanacerium bacterium, at different concentrating using fitter paper method, in vitro.
9- All tested bactericides were decreased from the growth of R. solanacerum bacterium compared with the control treatment. Efficacy tested bactericides were increased with increasing their concentration. copper sulphate was the most effective in inhibition the growth of R. solanacerum, while cefalexin was moderately effective and Gentamycin was less effective compared with other chemical factors.
10- Bio-agents (Bacillus subtilis, Bacillus megaterium, Pseudomonas fluorescence and Serratia marcescens) were tested against the growth of bacterial wilt pathogen R. solanacerum, In vitro.
11- Tested bio-agents were reduced from the growth of R. solanacerum compared with the control. Isolate of B. subtilis was the most effective against the growth of R. solanacerum compared with other bio-agents. While Ps. fluoresces and B. megaterium isolates were the moderately effective and isolate of S. marcescens was less effective compared with other bio-agents.
12- Application of bactericides (cefalexin, gentamycin,) and copper sulphate as soil drench and/ or tuber treatments, Resistance inducers (3D-Laminobutyric acid, Jasmonic acid and Salicylic acid) as tuber and/or foliar treatments and bio-agent (B. subtilis, megatherium and Ps.fluorescens)as soil drench and/or tuber treatments were evaluated to control potato bacterial wilt disease and on potato yield, under artificial inoculation conditions.
13- Bactericides were reduced from severity of potato bacterial wilt disease compared with control treatment. Cefalexin and gentamycin were the most effective to control the disease, while copper Sulphate was moderately effective to control potato bacterial wilt disease. Application of bactericides as soil drench treatment was more effective than tuber treatment against Potato bacterial wilt disease, under artificial inoculation conditions.
14- Resistance inducers (3D-L amino butyric acid, Jasmonic acid and Salicylic acid) were decreased from severity of potato bacterial wilt disease compared wilt control treatment, under artificial inoculation condition It could be noticed that disease severity was decreased was increased by increasing doses of abiotic agents. Salicylic acid and Jasmonic acid were the most effective to control the disease compared with other Resistance inducers and3D-L aminobutyric acid was moderately effective against the disease. While, application of resistance inducers as foliar treatment was more effective than tuber treatment against potato bacterial wilt disease, under artificial inoculation condition.
15- Application of bio-agent (B. subtilis, B. megaterium and Ps. fluorescens) isolate led to reduce severity of potato bacterial wilt disease under artificial inoculation conditions compared with the control. Meanwhile, isolate of B. subtilis was the most effective against the disease compared with other bio-agent and isolates of Ps. fluorescens B. megaterium were moderately effective against the disease .Application of B. subtilis and B.megaterium Isolates as soil drench treatment were more effective than tuber to control the disease but application of Ps. fluorescens isolate as tuber treatment more effective than soil drench treatment against the disease.
16- Bactericides (cefalexin, gentamycin) and copper Sulphate were the most effective to reduce severity of potato bacterial wilt disease under artificial inoculation condition, compared with resistance inducers and bio-agents treatments, but resistance inducers were moderately effective and bio-agents were less effective compared with other treatment.
17- Application of bactericides as soil drench and/or tuber treatments led to increase potato yield and to decrease percentage of actually infected tubers under artificial inoculation conditions compared with the control treatment. Meanwhile, Cefalexin was the most effective on the yield and percentage of actually infective tubers compared with the control, and gentamycin and copper Sulphate were moderately effective to increase the yield and to decrease percentage of actually infected tuber under artificial inoculation condition while, application of bactericides as soil drench treatment were more effective than tuber treatment on potato yield and percentage of actually infected tubers.
18- Resistance inducers (3D-Laminobutyric acid, jasmonic acid and salicylic acid) were applied as foliar and/or tuber treatments led to increase potato yield and to decrease actually infected tubers under artificial inoculation condition by R. solanacerum. Resistance inducers were the most effective on the yield and actually infected tubers compared with the control treatment. Salicylic acid and jasmonic acid were the most effective to increase potato yield and to decrease percentage of actually infected tubers, but aminobutyric acid was moderately effective. Application of resistance inducers as foliar treatment was more effective than tuber treatment.
19- Application of bio-agents (B. subtilis, B. megaterium Ps. fluorescens) strain as soil drench and/or tuber treatments led to increase potato yield and to reduce percentage of actually infected tubers, under artificial inoculation condition, with R. solanacerum compared with the control. Isolates of B. subtilis and Ps. fluorescens were more effective than B. megaterium isolate on potato yield and actually infected tubers. Bio-agents as soil drench were more effective than tuber treatment to increase the yield and to decrease percentage of actually infected tubers.
20- Also, bactericides were the most effective to increase potato yield and to decrease actually infected tuber compared with resistance inducers and bio-agents treatments. While, resistance inducers treatments were moderately effective and bio-agents treatment were less effective compared with other treatment on the yield and actually infected tubers.
21- Integration between salicylic acid as Resistance inducer and antibiotic were more effective on disease severity, potato yield and actually infected tubers than integration between Jasmonic acid as resistance inducer and antibiotic. Integration between salicylic acid as resistance inducer and cefalexin as antibiotic were the most effective to increase potato yield and to decrease disease severity and actually infected tubers compared with other treatments, but integration between jasmonic acid as resistance inducer and gentamycin as antibiotic were less effective on potato yield, severity of potato bacterial wilt disease and actually infects tubers, compared with other treatments.
22- Integration between bio-agents (B. subtilis and Ps. fluorescens strain) as soil drench treatment and resistance inducers (salicylic acid and jasmonic acid) as foliar treatment led to increases potato yield and to reduce severity of potato bacterial wilt disease and actually infected tubers compared control treatment, under artificial inoculation conditions with R. solanacearum. Integration between Ps. fluorescens isolate as bio-agent and resistance inducers were more effective than interaction between B. subtilis isolate as bio-agent and resistance induces on disease severity, potato yield and percentage of actually infected tubers. While, integration between Ps. fluoresces isolate and salicylic acid were the most effective to increase potato yield and to decrease disease severity and percentage of actually infected tubers compared with other treatments, but integration between B. subtilis isolate and Jasmonic acid were less effective compared with other treatments.
23- Integration between antibiotic as soil drench treatment and bio-agents as tuber treatment or resistance inducers as foliar treatment significantly reduced severity of potato bacterial will disease and actually infected tubers and significantly increased potato yield compared other treatment, but integration between bio-agents as soil drench treatment and resistance inducers as foliar treatment were moderately effective to decrease disease severity and actually infected tubers and to increase the severity yield. integration between Cefalexin as antibiotic and Ps. fluorescens isolate as bio-agent or salicylic acid as resistance inducer were the most effective on disease severity, percentage of actually infected tubers compared with other treatments, but integration between B. subtilis isolate as bio-agent and Jasmonic acid as resistance inducer were less effective compared with other treatment. Also, integration treatments were more effective on disease severity, actually infected tubers and the yield than alone treatments.