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ThesisItem Open Access Morphological and molecular variability of xanthomonas axonopodis pv. Punicae (Hingorani and singh) Vauterin et al. causing bacterial blight of pomegranate(UAS, Dharwad, 2009) Madhu.S.Giri; S.K.PrashanthiPomegranate (Punica granatum L.) is an important fruit crop of India and other subtropical countries. Bacterial blight caused by Xanthomonas axonopodis pv. punicae (Hingorani and Singh, 1959) Vauterin et al. is a major threat to pomegranate production. Morphological, physiological, biochemical and molecular diversity of the 16 isolates of Xanthomonas axonopodis pv. punicae collected from various parts of Karnataka was studied. Lokapur and Ramatala isolates produced highly mucoid colonies on YDCA and GYCA medium. The maximum colony size was found in case of Lokapur, Ramatala, Gulaganjikoppa and Kothabala isolates, while the least colony diameter was recorded in Uthnal isolate. YDCA, GYCA and YNA media supported good growth of all the isolates. Many isolates failed to grow on the XPS medium. The temperature 200C supported the maximum growth of 11 isolates, while 300C was found optimum for the remaining five isolates. All the isolates showed maximum growth at pH 5.0. However, Ramatala and Mudhol isolates showed good growth even at pH 8.0. Among sixteen isolates, only five isolates could hydrolyse starch and they showed variation in their ability to hydrolyse starch. Almost all the isolates produced strong to weak acids from sucrose, maltose and dextrose, where as Hagaribommanahally isolate failed to produce acid from sucrose and maltose. Bardol isolate failed to produce acid from sucrose. Uthnal, Bardol and Bandi isolates failed to produce hydrogen sulphide gas where as remaining isolates produced heavy to weak H2S gas. RAPD analysis distinguished the 16 isolates in to 2 major clusters; cluster A was represented by a single isolate i.e., Hagaribommanahally isolate of Bellary district and cluster B encompassed all other isolates. The maximum genetic similarity of 91% was observed between Gulaganjikoppa and Kurubararamanahally isolate; least similarity was found between Thavargere and Shravanagere isolates. Molecular diversity study indicated the fact that, the variation is independent of geographical location.ThesisItem Open Access Serodiagnosis and Molecular characterization of Bhendi Yellow vein mosaic virus(UAS, Dharwad, 2009) T.L.Prakasha; M.S.PatilBhendi (Abelmoschous esculentus (L.) Moench is one of the important vegetable crops grown in Karnataka. Bhendi crop suffers from several biotic stresses among the important diseases of this crop Bhendi yellow vein mosaic disease is one of the most severe diseases leading to heavy losses of the crop. Roving survey conducted during kharif 2008 and summer season 2009 in four districts of Karnataka indicated more severe disease incidence during summer season with disease incidence varying from 15.2 to 48.9 per cent. Maximum incidence of 48.9 per cent was noticed in UAS, Dharwad campus. During kharif, incidence varied from 0 to 19.5 per cent. The bioassay and RAPD-PCR analysis of whiteflies revealed the presence of Bbiotype in Dharwad on both cotton and bhendi which is a potential vector for the transmission of BYVMV. Gene encoding the coat protein of BYVMV had 771 bp which codes for 256 amino acids. It shared highest nucleotide (99.35%) and amino acid (99.65%) sequence identity with BYVMV Madhurai Variant 3 (AJ278861) and Barrackpur isolate (EF417918). Antiserum was produced in rabbits using partially purified virus preparation and DAS-ELISA was standardized and successfully used to detect BYVMV in infected leaves. Out of 16 field samples tested in DAS-ELISA, only two samples viz., bhendi and Ageratum conizoides showed positive reaction Sugars content was increased due to infection of BYVMV and the sugar content viz., Reducing sugars, non-reducing sugars and total sugars was found to be more in the susceptible variety (Pusa Sawani) than resistant variety (Arka Anamika). Phenol content and enzymatic activities (PAL, Chitinase and Peroxidase) were increased in BYVMV infected leaves rather than healthy leaves and their activity were low in susceptible variety when compared with the resistant variety.ThesisItem Open Access Investigations on the variability and management of turcicum leaf blight in maize caused by Exserohilum turcicum (pass) leonard and suggs(UAS, Dharwad, 2009) Sachin A.Khedekar; S.I.HarlapurTurcicum leaf blight of maize caused by Exserohilum turcicum (Pass.) Leonard and Suggs. is an important disease which results in heavy yield loss. Laboratory and field experiments were carried out to study the pathogenic variability and management aspects of the pathogen and disease. Survey indicated that, higher disease incidence was noticed in Sankeshwer, Haveri, Arabhavi and Dharwad. Eighteen isolates collected from different part of Northern Karnataka was studied in the laboratory. Arabhavi isolate (Et5) was very fast growing with high rate of sporulation. Among the five media studied potato dextrose agar (PDA) recorded maximum mycelial growth of fungus followed by PDA + Yeast medium. Maximum growth of fungus was observed at 300C in all the isolates followed by 250C temperature. A botanical product, cristol 56 SL and systemic fungicide, carboxin 200 FF were most effective in inhibiting the growth of the fungus. The plant extracts viz; nimbicidin and negunda extract at 5 and 10 per cent concentration were effective against the pathogen. Among the bio-control agents evaluated, Trichoderma harzianum found effective against the pathogen. Inbred lines viz., KDMI-13, CM-138, INDIMYT- 343, CM-501, CI-4, V-356, V-358, NEI-9202B, NG-14 and hybrids viz., Swarna, NAC-6004, NK-6240, JKMH-502, PAC-740, C-193 registered resistant reaction under artificial inoculate field condition. Seed treatment with carboxin 200 FF @ 2 ml/kg or Trichoderma harzianum @ 6g/kg and foliar spray of mancozeb 0.25% twice at 40 and 50 DAS, recorded minimum disease severity and highest grain yield. Seed treatment with carboxin 200 FF 2ml/kg seed and 2 sprays of 0.25% cristol 56 SL at 40 to 50 DAS found equally effective.ThesisItem Open Access Studies on Biological Management of Collar rot of Sesame caused by Sclerotium rolfsii Sacc(UAS, Dharwad, 2009) Praveenkumar.N.; M.G.PalakshappaSesame is one of the important oilseed crops of Karnataka. Sesame suffers from several diseases. Among them collar rot caused by Sclerotium rolfsii is the most destructive one causing 10-15 per cent loss. Hence, detailed studies on this pathogen including isolation, pathogensity test, standardization of inoculum level, survey of the disease in sesame growing areas of northern Karnataka, in vitro evaluation of botanicals, bioagents, biorationals, organic amendments and integrated disease management had been carried out. Rhizosphere population of microorganisms was estimated in different intervals in the treatments of integrated management of collar rot of sesame. A pure culture of S. rolfsii was obtained from sesame plants showing typical collar rot symptoms and its pathogensity to sesame was proved. Maximum incidence (5.9%) was recorded in MARS, UAS, Dharwad and minimum incidence (1.0%) in MARS, UAS, Raichur and Kanyadoddi village in Raichur taluka. Nimbicidin at 5 and 10 per cent, T. harzianum and cowurine + vermiwash at 2 and 6 per cent and cowurine + butter milk at 4 and 6 per cent were found effective in inhibiting mycelial growth and sclerotial formation of S. rolfsii. Vermicompost recorded least disease incidence (30.30%) followed by neem cake (33.33%). Rhizosphere microbial population increased in all integrated treatments tested. At 30 DAS the maximum population of fungi, bacteria and actinomycetes were noticed in T1 (FYM + seed treatment with T. harzianum), T2 (FYM + seed treatment with P. fluorescens) and T5 (FYM + drenching with jeevamrutha), respectively. The same trend was also noticed at 45 DAS. In the integrated management of sesame collar rot, the treatment T7 (FYM + seed treatment with carboxin) was found to be the most effective in reducing the disease and it recorded the least per cent disease incidence (33.33%).ThesisItem Open Access Studies on seed-borne fungal pathogens of chickpea and their management with special referance to Fusarium solani (Mart.) Sacc.(UAS, Dharwad, 2009) M.Chaitra; M.S.L.RaoThe present investigation on seedborne fungal pathogens of chickpea and their management with special reference to Fusarium solani (Mart.) Sacc. was conducted during 2007-2009 which included seed health testing of different chickpea cultivars, study of effect of seed mycoflora on germination and vigour, evaluation of seed health testing methods, seed to plant transmission studies, effect of different seed inoculum levels on wilt incidence and integrated disease management through use of seed dressing fungicides, botanicals and bioagents along with priming agents. Seed health testing of chickpea seed samples collected from different parts of northern Karnataka revealed the dominance of Fusarium spp. Seed washing technique revealed only the presence of saprophytic fungi like Aspergillus sp. Among the different seed health testing methods, 2,4-D blotter method was found to be good for the detection of Fusarium spp. in chickpea .Infected chickpea seeds exhibited poor germination and vigour . The pathogenic ability of seedborne Fusarium solani was proved by seedling symptom test under in vitro and glass house condition. The results of effect of different seed inoculum levels of F. solani on wilt incidence indicated that the seed inoculum level upto 5×104 conidia/10 ml resulted in maximum wilt incidence. Component plating technique proved the internal and external seedborne nature of F. solani. Seed dressing fungicides viz., carbendazim+iprodione, bio-agent Pseudomonas fluorescens and botanical garlic bulb extract were found effective in eliminating seed-borne fungal infections. Under glasshouse condition seed treatment with P. fluorescens + vermiculite recorded least per cent wilt incidence (12.53%) at 45 DAS. Under field condition, seed treatment with carbendazim+iprodine (0.2%) recorded highest yield (9.56 q/ha) and maximum net returns (Rs.12,960) with least wilt incidence.ThesisItem Open Access Studies on powdery mildew of sunflower caused by Erysiphe cichoracearum DC.(UAS, Dharwad, 2009) B.M.Dinesh; Shripad KulkarniSunflower is one of the important oilseed crops of India. Among biotic stresses powdery mildew caused by Erysiphe cichoracearum is economically important disease. Roving survey was conducted during late kharif and rabi seasons of 2008 in seven districts of Northern Karnataka. Maximum disease severity was noticed in Koppal (74.11%) and Haveri district (66.61%). Least severity was noticed in Bagalkot (30.94%) and Belgaum district (34.11%). The plants of 50 days old were highly susceptible to the infection of E. cichoracearum. The per cent reduction of chlorophyll a, chlorophyll b and total chlorophyll was more in susceptible variety than in resistant cultivar. In susceptible variety higher amount of total sugar, reducing sugar and non-reducing sugar were recorded than in resistant cultivar. Whereas, nonreducing and total sugar were synthesized at faster rate in susceptible cultivar than in resistant cultivar. Healthy leaves of resistant cultivar had 1.362 mg/g of total phenols and it was increased to 4.817 mg/g after infection. Total phenols were accumulated at faster rate in resistant cultivar (253.63%) than in susceptible cultivar (230.70%). Among the 91 germplasm lines screened under artificial epiphytotic condition seven lines viz., GMU601, 602, 605, 664, 672, 684 and 697 were found resistant against powdery mildew. In case of in vitro evaluation of botanicals and organics, azadirachtin (0.5%) and NSKE (5%) were found most effective in inhibiting conidial germination. Whereas, in field azadirachtin (69.07% and 7.11 q/ha) and NSKE (66.93% and 7.00 q/ha) managed the disease and increased yield significantly. In field evaluation of fungicides, two sprays of difenconazole at 0.05 per cent (3.56, 9.53 q/ha), propiconazole at 0.1 per cent (4.44, 9.47 q/ha) found superior as they recorded the lowest per cent disease index and higher seed yield. Highest cost benefit ratio was observed in propiconazole (1:6.86), difenconazole (1:6.13) and hexaconazole (1: 6.12).ThesisItem Open Access Variability and Management of Charcoal Rot of Sorghum Caused By Macrophomina phaseolina(Tassi) Goid(UAS Dharwad, 2009) Virupaksa.H.Prabhu; S.S.AdiverCharcoal rot of sorghum caused by Macrophomina phaseolina, is a severe disease particularly in rabi season grown crop. Thirty five infected sorghum stalk samples were collected from Karnataka, Maharashtra and Andhra Pradesh to assess the variability. Based on colony pigmentation, the cultures were assigned to four major groups on PDA and three groups on Czapek’s medium. Studies on toxin variability showed the symptoms such as drooping of leaves, blackening of leaves which was initiated at four hours and continued upto fourteen hours, thus revealing the existence of variation among the isolates. The sensitivity of isolates to copper sulphate at three different levels of concentrations found to differ to various concentrations tested. But with Carbendazim, the growth of all isolates were completely inhibited. Highest growth was observed in 7.0 pH, closely followed by 6.5 pH indicating preferential range to be between 6.5 and 7.00 pH. Peroxidase and Polyphenoloxidase enzyme analysis indicated that there was significant variation among the 35 isolates of M. phaseolina. RAPD data distinguished the 35 isolates into three major clusters. Management of charcoal rot of sorghum revealed that the seed treatment with carbendazim and seed treatment with T. harzianum + P. fluorescens showed superior results. Sixty four germplasm lines of sorghum screened. Charcoal rot was least in Dagadi Solapur, followed by GRS-1 and BCR-9. None of the genotypes showed resistant reaction. Employment of new source of resistance sources like local genotypes mentioned above can be effectively employed in resistance breeding programme to manage charcoal rot of sorghum.ThesisItem Open Access Epidemiology and management of bacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae (Hingorani and Singh) Vauterin et al.(UAS Dharwad, 2009) S.T.Yenjerappa; V.B.NargundConsidering the magnitude and resultant losses due to bacterial blight in pomegranate, investigations were undertaken on disease, pathogen, environment and management aspects. Survey revealed the highest disease incidence in Chitradurga, Anantapur and Koppal districts and lowest incidence and severity was recorded in Bellary district. The bacterium was rod shaped, gram negative and capsulated. It was positive to starch hydrolysis, gelatin, liquefaction and H2S production. Modified D-5 medium was found superior in supporting the growth of the pathogen. Cultural variability among the 20 different isolates revealed the variability in growth and colony characters. The isolates exhibited 100 per cent polymorphism for OPA20, OPB03, OPF07 and OPF10 primers showing significant molecular variability. Among the different seasons, mrigbahar was found most vulnerable and hastbahar was found relatively safe in avoiding the disease. Rainfall for a longer period, maximum temperature between 29.4-35.60C and minimum temperature between 19.5 to 27.30C, RH of 63-87 per cent were found favourable for the disease development and spread. Pathogen survived upto 20 to 22 and 18 to 20 weeks in the infected residues buried in sterilized and unsterilized soil conditions, respectively. Neem, tridax and achyranthes were the alternate hosts for the pathogen. Bordeaux mixture 1% spray was very effective in reducing the initial inoculum of the pathogen. In vitro and in vivo evaluation of bactericides indicated that bronip (0.05%) + COC (0.2%) was highly effective in managing the disease with higher yield levels. In biological control, Bacillus subtilis, Pseudomonas fluorescens and garlic extract (10%) were significantly effective in reducing the disease. Application of multinutrients (1%) recorded the lower incidence and severity of the disease. The IDM strategy evaluated was found successful and feasible in managing the disease than farmers’ method of disease control.ThesisItem Open Access Epidemiology and integrated management of Anthracnose of greengram(UAS Dharwad, 2009) Sunil A.Kulkarni; V.I.Benagimajor diseases of greengram. Survey work revealed that, the disease severity was found more in Bidar (49.43%) and least in Bijapur (23.86%) districts. The observations on loss estimation revealed that comparatively lower disease index and maximum BCR was recorded in plots receiving two sprays of carbendazim. The average grain yield loss of 40.18% and stalk yield loss of 46.90% was noticed due to anthracnose in unsprayed plots. The maximum mycelial weight was observed after 15 days of incubation. Solid medium like potato dextrose agar, liquid medium like Richard’s medium, temperature of 300C, RH of 95%, pH 6.5 and alternate cycles of light and darkness were found best for the growth and sporulation of C. truncatum. The spore load was maximum during last week of July and first week of August. The correlation studies between spore load, PDI and weather parameters indicated a negative correlation with temperature, while positively correlated with relative humidity and rainfall. The greengram crop sown on 4th June showed least disease severity. C. truncatum was survived upto 360 days in infected seeds and also in infected leaves stored under freeze condition. The flowering stage was found susceptible to the disease development. In host range studies only blackgram and horsegram had shown infection. The genotypes TM-96-2 and TARM-18 were found resistant to anthracnose. Further, comparatively lesser sugar and higher phenol content were observed in these varieties than in susceptible variety. In vitro evaluation revealed that, propiconazole, carbendazim, thiophanate methyl, benomyl, hexaconazole and carbendazim + mancozeb were found effective. Among botanicals azadirachtin was effective. Among bioagents and ITKs Trichoderma harzianum and cow urine respectively were most effective. In the management study hexaconazole was found to be effective in control of the anthracnose with maximum BCR