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ThesisItem Open Access Variability In Pyricularia grisea (Cooke) Sacc. and Integrated Management of Foliar Diseases of Pearl Millet(University of Agricultural Science, Dharwad, 2017-09) Roopadevi; Patil, P.V.ThesisItem Open Access Studies on Spot Blotch of Tetraploid Wheat Caused by Bipolaris sorokiniana (Sacc.) Shoem.(University of Agricultural Science, Dharwad, 2017-01) Pradeep P.E.; Kalappanavar, I.K.ThesisItem Open Access Studies on Etiology and Management of Wilt Complex of Betelvine (Piper betle L.)(University of Agricultural Science, Dharwad, 2017-09) Divya Bharathi A.R.; Benagi, V.I.Laboratory experiments were conducted at Department of Plant pathology, College of Agriculture, Dharwad and field experiments were carriedout under naturally infected farmer’s field at Kakol and Ranebennur of Haveri district to study the etiology and integrated management of wilt complex of betelvine (Piper betle L.). Roving survey conducted in Bagalkot, Belagavi, Davanagere and Haveri district depicted maximum wilt incidence in Davanagere district (17.2 %) during 2015-16 and in Haveri district (19.2 %) during 2016-17. The maximum disease incidence recorded in Kariyele and drumstick + Erythrina as supporting plants. Fusarium spp., Rhizoctonia bataticola, Sclerotium rolfsii and Meloidogyne spp. were major pathogens. Under variability studies, potato dextrose agar medium supported best growth of all fungal pathogens. Ten isolates of S. rolfsii, R. bataticola and 30 isolates of Fusarium spp. varied for morphological and cultural characters, the isolates of Fusarium spp. were further grouped based on their pathogenic and molecular variability. SGM-1, Swarna Kapoori, Andaman RPM and Mysore local were moderately resistant out of 20 genotypes. Under in vitro studies, non-systemic fungicide captan was effective. Systemic fungicides, hexaconazole, propiconazole and tebuconazole were effective. Carboxin 37.50 % + thiram 37.50 % and captan 70 % + hexaconazole 5 % WP were also effective. Garlic, black tulsi and turmeric extract (1:1:1) and Trichoderma harzianum (IOF isolate) was effective against all the three fungal pathogens. Adoptive module comprising of soil application of organic amendments (T. harzianum enriched Farm yard manure @ 1 kg/vine + Neem cake @ 250 g/vine), fungicides (carboxin 37.50 % + thiram 37.50 % WP @ 2.5 g/l and captan 70 % + hexaconazole 5 % WP @ 2 g/l) and nematicide (carbofuran 3G @ 100 g/vine) recorded lower disease incidence (14.57 %), highest yield (44.83 lakh leaves/ha) with the B: C ratio of 6.93:1.ThesisItem Open Access Studies on Fungal Foliar and Fruit Diseases of Pomegranate (Punica granatum L.)(University of Agricultural Science, Dharwad, 2016-08) Pavithra S.; Benagi, V.I.The leaf/fruit spot of pomegranate caused by various organisms such as Colletotrichum gloeosporioides, Alternaria alternata, Sphaceloma punicae, Cercospora punicae, Drechslera sp. and Phomopsis sp., take a heavy toll on the crop. Major pomegranate growing districts of Karnataka were surveyed for the prevalence of fungal diseases. Survey revealed that anthracnose and Cercospora disease severity was highest in Gadag and Belagavi districts respectively in mrig bahar. Scab disease severity was highest in Koppal district during ambia bahar. By standard tissue isolation, microscopic observation and by Koch postulates, the pathogens viz., C. gloeosporioides, C. punicae and Pestalotiopsis algarionsis were proved. Morphological and cultural characters of 30 isolates of C. gloeosporioides were studied. Majority of the isolates produced white mycelia, regular margin, coarse texture with fluffy growth and white to grey pigmentation. The isolates were identified as Colletotrichum sp. by sequencing the amplified ITS rDNA region, and analyzed in NCBI BLAST program. An attempt was made to study the effect of weather parameters on progress of anthracnose. During ambia bahar of 2015 and hasta bahar of 2015-16 RH was significantly positively correlated with disease. Variety Ganesh showed resistant to C. gloeosporioides as accumulation of defence enzymes like PPO (0.074 absorbance/min/g), PAL (0.028) and Peroxidase (0.029) were high in it. In vivo experiment over two locations revealed that captan 2 g/lit followed by vitavax power 1g/lit followed by Iprobenphos 1 g/lit followed by cabriotop 2 g/l followed by captan 2 g/l followed by vitavax power 1 g/l followed by Iprobenphos 1 g/lit followed by cabriotop 2 g/lit of water at 15 days interval gave per cent anthracnose disease reduction of 6.80 and also increase in fruit yield (11.87 kg/tree).ThesisItem Open Access Studies on Coat Protein Mediated Resistance Against Chilli Veinal Mottle Virus Associated with Murda Complex Disease in Chilli (Capsicum annuum L.)(University of Agricultural Science, Dharwad, 2017-06) Abdul Kareem M.; Byadgi, A.S.Molecular identification, characterization, development of recombinant gene construct and transformation work was carried out in Departments of Plant Pathology and Biotechnology, University of Agricultural Sciences, Dharwad. Chilli plants showing typical symptoms of murda complex were collected and total RNA was isolated from diseased and healthy samples of chilli. Subsequently cDNA was synthesized from the RNA using oligo dT primer and reverse transcriptase enzyme. The cDNA was used as a template for amplification of ChiVMV, GBNV, TMV and CMV using gene specific primers. Similarly, total DNA from virus infected and healthy samples of chilli plants was isolated and used as template for amplification of ToLCV using gene specific primers. None of chilli murda complex disease samples were amplified for ToLCV, GBNV, TMV and CMV except ChiVMV with amplicon of ~531 bp was amplified. Thus, the investigation focused on molecular identification, convincingly revealed ChiVMV association with the chilli murda complex. The ChiVMV coat protein gene (~531 bp) was cloned into pTZ57R/T cloning vector. Gene sequence and BLAST analyses clearly revealed that ChiVMV coat protein gene had 95 per cent homology with the reported nucleotide sequences. Recombinant gene construct was developed by sub-cloning the ChiVMV-CP gene into plant transformation pHS100 vector. Recombinant gene construct was mobilized into Agrobacterium tumefaciens LBA4404 strain. Agrobacterium mediated flower dip method of transformation was adopted to develop transgenic chilli plants expressing ChiVMV-CP gene. Among 55 T1 plants, 18 putative transformants showed positive results for PCR and GUS analysis. Post challenge inoculation studies identified twelve T1 transgenic plants viz., 1-1, 1-2, 2-2, 2-5, 3-3, 3-4, 4-2, 6-4, 7-2, 7-5, 8-1 and 10-5 with complete resistance to ChiVMV and six T1 transgenic plants viz., 3-1, 5-4, 6-2, 7-1, 7-3 and 11-3 T1 showed delayed symptoms. Resistant T1 transgenic plants can be used to mitigate ChiVMV with further validation.ThesisItem Open Access Molecular Characterization, Epidemiology and Management of Bhendi Yellow Vein Mosaic Virus(University of Agricultural Science, Dharwad, 2016-08) Rathod, Suresh; Byadgi, A.S.Okra (Abelmoschous esculentus L.) Moench is one of the important vegetable crops. It suffers from number of diseases with substantial yield loss. Of all the diseases, bhendi yellow vein mosaic disease is one of the most severe disease leading to heavy crop loss. The results of the roving survey revealed that disease was more severe during summer. Maximum mean PDI was recorded in Vijayapur district followed by Bagalkot, whereas lowest PDI was observed in Dharwad during both summer and kharif season. BYVMV infection produced the symptoms like vein clearing, veinal chlorosis, malformed leaves and reduction of leaf size. BYVMV coat protein gene was amplified using BYVMV coat protein specific primers. In nucleotide sequence comparisons, isolate under study shared highest nucleotide sequence identity with BYVMV Madhurai Variant 3, Aurangabad isolate, Barrackpore isolate and Dharwad isolate. The cross inoculation study using BYVMV specific primers indicated that out of six test plants, Alternanthera sessile and bhendi showed positive reaction in PCR when inoculated from bhendi source plant and vice versa. The BYVMV successfully amplified from both bhendi and Alternanthera sessile test sample indicated that the virus infecting bhendi and Alternanthera sessile was the same. Weather parameters with PDI revealed a highly significant positive correlation with minimum temperature and significant positive correlation with both morning and evening RH. Whitefly population had highly significant positive correlation with maximum temperature and significant negative correlation with rainfall. Management of BYVMV disease by spraying different insecticides, imidacloprid 17.80 % SL (0.05 %) followed by diafenthiuron 50 WP (0.75 g/lit) were best in minimising the incidence of the disease. Significantly lowest mean vector population on three top leaves/plant was recorded in treatment imidacloprid 17.80 % SL (0.05 %). Among the 262 genotypes/lines screened only two lines (Bhendi No. 64 and DBh-102) were highly resistant to BYVMV infection. Four were resistant and six lines were moderately susceptible. Remained were highly susceptible and susceptible reaction. None of the genotypes/lines moderately resistant to the disease.ThesisItem Open Access Epidemiology, Molecular Characterization for Resistance to Turcicum Leaf Blight and Integrated Management of Major Foliar Diseases in Maize(University of Agricultural Science, Dharwad, 2016-08) Hulagappa; Nargund, V.B.Survey was conducted during two kharif and rabi seasons (2014-15 and 2015-16) in northern Karnataka for recording foliar diseases severity. Among the foliar fungal diseases of maize turcicum leaf blight (TLB) caused by Exserohilum turcicum is major yield limiting factor. Survey study revealed that maximum disease severity (96.00 PDI) of TLB was noticed in Gurlapur village of Belagavi district. Kalburgi district remained free from all foliar diseases even at the cob formation stage. The maximum severity of TLB was recorded in 2014 kharif compared to 2015. Thirty isolates collected during survey showed morphological variation on PDA. The full length ITS rDNA region of E. turcicum was amplified with ITS-1 and ITS-4 primers. Genetic variation among isolates of E. turcicum was studied by analysis of the ITS-RFLP profile after the digestion with restriction enzymes (Taq I, and Hind II) which showed specific polymorphism. Field experiments were undertaken during two kharif seasons at MARS, Dharwad (2014 and 2015). Among 23 inbred lines screened under artificial epiphytotic condition, three lines (PDM-74-1, 4641 and 260) exhibited moderate resistant reaction.The application of different SSR markers successfully provided the information on similarity and/or diversity as well as the heterozygosity of the allelic loci for all the 23 inbred lines. Epidemiological study revealed a positive correlation with cumulative rainfall and temperature. The multiple linear regression equation was developed and the coefficient of determinative value (R2) was more than 0.90 in two consecutive kharif seasons. In the fungicidal management of TLB, spraying of propiconazole @ 0.1 per cent at 35, 50 and 65 days after sowing recorded least PDI (12.44) with maximum grain and fodder yield (73.01 q/ha and 10.33 t/ha). In the four integrated disease management modules, highest grain and fodder yield were recorded in chemical module (72.40 q/ha and 9.01 t/ha) with 2.58 B:C ratio.ThesisItem Open Access Studies on Viral Diseases of Cucumber(University of Agricultural Science, Dharwad, 2016-07) Revadi, Muttanna; Patil, M.S.Cucumber mosaic disease (CMD) infected plants produced dark green mottling, mosaic, dwarfing of vines. Chlorotic spots, yellowing, dark green islands and vein banding were typical symptoms of zucchini yellow mosaic disease (ZYMD). Tomato leaf curl disease (ToLCD) infected leaf samples exhibited bilstering, upward curling and crumpling. During kharif 2014 and summer 2015, highest mean CMD incidence was recorded in Dharwad (23.94 %) and least in Bagalkot (21.31 %). Haveri (6.79 %) and Bagalkot (5.80 %) were recorded highest and lowest mean ZYMD incidence. Highest mean incidence of ToLCD was noticed in Dharwad (3.14 %) and Belagavi recorded lowest incidence of 2.70 per cent. The coat protein genes of CMV (657 bp), ZYMV (242 bp) and ToLCV (492 bp) were amplified by specific and degenerate primers and further confirmed by sequencing. The nucleotide sequences of CMV, ZYMV and ToLCV Dharwad isolates revealed 97-99, 97-98 and 96-98 per cent homology respectively with the available sequences in NCBI. Coat protein gene of CMV-DWD isolate was cloned into PTZ57R/T (pCMRP13) and further sub-cloned pQE30 and moved in to E. coli M15. A SDS-PAGE indicated protein band of 26 KDa. Expressed CMV-CP was purified and used as an antigen. The M13K07 helper phages were amplified. Two scFv monoclonal antibody clones viz., pCMRPAB3 and pCMRPAB13 showed strong binding affinity to the CMV-CP. The pCMRPAB13 was validated using CMV infected field samples. CMV was mechanically transmitted to seven host crops, which produced mosaic, mottling, chlorotic spots and leaf distortion symptoms and showed 17-65 per cent transmission. ZYMV produced mosaic, vein banding and vein clearing symptoms on cucurbitaceous hosts. Adoptive module (M2) showed least incidence of CMD (6.56 %), ZYMD (3.78 %) and aphid (1.00 aphids/3 terminal leaves) and highest yield of 15.80 t/ha with 2.52 cost benefit ratio which was also on par with chemical intensive module (M3) in yield (14.25 t/ha) and cost benefit ratio (2.14).ThesisItem Open Access Studies on Soil Borne Fungal Diseases of Chickpea(University of Agricultural Science, Dharwad, 2015-11) Ravichandran S.; Hegde, Yashoda R.Chickpea (Cicer arietinum L.) is the most important Rabi pulse crop in India. Important soil borne fungal diseases observed during survey were wilt caused by Fusarium oxysporum f.sp. ciceri,(FOC) (27.07%), dry root rot caused by Rhizoctonia bataticola (RB) (37.06%) and collar rot caused by Sclerotium rolfsii (0.65%), alone and in combination (34.32%) with the disease incidence ranging from 1.4 to 23.4 per cent. In interaction studies, JG 11 and JAKI 9218 were moderately resistant to FOC, however were susceptible to RB and S. rolfsii. In cultural studies, FOC and RB attained maximum growth at 16 and 14 days respectively. Temperature of 25 – 300C and pH of 6 to 7 were optimum for growth of these two pathogens. 32 isolates of FOC were collected and classified into three groups based on growth rate virulence index and dry mycelial weight. 20 isolates of RB collected varied in growth and dry mycelial weight. In race identification of FOC by using differentials indicated that all isolates belong to race 1a and further confirmed by amplification with specific primer. ITS rDNA sequence analysis and specific primers confirmed the identity of isolates of FOC and RB. Twenty six genotypes showed resistant reaction against FOC in wilt sick plot in two years and five genotypes remained resistant even in glasshouse screening. All tested triazoles and comi product fungicides and eucalyptus leaf extract was effective in mycelial inhibition of both pathogens. Highest inhibition of FOC was observed in Trichoderma harzianum and RB was by Pseudomonas fluorescens. Seed treatment with carboxin + thiram recorded the lowest per cent disease incidence with the highest yield and cost benefit ratio in field experiment studies in Farmer’s field, (Bailhongal) and sick plot at Kalaburgi.
