Central Agricultural University, College of Post Graduate Studies in Agricultural Sciences, Umiam
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ThesisItem Open Access Bio-efficacy of Trichoderma formulation against damping-off caused by Pythium spp. and Rhizoctonia solani Kuhn. on tomato (Solanum lycopersicum)(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2019-11) Biam, Markidahun; Majumder, DipaliDamping-off is one of the most prevalent and damaging disease of tomato nurseries in Meghalaya, caused by Pythium spp. and Rhizoctonia solani Kuhn. These pathogens can kill both germinating seeds and young seedlings. Management of damping off by integration of biocontrol agents, specially the Trichoderma spp., not only can reduce doses of fungicides but will be a better management strategy against the damping off of pathogens. Considering the fact, present investigation was formulated and aimed on to evaluate bio-efficacy of Trichoderma formulation against Pythium spp. and Rhizoctonia solani kuhn. cause damping off in tomato. Out of 180 soil samples collected from different habitats (crop rhizosphere, compost manure, forest, jhum areas, pig manure, coal mine and lime stone) of 11 districts of Meghalaya, 97 Trichoderma isolates were identified based on their morphology. Dual culture assays of the twenty screened isolates against damping-off pathogens revealed that the 4 Trichoderma isolates viz. TR55, TR66, TR122 and TR136 were found highly effective in inhibiting Pythium spp. with percent inhibition of 89.26, 88.15, 88.89 and 87.78 respectively, whereas only 2 isolates viz. TR55 and TR122 were effective against R. solani with percent inhibition of 87.41 and 86.48, respectively. Isolate TR55 recorded as the best antagonist against both pathogens causing damping off. All 20 screened isolates were positive for ACC deaminase production whereas 17 were positive for chitinase production. Isolate TR 106 and TR 136 were the best in chitinase production with purple colour zone of 9 cm in diameter. Out of 20 screened isolates tested for other functional attributes (determining antagonistic potentials), 16 isolates were found positive for siderophore and ammonia production, whereas 13 isolates were positive for HCN production. Screening for plant growth promotion traits of 20 isolates revealed that all the isolates produced IAA and Phosphorous with values ranging from 0.33 to 4.96 μg/ml and 0.03 to 0.98 μg/ml, respectively. Presence of antibiotic biosynthetic genes in the 20 isolates by using gene specific primers detected that 12 isolates were positive for β-1,6-Glucanase (Tvbgn3), 10 isolates for Trichodiene synthase (tri5), 14 isolates for Serine protease (prb1) and 17 isolates for Endochitinase (ech42). Only 4 Trichoderma isolates showed presence of all the 4 antibiotic biosynthetic genes tested. Observations of the anamorphic characteristics of the Trichoderma isolates showed variation in anamorphic characters viz., size of phialides, phialospore and conidiophores among the isolates. The sequence analysis of the internal transcribed spacer regions 1 and 2 (using universal primer ITS1 and 4) of the rDNA of the 10 potential isolates showed that they belonged to 2 Trichoderma species viz., T. hamatum (TR 55, TR 66, TR 87 and TR 122) and T. harzianum (TR 64, TR 88, TR 106, TR 109 and TR 136) with amplicon at 600bp in all isolates. Dendogram was generated using alignments containing the ITS region revealed formation of two main clusters with closeness ranging from 13 to 96 per cent. The biopriming of tomato seeds with 4 Trichoderma isolates (TR55, TR66, TR122 and TR136) showed considerable increase in germination percentage and vigour index over control, with the highest germination percentage and vigour index recorded in TR55 (75.13 per cent and 47.99 per cent, respectively). Among the treatments (seed, soil and seed plus soil) highest reduction in incidences of pre-emergence and post emergence damping-off was obtained with the isolate, TR55 (seed plus soil treatment). It also exhibited increase in the growth parameters such as root length, plant height, number of leaves, number of flowers, fresh as well as dry fruit weight and yields of tomato; variety Hybri-017 in the treated crops as compared to the untreated control. The rhizosphere colonization of 4 potent isolates of Trichoderma spp. viz., TR55, TR66, TR122 and TR136 showed that their rate of colonization increases up to 45 days after sowing and reduced at 60 days after sowing in all the treatments. Colonization was highest in TR 55 (3.73 × 106) followed by TR 122 (3.63× 106), TR 66 (3.50× 106) and TR 136 (3.37× 106). Native Trichoderma isolates TR55, TR66 and TR122 performed better in terms of functional attributes viz., disease suppression, growth promotion, rhizosphere colonization, self-life in talc formulation, could be further evaluated under different climatic condition of the state for development of effective Trichoderma formulations found effective can be recommended as a component of integrated disease management practice to manage damping off of tomato in the nursery beds in Meghalaya.ThesisItem Open Access Characterization of arbuscular mycorrhizal fungi and endophytic bacillus in tomato roots and their antagonism against Fusarium Wilt.(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2021-07) Devi, Nongthombam Olivia; Devi, R. K. TombisanaTomato (Solanum lycopersicum M.) is one of the most popular vegetable ranking next to potato and widely grown in Meghalaya. Among the soil borne diseases, Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL) is a devastating disease causing wilting and death of tomato thereby inflicting major yield losses. Arbuscular mycorrhizal fungi (AMF) are found to be associated with 80-90% of plants including tomato. Bacillus endophytes and AMF are known to promote plant growth and suppress soil borne pathogens. In the present investigation, AMF spores were isolated from 20 sample sites coming under six districts and four agroclimatic zones of Meghalaya with highest number of spores/50 g soil recovered from Umsning (680.67 spores). A total of 41 AMF species were recovered and identified from 20 sample sites. Daistong with 15 AMF species had the highest species richness. Funneliformis mosseae, Glomus aggregatum, Glomus intraradices and G. fasciculatum were the dominating AMF species having isolation frequencies (IF) of more than 60%, whereas G. australe, F. badium, A. melleae and A. scrobiculata had IF of more than 45%. All the tomato roots collected from the 20 sample sites were colonized by AMF with Umiet (41%) recorded the highest colonization per cent. From trap culture, Umiet had the maximum spore density (1103 spore/50 g soil). All 41 AMF species isolated from field soil were also recovered from trap culture inoculum along with an additional 6 species viz. Archaeospora trappie, Acaulospora longula, Appendisphaera centroreticulata, F. geosporum, G. boreale, and G. viscosum from trap culture soil. Umiet with 19 AMF species had the maximum species richness. G. intraradices had the highest IF of 70% followed by F. mosseae, G. aggregatum, and G. fasciculatum, while AMF species with more than 50% IF were F. badium, A. mellae, A. scrobiculata and G. australe. AMF root colonization in trap plant maize was maximum in Umiet derived inoculum (92%). All the 47 AMF species showed variation in shape, size, colour and hyphal form attached to the spore walls. Out of the 12 dominating AMF species screened for growth promotion of tomato plant in pot experiment, F. mosseae and G. fasciculatum performed best in terms of plant and mycorrhizal parameters. A total of 130 endophytic Bacillus were isolated from tomato roots collected from 20 sample sites of Meghalaya. Based on biochemical tests, morphological character and bacterial identification software ABIS online all the 130 isolates were tentatively identified up to species level. The isolates belonged to the genera Bacillus, Paenibacillus and Viridibacillus with maximum of 17 isolates each tentatively identified as Bacillus amyloliquefaciens and B. thuringiensis. Out of 130 Bacillus isolates, 12 isolates showed more than 27.44% inhibition of growth of FOL in dual culture method of which isolates ERBS51 (58.43%) and ERBS10 (55.68%) recorded the maximum inhibition of FOL. Further, antagonistic test of the 12 potential isolates revealed ERBS51 (55.83% and 91.52%) followed by ERBS10 (43.37% and 87.28%) as the best one with highest FOL inhibition in sealed plate method and antagonistic activity in liquid media respectively. The 12 potential isolates were identified as Bacillus sp. (ERBS4, ERBS10, ERBS29, ERBS47, ERBS75, ERBS118), while other as B. velezensis (ERBS51), B. cereus (ERBS69 and ERBS119) and B. subtilis (ERBS80), B. swezeyi (ERBS115) and B.subtilis sub sp. spizizenii (ERBS130) using 16s rRNA gene with bacterial universal primer(27F/1492R) and Bacillus specific primers (BCF1/BCR2). All the 12 isolates were grouped together in Neighbour-joining phylogenetic tree. Majority of the isolates were positive for iturin, surfactin, and bacillomycin genes. The 12 isolates were further screened for hydrolytic enzyme production, antimicrobial and plant growth promotion (PGP) activities and found to have varying results. Isolate ERBS51 was found to be positive for majority of the attributes such as siderophore, ammonia production, phosphate, ZnCO3, ZnCl solubilisation, alpha amylase, cellulase, protease, pectinase and lipase production. ERBS51 (95% and 1472.50) followed by ERBS10 (88% and 1287.54) treated tomato seeds had the maximum germination and vigour index respectively. Pot and field experiment were conducted with F. mosseae, G. fasciculatum, ERBS51 (Bacillus velezensis) and ERBS10 (Bacillus sp.) both individual and combinations as treatments. The combined application gave better result than individual microbes as treatment. Among all the treatments given as single inoculum and all the possible combinations of the four microbes,F. mosseae+G. fasciculatum+B. velezensis+Bacillus sp. treatment as consortium with recorded highest disease reduction in wilt severity in both pot (77.44%) and field (66.74%) experiments respectively. F. mosseae+G. fasciculatum+B. velezensis+Bacillus sp. treatment also recorded high plant and yield attributes in both the conditions. F. mosseae, G. fasciculatum, B. velezensis and Bacillus sp. as a consortium could be used as a part of integrated management of Fusarium wilt of tomato in Meghalaya.ThesisItem Open Access Characterization of fluorescent pseudomonads and their evaluation against Ralstonia solanacearum(Smith) Yabuuchi under Meghalaya condition(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam) Kipgen, T.Lhingkhanthem; Majumder, DipaliUtilization of rhizospheric microbiota to induce plant growth and control of plant diseases is one of the important approaches to reduce environmental impact of hazardous chemicals. Fluorescent Pseudomonads are often predominant among plant rhizosphere associated bacteria. The rhizospheric fluorescent Pseudomonads of Meghalaya region have not yet been characterized and documented. The present investigation was focused on characterization of fluorescent Pseudomonads and their evaluation against Ralstonia solanacearum (Smith) Yabuuchi under Meghalaya condition. Soil samples were collected from rhizospheric regions of rice and maize crop from three districts viz., Ri-bhoi, East Khasi Hills and West Garo Hills districts of Meghalaya and 30 fluorescent Pseudo monads were isolated. On the basis of biochemical and cultural properties, 21 fluorescent Pseudomonads were identified as Pseudomonas jluorescens and tentatively designated as biovar I, II, III and V with 12, 7, 1 and 1 number of isolates respectively, whereas 3 isolates were identified as P. putida. The largest numbers of isolates were grouped in biovar I and most of these isolates were collected from rice rhizosphere. Hierarchical cluster analysis using Bray Curtis resemblance matrix on the basis of 16 biochemical tests of 21 Pseudomonas jluorescens, generated 3 distinct clusters at 96 per cent similarity level. Molecular characterization of 30 fluorescent Pseudomonads based on BOX Polymerase Chain Reaction (PCR) generated 12 amplification profile and the most prevalent profile was 'L' (9 isolates) with a band size of 750 bp, associated only with isolates of rice rhizosphere. Seven fluorescent Pseudo monads were screened on the basis of their HCN production and amplification by using pyrrolnitrin (PRNPrncf 5'CCACCAAGCCCGGCCAGGAGC-3' PRNPrncr 5'-GAGAAGAGCGGGTC GATGAAGCC-3') primer and tested for in vitro antagonism towards R. solanacearum, a wide spread, major bacterial pathogen of solanaceous crops. Isolate F.Pd19 was found most effective antagonist against R. solanacearum under in vitro condition with an inhibition zone of 4.03cm in diameter and may serve as promising bioagent, which need further in vivo investigation.ThesisItem Open Access Characterization of phylloplane microflora of tomato (Solanum lycopersicum L.) and their role against major foliar fungal diseases(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2020-07) Hajong, Monika; Rajest, T.Phylloplane is a leaf surface, which harbours a diverse kind of microbial populations. Foliar disease management was not as successful as compared in rhizosphere as the microbial growth on leaves are restricted by severe environmental conditions. Phylloplane microflora play a vital role in agricultural and environmental process as they can impact the ecological balance, plant growth, suppress or stimulate colonization and infection of the plant pathogens. Therefore, the aim of this investigation was to isolate and evaluate the potential strains from tomato phylloplane against the major foliar fungal diseases namely early blight, late blight and Septoria leaf spot. The surveys were conducted from different tomato growing areas of 7 districts namely Ri-bhoi, East Khasi Hills, West Jaintia Hills, East Jaintia Hills, East Garo Hills, West Garo Hills and South West Garo Hills of Meghalaya for the collection of tomato leaf samples. Total, 173 bacteria and 96 fungi were isolated from collected samples by following 3 different methods. Out of 3 different isolation methods, leaf impression method recovered the maximum microbial populations followed by leaf washing and without dilution plating method and leaf washing and serial dilution plating method. Bacteria were found predominant in tomato phylloplane compared to fungi. All the bacterial and fungal isolates were tentatively identified and grouped based on morphological and biochemical tests. The predominant bacteria tentatively identified were whitish colony (102 isolates) followed by yellow-pigmented bacteria (28 isolates), bacteria with cream colonies (20 isolates), fluorescens bacteria (10 isolates), pink-bacteria (8 isolates) and branching-like bacteria (5 isolates). The predominant fungi found were Phoma sp. followed by Trichoderma sp., Pythium sp., Penicillium sp., Fusarium sp., Acremonium sp., Aspergillus sp., Chaetomium sp., Cladosporium sp. Rhizopus sp., Botryodiplodia sp., Alternaria sp. and Camarosporium sp. Out of 173 bacterial isolates only 10 isolates were found effective by showing at least 50% growth inhibition of foliar pathogens under in vitro condition. The results of present investigation suggested that majority of the phylloplane fungi isolated from tomato are pathogenic in nature and only Penicillium sp. and Trichoderma sp., were found most effective by showing at least 50% growth inhibition of pathogens under in vitro condition. Only 10 bacterial and 10 fungal isolates were selected as antagonists against the pathogens based on their in vitro tests such as dual culture assay, antimicrobial and PGP traits. These 10 bacterial strains were further identified based on molecular method using 16S rDNA gene sequenced. The fungal strains were identified by National Centre for Fungal Taxonomy (NCFT), New Delhi. Among these 20 strains, only 2 best strains namely B. altitudinis ASH2 and P. chrysogenum ALH1L were further selected for talc-based bioformulation preparation. These talc-based bioformulations were further evaluated under pot and field condition against the late blight disease of tomato (P. infestans). Various mode of bioformulation delivery was used either in individual as seed treatment or soil treatment or root-dip treatment or foliar spray and in combination. Total 15 treatments were used under field condition including the control, and it was found that the combination treatment of B. altitudinis ASH2 and P. chrysogenum ALH2L (seed + soil + root-dip + foliar spray) was most effective in managing the late blight disease by recording only 8.33% and 41.67% disease incidence as compared to negative control (58.33%) even on 90th DAT. Also, maximum yield was recorded with these 2 treatments (48.36 and 46.28 t/ha/plot) as compared to negative control plot (23.94 t/ha/plot). Similarly, combination treatment with both the bioformulations respectively under pot experiment in both the seasons were also found the lower disease incidence with higher yield as compared to the control plant.ThesisItem Open Access Cultivation of ganoderma lucidum (W.Curt.:Fr.) P. karst and its antifungal properties against phytopathogenic fungi(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Imphal, 2019) Roopesh, M.; Devi, R. K. TombisanaIn the present study G. lucidum (W.Curt.Fr.) P. Karst was collected from wild. The mushroom was isolated by tissue culture and purified by hyphal tip cut method. Microscopic studies revealed that the mycelia produced clamp connections, fusiform chlamydospores and basidiospores were brown, ovoid and double walled with inter wall pillars separating the two layers. Spawn production on wheat grains took 15 days for complete mycelial colonization. The cultivation studies on different substrates, earliest duration (21 days) for spawn run on PS1 as compared to other substrates. Earliest fruiting primordia initiation (23 days) was observed on PS1, whereas 24 and 28 days on WS2 and SB3. No primordia formation was observed on sheesham sawdust at all. Earliest fruiting maturity (16 days) after primordial initiation was observed on SB3 even though it took long duration for primordia initiation, however a maximum duration of 20 days was recorded on WS3. A maximum stipe length of 5.37cm and with a pileus diameter of 4.77 cm were recorded on PS1. Biological efficiency was found highest (11.43%) on PS1 followed by WS2 (10.7%) and SB3 (9.18%) respectively. Maximum biological efficiency of G. lucidum (11.43%) was obtained from PS1 but lowest from PS3 (6.41%). Phytochemical analysis revealed the presence of carbohydrates and steroids but absence of alkaloids and flavonoids. Maximum antifungal activity of phytochemicals from aqueous (10.93 mm to 16.93 mm), methanol (11.90mm to18.66 mm) and acetone extracts (14.06 to 20.67 mm) against Aspergillus niger at 5, 10 and 15 % concentrations, whereas minimum against Sclerotium rolfsii (9.25 mm to 14.80 mm).ThesisItem Open Access Cultivation of shiitake mushroom (Lentinula edodes (Berk.) pegler) in woodlogs under net house conditions of Meghalaya(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Imphal, 2019) N., Madhan; Rajesh, T.Shiitake (Lentinula edodes (Berk.) Pegler) is an edible mushroom and type of wood decomposing fungi which belongs to the family Tricholomataceae. The present study was conducted to standardize the cultivation technique of Lentinula edodes on abundantly available natural resources (wood logs) and to analyze the composition of the fruiting bodies. Three mushroom strains DMR-32, DMR-388 and Meghalaya local were collected from Directorate of Mushroom Research (DMR), Solan, Himachal Pradesh and Department of Agriculture, Shillong, Meghalaya respectively. The spawn was prepared from these strains by using paddy grains as substrate. The wood logs of three different species viz., Castanopsis sp., Quercus griffithii and Lithocarpus elegans were collected from the College of Agriculture, Kyrdemkulai, Meghalaya. The logs were cut into uniform length of 120 cm and holes of diameter 1.2 cm were drilled in diamond pattern. The spawn produced from different mushroom strains were inoculated into the holes of drilled logs of different species and were sealed. Inoculation was done separately for each strain and each wood log. The logs were arranged in alternate pattern by crib stack method. After three months the logs were arranged in X or A frame method by using bamboo sticks as support. The logs were soaked in water for maintaining the optimum log moisture content of 50 to 60%. After few month mushrooms were harvested and analyzed in laboratory to find out their % nitrogen, protein and moisture content. The yield of the mushroom was correlated with the strains, tree species, size of the logs and weather parameters like temperature, RH. The results revealed that among the three strains and logs used, the strain DMR-388 was the most productive on Quercus tree logs with yield of 83.53 g per log at a temperature range of 17.5 to 27.5 and RH range of 65% to 90 %. The strain was also productive on the logs of Castanopsis sp. with yield of 78.56 g per log. The strain DMR-32 also produced good yields on Quercus and Catsanopsis. It was observed that the logs with diameter of 10 – 15 cm produced better yields compared to bigger (>18 cm) and small (<8 cm) sized logs. The results of laboratory analysis revealed that fruiting bodies by strain Meghalaya Local contained highest % Nitrogen of 4.12% and the highest protein content of 18.04%. The fruiting bodies of DMR-32 and DMR-388 contained % nitrogen in the range of 3.08 to 3.6 % and protein content in the range of 11.56 to 15.76%. The highest moisture content 85.64% was found in fruiting bodies of DMR-388 and the lowest (80.90 %) was recorded in DMR-32. However, the moisture content of all fruiting bodies was in the range of 80.90 to 85.64%. From the results of present study, it can be concluded that, the strain DMR-388 was best promising, high yielding strain and Quercus logs can be considered as viable logs for commercial cultivation of shiitake mushroom in Meghalaya. In addition to this, the strain DMR-32 and Castanopsis logs may also be considered as better alternatives.ThesisItem Embargo Eco-friendly Management of Alternaria Leaf Spot of Gerbera in Mid Hills of Meghalaya(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-09) Manickkam V; T. RajeshGerbera (Gerbera jamesonii L.) is a perennial dwarf herb belonging to the family Asteraceae (Compositae) which can be mainly propagated through vegetative methods (clumps and cuttings) to maintain the genetic purity and uniformity. The most destructive and economically important disease in gerbera is alternaria leaf spot incited by the fungus, Alternaria alternata (Fr.) Keissler. The leaf spot alters the vegetative growth of the plant which directly affects the reproductive growth i.e., flower yield and ultimately reduce the market value i.e., flower quality. The repeated isolation from infected leaf of gerbera revealed the association of Alternaria alternata, which was identified and confirmed after the cultural and morphological studies. A total of seven isolates of A. alternata were obtained from Ri-Bhoi district of Meghalaya. The isolates showed significant variations in colony colour, shape, texture and hyphal growth in the Potato dextrose agar (PDA) medium. The morphological variability study showed variation among the isolates. The conidial size was found highest in isolate LSG 4 (34.57-38.38 x 7.35-8.39 μm) and lowest in isolate LSG 5 (25.67-29.76 x 5.49-6.25 μm). The colony colour on PDA medium varied from white to olivaceous black with cottony to fluffy colony. Radial growth of the isolates in PDA medium after 10 days of incubation were found in the range of 81-90 mm. The pathogenic variability study revealed that the isolate LSG 4 produced lesions covering the maximum leaf area with the highest PDI (42.62 %) and considered to be the most virulent. Under in vitro condition, neem leaf extract (15 % w/v) showed the highest inhibition of mycelial growth (71.10 %) of the pathogen followed by black turmeric rhizome extract (15 % w/v) with 67.40 %, whereas allamanda leaf extract (5 % w/v) gave the lowest inhibition of mycelial growth (28.88 %). Dual culture assay carried out with the bio-control agents showed that Trichoderma harzianum recorded the highest inhibition (82.96 %) of the pathogen followed by Bacillus subtilis with 70.36 %, whereas Pseudomonas fluorescens displayed the lowest inhibition (7.77 %) against the three isolates tested. Compatibility study was conducted between T. harzianum and five botanicals viz., neem, lantana, aloe vera, allamanda and black turmeric. The results showed that lantana was highly compatible with T. harzianum as it gave the least inhibition (12.59 %) at 5 %. Pot experiment showed that the treatment of T. Harzianum combined with lantana gave the lowest per cent disease index (24.55 %) followed by hexaconazole (26.69 %) and the highest was observed in positive control (pathogen alone) with 60.77 %.ThesisItem Open Access Eco-friendly management of late blight [ Phytophthora Infestans,(Mont.) De Bary] of tomato in hill conditions of Meghalaya(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2009) Dkhar, Mariana; Dutta, RamThe present investigation was carried out for two consecutive years (2007-08 & 2008-09), which included study of Phytophthora infestans incidence at various growth stages of tomato, screening of 12 tomato genotypes for resistance /tolerance and evaluation of three bio-control agcnts/ two botanicals and four fungicides for management of late blight of tomato. There were significant differences in respect of disease rating and yield in both the cropping seasons. Among genotypes. CO-3 was found moderately susceptible and Rocky as highly susceptible. Whereas, rest of the genotypes were susceptible having varying degree of susceptibility, under mid-hill conditions of Meghalaya. The yield among botanicals evaluated. MATW-2 (native organic formulation) was found effective in managing the disease being next to fungicide, Ridomil MZ 72. Among Bio-control agents, the highest disease management was received by Nisarga compared to control. In in-vitro evaluation of botanicals bio-control agents and fungicides, the medium amended with MATW-2 reduced the maximum mycelial growth among botanicals, Nisarga among bio-control agents and Ridomil MZ 72 among fungicides, in terms of radial growth (cm). It was concluded from the study) that genotype CO-3 was found promising for cultivation in mid-hill conditions of Meghalaya and botanical MATW-2 in reducing the disease as well as enhancing the yield, hence, may be recommended for the management of late blight of tomato.ThesisItem Embargo Efficacy of endophytic and rhizospheric bacteria against Black rot disease of cabbage(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-11) Challam, Rijubanki; Devi, R. K. TombisanaCabbage is one of the most popular vegetables in the human diet owing to its low cost, widespread availability and nutritional values. Black rot disease is the major constraint of the crop resulting in lower productivity and significant losses. In the present study, black rot disease was observed in all the surveyed areas of East Khasi Hills, West Jaintia Hills and Ri Bhoi districts with incidence ranged from 39.35-72.32%. Mawklot village in the East Khasi Hills recorded maximum disease incidence of 70.74%. The bacterial pathogen associated with the disease was isolated and identified as Xanthomonas campestris pv. campestris through morphological, biochemical studies and pathogenicity test. Twenty five each of endophytic and rhizospheric bacteria were isolated from healthy cabbage and rhizospheric soil respectively collected from the surveyed areas. The best two each of endophytic and rhizospheric bacteria each showed maximum inhibition against the pathogen were selected and identified as Bacillus cereus, Bacillus velezensis, Stenotrophomonas maltophilia and Bacillus cereus on the basis of 16S rRNA sequencing. RCK7 (S. maltophilia) showed the maximum inhibition zone of 31.67 mm followed by ECB6 (B. velezensis) with 29.33 mm, RCJ5 (B. cereus) with 23.33 mm and ECJ4 (B. cereus) with 21.33 mm. T7 (B. cereus, B. velezensis, S. maltophilia and B. cereus) induced maximum seed germination and vigour index (98.33%, 1068.52) over T8 (70.00%, 368.67). Field study using various treatment combinations revealed that T7 showed the lowest disease index (30.13%) followed by T8 (tetracycline) of 32.94% and maximum was observed in T9 (control) of 64.44%. T7 was found to be superior in early maturation (62.93 days), larger head size (14.75 cm) and yield (32.57 t/ha) to other remaining treatments.ThesisItem Embargo Efficacy of multifaceted microbes against Fusarial wilt of chickpea.(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-09) Patel, Kailash; Devi, R. K. TombisanaChickpea is a leguminous crop rich in protein and minerals. Fusarial wilt is a major disease causing both qualitative and quantitative loss up to 100% worldwide. In the present investigation Fusarium oxysporum f.sp. ciceris (FOC) was isolated from diseased samples showing typical disease symptoms. The pathogen was confirmed based on morphology, pathogenicity test and molecular characterization using two different primers ITS4 and ITS6 and EF1 and EF2. Four fungicides were evaluated against growth of FOC. Among them carbendazim and propiconazole could completely inhibit at all the concentrations. Fifty endophytes were isolated from five leguminous plants. Out of which eight endophytes were selected showing more than 60% inhibition of growth of pathogen. Out of which four endophytes (ECP1, ECP8, Egg8, EMP4) as Bacillus cereus, two (ECP10, EGN2) as Bacillus subtilis, ECP5 as Enterobacter sp., ESB2 as Bacillus amyloliquifaciens, were identified based on 16S rRNA sequencing. Six microbial consortia containing four endophytes in each consortium were formulated and evaluated both in vitro and in vivo conditions. Among all the treatments, T5 (ECP8+ECP10+ ESB2+EGN2) was found superior in maximum seed germination (100%) and vigour index (2805.56) and lowest disease incidence of 8.06 and 9.33 % at 30 and 60 days after sowing to other treatments. T5 showed significantly increased plant growth and yield upto 19.82 q/ha than other treatments.ThesisItem Open Access Etiology and management of pod blight complex of soybean in Meghalaya(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2010) Tabyo, Tilling; Chandra, SatishThe disease is commonly referred to as pod blight complex by many researchers as more than one fungus have been reported from a number of soybean producing countries. The present investigation was focused on etiology, yield loss, resistance and management of disease by integrating botanicals, bioagents and fungicides in vitro as well as in vivo. Microscopic examination revealed the association of Colletotrichum truncatum with pod blight complex. Conidia (13.5-24.3 X 2.7-4.5 flm) were single celled, falcate and hyaline. Dual culture test revealed that the Trichoderma viride was more effective in reducing the radial growth than Trichothecium roseum. The slide test (agar block) for presence or absence of hyperparasitism and colonization potential of bioagents also confirmed the efficacy of T. viride in vitro. Two botanicals viz., Cymbopogon sp. and Neemazol (Azadirachta indica) were tested against C. truncatum by poisoned food technique. Cymbopogon sp. was found to be more effective as compared to Neemazol in reducing the radial growth of test pathogen. Simultaneously, four fungicides viz., propiconazole, tricyclazole, mancozeb and copper oxychloride were also evaluated. Results revealed that propiconazole was highly effective in reducing the growth followed by tricyclazole, mancozeb and copper oxychloride. Efficacy of botanicals and fungicides was evaluated for inhibition of conidial germination. Both were effective in inhibiting the conidial germination of C. truncatum but chemical fungicides were superior to botanicals. The highest inhibition percent was observed in case of propiconazole followed by tricyclazole, mancozeb, copper oxychloride, Neemazol and Cymbopogon sp. Neemazol was effective in inhibiting the conidial germination compared to Cymbopogon sp. Thirteen genotypes of soybean were screened under field conditions. Genotypes DSB 12, DS 2614, MACS 1188, MAUS 417 and MACS 1184 were moderately resistant while TS 2, MACS 1039, DS 2613, AMS I, RKS 52, NRC 80, MACS 1140and JS 335 were susceptible. Out of these, seven genotypes were selected for estimation of yield losses under protected and unprotected conditions. Out of seven genotypes MACS 1188, TS 2, AMS 1 and JS 335 were found to be tolerant against C. truncatum. This was calculated using maximin-minimax method. Management trial using different treatments revealed that propiconazole was best (PDT 2.33) with yield of 1396 kg/ha, followed by tricyclazolse, mancozeb, Neemazol and T.viride.ThesisItem Embargo Evaluation of antagonistic potential of endophytic and biofertilizing bacteria against White mould of carrot(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-07) Thokchom, Christina; Devi, R. K. TombisanaAmong the major diseases of carrot, white mould constitutes an important one which is prevalent worldwide. In this study, extensive surveys were conducted during August-September, 2021 in two different districts of Meghalaya i.e., Ri- Bhoi and East Khasi Hills districts in which disease incidence in the range of 3.9-8.36% was recorded. Laitjem village of East Khasi Hills showed maximum disease incidence of 8.36%. The correlation studies of disease incidence with weather parameters (maximum and minimum temperature, evening and morning relative humidity and rainfall) revealed that temperature and rainfall had positive relation with disease incidence for both the districts. In the market surveys conducted twice in the above two districts, disease incidence ranging from 25 to 30.47% was recorded and Bara bazaar of East Khasi Hills was recorded for highest incidence (30.47% and 30.28%) in both the surveys. Fungal pathogen associated with the disease was isolated and confirmed as Sclerotinia sclerotiorum based on morphology studies and pathogenecity test of the isolated pathogen. Twenty five endophytic (ECarrot) and twenty five biofertilizing (BCarrot) bacteria were isolated from healthy carrots and soil respectively collected from different carrot growing areas of the surveyed districts. Dual culture assay of the isolates against S. sclerotiorum revealed that ECarrot9 showed maximum mycelia inhibition of 72.15% followed by BCarrot21 (65.59%), ECarrot16 (60.33%) and BCarrot8 (50.89%). Based on antagonistic potential and plant growth promoting activities, two efficient endophytes (ECarrot9 and ECarrot16) and two biofertilizers (BCarrot8 and BCarrot21) were chosen for further evaluation in the field. ECarrot9, ECarrot16, BCarrot8 and BCarrot21 were identified as Bacillus amyloliquifaciens, Stenotrophomonas maltophilia, Burkholderia ambifaria and Bacillus megaterium respectively based on 16S rRNA sequencing. All these four isolates were found to be compatible and formulated 5 consortia. Out of these, four consortia consisting of two isolates each and one consisting of all the isolates. Field evaluation at different treatment combinations showed that T10 (seed treatment with Saaf) gave lowest disease index of 1.38%. However T9 (consortium consisting of all the isolates) gave disease index of 4.16% as compared to T11 (control) which gave disease index of 19.44%. T9 significantly improved plant growth (9.33 cm) and yield upto 93.33 q/ha. Studies on mass production of the consortium with efficient carrier system may be subsequently taken up in order to provide a safer and efficient management of the disease even in post harvest conditions.ThesisItem Open Access Evaluation of bacterial endophytes against ginger rhizome rot(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2018-08) Bamon, Meshanki; Majumder, DipaliGinger (Zingiber officinale Rosc.) is a major spice crop in India and Meghalaya is the third largest producer in the country. Rhizome rot, commonly known as soft rot is a major constraint in ginger cultivation. With the increase in awareness about the hazardous effects of the chemicals, exploitation of effective microorganisms like endophytes has been increasing witha greater pace for management of plant diseases. Keeping that in mind, the present investigation was formulated to evaluate 6 potential bacterial endophytes against pathogens associated with ginger rhizome rot complex in Meghalaya. Six potential bacterial ginger endophytes (GE-1, GE-2, GE-3, GE-4, GE-5 and GE-6) were screened based on several functional properties. It was recorded for that all the tested bacterial antagonists do not produced HCN, whereas all isolates were positive for ACC deaminase. Highest halo production for siderophore was recorded for GE-1 (21.67mm). Five isolates produced chitinase and protease enzymes except GE-2, whereas 3 isolates were recorded for production of cellulase (GE-1, GE-2 and GE-6) and amylase (GE-2, GE-3 and GE-6). None of the isolates produced pectinase enzyme. Four isolates were found positive for IAA production, whereas only one isolate GE-5 recorded for ammonia production. Phosphate (P) and Zinc (Zn) solubilisation test revealed that only GE-5 (1.17mm) was positive for P solubilisation, whereas GE-1 (0.29 cm2) and GE-5 (0.01 cm2) solubilised Zn. Growth of all isolates was observed in the pH ranged from 4 to 7. Alluminium (Al) tolerance tested revealed that only isolate GE-2 showed very good growth at Al concentration of 50 and 100 ppm, followed by GE-1, showed fairly good and very good growth at 50 and 100 ppm respectively. All isolates were found compatible with 5 fungicides tested viz., Copper oxychloride, Carbendazim, Mancozeb, Metalaxyl and Bordeaux mixture in all concentrations (0.05%, 0.1%, 0.2% and 0.3%).The bacterial endophyte GE-1 and GE-3 were insensitive to tetracycline and streptocycline at all concentration whereas, the other isolates were sensitive. Dual culture assay of isolates against pathogens associated with ginger rhizome rot complex viz., Pythium myriotylum, Fusarium sp, Ralstonia solanacearum revealed that the isolate GE-1 showed 80.98% suppression of P.myriotylum, GE-6 (67.85%) against Fusarium sp. and GE-3 (78.89%) against Ralstonia solanacearum. These endophytes were further evaluated growth promotion and disease suppression. In the field experiment, GE-1 was recorded with the greatest sprouting (98.89%), lower soft rot incidence (19.83%) and higher yield (0.59 kg/ plot) compared to chemicals like Mancozeb (90.0%, 12.58.0% and 0.2 kg/plot, respectively) and positive control (65.5%, 40% and0.13 kg/ plot, respectively). Based on the performance of endophytes, microbial consortia was prepared by using 3 better performed endophytes (GE-1, GE-3 and GE-6) and tested against pathogens of rhizome rot complex during storage in pits. Disease reduction for the rhizomes treated with microbial consortia under storage condition was recorded as 25%. GE 1 showed the highest population (1.6 x 1011 cfu/ml) in Trehalose (5 mM) amended medium, GE3 in Trehalose (15mM) amended medium and GE6 in glycerol (10 mM) amended medium for shelf life experiment. The experiment also revealed that all the isolates were found positive for siderophore production and negative for HCN production during storage (upto 60 days). It could be concluded from the present investigation that the bacterial endophytes viz,.GE-1, GE-3 andGE-6 could be successfully used for development of microbial consortia against ginger rhizome rot complex upon further evaluation under different field conditions of Meghalaya. Application of liquid bioformulation in consortia mode, amended with trehalose (15 mM) of these effective endophytes could be an important component of integrated management of ginger rhizome rot complex in Meghalaya.ThesisItem Embargo Evaluation of biocontrol potential of Beauveria bassiana (Balsamo) Vuillemin against major rice pathogens(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2021-12) Deb, Lipa; Devi, R. K. TombisanaBeauveria bassiana (Ascomycota: Hypocreales: Cordycipitaceae), a widely studied entomopathogenic fungus recently drawn attention worldwide as potential biocontrol agent not only against insect-pests but also against several plant pathogens. As potential alternative to injudicious chemicals uses in crop protection, B. bassiana plays multifarious roles as plant disease antagonist, endophytes, plant growth promoter as well as beneficial rhizosphere colonizers providing an excellent opportunity as biocontrol agent in plant disease management. The present study was conducted with an aim to evaluate biocontrol potential of native B. bassiana isolates against major rice pathogens by studying its antimicrobial, growth promoting and colonizing ability in rice. A total of fifty-three (53) native isolates of B. bassiana were obtained from six major districts of Meghalaya, identified based on morphological and microscopic characteristics further confirmed by PCR-based detection by using universal ITS (ITS1, ITS4) primers at 550 bp amplicon size. Under in vitro assay, out of 53 tested isolates, only 15 isolates of B. bassiana were screened based on their efficient antagonistic potential against three (3) fungal viz., Rhizoctonia solani, Pyricularia oryzae, Bipolaris oryzae and one (1) bacterial pathogen viz., Xanthomonas oryzae pv. oryzae of rice with per cent inhibition recorded maximum up to 71.15%, 63.33%, 62.59% and 84.00% respectively. Under antimicrobial studies, screened B. bassiana isolates (15) showed ability to release volatile inhibitory metabolites delimiting the growth of R. solani (86.48%), P. oryzae (67.78%), B. oryzae (90.18%) and X. oryzae pv. oryzae, respectively. Majority of the isolates showed ability to produce cell wall degrading enzymes (CWDEs) viz., caesinases (68.41%), cellulase (77.26%), lipase (61.66%), xylanase (81.54%), α-amylase (77.78%), protease (72.22%) and pectinase (76.46%) in addition to iron-chelating siderophore compounds (74.74%). Presence of virulent genes viz., Bbchit1, Cdep1, Bbhog1 and Bbjen1 were detected in majority of B. bassiana isolates by performing PCR amplification using gene-specific primers at 198 bp, 249 bp, 193 bp and 198 bp, respectively. However, under plant growth promotion (PGP) studies, majority of B. bassiana isolates showed ability to produce ammonia (NH3) and inole-3-acetic acid (IAA) of concentration maximum up to 3.49 μg/ml and 6.16 μg/ml respectively. In addition to that, B. bassiana isolates also qualified as potential phosphorus (P), potassium (K) and zinc (Zn) solubilizers with per cent solubilization efficiency recorded maximum up to 68.68%, 81.74% and 64.36%, respectively. Based on potential antimicrobial and PGP traits, only five (5) isolates viz., Bb4, Bb16, bb25, Bb44 and Bb53 were selected for further studies. Potential B. bassiana isolates showed ability to tolerate aluminium (Al) and iron (Fe) stress conditions with maximum tolerance limit up to 100 ppm and 275 ppm, respectively under different acid (pH) condition to the lowest up to pH 3.0, respectively. Further, potential B. bassiana isolates viz., Bb4, Bb16, Bb25, Bb44 and Bb53 were found compatible among each other and developed into liquid-based microbial consortium (Bb-MC). Biopriming of rice seeds with Bb-MC showed considerable increase in seedling growth parameters as compared to seed treatment with single isolates and control at 10th DAS and 25th DAS. Per cent colonization (%) of B. bassiana was recorded maximum in stems (96.00%) followed by leaves (92.00%) and roots (28.00%) on 14th dpi through combined application of seed, root and foliar spray techniques. However, association of B. bassiana isolates viz., Bb4, Bb16 and Bb44 as potential colonizer in rice was further confirmed by light microscopy studies and PCR-based detection assay. In addition to that, application of Bb-MC also performed better under pot and field conditions against sheath blight disease R. solani of rice by combined treatment of seed, seedling and four (4) foliar sprays of 10 ml Bb-MC in 1 litre water at 15 days interval after transplanting. Reduced disease incidence and severity of 22.87% and 37.07% was recorded against maximum yield of 2.83 tonne/ha as compared to inoculated control with 74.23% and 94.27%, respectively with yield of 1.36 tonne/ ha. With these findings, the multifaceted role played by B. bassiana as biocontrol agent as investigated in the present study paved substantial evidence that B. bassiana in addition to its entomopathogenic behaviour also act as potential plant disease antagonist, thus, providing a new dimension in crop protection by introducing newer concept in Integrated plant disease management programmes along with overall health of plant.ThesisItem Open Access Evaluation of potential bacterial endophytes against major vegetables pathogens(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2018-07) Malakar, Pranab; Majumder, DipaliUtilisation of the endophytes against plant pathogen is considerd as successful means for plant disease management. Bacterial endophytes have beneficial effects on host plants in terms of growth promotion and in suppression of diseases. Fungicides used for plant disease management leads to the residue deposition and known to cause various environmental and health hazards. Native endophytes could be the alternative for chemicals as a component of integrated disease management. Keeping in mind, the present investigation has been formulated to evaluate the potential bacterial endophytic antagonists against major vegetable pathogens. Forty two (42) bacterial endophytic isolates have been evaluated against four major vegetable pathogens viz., Colletotrichum lindemuthianum, Phomopsis vexans, Alternaria brassicicola and C. capsici. Although, most of the bacterial endophytes showed inhibition against tested fungal pathogens. However, NGB 21 showed best inhibition against C. lindemuthianum (60.49 %) and C. capsici (55.92 %), isolate BE 1 against P. vexans (71.85 %) and SVC 11 was recorded best inhibition against A. brassicicola (63.70 %). Four screened bacteria viz., NGB21, NE 1, SVC11 and MIW1 stresses were evaluated for functional properties and abiotic. NGB21was found to have better functional property (More production of ammonia and solubilising insoluble phosphate) and can grow in different abiotic stress conditions (low pH upto 4.5 and higher aluminium concentration of 150 and 200 ppm). Screened isolates were also evaluated for plant growth promotion and disease suppression on French bean (anthracnose disease) in the field condition. The bacteria were treated alone and in consortium mode along with different combinations of treatments. Seed treatment with microbial consortia (STMC), soil application of MC refore sowing (SMCBS) and fungicidal spray (carbendazim) recorded for less disease incidence (14.44 % at 81 DAS) while STMC recorded for maximum disease incidence (32.77 % at 81 DAS) among microrial consortia combinations evaluated. PGP attributes of MC were also evaluated where it was observed that showed STMC + SMCBS + FS better performance compared to the other treatments. Isolates NGB21 and BE 1 as well as the method of application i.e., STMC + SMCBS + FS could be further tested for their antagonism and plant growth promotion under field condition in Meghalaya for further use as a component of integrated disease management for vegetable cultivation.ThesisItem Embargo Evaluation of potential rhizospheric fungal antagonists against banded leaf and sheath blight of maize caused by Rhizoctonia solani f. sp. sasaki (Kuhn.) Exner(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2022-06) Debbarma, Manashi; Rajesh, T.Rhizosphere represents the most dynamic ecosystem providing a close association between plant root and rhizosphere associated microbial communities. Among the microbial communities colonizing the rhizosphere, Rhizospheric Fungi (RF) hold prominent position but are less explored than that of rhizospheric bacteria. RF plays a vital role in agricultural and environmental process as they can impact the ecological balance, plant growth, suppress or stimulate colonization as well as antagonism of plant pathogens. Therefore, the present investigation was aimed to isolate and evaluate the potential antagonists from maize rhizosphere against Banded leaf and Sheath blight of maize caused by Rhizoctonia solani f. sp. sasaki. Through extensive surveys conducted in different maize growing areas of Meghalaya, soil samples were collected from maize rhizosphere region from eight (8) districts viz., Ribhoi, West Garo Hills, North Garo hills, West Khasi Hills, West Jaintia hills, South West Garo Hills, East Khasi Hills and East Jaintia Hills. A total of eighty (80) fungi were isolated and recovered from rhizospheric soil by serial dilution method, of which majority of isolates showed higher inhibition of 50-80% against R. solani, belongs to the genus Trichoderma sp. (20 isolates) followed by Penicillium sp. (18), Aspergillus sp. (10), Phoma sp. (10), Acremonium sp. (6), Fusarium sp. (5), Chaetomium sp. (4), Metarrhium sp. (2) and Pythium sp. (5). Further, eighty (80) isolates were identified based on morphological and microscopic characteristics. Out of twenty (20) Trichoderma isolates, twelve (12) isolates were found most effective based on their antagonistic potential and were selected for further studies based on antimicrobial and plant growth promotion (PGP) traits. Potential Trichoderma (12) isolates were further identified based on molecular method using ITS primers and accession number was obtained from NCBI. In addition to that, systemic fungicides were evaluated against R. solani f. sp. Sasaki using poisoned food technique, of which carbendazim @ 0.1% showed higher inhibition of 94.44% against R. solani f. sp. sasaki. Among these twelve (12) isolates, only one best RF antagonist viz., RF 44 (T. harzianum) as liquid bioformulation was further evaluated for its efficacy against BLSB of maize (R. solani f. sp. sasaki) under field condition. Various mode of bioformulation delivery either as individually or in combination of seed and soil and foliar were evaluated. In total eleven (11) treatments were evaluated, of which the treatment combination of soil + seed + foliar application + liquid was found most effective in managing the disease showing only 29% disease incidence as compared to control which showed 71% disease incidence. In addition to that, yield per plant i.e., 0.65 kg/plant was also found significantly higher as compared to control i.e., 0.32 kg/plant. Therefore, the potential RF antagonist (RF 44) can be used as effective biological control agent against BLSB of maize which further requires field trial under different locations in this region.ThesisItem Open Access Exploitation of endophytes for the management of Ascochyta blight of Cowpea(College of Post Graduate Studies in Agricultural Sciences, CAU-Imphal, Umiam, 2021-03) Sireesha, Chinka; Devi, R. K. TombisanaAscochyta blight caused by Ascochyta phaseolorum is one of the most important diseases of cowpea. The disease also occurs frequently in Meghalaya due to the favourable weather factors prevailing in the state. Extensive surveys were conducted during the consecutive months of June, July, and August, 2019 throughout the selected six localities from two districts of Meghalaya namely Ri-Bhoi and East Khasi Hills. Highest per cent disease index was recorded in Umroi (46.20%), followed by Umiam (43.34%). Least per cent disease index was recorded in Bhoirymbong (17.82%) and Umeit (20.38). Fifteen cowpea genotypes were screened under natural conditions. Three genotypes such as TCR-216, Catjang and TCR120 showed resistant reaction, Seven genotypes such as TCR4, TCR15, TCR22, TCR34, TCR36, CP122 and CP-Whitelong were found moderately resistant, three genotypes such as TCR3, TCR12 and CP4 were found susceptible and two genotypes such as CP-7 and Pynthoee-2 were found highly susceptible against Ascochyta blight. Six bacterial endophytes viz., BS80, BS190, BS193, BS216, FP1 and FP2 were subjected to dual culture test against A. phaseolorum. Of the six endophytes tested, three endophytes viz., BS80, BS190 and FP1 revealed significant inhibition of growth of pathogen 54.30%, 50.33% and 47.76% respectively, were found to be compatible and were used to develop consortia (MC1, MC2, MC3 and MC4). Evaluation of endophytes alone and in consortia were done on Vigour index of cowpea seeds in vitro, MC4 (BS80+ BS190+ FP1) showed highest Vigour index (Vi) of 1966.83 as compared to Control which gave Vi of 1021.5. Among the fungicides tested, propiconazole and carbendazim gave 100% inhibition at 0.05% concentration under in vitro. Field experiment was conducted in which treatment consisting of seed+ foliar treatment with microbial consortium 4 showed PDI of 19.10% followed by MC2 and carbendazim@0.05%. Plant height (125.21cm), No. of pods per plant (22.67), pod length (37.55cm) and pod weight (74.93g) were found maximum in MC4 due to synergistic consortia of Bacillus subtilis and Pseudomonas fluorescens followed by chemical (124.21cm, 21.37, 36.42cm and 73.73g). The formulation was found significant in managing the disease under in vivo condition. Hence, endophytes may be evaluated in multilocation trials and can be implemented as a part of Integrated Disease Management.ThesisItem Open Access Formulation of bacterial endophyte consortium for the management of Alternaria Blight of mustard(College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University , Imphal, 2018-07) Thokchom, Sushanti; Devi, R. K. TombisanaBroad leaf mustard (Brassica juncea var. rugosa) is one of the most highly consumed rabi vegetable crops of North East India. Alternaria blight, caused byAlternaria brassicae is the major foliar disease infecting the crop at all stages of growth. Bacterial endophytes have been reported to play a major role in the management of plant diseases as well as in plant growth promotion. In the present investigation, fifty six bacterial endophytes belonging to the group Bacillus and fluorescent Pseudomonads were isolated from 20 different cultivars of mustard (Brassica juncea) collected from different regions of North East India. The bacterial endophytes were isolated from seed, root and leaves of these cultivars. Biochemical tests were performed for tentative identification of the isolates upto species level by comparing with the Bergey’s Manual of Determinative Bacteriology. Thirty one isolates of Bacillus were isolated from which 11 were identified as Bacillus cereus, 9 as B. subtilis and 6 as B. megaterium and the remaining 5 as Bacillus sp. Out of 25 isolates of fluorescent Pseudomonad obtained, 13 isolates were identified as Pseudomonas fluorescens, 7 isolates as P. putida, 2 isolates as P. aeruginosa and the remaining 3 as Pseudomonas sp. All the isolates were subjected to dual culture assay against Alternaria brassicae, and from which isolates BS8, BS15, BS21 and FP13 showed maximum inhibition of 59.63, 65.93, 58.52 and 63.33 per cent respectively. When tested for functionalproperties, BS21 was able to produce IAA as well as ammonia, BS15 and FP13 were able to produce only Ammonia whereas BS8 was able to solubilise Phosphate. The formulation (MC) was developed using the 4 efficient compatible endophytes that were screened on the basis of antagonistic and PGP properties. In vitro Plant Growth Promoting activity showed Vigour Index (VI) of 714.55 in the seeds of cultivar MKH2 treated with MC (108 cfu/ml) as compared to the Control which gave VI of 412.5. In vivo experiment was conducted in which the treatment consisting of seed+ seedling root dip+ foliar application with MC showed Percent Disease Index (PDI) of 16.30±0.74 compared to positive control which gave PDI of 52.59±3.92. The formulation may be further tested for its efficacy in field condition. Studies on mass production of the formulation with efficient carrier system may be taken up in order to provide a safer and efficient management of Alternaria Blight of Mustard.
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