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Acharya N G Ranga Agricultural University, Guntur

The Andhra Pradesh Agricultural University (APAU) was established on 12th June 1964 at Hyderabad. The University was formally inaugurated on 20th March 1965 by Late Shri. Lal Bahadur Shastri, the then Hon`ble Prime Minister of India. Another significant milestone was the inauguration of the building programme of the university by Late Smt. Indira Gandhi,the then Hon`ble Prime Minister of India on 23rd June 1966. The University was renamed as Acharya N. G. Ranga Agricultural University on 7th November 1996 in honour and memory of an outstanding parliamentarian Acharya Nayukulu Gogineni Ranga, who rendered remarkable selfless service for the cause of farmers and is regarded as an outstanding educationist, kisan leader and freedom fighter. HISTORICAL MILESTONE Acharya N. G. Ranga Agricultural University (ANGRAU) was established under the name of Andhra Pradesh Agricultural University (APAU) on the 12th of June 1964 through the APAU Act 1963. Later, it was renamed as Acharya N. G. Ranga Agricultural University on the 7th of November, 1996 in honour and memory of the noted Parliamentarian and Kisan Leader, Acharya N. G. Ranga. At the verge of completion of Golden Jubilee Year of the ANGRAU, it has given birth to a new State Agricultural University namely Prof. Jayashankar Telangana State Agricultural University with the bifurcation of the state of Andhra Pradesh as per the Andhra Pradesh Reorganization Act 2014. The ANGRAU at LAM, Guntur is serving the students and the farmers of 13 districts of new State of Andhra Pradesh with renewed interest and dedication. Genesis of ANGRAU in service of the farmers 1926: The Royal Commission emphasized the need for a strong research base for agricultural development in the country... 1949: The Radhakrishnan Commission (1949) on University Education led to the establishment of Rural Universities for the overall development of agriculture and rural life in the country... 1955: First Joint Indo-American Team studied the status and future needs of agricultural education in the country... 1960: Second Joint Indo-American Team (1960) headed by Dr. M. S. Randhawa, the then Vice-President of Indian Council of Agricultural Research recommended specifically the establishment of Farm Universities and spelt out the basic objectives of these Universities as Institutional Autonomy, inclusion of Agriculture, Veterinary / Animal Husbandry and Home Science, Integration of Teaching, Research and Extension... 1963: The Andhra Pradesh Agricultural University (APAU) Act enacted... June 12th 1964: Andhra Pradesh Agricultural University (APAU) was established at Hyderabad with Shri. O. Pulla Reddi, I.C.S. (Retired) was the first founder Vice-Chancellor of the University... June 1964: Re-affilitation of Colleges of Agriculture and Veterinary Science, Hyderabad (estt. in 1961, affiliated to Osmania University), Agricultural College, Bapatla (estt. in 1945, affiliated to Andhra University), Sri Venkateswara Agricultural College, Tirupati and Andhra Veterinary College, Tirupati (estt. in 1961, affiliated to Sri Venkateswara University)... 20th March 1965: Formal inauguration of APAU by Late Shri. Lal Bahadur Shastri, the then Hon`ble Prime Minister of India... 1964-66: The report of the Second National Education Commission headed by Dr. D.S. Kothari, Chairman of the University Grants Commission stressed the need for establishing at least one Agricultural University in each Indian State... 23, June 1966: Inauguration of the Administrative building of the university by Late Smt. Indira Gandhi, the then Hon`ble Prime Minister of India... July, 1966: Transfer of 41 Agricultural Research Stations, functioning under the Department of Agriculture... May, 1967: Transfer of Four Research Stations of the Animal Husbandry Department... 7th November 1996: Renaming of University as Acharya N. G. Ranga Agricultural University in honour and memory of an outstanding parliamentarian Acharya Nayukulu Gogineni Ranga... 15th July 2005: Establishment of Sri Venkateswara Veterinary University (SVVU) bifurcating ANGRAU by Act 18 of 2005... 26th June 2007: Establishment of Andhra Pradesh Horticultural University (APHU) bifurcating ANGRAU by the Act 30 of 2007... 2nd June 2014 As per the Andhra Pradesh Reorganization Act 2014, ANGRAU is now... serving the students and the farmers of 13 districts of new State of Andhra Pradesh with renewed interest and dedication...

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Subject: Plant Pathology × End date: 2019 × Start date: 2017 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    STUDIES ON URDBEAN LEAF CRINKLE DISEASE ONURDBEAN [Vigna mungo (L.) HEPPER]
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) USHA RANI, L; MANOJ KUMAR, V
    The present investigation on “Studies on urdbean leaf crinkle disease on urdbean [Vigna mungo (L.) Hepper]” was carried out at Agricultural College, Bapatla, Guntur district, Andhra Pradesh during 2018-19. Blackgram cv LBG 752 belonging to Leguminosae tested for their reaction to Urdbean leaf crinkle disease(ULCD) by sap incoulation method, the disease symptoms with crinkling and curling of infected leaves . Seed treatment with hot water (500C for ten min) significantly lowered the incidence (10%) of ULCD followed by seed treatment with 16% trisodium orthophosphate (20.00%) when compared to untreated control (28.33%). Aphid (Aphis craccivora) transmitted ULCD with an acquisition access period of ten minutes (10.00%) and inoculation access period of 24 h (20.00%). Maximum ULCD incidence was noticed with 20 aphids per plant (13.33%). Beetle (Henosepilachna dodecastigma) transmitted ULCD with an acquisition access period of six hours (3.33%) and inoculation access period of 12 hours (6.67%). ULCD infected sample showed the highest protein content when compared to healthy samples. Phenol content was also the highest in ULCD infected plants when compared to healthy plants. When the healthy leaf tissues were assessed, the highest protein content was observed at 40, 55 and 70 DAS in MgSO4 @ 0.2% + ZnSO4 @ 0.2% with 1.43, 1.71 and 2.35 mg/100mg of leaf tissue respectively and the lowest was in check 1.34, 1.41and 1.63 mg/100 mg of leaf tissue at the respective interval 15 days from 40 DAS and in infected maximum was observed in ZnSO4 @ 0.2% (1.97, 2.18 and 2.34 mg/100 mg at 40, 55 and 70 DAS) of leaf tissue and minimum was observed in check (1.44, 1.69 and 1.85 at 40, 55 and 70 DAS). 13 The maximum phenol content in healthy leaf tissue at 40, 55 and 70 DAS in MgSO4 @ 0.2% + ZnSO4 @ 0.2% with 0.60, 0.66 and 0.72 mg/100mg of leaf tissue sprayed plots while minimum was in check (0.34, 0.40 and 0.45 mg/100mg respectively). In infected tissues the highest phenol was observed at 40, 55 and 70 DAS inMgSO4 @ 0.2% + ZnSO4 @ 0.2% with 0.89, 0.92 and 0.97 mg/100mg and the lowest was observed in check (0.51, 0.55 and 0.59 mg/100mg). Presence of auxins was tested using TLC plates and the Rf values are recorded as 0.92, 0.896 and 0.901 in stranded, infected and healthy leaf samples respectively. Among the micronutrients tested, spraying of MgSO4 @ 0.2% + ZnSO4 @ 0.2% recorded significantly lowest AUDPC value (466.97) of ULCD followed by ZnSO4 @ 0.2% (567.84) as against unsprayed control (955.92). The highest B:C ratio was found in MgSO4 @ 0.2% + ZnSO4 @ 0.2%(2.11) and lowest in control (1.42).
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    ThesisItemOpen Access
    BIOEFFICACY OF FUNGICIDES AND THEIR COMPATIBILITY WITH INSECTICIDES IN MANAGING BLACKGRAM DISEASES
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) EDEN GEORGIA, K; ANIL KUMAR, P
    In toto, nine combinations, viz., azoxystrobin + triazophos, azoxystrobin + acetamiprid, azoxystrobin + chlorantraniliprole, propiconazole + triazophos, propiconazole + acetamiprid, propiconazole + chlorantraniliprole, mancozeb + triazophos, mancozeb + acetamiprid and mancozeb + chlorantraniliprole were assessed for their physical and chemical compatibility at three doses, i.e., recommended dose, half the recommended dose and double the recommended dose using three types of water, i.e., distilled water, tap water and standard hard water. All the combinations were found physically (sedimentation test and specific gravity) and chemically compatible (pH and E.C). Pot culture experiments indicated no phytotoxic effect on 21 day old blackgram plants indicating test combinations were not detrimental to plants. Against blackgram powdery mildew, pooled analysis of kharif and rabi 2018-19 data revealed that propiconazole (3.65 PDI and 91.94% disease reduction) and its combination with triazophos (5.67 PDI and 87.49% disease reduction) gave significantly superior control of powdery mildew. Against Alternaria leaf spot, pooled analysis of kharif and rabi 2018-19 data revealed that i.e., azoxystrobin (25.61 PDI and 63.97% disease reduction) and its combination with triazophos (27.49 PDI and 61.33% disease reduction) gave significantly superior control of Alternaria leaf spot. Against flea beetle and Spodoptera litura, the incidence of which was noticed only during kharif 2018-19, and spotted pod borer, Maruca vitrata, the incidence of which was noticed both in kharif and rabi 2018-19, chlorantraniliprole alone was found xvii best among all the treatments. Against whitefly, Bemisia tabaci, the incidence of which was noticed only during rabi 2018-19, acetamiprid alone (54% reduction in whitefly population) was found best. Pooled data of kharif and rabi 2018-19 indicated superiority of azoxystrobin + chlorantraniliprole sprayed plots (11.36 q ha-1) followed by azoxystrobin + triazophos (10.94 q ha-1). When insecticides were combined with mancozeb, yield levels were reduced compared to other combinations i.e., either with azoxystrobin or propiconazole. When yield attributing characters were analysed based on pooled data of kharif and rabi 2018-19, number of primary branches per plant, number of pods per plant, number of seeds per pod and test weight were significantly higher in azoxystrobin + chlorantraniliprole sprayed plots followed by azoxystrobin + triazophos sprayed plots. The present investigation revealed that though yield levels can be increased with compatible pesticide combinations, care need to be taken to assess synergistic and antagonistic effects of pesticides on one another.
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    ThesisItemOpen Access
    EPIDEMIOLOGY AND MANAGEMENT OF FUNGAL FOLIAR DISEASES IN COTTON UNDER HIGH DENSITY PLANTING SYSTEM
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) YAMUNA, CHUKKA; SREE LAKSHMI, B
    Present investigation was taken up to study the epidemiology and management of fungal foliar diseases in cotton under high density planting system. Symptoms were found to be distinct in each of the fungal foliar diseases. Circular brown spots with or without zonations were observed in Alternaria leaf spot whereas, target board symptom with yellow halo was characteristically observed in Corynespora leaf spot. Helminthosporium leaf spots were with purple margins, Circular brown spots with sporodochia in spherical rings occurred in Myrothecium leaf spot while, irregularly angular, pale translucent spots with a definite margin on the under surfaces in grey mildew infection. In case of rust infection, light orange uredo sori appeared on the under surface of affected leaves. Observations were taken during different stages of crop viz., seedling, squaring, flowering, boll formation and boll development, boll maturity and bursting and boll bursting and picking stages to assess the incidence of fungal foliar diseases of cotton in compact genotypes under High Density Planting System (HDPS) and Normal Planting System (NPS) at RARS, Lam, Guntur. Incidence of Alternaria leaf spot was persistent in all the fields from seedling stage to harvesting stage, Corynespora leaf spot was observed during boll maturity and bursting stage while grey mildew and rust developed during boll bursting and picking stage, Myrothecium and Helminthosporium leaf spots did not appear at any stage of the crop. The Per cent disease index (PDI) of Alternaria leaf spot was high under HDPS at all the stages when compared to NPS. Peak PDI of Alternaria leaf spot ranged from 11 to 22% in HDPS and 10 to 20% under NPS during boll formation and boll development stage. Among the coordinated compact genotypes, the average PDI was xviii 16.6 and 15.7% under HDPS and NPS respectively. Corynespora leaf spot was observed only during boll maturity and bursting stage to an extent of 3 to 4% under HDPS and 1 to 4% under NPS. Grey mildew and rust diseases were observed during boll bursting and picking stage only to an extent of 3.5 to 6.5% and 4.5 to 8.0%, respectively under HDPS and 4.25 to 10.0% and 5 to 12%, respectively under NPS. Multiple regression analysis of Alternaria PDI data from kharif 2018-19 under HDPS with weather parameters indicated significantly positive correlation between PDI and minimum temperature, morning relative humidity, sunshine hours, rainy days and evaporation. While under NPS minimum temperature, rainfall and wind speed showed significant negative correlation with PDI. In Corynespora leaf spot under HDPS there was a significant positive correlation between PDI and maximum temperature, while under NPS morning relative humidity showed significant positive correlation. Incase of grey mildew, under HDPS, it was observed that morning relative humidity, rainfall and evaporation showed significant positive correlation, while under NPS morning relative humidity showed significant positive correlation. With respect to rust under HDPS, there was a significantly positive correlation between PDI and minimum temperature, morning relative humidity. In NPS minimum temperature and rainy days showed significant negative correlation with PDI. Among the eight fungicides tested in vitro, hexaconazole @ 0.2%, propiconazole @ 0.1%, hexaconazole + captan @ 0.1% and mancozeb @ 0.3% showed highest inhibition of the mycelia growth of A. macrospora, C. cassiicola, M. roridum and H. gossypii followed by trifloxystrobin + tebuconazole @ 0.05% over check. All the four selected fungicides were significantly reduced the cotton fungal foliar diseases under natural conditions. Maximum reduction of diseases was recorded with three sprays of hexaconazole @ 0.2% i.e., Alternaria leaf spot (4.41%) equivalent to 81.2% disease reduction over control, Corynespora leaf spot (2.50%) with 64.2% disease reduction over control, grey mildew (4.17%) with 59.6% reduction over control and rust (4.66%) with 62.7% reduction over control, followed by three sprays of hexaconazole + captan @ 0.1% i.e., Alternaria leaf spot (5.00%) equivalent to 78.7% disease reduction over control, Corynespora leaf spot (3.06%) with 56.2% disease reduction over control, grey mildew (4.73%) with 54.2% reduction over control and rust (5.00%) with 60.0% reduction over control. Hexaconazole @ 0.2%, hexaconazole + captan @ 0.1%, propiconazole @ 0.1% and mancozeb @ 0.3% were effective in reducing these foliar diseases and improving growth in terms of number of sympodial branches per plant and boll number per plant which ultimately led to significantly higher yields in kharif 2018-19. The highest yield (3613.3 kg ha-1) and B: C ratio (3.06) were obtained with hexaconazole @ 0.2% over unsprayed check.
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    ThesisItemOpen Access
    STUDIES ON SEED BORNE NATURE AND MANAGEMENT OF ALTERNARIA LEAF SPOT IN BLACKGRAM
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) PRATHYUSHA, DIGUMARTHI; ADINARAYANA, M
    Black gram (Vigna mungo L. Hepper) is a premium pulse crop amongst all pulses and is also rich in phosphoric acid. It is affected by fungi, bacteria, viruses, nematodes and also abiotic stresses. Among the fungal diseases, Alternaria leaf spot disease caused by the Alternaria alternata (Fr.) Keissler is becoming a major problem in blackgram growing areas of Andhra Pradesh. The survey on occurence of blackgram Alternaria leaf spot in Guntur and Krishna district of A.P, revealed that the disease kept on increasing with increase in the age of the crop. There was no disease observed upto 30-35 days old crop. In Guntur district during kharif, the disease progressed upto 54.30% in Mangalagiri mandal and 52.64% in Tadikonda mandal at 60 DAS and during rabi the disease progression was up to 49.49% in Mangalagiri and 48.66% in Ponnur mandal at 60 DAS. In Krishna district during kharif the disease progressed up to 63.04% in Kanchikacherla and 52.20% in Veerullapadu mandal at 60 DAS. Among the 83 blackgram genotypes screened during kharif and rabi 201819, none of the genotypes were found resistant. 14 genotypes were moderately susceptible, 15 genotypes were susceptible and rest of the genotypes were highly susceptible. xv Total phenols, total proteins, total sugars (0.82-0.84, 7.84-7.99 and 1.731.74 mg/100 mg of leaf tissue respectively) were higher in moderately susceptible genotypes than that of highly susceptible genotypes (0.51-0.57, 7.077.14, 1.46-1.47 mg/100 mg leaf tissue respectively). The test pathogen A. alternata was found to be both externally and internally seed borne. Among the externally seed borne mycoflora detected, A. alternata and Aspergillus spp. were higher in association with blackgram seeds ranged from 13 to 26% (mean 19.62%) and 17-29% (mean 23.62%) respectively. In case of internally seed borne association, A. alternata was ranged from 5-16% (mean 10.12%) and showed higher association than the other fungi. The seed mycoflora of blackgram exhibited different distribution pattern as externally and internally seed borne and among which A. alternata and Aspergillus had higher colonizing frequency (CF) and isolation recovery (IR) in case of externally seed borne, and in case of internally seed borne A. alternata exhibited higher CF and IR than the rest of the seed fungi, irrespective of location. For externally seed borne mycoflora, the highest Simpson‟s diversity index (DI = 0.785) and Shannon-Wiener diversity index (H‟ = 1.642) were in the seed samples from Mangalagiri mandal. The highest species richness (0.347) and evenness (0.916) were also recorded from seed samples of Mangalagiri mandal. The highest diversity of internally seed borne fungi was in seeds from Tadikonda mandal with the highest DI (0.783) and H‟ (1.635) while the greatest species richness (0.550) and evenness (0.912) were also recorded from the seed samples of Tadikonda mandal. Among the seven chemicals tested in vitro mancozeb @ 0.25% and hexaconazole @ 0.20% showed highest inhibition (100%) of the mycelial growth of A. alternata followed by trifloxystrobin + tebuconazole @ 0.05% (78.93%) over check. All the chemicals evaluated were significantly effective in reducing the Alternaria leaf spot on blackgram in vivo. Maximum reduction of disease was recorded with combination treatment i.e., seed treatment (ST) with mancozeb @ 0.25% followed by two sprays (FS) of trifloxystrobin + tebuconazole @ 0.05% (25.51) which with 61.65% disease reduction over unsprayed check followed by two sprays of trifloxystrobin + tebuconazole @ 0.05% (27.62%) alone, with 58.47% disease reduction and azoxystrobin (FS) @ 0.05% (28.95%) alone with 56.47% disease reduction over unsprayed check. Apart from reducing the disease they were also effective in improving growth in terms of pod number per plant and seeds per pod which ultimately led to significantly higher yields in both kharif and rabi 2018-19. The highest yield (12.06 q ha-1 in kharif and 12.75 q ha-1 in rabi) and B:C ratio of (2.73 in kharif and 2.77 in rabi) were obtained with combination treatment i.e., mancozeb (ST) @ 0.25% and trifloxystrobin + tebuconazole (FS) @ 0.05%.
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    ThesisItemOpen Access
    STUDIES ON ANTAGONISTIC POTENTIAL OF METHYLOTROPHIC BACTERIA AGAINST Sclerotium rolfsii IN GROUNDNUT (Arachis hypogaea L.)
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) SUSHITHA; MANOJ KUMAR, V
    Groundnut (Arachis hypogaea L.) is one of the important economic oilseed crops of the world. Fungal, virus and bacterial pathogens attack the crop at various stages of growth and cause severe yield losses. Among the soil-borne fungal diseases of groundnut, stem rot caused by Sclerotium rolfsii Sacc. is a disease of economic significance throughout the world, which causes yield losses of 10-25%, but under severe disease conditions, yield loss up to 80% was observed. The present investigation on “Studies on antagonistic potential of methylotrophic bacteria against Sclerotium rolfsii in groundnut (Arachis hypogaea L.)” was aimed at isolating native methylotrophic bacterial isolates from the phyllosphere and rhizosphere of groundnut plants collected from different places of Guntur district and to study the efficacy of the isolates in controlling the stem rot pathogen S. rolfsii and in enhancing growth of groundnut plants. As many as 35 isolates of methylotrophs (20 from phyllosphere and 15 from rhizosphere) were isolated from groundnut plants and morphological and biochemical characterization was done. All the isolates were screened rapidly for their antagonistic potential against S. rolfsii using dual culture technique. Eight isolates out of 35 isolates was found better in inhibiting the mycelial growth of the pathogen with and inhibition per cent ranging from 8.78 to 18.54 per cent. When antagonistic potential of methylotrophic bacteria against S. rolfsii was evaluated under pot culture, PPFM 6 and PPFM 3 was found better in inhibiting the disease and PPFM 3 was found better in enhancing shoot length and root length. Highest vigour index was obtained when PPFM 6 was applied. Among all methods of isolates combined application of methylotrophic bacteria through seed treatment and soil application was found better in controlling stem rot and enhancing the plant growth. xiv The plant growth promotional ability of methylotrophs was evaluated under pot culture without pathogen inoculation. The methylotrophic bacterial isolate PPFM 3 significantly enhanced germination, shoot length, root length and vigour index of plants compared to remaining isolates tested. Combined inoculation of bacteria through seed treatment and soil application was found as the most effective method in enhancing growth compared to seed treatment and soil application. The isolate PPFM 3 was selected for field management of stem rot, because it was found better in inhibiting stem rot and enhancing growth of the plant at the same time. Among different treatments employed for management of stem rot under field conditions, seed treatment with bacteria+ tebuconazole seed treatment+ soil application of bacteria was found better in inhibiting stem rot with 86.12 per cent reduction of stem rot over control and in enhancing the growth of the plant measured in terms of germination, shoot length, root length and yield. The treatments applied for management of stem rot also controlled late leaf spot severity in the field. Foliar application of methylotrophs was found most effective among all the treatments with 51.32 per cent disease reduction over control, followed by the treatment seed treatment with bacteria+ tebuconazole seed treatment+ soil application of bacteria with 44.30 per cent reduction over control.
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    ThesisItemOpen Access
    CHARACTERIZATION OF SORGHUM TURCICUM LEAF BLIGHT PATHOGEN AND ITS MANAGEMENT
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) SUMANTH KUMAR, M; PRASANNA KUMARI, V
    In the present research on “Characterization of sorghum turcicum leaf blight pathogen and its management”, survey was undertaken to assess the turcicum leaf blight (TLB) severity in major sorghum growing mandals of Guntur and Prakasam districts. PDI of 30.12% in Prakasam and 27.22% in Guntur district was recorded. The cultural variability of E. turcicum isolates on PDA was assessed at 8 DAI. Initally mycelium was white and later turned to greenish black (2.5/10Y). The soluble pigment production varied from dark bluish to bluish black. Among all the isolates, Prakasam isolates KTP (8.96 cm) and ELC (8.94 cm) were significantly rapid in their radial growth with growth rate varying between 0.47 mm h-1 to 0.21 mm h-1. Sporulation varied from 0.02 x104 spores/ mm2 (SMG) to 0.35 x 104 spores/ mm2 (IRP). The mean conidial size of E. turcicum isolates ranged from 56.13-72.39 x 15.0015.83 μm and septa varied from 5.67 to 6.71. Conidiophore size ranged from 140.38 to 183.38 x 6.32 to 7.02 μm. The incubation period of the isolates varied between 24 h (SMG) to 37.33 h (IRP) with least lesion size in DVT (1.68 cm) at 20 DAI. Maximum PDI of 28.64% was recorded with the SMG isolate Molecular variability was analysed using a total of 25 RAPD arbitrary primers for 12 fungal isolates. A total of 84 bands were obtained that showed 100% polymorphism. The PIC (Polymorphic Information Content) values varied from 0.10 to 0.46. The highest PIC value was recorded with OPA-03 primer, followed by OPH-18 (0.41). The similarity coefficient varied between 0.45 and 1.00. The lowest similarity 0.45 was noticed between KMR and BPT while the highest similarity was noticed xv between the isolates of RJP and EDM of 0.93. The dendrogram obtained had two clusters or groups irrespective of the isolates obtained from the geographical distribution. Among the Guntur district isolates, from Bapatla mandal BPT and DVT isolates had 54 per cent dissimilarity and Muppalla isolates IRP and BVM had 68% similarity indicating the existence of different isolates. However, Rajupalem isolates were noticed with 92% similarity (RJP and RDG) and limited variation indicates absence of variation among the isolates. Similarity of 87% existed between isolates especially EDM (Prakasam district, Komarolu isolate) and RDG (Guntur district, Rajupalem isolate) though geographically far apart. Under in vitro conditions henna @15% concentration was found to inhibit the radial growth of pathogen significantly (2.64 cm) and could significantly inhibit sporulation to maximum extent (0.007 x104 spores/ mm2). Panchagavya @ 10% was found significantly effective among the cow based natural products with complete inhibition of mycelial growth and sporulation. Combined treatment of Trichoderma (ST+ FS) + Panchagavya @15% (ST+FS) treatment was found most effective in controlling the disease even two weeks after second spray (64DAS) with the lowest PDI (18.89%) and with minimum area under disease progress curve of 474.26 as against unsprayed check (760.49). Treatment 5 - Trichoderma (ST+ FS) + Panchagavya @15% (ST+FS) was found with highest number of grains per panicle 502.40 with highest test weight of 3.44 g, yield of 2388 kg ha-1. However, the benefit cost ratio (BCR) of the different treatments varied from 0.70 to 1.56 with the highest BC ratio being recorded with fungicidal spray of 0.25% mancozeb (1.56). However, among non chemical treatments best B: C ratio was obtained in T4 (Trichoderma (ST+ FS) + Henna @ 15% FS) with 1.48 followed by T 5 with a BC ratio of 1.40 treatments which represents a potential alternative to fungicide treatments.
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    ThesisItemOpen Access
    STUDIES ON ANTAGONISTIC POTENTIAL OF TRICHODERMA SPP AGAINST GROUNDNUT SOIL BORNE PATHOGENIC FUNGI
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) AMRUTHA VEENA, G; PADMODAYA, BHASKARA
    Roving survey was carried out during Kharif 2014 in five districts of Andhra Pradesh for studying collar rot, root rot and stem rot disease incidence. Highest average collar rot incidence (23.00%) was observed in Yerraguntla mandal of Kadapa district, highest average stem rot incidence (19.50%) in Gangadhara Nellore mandal of Chittoor district and highest average root rot incidence (22.00%) in Kadiri mandal of Ananthapur district. Pathogens were isolated from the plants exhibiting typical symptoms of the disease, and pathogenecity test proved Koch postulates. In vitro efficacy of five fungicides viz., thiram, mancozeb, carbendazim, tebuconazole and thiram+vitavax were evaluated against three pathogens using poisoned food technique at five different concentrations. All the five fungicides were effective against A. niger at all the concentrations tested. Carbendazim was ineffective against S. rolfsii at 1000 ppm. Except thiram remaining four fungicides gave 100% inhibition against R. bataticola. A total of fifty Trichoderma isolates were isolated from rhizosphere region of healthy groundnut plants which were designated as Groundnut Rhizosphere Trichoderma (GT-1 to GT-50). When these isolates were screened against S. rolfsii, thirty isolates gave more than 50% inhibition, remaining twenty isolates overgrew over S. rolfsii. When these potential thirty isolates were tested against R.bataticola, Trichoderma isolate-34 (GT-34) showed xx maximum inhibition of growth of Rhizoctonia bataticola (69.44%) followed by Trichoderma isolate-28 (67.78%) and Trichoderma isolate-38 (63.88%). Against A.niger, Trichoderma isolate-28 showed highest inhibition (77.78%) followed by Trichoderma isolate-49 (77.22%) which were on par with each other. The five effective Trichoderma isolates (Trichoderma isolate-9, 28, 34, 38 and 49) showing antifungal activity against pathogens were further evaluated to identify the mechanism of antagonism. Trichoderma coiled around the mycelium of S. rolfsii and R.bataticola penetrated into the mycelium and lysed leading to disruption of cell contents. Volatile and nonvolatile metabolites of five Trichoderma isolates significantly inhibited the mycelial growth of the three pathogens. Among the five antagonists, Trichoderma isolate-9 showed highest inhibition. This isolate highly inhibited the growth of A. niger followed by R. bataticola and S. rolfsii. Least inhibition was shown by Trichoderma isolate-49. Biochemical characterization of potential Trichoderma isolates revealed that more chitinase was produced than β-1, 3 glucanase and cellulose. Uv irradiation was induced for five potential isolates to induce mutations. Five stable mutants were able to inhibit the mycelial growth of three pathogens significantly higher than the wild isolates. In vitro effect of five fungicides were evaluated against wild and mutant Trichoderma isolates. Mancozeb was compatible with both wild and mutant isolates. Remaining four fungicides completely inhibited the growth of Trichoderma isolates. Urea, SSP, MOP and Gypsum had no inhibitory effect against wild and mutant Trichoderma isolates. DAP, 19:19:19, 14:35:14 were relatively incompatible with wild isolate GT-9 at higher concentrations, while the compatibility increased with mutant Trcichoderma. Highest mycelial dry weight was obtained at 300C followed by 250C and 350C. At higher temperatures sporulation was scanty. Trichoderma isolates-9, 34, 38 and 49 were identified as Trichoderma asperellum and Trichoderma isolate-28 as Trichoderma hamatum using ITS primers. OPC-16 primer produced polymorphic band of size 512 bp which was developed as SCAR marker to differentiate wild and mutant Trichoderma isolates. The kharif, 2016 and 2018 field experiment results revealed that seed treatment+soil application (basal)+soil drenching of mutant Trichoderma+mancozeb seed treatment recorded highest germination percentage (91.67), lowest collar rot (3.09%), stem rot (2.74%), root rot incidence (5.49%), highest pod yield (1961.50 kg ha-1) and haulm yield (2573.50 kg ha-1).
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    ThesisItemOpen Access
    STUDIES ON DIVERSITY OF Sclerotium oryzae, Catt AND MANAGEMENT OF STEM ROT OF RICE
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) VANI, YERRANAGARI; Sarada Jayalakshmi Devi, R
    The stem rot of rice caused by Sclerotium oryzae (Catt.) is one of the major limiting factors for rice production in the Indian subcontinent. In an attempt to found the variability at cultural, morphological and genomic level and also to develop effective integrated management practices for rice stem rot, a total of twelve isolates of the pathogen and native bacterial biocontrol agents were collected from major rice growing areas of Andhra pradesh. The isolates of Sclerotium oryzae were designated as SOP1- SOP 12 whereas Pseudomonas fluorescens isolates designated as SOA- SOA-12. Among the isolates of Sclerotium oryzae, Catt, cultural and morphological variability was assessed and by the utilisation of carbon resources on PDA, OMA and CZA media and by the mycelial growth rate on PDA. Among these media, PDA was well supported for growth compared with other media. Isolates were categorized into four groups, Group 1 with fastest growing, Group 2 with fast growing , Group 3 with medium growing and Group 4 with slow growing isolates based on time taken for 90mm diameter of mycelial formation on PDA. To know the polymorphism among the collected isolates of Sclerotium oryzae, Catt using RAPD analysis, primer survey was done with eight primers of OPA-2, OPA-3, OPA19, OPB-5, OPB-7, OPB-10, OPC-7 and OPC-10 for the amplification of DNA. Among them, OPB-5 and OPC-10 primers generated 17 percent polymorphism. The isolates of Pseudomonas fluorescens were screened against mycelial growth of Sclerotium oryzae with dual culture and significantly highest percentage of inhibition were noticed in SOA-10 with 97.44 % and lowest inhibition recorded in SOA-2 with inhibition of 37.56 %. Due to its high efficacy SOA-10 was selected for further studies. A total of five fungicides viz., Hexaconazole, Difenoconazole, Tebuconazole, Trifloxystrobin + Tebuconazole, Pyraclostrobin and Krysoxim methyl of different concentrations in ppm were evaluated for their efficacy against mycelial growth and sclerotial viability of S. oryzae in rice system. Among them, difenconazole showed 100 percent highest inhibition and pyraclostrobin with least inhibition of 72.52 percent on mycelial growth. Incase of sclerotial viability difenconazole recorded highest inhibition and kresoxim methyl recorded least inhibition at different concentrations in minimum and maximum time intervals. The compatability between effective fungicide (difenconazole) and potential antagonist (SOA-10) revealed good compatability at lowest concentration (500 ppm). During rabi 2018-19, field trial was conducted to evaluate the efficacy of effective fungicide and potential antagonist by artificial disease inoculation at late tillering stage. Different strategies were followed in the field, highest grain yield, straw yield and lowest PDI obtained in T6.
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    ThesisItemOpen Access
    CHARACTERIZATION OF VIRUSES ASSOCIATED WITH LEAF CURL AND STEM NECROSIS DISEASES OF BLACKGRAM IN ANDHRA PRADESH
    (ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR, 2019) PRASAD, KURAKU; SARADA JAYALAKSHMI DEVI, R
    Survey was carried out for disease incidence of leaf curl and stem necrosis during rabi 2018-19 in three blackgram growing districts of A.P. The mean disease incidence ranged from 4.10-6.26 %. The disease was successfully transmitted onto cowpea and back to blackgram from cowpea by mechanical inoculations. It produce typical local lesions and veinal necrosis on cowpea and leaf curling, necrosis of petiole, buds, leaves and other parts on blackgram. Total RNA was isolated and amplified by RT-PCR with GBNV/ TSV primers. An amplicon of 800bp was obtained with GBNV but not with TSV primers. About 800bp product was purified, sequenced and determined its length as 831 nucleotides and codes for 276 amino acids. The sequence homology studies with other GBNV isolates from data base shared 93-100 % and 94.5% to 100% sequence identity with GBNV at the nucleotide and amino acid levels, respectively. Phylogenetic tree was generated by comparing with 20 other reported Tospoviruses at nucleotide level by neighbour joining method and present isolate formed unique cluster with GBNV isolates. Among 21 genotypes screened by artificial inoculations, 5 genotypes (NDUK-15-222, TU-40, OBG-32, GKB-3, KPU-12-213) were found disease free, 2 genotypes (TBG-130, VBG-12-111-1) were found resistant, 4 genotypes (GBG-1, TBG-129, LBG-20, IPU-2-43) were found moderate resistance, 6 genotypes (LBG-645, LBG-623, TBG-104, SRI, LBG-787, TUTIMINUMU) were found susceptible, 4 genotypes (LBG-752, LBG-685, PU-31, BUTTAMINUMU) were found highly susceptible.