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Acharya N. G. Ranga Agricultural University, Guntur (AP)

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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201710
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Subject: Plant Pathology × End date: 2017 × Start date: 2017 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    STUDIES ON FUSARIAL WILT OF CHILLI (Capsicum annuum L.)
    (Acharya N.G. Ranga Agricultural University, 2017) VIJAY KUMAR, V; SARADA JAYALAKSHMI DEVI, R
    The present investigation on “Studies on Fusarial Wilt of Chilli (Capsicum annuum L.)” was carried out in order to assess the prevalence of Fusarium wilt in major chilli growing mandals of Kurnool, Prakasam and Guntur districts of Andhra Pradesh, to find the variability among 19 isolates at morphological and molecular level, and to evaluate the native bio control agents against Fusarium wilt in vitro. The results obtained are summarized below: Survey conducted in three districts revealed that incidence of Fusarial wilt was more in Kurnool district (30.78 %), followed by Prakasam district (26.36 %) and least was recorded in Guntur district (19.2 %). Nineteen pathogen isolates were collected and the fungus associated with the wilt disease in chilli was isolated by tissue segment method and was identified as Fusarium solani (Mart.) Sacc. by morphological and molecular characterization. Pathogenicity of the fungus F. solani was proved by soil inoculation and root dip inoculation methods using three week(four leaf stage) old susceptible chilli (cv. Jyothi) seedlings. Assessment for variability in morphological characters such as radial growth, colony character, pigmentation, micro and macroconidia lengths and septation was done. The length × breadth of the macroconidia usually varied between 15-37.5μm x 2.5-4μm and that of the microconidia was around 2.5-15μm x 2-3μm among the isolates. The septation of the macroconidia was 3 to 5 and the microconidia were usually aseptate or single septate, formed singly. DNA isolation was done and molecular characterization was performed by using Fusarium genus specific ITS primers Fu-1f and Fu-1r, products were in the size range of 466 bp and sequences exhibited a high level of identity for F. solani. Sequences were deposited in GenBank under accession number KX581731 to KX581749.A Phylogenetic tree inferred from ITS2 rDNA region sequences and generated from the neighbor joining (NJ) method illustrated that all the F. solani species clearly form a single distinct clade, and this result was supported by a high bootstrap value. Almost no variation was observed among the sequences of F. solani isolates, which clustered in a single group with 100% homology. Additionally, little variation existed within the ITS region sequences of the F. solani isolates, except for the KX581731 (Yerragondapalem) and KX581735 (Ramallakota) isolates. A total of twenty Trichoderma isolates, thirty two Pseudomonas isolates and twelve Bacillus isolates were obtained from rhizosphere samples. Potential Trichoderma sp. (T4) was identified as T. harzianum by National Fungal Culture Collection of India (NFCCI), Agharker Research Institute, Pune. Potential bacterial bio control agents were identified by molecular tools i.e., 16S rDNA specific target primers viz., fP1 and rP2 which resulted in a fragment in the size range of 1300 bp, and sequences exhibited a high level of identity for P. aeruginosa and B. cereus respectively, deposited in GenBank under accession number KX581726 to KX581730. In vitro studies, using biocontrol agents against test pathogen F. solani in dual culture techniques revealed Trichoderma isolate T4, Pseudomonas isolate P18 and Bacillus isolate B11 showed maximum inhibition of growth of F. solani by 86.15 %, 85 %and 66.94 %. Of the twenty seven treatments, there was no disease incidence in the treatments T23 (seedling application of all three potential bioagents) and also improved the growth of chilli seedlings when compared to control. Among six individual treatments with biocontrol agents either seedling treatment or soil application, fungal bioagentT. harzianum (isolate T4) showed minimum per cent disease incidence. Combined application of biocontrol agents, maximum reduction was observed in treatment T23 (seedling application of all three potential bioagents) in which there was no disease incidence. PDI was recorded coupled with vigorous growth of chilli seedlings followed by T24 (seedling and soil treatment of three potential biocontrol agents) where PDI recorded as 2.2. Statistically significant increase (12.13 mm) in the root length of chilli seedlings was observed in treatment T23 i.e., seedling application of consortium containing three potential bioagents, but in the case of shoot length,treatment T24 (seedling and soil treatment of three potential biocontrol agents) recorded highest (35.16 mm). The treatment T21 (soil application of T. harzianum + B. cereus) recorded a highest fresh weight & dry weight i.e., 68.06 g & 32.16 g respectively followed by the treatments T13 (seedling application of P. aeruginosa + soil application of B. cereus) and T14 (seedling application of B. cereus + soil application of T. harzianum) which were significantly on par with T21 indicating no significant difference. To conclude, integration of seedling and soil application involving compatible native biocontrol agents like T4, P18 and B11 resulted not only in controlling the wilt disease but also growth promotion of chilli seedlings.
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    ThesisItemOpen Access
    EFFECT OF AGRO CHEMICALS AND BIOCONTROL AGENTS ON THE VIABILITY OF SCLEROTIA OF RICE SHEATH BLIGHT PATHOGEN Rhizoctonia solani Kuhn.
    (Acharya N.G. Ranga Agricultural University, 2017) SANDHYA, YERRAGURAVAGARI; RAJAN, C.P.D.
    The present investigation was carried out to study the effect of agro chemicals and biocontrol agents on the viability of sclerotia of Rhizoctonia solani Kuhn. Rice sheath blight pathogen R. solani was isolated from the diseased samples obtained from Agricultural Research Station, Nellore. Its pathogenicity was proved by using detached leaf technique. The herbicides viz., Glyphosate, 2,4-D Sodium salt, Butachlor, Pretilachlor, Oxadiargyl, Pyrazosulfuron ethyl, Bensulfuron methyl 0.6% + Pretilachlor 6%, Cyhalofop-butyl, Bispyribac sodium and Ethoxy sulfuron were tested at recommended concentrations were significantly superior over control in checking the mycelial growth of R. solani. Glyphosate, Butachlor, Pretilachlor showed 100 per cent inhibition. Among the ten herbicides tested against sclerotial viability, only two, viz., Butachlor and Pretilachlor were found to be effective in inhibiting the sclerotial germination even at lower incubation period of 5 min. both in soil application and in vitro. Glyphosate inhibited sclerotial germination at higher incubation periods i.e., 18 h and 24 h. Rest of the herbicides tested were ineffective in inhibiting the sclerotial germination even though they were effective in inhibiting mycelial growth. xviii Pseudomonas fluorescens isolates NLR-B1, NLR-B2, NLR-B3 were tested in dual culture against R. solani among which NLR-B3 isolate was found to be more antagonistic in vitro against R. solani than other two isolates. Sclerotial germination was tested after incubating in NLR-B3 bacterial suspension in the concentrations from 10-4 to 10-8 CFU/ml, there was no inhibition in sclerotial germination at 10 min incubation at all concentrations of bacterial suspension, where as at 20 min incubation, inhibition of sclerotial germination was 73.33 per cent at 10-4 concentration, 43.33 per cent at 10-5 concentration, 30 per cent at 10-6 concentration and there was no inhibition of sclerotial germination at 10-7 and 10-8 concentrations. At the incubation period of 30 min. inhibition in sclerotial germination was 53.33 per cent at 10-4 concentration, 36.67 per cent at 10-5 concentration, 30 per cent at 10-6 concentration. Similar inhibition of 13.33 per cent was observed both at 10-7 and at 10-8 concentration. Per cent inhibition increased with increase in concentration of bacterial suspension at 20 and 30 min incubation periods. The bacterial suspensions at the earlier concentrations were added to the soil and incubated for 10 days after which the sclerotia were retrieved and tested for their viability, the inhibition of sclerotial germination was 56.67 per cent at 10-4 concentration, 36.66 per cent at 10-5 concentration and 16.66 per cent at 10-6 concentration. However at lower concentration of 10 -7 and 10-8 there was no inhibition of sclerotial germination. There was a significant increase in per cent inhibition of sclerotial germination with increase in concentration of the bacterial suspension. The efficacy of seed treatment with different fungicides viz., Carbendazim, Propiconazole, Hexaconazole, validamycin, Tebuconazole, Thifluzamide, Azoxysrtrobin, Difenoconazole, Tebuconazole 50% + Trifloxystrobin 25% (Nativo) on the viability of sclerotia admixtured with the seed was tested, in which all the tested fungicides showed 100 per cent inhibition of sclerotial germination in both wet and dry seed treatments. The seed admixtured with sclerotia was treated with different fungicides given above, and the effect of sclerotia on germination and seedling growth was tested by paper towel and pot culture methods. All the seed was germinated in both paper towel and pot culture methods. The efficacy of fungicides on seedling growth varied in both wet and dry seed treatments. All the tested fungicides showed increased seedling growth (root length and shoot length) except Carbendazim and Tebuconazole 50% + Trifloxystrobin 25% (Nativo) when compared to control in both paper towel and pot culture methods. xix Effect of Trichoderma silver nano particles on mycelial growth of R. solani at three different concentrations i.e., 75, 100 and 125 ppm were tested. Among the three concentrations, the highest inhibition (88.19 %) was observed at 125 ppm followed by 100 ppm (52.93 %). The effect of Trichoderma silver nano particles were also tested on sclerotial viability of R. solani in vitro. Among the four tested concentrations (50, 75, 100 and 125 ppm) the highest per cent inhibition was observed at 125 ppm (85 %) followed by 100 ppm (47.50 %)
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    ThesisItemOpen Access
    EFFICACY OF COMBINED BIOFORMULATION OF Pseudomonas fluorescens AND Trichoderma spp. IN THE MANAGEMENT OF DRY ROOT ROT AND STEM ROT OF GROUNDNUT
    (Acharya N.G. Ranga Agricultural University, 2017) MAHENDRA, M; REDDI KUMAR, M
    In the present investigation, six native rhizosphere isolates of Trichoderma spp. and five native rhizosphere isolates of P. fluorescens were isolated, screened for their biocontrol potential against M. phaseolina and S. rolfsii incitants of dry root rot and stem rot of groundnut, respectively under in vitro condition. The potential isolates were formulated in solid and liquid carrier materials and assessed for their viability periodically at 30, 60 and 90 days after storage at 4oC and at room temperature (30oC), the potential isolates were further assessed in vivo in pot culture against groundnut dry root rot and stem rot respectively. The groundnut dry root rot pathogen was isolated from the infected plants showing typical symptoms viz., withering and drying of plants, presence of dark tap root, shredding of bark coming out in the form of flakes and devoid of lateral and finer roots, purified by single hyphal tip method and identified as M. phaseolina. The groundnut stem rot pathogen was isolated from the infected plants showing typical symptoms such as drying of leaves and wilting of either individual branches (or) the whole plant and presence of whitish mycelium on soil surface near stem. When such infected plants were pulled out showed profuse whitish mycelium along with sclerotial bodies on stems and roots at collar region. The pathogen was purified by single hyphal tip method and identified as S. rolfsii. Cultural and morphological variability studies among four isolates of M. phaseolina revealed that, the isolates SgMp and TpMp were categorized as fast growing isolates among all isolates, the isolate SmMp produced bigger size xvii (94.30 µm) microsclerotia when compared to other isolates. The isolate SmMp produced blackish mycelium while others produced greyish mycelium. Cultural and morphological variability studies among four isolates of S. rolfsii revealed that, the isolates DmSr and SgSr were categorized as fast growing isolates, the isolate SgSr produced maximum number (186) of sclerotia per Petri plate after ten d of incubation with bigger sclerotia measuring 0.90 mm diam compared to other isolates. The isolate TpSr produced highly fluffy mycelium while others produced partially fluffy mycelium. Based on morphological features, the six rhizosphere Trichoderma isolates were identified as T. harzianum (designated as GRT1, GRT3, GRT4 and GRT6) and T. viride (designated as GRT2 and GRT5). The five P. fluorescens isolates obtained on fluorescent Pseudomonas selective medium were designated as PF1 to PF5. Based on radial growth on PDA, Trichoderma Iiolates GRT1, GRT2 and GRT6 were considered as fast growing isolates while, GRT4 and GRT5 as medium growing isolates and GRT3 as slow growing isolate. Among six Trichoderma isolates tested against each four isolates of M. phaseolina and S. rolfsii, the isolates GRT1, GRT2, GRT4 and GRT5 were found effective in inhibiting the growth of both the pathogens in vitro. Among five P. fluorescens isolates tested against each four isolates of M. phaseolina and S. rolfsii, the isolates PF3 and PF4 were found effective in inhibiting the growth of both the pathogens in vitro. Results from the compatibility studies between potential Trichoderma and P. fluorescens isolates revealed that, the Trichoderma isolate GRT4 (T. harzianum) and P. fluorescens isolate PF4 were highly compatible with minimum per cent inhibition (21.48%) compared with other combinations, used for developing formulations. Results from the shelf life studies of Trichoderma formulations revealed that, talc based formulations maintained higher inoculum density even after 90 d of storage both at room temperature (30oC) and at 4oC when compared to other formulations. Results from the shelf life studies of P. fluorescens formulations revealed that, talc, glycerol based formulations maintained higher inoculum density even after 90 d of storage both at room temperature (30oC) and at 4oC, respectively when compared to other formulations Pot culture studies revealed that among the twelve treatments imposed in managing groundnut dry root rot and stem rot diseases, treatment T10 i.e. seed treatment with P. fluorescens @ 10 g + Trichoderma spp. @ 8 g kg-1 of seed along with soil treatment with combined bioformulation @ 2 L + 80 kg of FYM + 5 kg of neem cake acre-1 was found to be superior as it recorded the highest germination percentage, highest initial, highest final population of groundnut, least PDI, maximum shoot, root lengths and maximum fresh and dry weights
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    ThesisItemOpen Access
    CHARACTERIZATION AND MANAGEMENT OF Alternaria sesami (KAWAMURA) MOHANTY AND BEHARA ON Sesamum indicum L.
    (Acharya N.G. Ranga Agricultural University, 2017) JYOTHSNA, VULIMIRI; PRASANNA KUMARI, V
    The present study on the characterization and management of Alternaria sesami on Sesamum indicum was taken up at the Agricultural College, Bapatla during 2016-2017. Alternaria leaf spot was mainly observed on the leaves in the form of minute brown spots that were round to irregular with concentric rings measuring up to one centimeter diameter. Disease prevalence and severity was less in young and vigorously growing plants, whereas in old and senescing plants it was more. Among Elamanchili and Nakkapalli mandals of Visakhapatnam district surveyed for Alternaria leaf spot occurrence, Elamanchili mandal was found with low disease severity that ranged from 9.57 to 15.62 % while in Nakkapalli mandal it varied between 22.07 and 60.80% with highest mean severity of 42.04 %. Alternaria sesami isolates when cultured on potato dextrose agar were mostly in hues of grayish brown colour with fluffy centre. Radial growth among isolates after seven days of incubation varied from 4.08 to 5.28 cm, while sporulation varied between 5.33 x 104 and 71.67 x 104 ml-1 . Conidial dimensions of 12 isolates varied from 24.88-34.64 X 9.61-12.13 µm with beak length of 5.12-8.32 µm. Number of horizontal and vertical septa varied from 2.76 to 3.82 and 1.31 to 1.76 respectively. EC of the halo primed solution was significantly high compared to other solutions used for priming (70.13 µS cm-1 ). An increase in EC was observed after hydro (from 0.02 to 0.20 µS cm-1 ) and bio priming (from 0.12 to 0.41 µS cm-1 ) for 24 h. Significantly high per cent germination was observed when hydro primed for 24 h (85.55 %) followed by hydro priming for 12 h (80.00 %) and 6 h hydro priming (73.33 %) and control (72.22 %). The highest per cent increase of 45.29 % over normal practice (mancozeb @ 0.25 % incubated for 6 h) was recorded when hydro primed for 24 h. There was no significant difference in mean germination time (MGT) of sesame seed in any of the treatments after 24 h of incubation. After two days of incubation, minimum MGT was observed in the six hour bio primed and 24 hour hydro primed treatment (3.03 days). Minimum MGT was in 6 h bio primed seed (9 days) while it was maximum in 24 h halo primed seed (9.53 days) after three days of incubation. Seedling vigour index was significantly high when hydro primed for 24 h (217.00) and least when bio primed for 12 h (62.54). Increase in seedling vigour index (108.77 %) was noticed over normal practice i.e., seed treatment with mancozeb @ 0.25 % for 6 h. In Alternaria leaf spot disease management, fungicidal treatment involving two sprays of propiconazole @ 0.1 % was found with significantly lowest PDI (53.89 %) with highest yield (463 kg ha-1 ). However, among the botanicals, neem leaf extract @ 5 % sprayed twice was effective in reducing the disease (PDI of 65.00 %) with an yield of 441 kg ha-1 next to propiconazole and chlorothalonil @ 0.2 % was on a par with chemical fungicide mancozeb @ 0.25 % sprayed twice. In yield economics, the highest net returns were registered in propiconazole treatment (Rs. 22,161 ha-1 ) that was followed by neem leaf extract treatment (Rs. 20,445 ha-1 ). Similarly, the highest benefit: cost ratio of 1.59 was obtained in propiconazole used treatment and was followed by neem leaf extract treatment (1.54).
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    ThesisItemOpen Access
    STUDIES ON EARLY AND LATE LEAF SPOT DISEASES OF GROUNDNUT (Arachis hypogaea L.)
    (Acharya N.G. Ranga Agricultural University, 2017) LALITHA, DULLA; MANOJ KUMAR, V
    Groundnut, Arachis hypogaea (L.), is an important oilseed crop and is the primary source of vegetable oil in India. It is popularly known as peanut. It is also called wondernut, earthnut and monkey nut. It is native to South America from where it spread throughout the world. It was introduced to India around 16th century by the Portuguese. (Hegde, 2005) Groundnut seed has high protein (25-28%), which is of high biological value and oil content (43-55%) (Naeem-Ud-Din et al., 2009). It contains more protein than meat and about two and half times more than in eggs, and far more than any other vegetable food except yeast (Thakur et al., 2013). Groundnut is one of the world`s most popular and universal crop, cultivated in more than 100 countries on six continents. China and India are the largest producers of groundnut. Groundnut is the largest source of edible oil in India and constitutes roughly about 50% of the total oilseeds production. Among the major groundnut growing states of India, there has been consistent increase in area under cultivation in Andhra Pradesh, Tamil Nadu, and Karnataka. (Shinde et al., 2010). In India the crop is cultivated in kharif and rabi with an area of 5.27 M ha with a production of 9.72 M t and productivity of 1750 kg ha-1 during 2013-2014 (Department of Agriculture and Cooperation, Ministry of Agriculture, Government of India, 2014). In A. P., during 2015-16 groundnut occupied an area of 0.09 M ha with a production of 0.20 M t and productivity of 2214 kg ha-1 (Agriculture Action Plan, 2015-16).
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    ThesisItemOpen Access
    STUDIES ON THE MANAGEMENT OF FUNGAL FOLIAR DISEASES OF BLACKGRAM [VIGNA MUNGO (L.) HEPPER] IN GUNTUR DISTRICT OF ANDHRA PRADESH
    (Acharya N.G. Ranga Agricultural University, 2017) GUNASRI, REDDI; MANOJ KUMAR, V
    Investigations on “Studies on the management of fungal foliar diseases of blackgram [Vigna mungo (L.) Hepper] in Guntur district of Andhra Pradesh” was carried out in the Agricultural College Farm, Bapatla, Guntur district, Andhra Pradesh during rabi, 2016-17. A survey was conducted during rabi, 2016-17 in Guntur district of Andhra Pradesh to record the occurrence and severity of fungal foliar diseases at 30-35, 40-45 and 50-55 DAS. Two mandals were selected based on the preceding year blackgram cultivation statistics, in each mandal two villages and in each village two fields were surveyed. There was no record of any fungal foliar disease at 30-35 DAS. At 45-50 DAS, overall mean PDI of Corynespora leaf spot (Corynespora cassiicola) PDI was 31.89% and at 50-55 DAS it was 67.27%. The overall mean PDI of Cercospora leaf spot (Cercospora canescens) at 40-45 DAS was 28.88% and at 50-55 DAS it was 53.70%. The overall mean PDI of powdery mildew (Erysiphe polygoni) at 40-45 DAS was 22.85% and 63.22% at 50-55 DAS. During rabi, 2016-17, Corynespora leaf spot PDI of six genotypes viz., LBG 752 (r= -0.635), LBG 709 (r=-0.656), KU-15-6 (r= -0.637), LBG 20 (r= -0.640), LBG 791 (r= -0. 648) and LBG 685 (r= -0.654) showed a significant negative correlation with mean minimum temperature. Cercospora leaf spot PDI of three genotypes viz., LBG 752 (r= -0.642), LBG 709 (r=-0.660) and T9 (r= -0.636) showed a significant negative correlation with mean minimum temperature. Powdery mildew PDI of six genotyes LBG 752 (r= -0.654), KU-15-3 (r=-0.655), LBG 709 (r=-0.664), KU-15-6 (r= -0.678), LBG 791 (r= -0.650) and PU 31 (r= -0.633) showed significant negative correlation with minimum temperature. Regression analysis for PDI of Corynespora leaf spot, Cercospora leaf spot and powdery mildew revealed that maximum temperature and minimum temperature influenced the development of the disease in all the genotypes. Out of 16 genotypes (including check) evaluated for their reaction to fungal foliar diseases, two genotypes T9 and LBG 645 were moderately resistant to Corynespora leaf spot. The genotype LBG 645 was rated as moderately resistant to Cercospora leaf spot. Ten genotypes viz., LBG 20, LBG 791, LBG 685, LBG 645, LBG 787, PU31, LBG 790, KU-15-13, LBG 792 and T9 were categorized as moderately resistant to powdery mildew. Studies on the management of fugal foliar diseases with fungicides have revealed that two sprays of Azoxystrobin 23 SC @ 0.05% has recorded significantly lowest severity of Corynespora leaf spot (53.52%). Carbendazim 50 WP @ 0.05% has significantly reduced the Cercospora leaf spot severity (33.75%). Trifloxystrobin 25% WG + Tebuconazole 50% WG @ 0.05% has absolutely controlled (0%) the powdery mildew. Highest seed yield (9.33 q ha-1 ), highest test weight (6.40 g), highest B:C ratio (1.72), lowest per cent seed discolouration and per cent shrivelled seed were recorded with Azoxystrobin 23 SC @ 0.05%.
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    ThesisItemOpen Access
    EPIDEMIOLOGY AND MANAGEMENT OF ALTERNARIA LEAF SPOT IN COTTON
    (Acharya N.G. Ranga Agricultural University, 2017) MOHAN VENKATA SIVAPRASAD, BANDI; SREE LAKSHMI, B
    Alternaria leaf spot/blight of cotton caused by Alternaria macrospora Zimmermann is the most commonly occurring disease in Andhra Pradesh. A. macrospora is found to be an aggressive pathogen which can attack all crop growth stages starting from seedling stage to harvesting manifesting in seed rot, damping off, seedling blight, mummification of bolls etc. Under severe conditions it causes severe defoliation, cracking, breaking of stems and reduction in boll formation. Epidemiological studies indicated that irrespective of different dates of sowing, Alternaria leaf spot occurred at its first peak intensities (17.5%, 18.25% and 18.33%) in 44th meteorological week (Oct 29-Nov 4) and its second maximum intensities (39.25%, 33% and 33.5%) in 1 st standard meteorological week (Jan1- Jan7). Among the weather parameters sunshine significantly influenced the disease progress in susceptible Jadoo BG II hybrid. Fungicides viz., mancozeb, carbendazim, hexaconazole, propiconazole and carbendazim 12% + mancozeb 63%; botanicals viz., neem leaf, garlic clove extracts and biocontrol agents T. harzianum strain 1, P. fluorescens strain 1 and B. subtilis significantly inhibited the growth of A. macrospora in vitro. Interactions with all the Trichoderma strains in dual culture revealed lysis of A. macrospora with evidence of protoplast aggregation, wrinkling of mycelium and germination of Trichoderma conidia on Alternaria mycelia. Field evaluation of seed treatment and foliar spray of selected fungicides, botanicals and biocontrol agents against Alternaria leaf spot of cotton showed that ST with carboxin + thiram (vitavax power) at 2 g kg-1 of seed and 0.1% carbendazim + mancozeb sprays, three times, at 15 days interval recorded the lowest per cent disease index (6.8), the highest yield (1571.4 kg ha-1 ) and the highest benefit cost ratio (1.61) compared to per cent disease index (35), yield (1013 kg ha-1 ) and benefit cost ratio (0.69) in control.
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    ThesisItemOpen Access
    STUDIES ON THE MANAGEMENT OF FUNGAL FOLIAR DISEASES OF GROUNDNUT IN GUNTUR DISTRICT OF ANDHRA PRADESH
    (Acharya N.G. Ranga Agricultural University, 2017) BHAVANI, BASAVALA; MANOJ KUMAR, V
    Investigations on “Studies on the management of fungal foliar diseases of groundnut in Guntur district of Andhra Pradesh” was carried out in the Agricultural College Farm, Bapatla, Guntur district, Andhra Pradesh during late kharif 2016-17. A survey was conducted during rabi 2016-17 in Guntur district of Andhra Pradesh. Fungal foliar disease severities were recorded in the surveyed villages of Karlapalem and Pittalavanipalem mandals of Guntur district at 30-35 and 55-60 DAS. Mean ELS PDI of Guntur district at 30-35 DAS was 12.86 %. Mean LLS PDI of Guntur district was 12.87 % at 30-35 DAS and 30.73 % at 55-60 DAS. During late kharif 2016-17, ELS PDI of K-6 and Vemana showed significant positive correlation with mean minimum temperature (r = 0.556* and r = 0.604* respectively). Regression analyses for PDI of ELS and weather factors revealed that maximum temperature and minimum temperature have influenced the development of ELS on the genotypes RSB-87, Vemana, JCG-88, AVT-1666, AVT-1638 where as maximum temperature, minimum temperature and morning relative humidity influenced disease development on GG-2, Kisan, ALR-3, K-9, Abhaya, Narayani, ALR-1, Anantha and K-6. Late leaf spot PDI of K-6 showed significant positive correlation with sunshine h (r = 0.592*) and negative correlation with minimum temperature (r = -0.819*), rainfall (r = -0.568*) and all other tested genotypes showed significant negative correlation with mean minimum temperature. Rust PDI on all the test genotypes showed significant negative correlation with mean minimum temperature. Regression analyses with PDI of LLS and rust with weather factors revealed that maximum temperature and minimum temperature influenced the development of LLS and rust severity in all the genotypes. Out of 14 genotypes (including check) evaluated for their resistance to fungal foliar diseases, RSB-87, Kisan, Vemana, GG-2, K-9, AVT-1638, Abhaya, Anantha, JCG-88, AVT-1666, ALR-1 and ALR-3 were moderately resistant and other two genotypes (K-6 and Narayani) were susceptible to LLS. The genotypes JCG-88, AVT 1666 and AVT-1638 were resistant, nine genotypes viz., RSB-87, Kisan, Vemana, GG-2, ALR-3, K-9, Abhaya, ALR-1, Anantha were moderately resistant. K-6 (check) and Narayani were susceptible to rust. Studies on management of fungal foliar diseases with fungicides have revealed that three sprays of tebuconazole + trifloxystrobin 75 WG (50 %+ 25 % w/w) @ 0.09 % at the occurrence and at two weeks interval recorded the lowest severity of ELS (25.56 %), LLS (32.42 %) and rust (18.56 %) and improved dry pod weight, number of pods per plant and was the most economical.
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    ThesisItemOpen Access
    PHYLOGENETIC VARIATION AND FUNGICIDAL MANAGEMENT OF CERCOSPORA ABELMOSCHI ELL. AND EV. INFECTING OKRA
    (Acharya N.G. Ranga Agricultural University, 2017) AMULYA, G; PRASANNA KUMARI, V
    The present study on phylogenetic variation and fungicidal management of Cercospora abelmoschi Ell. and Ev. infecting okra was taken up in the Agricultural College, Bapatla during 2016-2017. Cercospora leaf spot was mainly observed on the lower surface of leaves in the form of sooty to dark olivaceous colour, indistinct or none, fruiting effuse, forming angular vein limited areas in dense patches of conidiophores and conidia. Cercospora infected leaves were collected during kharif 2016 from eight different okra growing villages in Guntur district, Andhra Pradesh which were used for in planta isolation of fungal DNA using universal primers ITS 1 and ITS 4. The 550 bp amplicon thus obtained was restricted with hexa cutters, EcoRI, BamHI and tetra cutter Taq1 to find variability among Cercospora isolates. EcoRI found two restriction sites in all isolates except the Yazali isolate while BamHI found single restriction site in all the isolates with length polymorphism in Yazali isolate. Taq1 restriction indicated a high degree of genetic diversity among the isolates and was represented by three different banding patterns while in three isolates there was no restriction sites. Dendrogram constructed from similarity coefficients showed that Yazali isolate seperated into a group upon digestion with EcoRI and BamHI. Taq1 digestion of Yazali isolate clustered with Thimmareddipalem isolate. The results revealed that, polymorphism existed among the Cercospora isolates collected from Guntur district. The changes in single nucleotide resulted in variation in restriction sites for the different restriction enzymes used. Among all the tested fungicides, trifloxystrobin + tebuconazole @ 0.1% showed significant reduction of the disease on both lower leaves (35.61%) and upper leaves (12.98%), leading to the significant increase in yield (101.75 q ha-1 ). However, highest benefit cost ratio was recorded with propiconazole @ 0.1% (3.62). Phenol content in lower leaves(1.58 mg g-1 ) and upper leaves (1.52 mg g-1 ), total protein content in lower (9.32 mg g-1 ) and upper leaves (9.23 mg g-1 ) were significantly higher in trifloxystrobin + tebuconazole @ 0.1% applied plants. Total sugar content in lower (12.33 mg g-1 ) and upper leaves (10.08 mg g-1 ) were low in trifloxystrobin + tebuconazole @ 0.1% treatment. The reduction in Chlorophyll a and chlorophyll b was observed to be lowest in lower leaf (1.15 and 1.06 mg g-1 respectively) and upper leaf (1.28 and 1.02 mg g-1 respectively) in trifloxystrobin + tebuconazole @ 0.1% sprayed plants. The reduction in the total chlorophyll content was relatively less in trifloxystrobin + tebuconazole @ 0.1% as compared to other treatments due to reduced disease intensity and thus maintaining greenness of the leaves. Significant negative correlation existed between disease severity and total phenols (-0.903), total proteins (-0.903), chlorophyll a (-0.901), chlorophyll b (-0.788), total chlorophyll (-0.856) while significant positive correlation existed between total sugars and disease severity (0.932). Significantly high positive correlation existed between proteins and phenols (0.862), total chlorophyll (0.889), chlorophyll a (0.844), chlorophyll b (0.868). Similarly, significant high positive correlation existed between phenols and total chlorophyll (0.854), chlorophyll a (0.803), chlorophyll b (0.839). Significantly high negative correlation between total sugars and phenols (-0.924), proteins (-0.836), chlorophyll a (-0.919), chlorophyll b (-0.838), total chlorophyll (-0.897) existed.
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