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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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ThesisItem Open Access STUDIES ON THE INTEGRATION OF CHEMICAL AND BIOLOGICAL METHODS FOR THE MANAGEMENT OF RICE STEM ROT DISEASE CAUSED BY Sclerotium oryzae Catt.(Acharya N.G. Ranga Agricultural University, 2018) RANGA RANI, ATLA; RAJAN, C.P.D.Stem rot of rice, caused by Sclerotia oryzae Catt. is a serious threat to rice production in India. Fungicides provide control of this pathogen but also have ill effects on the environment. In an attempt to develop better integrated strategies using fungicides and bacterial bio agents for management of stem rot disease, a total of eight isolates from different localities of Nellore district were isolated. The isolates of S. oryzae were designated as SO 1, SO 2, SO 3, SO 4, SO 5, SO 6 SO 7 and SO 8. Variability among these isolates of S. oryzae based on growth rate on PDA and also in utilizing various carbon sources was assessed using four different growth media. Depending on the growth rate on PDA medium, these isolates of S. oryzae could be categorised into four groups. Group 1 had the very fast growing isolate SO 3. Group 2 comprised of four isolates SO 1, SO 4, SO 6 and SO 7 which were fast growing. Group 3 consisted of the medium growing isolates i.e. SO 2, SO 8. Group 4 consisted of isolate SO 5 is very slow growing. Among the growth media tested, PDA was best supported for growth of all isolates and there was no growth of all the isolates of S. oryzae grown on CDA. Among the eight isolates, isolate SO 3 which was fast growing with abundant sclerotial production was selected for further studies. A total of thirteen antagonistic bacteria were isolated from rhizosphere soil of rice. Highest inhibition was recorded in case of RRB-2 (74.07%) followed by xiii RRB-4 with 70.73% inhibition, RRB-1 with 65.92% inhibition and RRB-3 with 62.22% inhibition. Least inhibition was observed with RRB-12 (31.84%) and with RRB-13 (33.31%). Four of these effective bacterial antagonists were used for further studies. Thirteen plant extracts, five plant essential oils and five natural preparation were tested for their bio efficacy against S. oryzae at different concentrations. The extract (powdered seeds) of Brassica juncea was found to be the most effective in inhibiting the growth of S. oryzae (100%) at 20 and 25% concentrations followed by rhizome extract of Curcuma longa (84.81) at 20% concentration, bulb extract of Allium sativum (84.44) at 2.0% concentration, leaf extract of Eucalyptus glubulus (76.29%). The bulb extract of Allium cepa recorded the least mean inhibition (4.40%) of S. oryzae at 5%. Out of the five essential oils, lemon grass oil showed 100 % inhibition of the test fungus at all tested concentrations. Spearmint oil at 1%, 1.5% and 2% concentrations and eucalyptus oil at 2% and 3% concentrations recorded 100% inhibition in the growth of S. oryzae. The mustard oil at 0.5% concentration recorded least inhibition (7.77%) followed by neem oil at 0.5% concentration with 19.25% inhibition in the growth of S. oryzae. Among the natural preparations, neemasthra was found to be the most effective in inhibiting the growth of S. oryzae (55.56%) followed by brahmasthra (49.66%), agniasthra (36.66%) and jeevamrutham (35.56). The neem seed kernel recorded the least mean inhibition (2.23%) of S. oryzae at 5000 ppm. Among the fifteen fungicides tested, Carbendazim, Propiconazole, Hexaconazole, Difenoconazole, Tebuconazole, Trifloxystrobin + Tebuconazole, Azoxystrobin, Isoprothiolane, Mancozeb + Carbendazim, Benomyl and Thiophanate-methyl completely (100%) inhibited the growth of S. oryzae at all concentrations in vitro. Thifluzamide (0.04%) recorded least per cent inhibition. Twelve fungicides were tested in vitro for the compatibility with potential biocontrol agents viz., RRB-1, RRB-2, RRB-3 and RRB-4. Isolate RRB-4 was found to be most compatible antagonistic bacteria as it has shown highest compatibility when compared to other isolates. Hexaconazole showed highest compatibility with all the four isolates followed by propiconazole. Effective fungicides and antagonistic bacterial isolates in in vitro studies were evaluated under field conditions. Results of pooled analysis of Rabi 2016-17 and early Kharif 2017-18 revealed that, among the fungicides, treatment Hexaconazole recorded lowest PDI. While among the bacterial antagonists, treatment Root dipping with RRB-4 + foliar spray showed less PDI after second spray. Hence, these two treatments were selected for further field trial during Rabi 2017-18 to evaluate the strategies involving the integration of effective fungicide and bacterial antagonist for the management of rice stem rot disease. Pooled analysis of the yield data revealed that the highest grain yield was recorded in Hexaconazole treatment (7.43 t/ha) followed by Difenoconazole (7.29 t/ha), Tebuconazole (7.19 t/ha), Root dipping with RRB-4+ foliar spray (6.97 t/ha), Carbendazim (6.91 t/ha) and Mancozeb + Carbendazim (6.89 t/ha). Least grain yield was xiv observed in untreated control (5.22t/ha) followed by Root dipping with RRB-3+ foliar spray (5.74 t/ha) which were statistically at par with each other. In case of straw yield, Hexaconazole treatment (7.22 t/ha) recorded highest straw yield followed by Difenoconazole; 6.88t/ha and Propiconazole; 6.84 t/ha which were statistically at par with each other. Least straw yield was observed in untreated control (5.47 t/ha). During Rabi 2017-18, the evaluation of the strategies of integration of effective fungicide Hexaconazole (0.2%) and the antagonistic isolate RRB-4, results revealed that, among the seven treatments consisting of different strategies, the following strategies were found superior. 1. Alternate sprays with hexaconazole and RRB-4 (40.00 PDI; 7.56 t/ha grain yield and 10.26t/ha straw yield). 2. Seedling dip with RRB-4 and two sprays followed by two sprays with hexaconazole (44.40 PDI, 6.95 t/ha grain yield and 8.53 t/ha straw yield). 3. Two sprays with hexaconazole followed by two sprays with RRB-4 (48.35 PDI, 7.37 t/ha grain yield and 7.73 t/ha straw yield).ThesisItem Open Access CHARACTERIZATION AND MANAGEMENT OF Alternaria porri (Ellis) Cif. CAUSING PURPLE LEAF BLOTCH OF ONION (Allium cepa L.)(Acharya N.G. Ranga Agricultural University, 2018) NAGA LAKSHMI, T; SARADA JAYALAKSHMI DEVI, RPurple leaf blotch caused by Alternaria porri is one of the most destructive diseases of onion causing significant bulb yield losses. Keeping in view the importance of disease, studies were conducted on cultural, morphological, pathological and molecular diversity, in vitro efficacy of fungicides and integrated management of disease at field by using fungicides and bioagents at Horticultural Research Station (HRS), Anantharajupeta. Survey was carried out to understand the disease severity in major onion growing areas i.e YSR Kadapa and Kurnool districts of Andhra Pradesh. Cultural and morphological characters of the native isolate were studied on six different media viz. Carrot agar, Corn meal agar, Czapek’s Dox agar, Host leaf extract agar Potato dextrose agar and Yeast extract agar medium. Out of all the media tested, growth was fast in Czapek Dox medium and slow in corn meal agar medium. Sporulation was best in Host leaf extract agar and potato dextrose agar and less in corn meal agar and Yeast extract agar medium. The pathogen produced septate mycelium. Conidiophores were produced either singly or in small groups. The conidiophores were straight or flexuous some times geniculate, septate, pale or mild brown in colour and measured upto 135μ long and 7-10 μ thick, with one to several conidial scars. xvii Conidia are straight or curved, rostrate, beak generally equal to the length of the body of the conidium pale brown to mild golden brown in colour. Overall length of the conidia ranged from 70-265 μ, 10-21 μ thick in the broadest part with 7-12 transverse and zero to six longitudinal septa, beak flexuous, pale 2-4 μ thick and tapering. A total of 15 Alternaria porri isolates were collected from different locations of Andhra Pradesh, Karnataka and Telangana. Later the isolates were identified and pathogenicity and virulence studies were conducted and found that leaves and the morphological character of the re-isolated organisms confirmed the pathogenicity. Among the isolates, Anantharajupeta (AP-1), Mydukur (AP-3), Gonegandla (AP-4) and Nandikotdur (AP-5) isolates were found highly virulent and potential with highest 41.67 to 56.58 PDI. Cultural and morphological characters of 15 isolates were studied. Conidial length of the isolates ranged from 23-170μ, with an average length of 96.5μ, width from 15-23μ, beak length ranging from 6-29μ and with beak width of 4-9μ. Colour from pale to mild golden brown, horizontal septa ranging from 3-13, with an average of 6-8 between isolates and vertical septa ranging from 0-5, with an average of 2-3 between isolates. Colony growth rate was fast in 8.14 mm in AP-1 and slow in 3.43 mm in KA-2 with an average growth rate of 5.74 mm per day among the fifteen isolates. Molecular characterization was done using 5.8s rDNA specific ITS1 and ITS4 primers. All the 15 isolates of A. porri yielded single PCR amplified product of 560 bp confirming the pathogen identity. Out of 15 isolates, five samples viz., AP-1, AP-4, AP-5, KA-2 and TS1 were sequenced and phylogenic tree was constructed and isolates were divided into two clades. Two groups AP-1 and AP-4; KA-2 and TS-1 were aligned in Clade I and AP-5 alone was grouped in clade II. Genetic diversity studies were carried out to assess the degree of genetic diversity/relatedness among 15 isolates of A. porri. Out of 10 SSR molecular markers used, only four SSR primers i.e., SSR-5 (115 bp) for KA-4, SSR-7 (215 bp) for KA-3, SSR-8 (250 and 340 bp) for AP-2 and SSR-10 (153, 237, 245 and 450 bp) for AP-6, AP-3, AP-6 and AP-4 respectively, produced unique bands. The PIC (Polymorphic Information Content) value ranged between ranged from 1.0 (SSR-1 and SSR 6) to 0.249 (SSR-1 and SSR-4) with an average of 0.826 for all 10 primers among the 15 isolates. In vitro screening of eight fungicides against native pathogen isolate revealed the efficacy of fungicides at varied levels. Hexaconazole was found effective and inhibited cent per cent growth at 1000 and 1500 ppm. Mancozeb was least effective and the mean inhibition per cent was 53.63 among the treatments. The highest toxicity index was observed in hexaconazole xviii (454.85) followed by propiconazole (431.05) on maximum toxicity index of 500. The least toxicity was 268.16 in the treatment of Mancozeb. In vivo evaluation of fungicides revealed that, hexaconazole at 0.1% with 12.50% of PDI and highest CB ratio (2.11) was found significantly superior over other treatments. Increased bulb yield over control and other treatments was observed in hexaconazole. Area under disease progress curve (AUDPC) calculated and yield (t/ha) data were also recorded. The data reveals that in T2 (Hexaconazole 0.2%), lowest AUDPC (399) was observed with highest yield (29.30 t/ha). While in control, highest AUDPC (1008) and lowest yield (9.67 t/ha). Fourteen fungal bioagents viz., Th-1, Tsp-2, Tsp-3, Th-4, Tsp-5, Tkn-6, Th-7, Tlb-8, Trs-9, Th-10, Tsp-11, Tsp-12, Tsp-13 and Tsp-14 comprising of Trichoderma harzianum, , T. koningii, T. reesii and T. longibrachiatum and six bacterial bioagents viz., P. fluorescens-1- Pf- 6 were evaluated against the pathogen and Th4 significantly superior in both in non volatiles (59.97%) and volatiles (57.325%) production over other Trichoderma isolates tested. Evaluation of 28 onion cultivars/ lines under two different agro-climatic conditions i,e., Anantharajupeta and Mahanandi to find the source of resistance, revealed that none of the genotypes was found to be either resistant or immune to the disease . However, the cultivars Bhima Super and Arka Kalyan showed moderately resistant reaction at both the locations. Management studies conducted over two seasons revealed that the integrated strategy with soil application of T.harzianum enriched FYM @ 100 kg/ha + seed treatment with T.harzianum @ 8g/kg of seed + two foliar sprays, one with liquid formulation of T.harzianum @ 5 ml/lt at first appearance of the disease followed by hexaconazole @ 0.2% at fortnightly interval was found significantly effective in reducing the disease intensity by recording a lowest PDI (14.09) with 79.69% disease reduction and yield 29.94 t/ha with 87.81% increased yield over control. This treatment recorded highest (1.99) cost benefit ratio, which was followed by tolerant variety Bhima Super (1.81).ThesisItem Open Access CHARACTERIZATION OF Pyricularia oryzae Cavara, INCITANT OF RICE BLAST AND ITS MANAGEMENT(Acharya N.G. Ranga Agricultural University, 2018) BHASKAR, B; SARADA JAYALAKSHMI DEVI, RThe present investigation was undertaken with an aim to know the variability between leaf blast and neck blast pathogen populations. Studies carried out on the variability of isolates using cultural, morphological, pathological and molecular characteristics. In another study efforts were made to identify the promising lines for both leaf blast and neck blast resistance. Attempts were also made to manage the disease with biocontrol agent P. fluorescens, fungicides and their integration. Survey was conducted in nine major rice growing districts of Andhra Pradesh during 2015-16. The highest mean blast disease incidence 29.05% was recorded in Nellore district. The lowest mean PDI 20.79% was recorded in Srikakulam district. Regarding the mandals, highest mean blast incidence was recorded in Kovvur mandal of Nellore district with 38.99% in a range of 20.45% to 51.14%. The lowest incidence 15.41% with 10.94% to 21.02% range was noticed in Madugula mandal of Visakhapatnam district. The disease incidence was highly varied among the cultivars rather than the locations. The ascending order of the cultivars regarding the mean disease incidence was NDLR-8 (3%) < MTU-3626 (4.46%) < MTU-1121(5.89%) < NLR-34449 (11.09%) < RGL-2537 (12.86%) < MTU-1061 (16.83%) < MTU-1001 (19.74% ) < ADT-37 (23.81%)ThesisItem Open Access STUDIES ON THE MANAGEMENT OF RICE GRAIN DISCOLORATION CAUSED BY FUNGI(Acharya N.G. Ranga Agricultural University, 2018) SURESH RAO, S; REDDI KUMAR, MThe present investigation on “Studies on the management of rice grain discoloration caused by fungi” was carried out in order to assess the prevalence of rice grain discoloration in major rice growing mandals of Nellore and Chittoor district of Andhra Pradesh, and to evaluate efificacy of rice based fungicides plant extracts and natural preparations rice based fungicides, plant extracts and natural preparations in vitro and field conditions for its management. Roving survey conducted during 2017-18 in Chittoor and Nellore districts of Andhra Pradesh revealed that, In Nellore district, incidence of rice grain discoloration was more in Vasili village (36.85 %) of Atmakur mandal and least (20%) was observed in Kovur village of Nellore Rural mandal. While in Chittoor district, the incidence of disease was more in Yerpedu (32.26 %) village of Yerpedu mandal, least in Nagiri village (19.79%) of Nagiri mandal. A total of seven fungal genera using blotter method and twelve fungal genera using agar plate method were isolated. Total 12 fungi viz; Alternaria alternata, Aspergillus flavus, Aspergillus niger, Bipolaris oryzae, Curvularia lunata, Curvularia clavata, Fusarium moniliforme, Fusarium oxysporum, Sarocladium oryzae, Rhizopus stolonifer, Chetomium sp. and Alternaria padwickii. xvii Emphasis being laid to isolate the mycoflora associated, their identification, and cultural and morphological characterization was carried out. Pathogenicity test was conducted using panicle detached method. From the results, it was evident that the panicle dipped in F. moniliforme spore suspension showed significantly higher disease incidence (26.27 %) followed by C. lunata (21.80 %). Lowest disease incidence was observed with A. padwickii (10.34%). Based on the results F. moniliforme and C. lunata were selected as predominant and effective pathogens and used for further studies. To evaluate the bio-efficacy of rice based fungicides, Plant extracts and Natural compounds against predominantly occurred pathogens viz; F. moniliforme and C. lunata in vitro, poisoned food technique was used. Among the six fungicides tested against F. moniliforme and C. lunata, Trifloxystrobin (25%) + Tebuconazole (50%) WG and Tebuconazole proved to be highly effective in inhibiting the mycelial growth compared with other fungicides and control. Hence, these two fungicides were selected for further field studies. Among the six plant extracts tested against F. moniliforme and C. lunata, garlic extract exhibited higher antifungal activity even at low concentrations followed by neem extract. Hence, these two plant extracts were considered as effective and used for further field studies. However, among all the natural preparations tested against F. moniliforme and C. lunata, Jeevamrutha proved to be highly effective in inhibiting the mycelial growth followed by Modified panchagavya. Hence these two natural products were selected for further field studies. Bio-efficacy of effective fungicides, plant extracts and natural preparations were tested under field conditions during Rabi 2017-18. The experimental plot was laid at Agricultural Research Station, Nellore. During flowering stage i.e., 60 DAS first spray was conducted. Number of panicles pe hill, number of normal grains per panicle and number of discoloured grains per panicle were measured after imposing treatments. Least per cent disease incidence was recorded with treatment T1-nativo @ 0.4gm/lt (5.51 %) followed by T2-Tebuconazole @ 0.5 ml/lt (7.45 %). Among plant extracts T3- Garlic extract @ 3 per cent (7.58 %) was found effective followed by T4- Neem leaf extract @ 20 per cent (8.34 %). While among natural preparations, T5– Modified panchagavya @ 4 per cent and T6- Jeevamrutham @ 3 per cent had shown equal effect (9.11 %). There is significant difference between treatments and at par each other. Similarly, lowest number of discoloured grains was recorded with treatment T1 (8 grains/panicle) followed by treatment T2 and T3 (10 grains/panicle). xviii Second spray was initiated after fortnight interval by imposing the same treatments as done in the first spray. Data on Per cent disease incidence (PDI), Number of of discoloured grains per panicle and yield related parameters viz; Panicle weight, Grain yield, Straw yield and Test weight of normal grains were recorded. Among all the treatments tested, least per cent disease incidence was observed in treatment T1 (5.03 %) followed by T2 (5.78 %), T3 (6.53 %) and highest disease incidence was observed with control T7 (10.40 %) and there is significant difference between treatments and at par with each other. Similarly, lowest number of discoloured grains were recorded with treatment T1 (7.0) and highest with control (T7) (10.40 %). Higher panicle weight (2.96 g), grain yield per 5 m2 plot (3.23 kg), straw yield (1.81 kg) and test weight of normal grains was highest (17.13 g) was recorded in treatment (T1) over control. To know the effect of effective fungicides, botanicals and natural preparations on germination percentage (%), shoot length (cm), root length (cm), shoot: root ratio and vigour index of rice seedlings, blotter method was followed. Maximum germination percentage (96.67 %) and shoot length (8.78 cm) was recorded in Treatment (T1), maximum root length (14.10 cm) and shoot root ratio was observed with treatments T2 and T4 respectively over controlThesisItem Open Access ASSESSMENT OF THE ROLE OF SOIL MOISTURE AND TEMPERATURE IN CAUSING DRY ROOT ROT BY Rhizoctonia bataticola (Taub.) Butler IN PIGEONPEA (Cajanus cajan (L) Millsp.)(Acharya N.G. Ranga Agricultural University, 2018) SHARATH CHANDRAN, U.S.; VEMANA, KPigeonpea cultivation is subjected to high yield losses every year. Dry root rot or Macrophomina stem canker caused by Rhizoctonia bataticola (Taub.) Butler [synonym- Macrophomina phaseolina (Tassi) Goidanich] of pigeonpea is an emerging and serious problem in late sown or summer crops and in perennial or ratooned pigeonpea. A very little work has been done on dry root rot pathogen in pigeonpea crop. Keeping in mind the importance of this emerging disease with respect to changing climate, the present study involving cultural, morphological and pathological variability among the isolates, effect of temperature, moisture and pH on the growth and development of the pathogen and various biochemical alterations occurring with respect to disease development in pigeonpea was studied. All the investigations were conducted under laboratory and glasshouse during 2016-17 at Legumes Pathology Division, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad. Cultures of the R. bataticola of pigeonpea was procured from the Legumes Pathology division, ICRISAT. The isolates were sub-cultured, molecular characterized and serially designated as Rb1 to Rb10. Pathogenicity test against pigeonpea variety Bahar using paper towel technique as employed to find out the virulent isolates. Maximum disease severity rating of 8 was observed in Rb 6 inoculated plants followed by 7.3 in Rb 1 and Rb 4 inoculated plants. xiii Influence of different media, temperature and pH were tested on the growth of R. bataticola isolates. Carrot agar and PDA was found to support maximum colony growth of all the isolates. The optimum temperature for growth was found to be 35°C at par with 30°C. At 45°C no growth was observed even after 72 HAI. The optimum pH range for growth was found to be 5-7, where the maximum colony growth of 90.00 mm was attained at 48 HAI. At pH 3 and 9 the growth was drastically reduced. Cultural and morphological variability existed among the isolates tested. The radial growth at 48 HAI ranged from 71.17 mm (Rb 6) to 50.67 mm (Rb 2). The colony colour varied from black to grey except for Rb 1 producing off white colonies. In soybean and mungbean isolates, the colony colour was brown. The colony texture was fluffy to partially fluffy and aerial mycelium was observed in all the isolates. The shape of the sclerotia varied from round to oblong. The colour of sclerotia was recorded to be black in all cases except for soybean and mungbean isolates which were brown. The sclerotial texture varied from smooth to rough. The average length and width of sclerotia varied from 9.97 and 9.71 (Rb 1) to 5.50 and 3.60 (Rb 5). The average sclerotial intensity varied from 15.60 (Rb 5) to 76.15 (Rb 9) The average sclerotial initiation days varied from 2 to 3 days with the exception of Rb 1 showing the maximum of 4.67 days. Temperature and soil moisture plays an important role in the infection and disease development by the pathogen in susceptible genotypes. Disease severity was observed to increase in plants with the increase in temperatures up to 35°C, above which physiological wilting was observed. In case of different soil moisture regimes, R. bataticola inoculated plants grown at 60% SMC showed maximum reduction in dry weight and thereby disease severity. Progressively the disease severity was observed to decreases with increase in SMC. A wide range of alterations in the biochemical factors within the plants were activated in response to pathogenic infection. The total sugars was observed to reduce with progressive time points of inoculation, whereas phenols and plant defence enzymes like PO, PPO and PAL was observed to increase due to infection. In case of dry root rot, the disease expression and biochemical activity was higher in plants maintained at 60% SMC as compared to those from 100% SMC. It is concluded that the climatic factors such as temperature and soil moisture has a direct influence over the growth and disease development by the pathogen R. bataticola. Thus in the advent of climate change, dry root rot of pigeonpea could gain the status of a severe disease of pigeonpea.ThesisItem Open Access STUDIES ON THE MANAGEMENT OF POD ROT DISEASE OF GROUNDNUT(Acharya N.G. Ranga Agricultural University, 2018) RAMANJINEYULU, P; VISWANATH, KGroundnut (Arachis hypogaea L.) is the fourth important source of edible oil and third most source of vegetable protein. It is susceptible to losses incited by soil borne pathogens due to the close association of the pods with the soil. Among soil borne diseases of groundnut, pod rot is a complex disease and emerging as a serious disease in different agro-climatic zones of Andhra Pradesh due to change in soil moisture, pH, soil temperature and crop sequence facilitating rapid multiplication of different micro-flora in crop rhizosphere. In the survey on the pod rot incidence in groundnut, the mean pod rot disease incidence in Chittoor district varied from 11.4 to 28.6 per cent while in the Anantapur district, the mean pod rot incidence varied from 8.5 to 30.0 per cent. In the Chittoor district, from the 34 pod rot affected samples collected from the seven mandals, nine isolates of Fusarium spp., five isolates of Rhizoctonia bataticola and seven isolates of Sclerotium rolfsii. Similarly from the Anantapur district, one isolate of Fusarium spp., five isolates of R. bataticola and three isolates of S. rolfsii were isolated from 12 samples. A total of four Trichoderma isolates and four bacterial isolates were isolated from the rhizosphere soil samples. In the evaluation of the efficacy of four isolates of Trichoderma spp, against all the isolates of Fusarium spp, R. bataticola, S. rolfsii, the highest inhibition of 35.8, 67.7 and 57.2 per cent was recorded on TF2, TRb5, TSr5 isolates respectively. Similarly with four isolates of rhizospheric bacteria against all the isolates of Fusarium spp., R. bataticola, S. rolfsii the highest inhibition of 56.6, 64.4, and 69.1 per cent was recorded on TF3, TRb10, TSr2 isolates respectively. Based on the dual culture study results, the potential isolate of Trichoderma sp. (TT4) and TB3 isolate of rhizospheric bacteria along with pathogen isolates which exhibited the lowest mean per cent inhibition viz., TF1 of Fusarium sp., TRb8 of R. bataticola and TSr6 of S. rolfsii were selected for the in vitro as well as in vivo studies. Among the fungicides tested against TF1 isolate of Fusarium sp.; TRb8 isolate of R. bataticola and TSr6 isolate of S. rolfsii, tebuconazole and tebuconazole + trifloxystrobin has shown cent per cent inhibition at all the three concentrations. The effective fungicide tebuconazole, potential isolates of Trichoderma sp (TT4) and rhizospheric bacteria (TB3) identified under in vitro studies were evaluated under in vivo by integrating the respective components in pot culture. In the studies against the three isolates of pathogen viz., Fusarium sp (TF1), R. bataticola (TRb8), S. rolfsii (TSr6), the integrated treatment T6 i.e. seed treatment with tebuconazole @ 1g/kg of seed + soil application of potential fungal and bacterial bio agents + soil application of gypsum at 45 DAS has recorded the lowest pod rot incidence of 11.4, 20.7 and 6.0 per cent respectively. From the present study it can be concluded that the groundnut pod rot disease is complex in nature due to the association of more than one soil borne pathogens for the control of which there is a need for the integration of cultural, biological and chemical methods in disease management.ThesisItem Open Access EVALUATION OF ORGANIC PRODUCTS ON THE VIABILITY OF THE SCLEROTIA OF RICE SHEATH BLIGHT PATHOGEN, Rhizoctonia solani Kuhn.(Acharya N.G. Ranga Agricultural University, 2018) RAJESWARI, EMANI; PADMODAYA, BThe present investigation was carried out to study the effect of organic products on the mycelial growth and 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 and pathogenicity was proved by using detached leaf technique. The organic amendments viz., neem, groundnut, karanj, sunflower, gingelly and castor cakes were screened against R. solani by poisoned food technique. All the amendments tested at 5, 10 and 15 per cent concentrations were significantly superior to control in checking the mycelial growth of the fungus. Among the tested organic amendments, groundnut cake showed 100 per cent inhibition at 15 per cent concentration followed by neem cake (86.66%) inhibition. The least inhibition was recorded with castor cake (44.44%). Among the six organic amendments tested against sclerotial viability only two viz., neem and groundnut cakes were found to be effective in inhibiting the sclerotial germination at higher incubation periods i.e. 24 h. Rest of the amendments tested were ineffective in inhibiting sclerotial germination even though they were effective in inhibiting the mycelial growth. Neem cake and groundnut cake were also effective in inhibiting sclerotial germination when applied to soil. xvi Bioefficacy of six plant extracts viz., Azadirachta indica, Calotropis indica, Datura stramonium, Lantana camara, Allium sativum, Pongamia glabra Vent. against R. solani were screened by poisoned food technique among which leaf extract of A. indica was found to be most effective in inhibiting the growth of R. solani (85.18%) followed by clove extract of A. sativum (72.59%). It was found that higher the concentrations of extracts, greater will be the inhibition of mycelial growth of R. solani. Among the six plant extracts tested against sclerotial viability only two viz., clove extract of A. sativum and leaf extract of A. indica were found to be effective in inhibiting the sclerotial germination even at lower incubation periods i.e. 5 min, both in soil application and in vitro. While L. camara and D. stramonium inhibited sclerotial germination at higher incubation periods i.e. 18 h and 24 h. Rest of the plant extracts tested were ineffective in inhibiting sclerotial germination even though they were effective in inhibiting the mycelial growth. Natural preparations used in organic farming viz., cow urine, panchagavya, beejamrutham, jeevamrutham and modified panchagavya were tested against R. solani using poisoned food technique. All the natural preparations at different concentrations were significantly superior to control in checking the mycelial growth of the fungus. Among the tested preparations, jeevamrutham and beejamrutham showed 100 per cent inhibition on the mycelial growth. The above natural preparations were also screened against sclerotial viability of test pathogen, in which all except cow urine were found to be effective in inhibiting sclerotial germination under in vitro. Beejamrutham and panchagavya were found to be effective in inhibiting sclerotial germination even at lower incubation period of 6 h. While jeevamrutham and modified panchagavya inhibited sclerotial germination at higher incubation periods i.e. 18 h and 24 h. Cow urine was ineffective in inhibiting sclerotial germination even though it was effective in inhibiting the mycelial growth. Panchagavya and jeevamrutham were found to be effective in inhibiting the sclerotial germination when applied to soil. The efficacy of seed treatment with different organic products viz., neem cake, groundnut cake, leaf extract of A. indica, clove extract of A. sativum, panchagavya, jeevamrutham and beejamrutham on the viability of sclerotia admixtured with the seed was tested, in which all the treatments showed significantly highest sclerotial inhibition except neem cake (83.33%) and groundnut cake (76.66%). xvii The seed admixtured with sclerotia was treated with different organic products as mentioned above, and the effect of sclerotia on germination and seedling growth was tested by paper towel method. All the seeds germinated in paper towel method. All the tested organic products showed increased seedling growth (root length and shoot length) except groundnut cake when compared to control in paper towel method. The efficacy of organic products viz., neem cake, groundnut cake, leaf extract of A. indica, clove extract of A. sativum, panchagavya, jeevamrutham and beejamrutham through detached leaf technique was observed. Symptoms were not observed on the leaf bits treated with neem leaf extract, panchagavya, garlic and jeevamrutham and found to be effective.ThesisItem Open Access STUDIES ON THE Sclerotium rolfsii Sacc. INCITANT OF STEM ROT OF GROUNDNUT (Arachis hypogaea L.)(Acharya N.G. Ranga Agricultural University, 2018) RAGHAVENDRA, BACHU; SRINIVAS, TThe present investigation was carried out to study the groundnut stem rot causing pathogen Sclerotium rolfsii Sacc. The causal organism was isolated from the infected portion of the stem collected from the fields of S.V. Agricultural College, Tirupati. Pathogenicity of the fungus was tested by soil infestation method. Effect of different inoculum densities of S. rolfsii on the development of stem rot of groundnut was assessed using soil infestation method in pot culture under green house. At 14 days after sowing, highest germination (45.83%), root length (12.37 cm) and shoot length (15.16 cm) was observed at 1 per cent inoculum density. Least germination (16.66%), root length (7.50 cm), shoot length (8.33 cm) was observed at 5 per cent inoculum density. Germination percentage, root length and shoot length of groundnut was gradually decreased with increase of inoculum densities from 1 to 5 per cent. Disease symptoms were not observed in any of the treatments, however development of sclerotial bodies were observed at 4 and 5 per cent inoculum. Influence of soil temperature, soil pH and soil moisture levels were observed on the viability of sclerotia. Maximum sclerotial germination (100%) was observed at soil temperature of 27o and 30oC and lowest at 20oC. From the study it was observed that optimum soil temperature for survival of sclerotia is 27-30oC and the germination is affected if temperature is decreased below 25oC and also above 35oC. Soil pH 7.2 and 7.5 was found to be best (100%) for sclerotial germination and pH 9.0 was found to be less favourable showing least (76.66%) sclerotial germination. Soil moisture levels of 50% (control) and 40% were found to be best for sclerotial germination (100%). Least germination (76.67%) was observed at 100% moisture, indicating that increase in soil moisture decreases the sclerotial viability. xv The antagonistic effect of three Trichoderma viride isolates (Tr-DM, Tr-SNG and Tr-RGP) and three Pseudomonas fluorescens isolates (Pf-DM, Pf-SNG and Pf-RGP) were assessed against S. rolfsii by dual culture technique. Among the T. viride isolates, maximum inhibition (87.19%) was observed with the DM-Tr and among P. fluorescens isolates maximum inhibition (28.25%) was observed with the Pf-DM isolate and they were significantly different from each other. Efficacy of ten fungicides belonging to systemic and non-systemic groups were observed at various concentrations against mycelial growth of S. rolfsii by using poison food technique. Among different fungicides tested, fungus was most sensitive to systemic fungicides azoxystrobin, tebuconazole, hexaconazole, carboxin and non-systemic fungicide mancozeb showing complete mycelial growth inhibition (100%) at all the concentrations tested. Among systemic fungicides, carbendazim and among non-systemic fungicides, copper oxychloride was found to be less effective in inhibiting the mycelial growth of S. rolfsii. Efficacy of different herbicides viz., pendimethalin, quizalofop ethyl, imazethapyr were observed at various concentrations against mycelial growth of S. rolfsii by using poison food technique. Among them, quizalofop ethyl showed maximum inhibition of mycelial growth (100%) at higher concentration (1000 ppm) and imazethapyr was found to be less effective in inhibiting the fungus. Studies conducted to identify the effective dosage of T. viride (Tr-DM) isolate on germination of sclerotial bodies of S. rolfsii and observed that at higher concentration (1 x 108) maximum sclerotial inhibition was observed i.e., 66.66% inhibition over control and least sclerotial inhibition (43.33%) was observed at 1 x 104 concentration, this indicates that increase in spore concentration increases sclerotial inhibition. Similarly, sclerotial germination was tested against effective P. fluorescens isolate (Pf-DM) suspension at the concentrations from 10-4 to 10-8 CFU/ml and the inhibition of sclerotial germination was 66.66 per cent at 10-4 and 10-5 concentrations, 46.66 per cent at 10-6 and 10-7 concentrations. Lower sclerotial germination (36.66%) was observed at concentration of 10-8 (lower concentration). There was a significant increase in per cent inhibition of sclerotial germination with increase in concentration of the bacterial suspension. All the above mentioned fungicides were tested at recommended dosage against the sclerotial germination in soil. Among different fungicides tested, highest inhibition (100%) was observed with the fungicides mancozeb, tebuconazole, hexaconazole and carboxin and least inhibition (16.66%) was observed with validamycin. Similarly, different herbicides were tested and quizalofop ethyl was highly effective in inhibiting the germination of sclerotia recording 36.66 per cent inhibition. xvi Compatibility among effective fungicides, herbicide and their combinations on the effective T. viride isolate (Tr-DM) has revealed that mancozeb was highly compatable with effective T. viride isolate (Tr-DM) and did not show mycelial growth inhibition, hence this fungicide was used for further pot culture study. Efficacy of effective herbicide, fungicide and bioagent was tested against S. rolfsii through pot culture under greenhouse conditions. Among different treatments, T6 (T. viride @ 10 g/kg soil+ mancozeb @ 0.3% a.i/kg soil + quizalofop ethyl @ 0.3% ml a.i./kg soil) did not show disease incidence upto 30 DAS with highest groundnut seed germination (91.67%), root length (22.33 cm) and shoot length (32.67 cm). In addition, disease incidence was not observed with T8 (control), T6 (T. viride @ 10 g/kg soil+ mancozeb @ 0.3% a.i/kg soil + quizalofop ethyl @ 0.3% ml a.i. /kg soil), T4 (mancozeb @ 0.3% a.i/kg soil + quizalofop ethyl @ 0.3% ml a.i. /kg soil), T3 (mancozeb @ 0.3% a.i/kg soil) and T1 (quizalofop ethyl @ 0.3% ml a.i./kg soil). Highest dry weight of the plant was recorded at T8 (control) (3.66 gm) followed by T4 (mancozeb @ 0.3% a.i/kg soil + quizalofop ethyl @ 0.3% ml a.i./kg soil), and T6 (T. viride @ 10 g/kg soil+ mancozeb @ 0.3% a.i/kg soil + quizalofop ethyl @ 0.3% ml a.i./kg soil) (3.26 gm). From the study it was clear that integrated treatment T6 (T. viride @ 10 g/kg soil+ mancozeb @ 0.3% a.i/kg soil + quizalofop ethyl @ 0.3% ml a.i. /kg soil) is highly effective with high groundnut seed germination, root length, shoot length, dry weight of the plant and least disease incidence.ThesisItem Open Access STUDIES ON THE ROLE OF STRUCTURAL AND BIOCHEMICAL DEFENSE COMPONENTS AGAINST BLACKGRAM POWDERY MILDEW (Erysiphe polygoni D. C.)(Acharya N.G. Ranga Agricultural University, 2018) RAGA SRAVANTHI, B; MANOJ KUMAR, VBlackgram or urdbean [Vigna mungo (L.) Hepper] is one of the important pulse crops which is grown as a source of income and nutrition to billions of people in south east asia. The crop is affected by fungi, bacteria, viruses, nematodes and also abiotic stresses. Among the fungal diseases, powdery mildew is one of the serious constraint that causes potential yield loss in India. Powdery mildew symptoms develop as small, white specks on the upper surface of the leaves which later coalesced forming bigger patches. Initial mycelial growth was sparse, and later the mycelium matured and produced conidiophores and conidia which appeared as a thick powdery mass on both the surfaces. Complete coating of white powdery fungal mass on leaves, stems, pods. Leaves turn to chlorotic and leading to defoliation. The pathogen was observed to produce dirty white hyaline mycelium and barrel shaped conidia measuring 30 x 16 μm at 400X magnification A total of fifty three blackgram genotypes were screened against powdery mildew. During kharif 2017-18, none of the genotypes was found resistant. Eleven genotypes viz., LBG 787, LBG 645, RBU 12-02, TPU 4, TU 94-2, VBG 12-034, VBG 13-003, VBG 12-111, NDUK 15-222, PU-1518 and PU-6 were moderately susceptible, twenty six genotypes were susceptible and sixteen genotypes were highly susceptible. Eight blackgram genotypes were selected and categorized as moderately resistant (LBG-752, PU-31), moderately susceptible (RBU 12-02, TU 94-2), susceptible (PU-1540, PU-1503) and highly susceptible (KPU 12-1730, PU-1520). Significant negative correlation occurred between powdery mildew severity and morphological characters of different genotypes, leaf area of middle leaves (‘r’= -0.766), leaf thickness of upper (‘r’= -0.879), middle (‘r’= -0.907) lower leaves (‘r’= -0.881), trichome density on adaxial surface of upper (‘r’= -0.889), middle (‘r’= - 0.968), lower (‘r’= -0.906) and on abaxial surface of upper (‘r’= - 0.952), middle (‘r’= - 0.899), and epicuticular wax of upper (‘r’= -0.943), middle (‘r’= - 0.951) and lower (‘r’= - 0.976) showed significantly negative correlation with powdery mildew severity, where as stomatal frequency on adaxial surface of upper (‘r’= 0.905), middle (‘r’= 0.843), lower (‘r’= 0.935) and on abaxial surface of upper (‘r’= 0.942), middle (‘r’= 0.929), lower (‘r’= 0.916) leaves were positive correlation with disease severity. Biochemical compounds such as phenols, peroxidase and phenylalanine ammonia lyase were higher in moderately resistant genotype PU-31. Phenol content in inoculated plants was negatively correlated with disease severity at all intervals 5 DAI (‘r’= - 0.915), 10 DAI (‘r’= - 0.925), 15 DAI (‘r’= - 0.943), 20 DAI (‘r’= - 0.814). Peroxidase activity and phenylalanine ammonia-lyase activity in inoculated plants was negatively correlated with disease severity at all intervals i.e., at 4 DAI (‘r’= - 0.978; ‘r’ = - 0.931), 8 DAI (‘r’= - 0.988; ‘r’= - 0.910), 12 DAI (‘r’= - 0.990; ‘r’= - 0.963), 16 DAI (‘r’= - 0.914; ‘r’= - 0.965 respectively).