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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 VARIABILITY OF Rhizoctonia solani Kühn. INCITANT OF RICE SHEATH BLIGHT DISEASE AND ITS MANAGEMENT(ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, 2024-05-16) YERRAGURAVAGARI SANDHYA; Dr. M. REDDIKUMARThe present investigation was carried out to study the variability of Rhizoctonia solani Kühn . incitant of rice sheath blight disease and its management. Survey for occurrence and distribution of rice sheath blight disease was conducted in West Godavari, East Godavari, SPSR Nellore, YSR Kadapa and Chittoor districts of Andhra Pradesh during Kharif 2019. Among all the villages surveyed, the highest per cent disease incidence was observed at Penumanchili village (45.66 %) of West Godavari district and the lowest disease incidence was recorded at Koppolu (11.31%) in YSR Kadapa district. A total of thirty pathogen isolates were isolated from the disease samples collected during survey and their pathogenicity was proved in pot culture studies by following typha bit inoculation method. Sheaths from healthy plants in disease- infected field were collected during the survey and thirty bacterial endophytes were isolated from the samples. The cultural variability among the 30 isolates of test pathogen, R. solani was studied on PDA medium. Based on the growth after 72h incubation, ten isolates were categorized into fast growers (65-69 mm growth) and twenty moderate growers (60-64mm growth). Based on the pigmentation of the colony the cultures were assigned to five groups. i.e, ten isolates (Group I- white), three isolates (Group II-Yellowish white), seven isolates (Group III-pale brown), six isolates (Group IV – brown) and four isolates (Group V - dark brown). There was a significant variation among the isolates in the time taken for initiation of sclerotia, which ranged from 5- 9 days, hyphal width varied from the lowest 13.59 μm to the highest 31.66 μm. The colour of sclerotia produced by different isolates was white initially and became dark brown with maturity. Number of sclerotia produced ranged from the lowest 3 to the highest 89. Based on the sclerotia location in the fungal colony, the R. solani isolates were divided into three groups. xx The first group with sclerotia formed in the aerial surface, the second group with sclerotia embedded in the fungal mycelium. The third group with both aerially formed and embedded sclerotia. Pattern of the sclerotia formation was also varied among isolates. Size of the sclerotia ranged from 0.8 to 2.8 mm. Based on texture of sclerotia, isolates were categorized into two groups i.e, smooth and rough. Three rice varieties with varying degree of tolerance to sheath blight disease, viz. NLR-34449 (susceptible), IR-64 (moderately susceptible), Tetep (moderately resistant) was selected for pathogenic variability studies of R. solani isolates. Relative lesion height (RLH) per centage was recorded 10 days after inoculation with pathogen. On NLR- 34449 variety, isolates WAK, NNA, NPC showed highly virulent reaction. WAP, NPP, YVP, YVV, YPL, YPD, YPS and CSS were moderately virulent, however WAA, WTJ, WTM, WTT, ERR, ERV, ERG, EAA, EAM, EAD, NNK, NNN, NPK, YVK, CSA, CSM, CYY, CYK and CYP isolates showed less virulent reaction. On IR- 64 variety, isolate WAK, NNA showed highly virulent reaction. NPC showed moderately virulent response and rest of all the isolates showed less virulent reaction. On Tetep variety, WAK and NNA showed moderately virulent reaction and rest of the isolates showed less virulent reaction. Considering the reaction on all the three rice varieties, isolate WAK showed the highest RLH i.e., 54.66%, 49.03%, and 39.46% on NLR 34449, IR64 and Tetep respectively. WAK isolate was used for further in vitro and field management studies. RAPD analysis was conducted to know the molecular variability among R. solani isolates. Among 20 primers used, eight primers namely; OPA-07, OPA 10, OPB-17, OPC-11, OPC-19, OPE-06, OPF-14 and OPG-11, gave reproducible polymorphism among the 30 isolates. The observed polymorphism among the isolates was 100 per cent in all eight primers. The PIC (Polymorphic Information Content) values were ranged from 0.36 (OPC-11) to 0.49 (OPG-11) with an average PIC value of 0.44 wherein all the primers studied had showed very high variation among the isolates. Genetic relatedness among the R. solani isolates was showed through UPGMA cluster analysis dendrogram. The grouping pattern of the isolates in different clusters indicated that there was less variability among the isolates of the same mandal of one district as they were grouped under same sub cluster except few isolates YVK, YVV, CSM, CYY, YPL, EAD, YVP, NPC and ERR which have separated from their respective mandal isolates and grouped with different sub clusters indicating more variability thus they might had undergone more evolution than others. Hypergeometric probability was calculated among the ten isolates of test pathogen R. solani. Highly virulent to moderately virulent isolates were selected for this studies. WAK, NNA, NPC are highly virulent WAP, NPP, YVP, YVV, YPL, YPD, YPS, CSS are moderately virulent. When the isolates were studied through hypergeometric probability pattern of accidental matching bands gave least probability value (0.014286) between NPC×YVP isolates indicating their accidental similarity is less and they are very close each other and represented in single cluster in dendrogram. Similarly, the next least probability value 0.0833333 was observed between YPS and YPD isolates which are isolated from YSR Kadapa district indicating their close relationship. The highest probability value was between WAK and CSS isolates xxi i.e., 0.978571 indicating that their accidental similarity is more. This means that they have very little association or they are totally different isolates. Eight different fungicides were tested at different concentrations against R. solani were significantly superior over control in checking the mycelial growth. At tested concentrations, 100 % inhibition was observed in all the fungicide treatments except pencycuron. Pencycuron showed decreased inhibition with decreased concentration, 94.77% inhibition at 1500 ppm followed by 93.84 % at 1000 ppm and 92.11% at 500 ppm. Bacterial endophytes were tested against R. solani by dual culture test. NBE-4 bacterial isolate showed highest inhibition of 54.28%. Hence it was selected for characterization studies and in vivo studies like compatibility. NBE4 was rod shaped when observed under compound microscope (1000X) and gram positive in Gram staining test. 16Sr DNA region of potential endophyte NBE4 was amplified using primers 27F and 1492R. 16SrDNA gene sequence of the potential endophyte was compared with gene sequences available at NCBI database through BLASTn search. The gene sequence of the strain NBE4 endophytic bacteria exhibited highest identity of 99.46% with Bacillus sp. strain MR-1/2 (MG548383.1) and its species name was not identified yet. The sequence of the endophyte was submitted to NCBI gene bank and got accession number OK655750. The molecular identity of the strain was confirmed as genus Bacillus species, hence given name as Bacillus sp. NBE4 and it formed a cluster with B. toyonensis, B. mobilis, B. pacificus and B.cereus when a phylogenetic tree was constructed with type strains of genus Bacillus using MEGA (ver. 7) software, which depicts that its sequence was more similar with these species. Eight different fungicides evaluated using poisoned food technique were used to test their compatibility with NBE4 endophyte by using Agar well Diffusion method. Among the tested fungicides, pencycuron 250 SC, azoxystrobin 18.2% + difenoconazole 11.4% SC, iprobenfos 48% EC, showed 0% inhibition of endophytic bacteria i.e., on par at all the concentrations with control (0% inhibition). Among these three, azoxystrobin18.2% +difenoconazole 11.4% SC was selected for field trials because pencycuron showed less per cent inhibition against the R. solani when compared to azoxystrobin18.2% +difenoconazole 11.4% SC. In addition, azoxystrobin18.2% + difenoconazole 11.4% SC not only effective against sheath blight but also against other major rice diseases when compared to iprobenfos 48% EC. Efficacy of certain resistance inducing chemicals salicylic acid, benzoic acid, naphthalene acetic acid, jasmonic acid @ 50, 100, 150 ppm against R. solani were tested in pot culture. Plants treated with salicylic acid showed less disease severity of 20.80% and 20.76% at 100 and 150 ppm concentration, respectively, and both are statistically at par, whereas at 50 ppm concentration disease severity was 22.80% which was significantly higher than the other two concentrations. Induction of defense-related enzymes like PAL (Phenylalanine Ammonia Lyase), Peroxidases and Polyphenol oxidases due to application of resistance -inducing chemicals were estimated at 2,4,6 and 8 days after inoculation. There was significant change in production of these enzymes before application to after application indicating that these chemicals have ability to xxii increase defense enzyme activity in rice plants and activity was increased up-to 6 days and there after decreased gradually. The highest and significant activity of enzymes was found in salicylic acid (SA) treatment and the disease severity also recorded less in this treatment. To know the efficacy of chemicals and bioagent under field conditions an experiment was conducted in both Kharif 2020 and Rabi 2020-21 on NLR-34449 (Susceptible variety) in Randomized Block Design (RBD). In the Kharif, Per cent disease incidence in all the treatments were significantly less as compared to control 63.28% at 70 DAT. Among all the treatments, the lowest per cent disease incidence was recorded in treatment T9 (seed treatment with carbendazim 1g l-1 + seed treatment with bacterial antagonist + root dipping with bacterial antagonist before transplanting + foliar spray with azoxystrobin 18.2% + difenoconazole 11.4% SC @ 1000 ppm + foliar spray of salicylic acid @ 100 ppm) 26.45% and T7 (seed treatment with carbendazim 1g l-1 + seed treatment with bacterial antagonist + root dipping with bacterial antagonist before transplanting + foliar spray with azoxystrobin 18.2% + difenoconazole 11.4% SC@ 1000 ppm) 26.50% which are at par each other and their disease reduction over control was 58.20% and 58.12% respectively. In the Rabi season, per cent disease incidence in all the treatments were significantly less as compared to control 65.99% at 70 DAT. Among all the treatments, the lowest per cent disease incidence 27.73%, 28.00% was recorded in treatment T9 and treatment T7 respectively and both were at par, their disease reduction over control was 57.97 and 57.56% respectivelyThesisItem Open Access STUDIES ON STEM ROT DISEAS STEM ROT (Sclerotium oryzae Catt.) DISEASEE OF RICE(ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, 2024-05-16) PICHIGUNTLA RAMANJINEYULU; Dr. T. SRINIVASRice (Oryza sativa) is an important food crop and it is the staple diet of over three billion people around the world, particularly in Asia. Rice diseases caused by fungi are considered the main constraint in rice production and cause both qualitative and quantitative losses. Stem rot disease caused by Sclerotium oryzae Catt. which was considered as a minor disease earlier has now become one of the major limiting factors in rice cultivation. A roving survey on incidence of stem rot of rice in major growing regions of Andhra Pradesh, Telangana and Tamil Nadu states of southern India was conducted during Kharif- 2019. Disease incidence was varied among the locations. The highest mean incidence (5.97%) was recorded in Andhra Pradesh with a range of 3.20 to 9.83, followed by Telangana (2.34) ranged from 1.02 to 3.97 and the lowest mean per cent incidence (2.08%) was recorded in Tamil Nadu with a range of 0.00 to 3.51. Among all the areas surveyed the highest mean per cent incidence (12.92%) was recorded in Karapa mandal with a range of 12.53 to 13.30 and the lowest incidence (0.00%) was recorded in Devakottai block, Sivagangai district of Tamil Nadu. Incidence was observed among all the prominent cultivars of particular region. A total of 36 S. oryzae isolates were isolated from 60 diseased samples. Koch postulated were proved on susceptible rice cultivar Prabhat (MTU3626). Among the isolates, So15 has produced the highest mean per cent disease index (PDI) (39.51) with maximum AUDPC (489.52 units2 ) and an infection rate of 0.065 units day-1. There was no correlation between the virulence nature of S. oryzae isolates with their geographical regions from where they have been collected. Based on the above observation So15 was considered as virulent isolate and used for the subsequent studies. The variability in cultural characteristics among thirty-six isolates of S. oryzae was carried out. There was difference in cultural characteristics such as radial growth of the colony, margin, colour, zonations and sclerotial characters like time taken for initiation, maturation, colour, position and pattern of sclerotia formation (whorls). The highest significant negative correlation was observed between radial growth - sclerotia initiation and radial growth- sclerotia maturation (r2 = -0.52, n=36, p<0.05). There was no correlation between cultural characters and virulence nature of S. oryzae. Cultural variability was evaluated in all the 36 isolates by cluster analysis and dendrogram generated using R (Version 3.4.0) statistical tool. Three major groups (I, II and III) were xviii formed. The group I included seven isolates, group II included a total of nine isolates and group III consists the remaining twenty isolates. ITS region of all the isolates were amplified with ITS1 and ITS4 universal primers. All the isolates were appeared as identical at amplified fragment of 750bp. The genetic diversity of S. oryzae isolates was studied using a total of 27 ISSR primers which given repeated results out of 50 primers screened. A total of 424 alleles and among them 4 monomorphic bands were identified. The percentage of polymorphic loci ranged from 85.70 to 100 with an average 99.03 suggesting high diversity within S. oryzae populations. Cluster analysis based on the UPGMA method using pooled ISSR data (27 primers, 424 loci, 6206 bands) grouped thirty-six S. oryzae isolates into five main clusters (I–V) based on their geographical origin at the Jaccard similarity coefficient of 0.55. The effect of mineral nutrition on the stem rot incidence was assessed under pot culture. The PDI at the initial disease development (52DAS) was the highest in treatments received recommended dose of N, P, Zn, Fe without K (T5) (14.40) and recommended dose of N, K, Fe, Zn without P (T4) (12.35) denoting role of potassium and phosphorus in disease incidence. At 66 days of crop age,the highest PDI (39.51) was recorded in the treatment which received no potassium fertilization with 429.22 AUDPC units2 . There was no significant difference between treatments viz., double the recommended dose of NPK (T2) (24.69; 288.06AUDPC units2 ), recommended dose of N, P, K, Fe without zinc (T6) (24.69; 259.26AUDPC units2 ), recommended dose of N, P, K, Zn without Fe (T7) (23.46; 257.82AUDPC units2 ) and double the recommended dose of N, P, K, Zn, Fe (T9) (23.46; 283.75AUDPC units2 ) which shows that, there was no significant role of Zn and Fe in disease development. The lowest PDI was recorded in recommended dose of N, P, K, Zn, Fe (T8) (18.52; 237.66 AUDPC units2 ) with the highest per cent disease reduction (55.88%) over control. Hence there was a need for balanced fertilization. In the experimentation of effect of abiotic stress on stem rot incidence, the highest PDI(24.69) was recorded under water stagnation conditions with a maximum of 273.66 AUDPC units2 besides, high initial disease development (10.29) and was on par with control (21.60, 190.84 AUDPC units2 ). The lowest PDI(9.26; 90.04 AUDPC units2 ) was recorded in drought and alkalinity conditions. Twenty six rhizosphere bacteria were evaluated for their inhibitory effect on mycelial growth of virulent S. oryzae isolate (So15) in vitro. Among them, RB17 showed the highest per cent inhibition (58.15%) and was considered as potential bioagent and used for further studies. The preliminary cultural and biochemical studies showed RB17 belongs to Bacillus sp. Sequencing of 16s rRNA (1560bp bp PCR product) exhibited 93.15 per cent identity with reference B. subtilis strain ZW (Accession no. CP092369.1) in NCBI database and was named as Bacillus subtilis strain BsIIRR (Accession no. ON024393.1). In vitro evaluation of efficacy of six organic amendments (OAMs) against the virulent isolate of S. oryzae (So15) was carried out. Karanja cake have shown cent per cent mycelial growth inhibition followed by vermicompost (76.67%) and poultry manure (74.44%) at 5 per cent concentration. In evaluation of OAMs on sclerotial germination, none of them were inhibited after 6hr of dipping period. Neem cake have recorded the highest per cent inhibition (73.33%) which was on par with karanja cake (70.00%) after 24hr of dipping period. Even though some organic amendments inhibited mycelial growth failed to suppress sclerotial germination. xix The bio efficacy of twelve fungicides were evaluated against the virulent isolate of S. oryzae (So15) in vitro. All fungicides at all five concentrations inhibited the mycelial growth when compared to control except Validamycin 3% L at 250ppm. Among the fungicides tested, Tebuconazole 250 EC (25.9% w/w) had completely (100%) inhibited the mycelial growth of the pathogen at all five concentrations. In evaluation of fungicides on sclerotial germination, none of them were inhibited after 6hr of dipping period. There is a significant difference between treatments after 24hr of dipping period. Hexaconazole 4% + Zineb 68% WP, Hexaconazole 5% EC, Tebuconazole 250 EC (25.9% w/w) and Difenconazole 25% EC fungicides inhibited one hundred per cent followed by Metiram 55% + Pyraclostrobin (5%) WG, Propiconazole 25% EC and Azoxystrobin 18.2% + Difenconazole 11.4% SC (86.67%). The effective fungicide i.e., Tebuconazole 250 EC (25.9% w/w) and organic amendment i.e., karanja oil cake were tested for their compatibility with the bacterial biocontrol agent, Bacillus subtilis strain BsIIRR (Accession no. ON024393.1) in vitro. The turbidity increased with increase in incubation time as in control which showed compatibility of bacteria with fungicide and organic amendment. The in vitro studies had revealed, Bacillus subtilis strain BsIIRR (Accession no. ON024393.1), karanja cake and Tebuconazole 250 EC (25.9% w/w) as effective against virulent S. oryzae isolate (So15)and were used for in vivo studies. A biointensive management study for control of stem rot was conducted in farmer field at Kaikaram village, Unguturu mandal of West Godavari district of Andhra Pradesh during Kharif- 2020 and Kharif- 2021 on susceptible cultivar MTU1121. Among the treatments, root dipping of seedlings with Bacilluss subtilis strain BsIIRR (ON024393) at 10% + soil application of karanja cake @ 125 kg ha-1 + spraying of Tebuconazole 250 EC (25.9% w/w) @ 1ml/L at 45 and 60 days of crop age (T7) recorded the lowest PDI (15.74) and the highest yield (6.26 t/ha) over all other treatments including control with B:C ratio of 1.76. Hence for the cost-effective management of stem rot, root dipping of seedlings with Bacilluss subtilis strain BsIIRR (ON024393) at 10% + soil application of karanja cake @ 125 kg ha-1 + spraying of Tebuconazole 250 EC (25.9% w/w) @ 1ml/L at 45 and 60 days of crop age proved to be the bestThesisItem Open Access STUDIES ON Rizoctronia Bataticola Butler causing Dry Root Rot Desease in Grounbdnut(Acharya N G Ranga Agricultural University, 2024-05-06) PAMALA PRINCE JAYA SIMHA; Dr.R.SARADA JAYALAKSHMI DEVIThesisItem Open Access “VARIABILITY STUDIES ON Pyricularia grisea [(Cooke) Sacc.] INCITANT OF BLAST DISEASE IN FINGER MILLET AND ITS MANAGEMENT”(Acharya N G Ranga Agricultural University, 2024-05-06) PADMA ANGADI; Dr. R. SARADA JAYALAKSHMI DEVIThe study was under taken with an aim to know the variability among isolates of Pyricularia grisea causing blast disease in finger millet. Studies were carried out on survey of blast disease to identify the hotspots in major finger millet growing areas of Andhra Pradesh, variability of isolates using cultural, morphological and molecular characteristics and evaluating the bacterial bio-control agents and fungicides against pathogen under in vitro. Efforts were made to identify the promising lines for leaf, neck and finger blasts and knowing suitable weather conditions for occurrence of disease. Attempts were also made to manage the disease with biocontrol agent P. fluorescence, fungicides and their integration. Survey was conducted during Kharif 2020 and Kharif 2021 in seven major finger millet growing districts of Andhra Pradesh. The highest mean blast disease incidence of 56.06% was recorded in Vizianagaram district. The lowest mean disease incidence of 7.85% was recorded in Prakasam district. Regarding mandals, the highest mean blast incidence of 56.59% was recorded in Salur mandal of Vizianagaram district in the range of 53.86 to 59.20% during 2020 and 52.35 to 59.65% during 2021 and lowest incidence of 7.36% with the range of 5.02 to 9.01% and 4.65 to 9.78% was noticed in Racherla mandal of Prakasam district during 2020 and 2021 respectively. The blast samples were collected from different locations of Andhra Pradesh and a total of 20 monoconidial isolates of Pyricularia grisea were isolated. The variability in cultural characteristics viz., colony colour, growth pattern, elevation (flat/elevated growth), sectored or non-sectored, zonations and wrinkle formation were studied among the isolates of P. grisea isolates on Oat Meal Agar medium. Efforts were made to study radial growth sporulation of virulent P. grisea isolate (VIZ-1) in different cultural conditions viz., different media and light conditions. Good amount of sporulation was observed in observed in Finger millet Leaf extract Agar (FLA) medium with 1.81 × 105 ml at 5 days after inocultion followed by OMA with 1.68 × 105 ml at 7 days after inoculation. No significant difference was observed among three light conditions i.e. light (1.07 × 105 ), dark (0.87 × 105 ) and light+dark (0.73 × 105 ). Morphological variability among P. grisea was studied through conidial xvii morphology. Among the isolates, the overall size of the conidia was in the range of 20.74-23.01 μm × 7.00-9.16 μm (Length × Width). The molecular variability of P. grisea isolates was studied using 25 SSR markers, of which seven were polymorphic. The genetic diversity was ranged from 0.180 (MGM 437) to 0.742 (Pyrms 63) with an average of 0.491. Dendrogram using Neighbor Joining (NJ) resulted in formation of three mega clusters in which cluster I was further sub grouped into sub-cluster IA, which includes eight isolates and sub cluster IB contains one. Cluster II was further sub grouped into sub-cluster IIA, which includes six isolates and sub-cluster IIB includes only one isolate. However, cluster III was further divided into sub cluster IIIA which includes three and IIIB includes only one isolate. The RAPD analysis revealed that, out of 8 RAPD primers, 7 primers produced polymorphic alleles which were selected for genetic diversity analysis. A total of 84 reproducible alleles with an average of 12 fragments per primer were produced using 7 RAPD primers. All the markers displayed polymorphic alleles. Of the total alleles (84), one allele (OPA-07) was monomorphic with 15.38% monomorphism and 84.61% polymorphism which contains two monomorphic bond with PIC value of 0.2874. Whereas 6 primers produced 100% polymorphism with PIC value ranged from 0.1769 to 0.3429 and total number of polymorphic bands were ranged from 8 to 14. Dendrogram constructed to reveal the pattern of relatedness among twenty P. grisea isolates using DARwin 6 software on the basis of RAPD polymorphism. Cluster I is further divided into sub-cluster IA which consisting of nine isolates Sub-cluster IB of with two isolates. Cluster II further divided into cluster IIA which consisting of four isolates and sub-cluster IIB contains only one isolate. However, cluster III further divided into sub-cluster IIIA which contains three isolates and sub-cluster IIIB contains only one isolate. A total of 23 bacterial bio-control agents were isolated from rhizospheric soil of healthy finger millet plants and three isolates were collected from ARS, Vizianagaram for in vitro studies. Bacterial bio-control agents were evaluated for their antagonistic effect on P. grisea under in vitro conditions. Results revealed that, maximum inhibition of mycelium growth (79.54%) was noticed in BVP-1isolate and least mycelial inhibition was noticed in BJR (11.30%) isolate. Studies on In vitro evaluation fungicides against the pathogen revealed that Tricyclazole 75% WP, Carbendazim 50% WP and Tebuconazole 50% + Trifloxystrobin 25% WG inhibited the mycelial growth completely. Compatibility studies of fungicide and bio-agent revealed that Tebuconazole 50% + Trifloxystrbin 25% WG and Carbendazim 50% WP at all concentrations were found to be compatible with zero per cent inhibition of bacterial bio-control agent. 74 lines of finger millet including local check VR 708 were screened for their resistance against blast in field conditions. Results showed that for leaf blast five lines were found as highly resistant, 31 lines found as resistant, 23 lines were recorded as moderately resistant and 15 lines were found to be susceptible. For neck blast, 30 lines were recorded as resistant, 29 lines shown moderately resistant, 15 lines were reacted as susceptible. Out of 75 lines screened, 20 lines showed moderate resistance, 41 lines with susceptible reaction and 14 lines including VR 708 showed highly susceptible reaction to finger blast incidence. xviii Correlation and regression analysis of weather parameters with disease development revealed that blast disease severity was shown to be higher during the early planting window, possibly due to comparatively high relative humidity, rainfall and a greater number of rainy days, all of which favor disease development. The effective fungicides and potential bacterial bio-control agent were used in integrated disease management of finger millet blast at S.V. Agricultural College, Tirupati and ARS, Vizianagaram during Kharif 2021, the treatment T7 and T8 were found effective for leaf, neck and finger blast with yield.ThesisItem Open Access “IN VITRO EVALUATION AND CHARACTERIZATION OF BIOCONTROL AGENTS ISOLATED FROM DIFFERENT AGRO-CLIMATIC ZONES OF ANDHRA PRADESH AGAINST MAJOR SOIL-BORNE PATHOGENS viz., Rhizoctonia solani, Sclerotium oryzae AND Fusarium oxysporum f.sp. ciceri ”(Acharya N G Ranga Agricultural University, 2024-05-06) MALIKIREDDY SWATHI; Dr. M.K. JYOSTHNAThe present investigation was carried out to evaluate and to characterize the biocontrol agents isolated from different agro-climatic zones of Andhra Pradesh against major soil-borne pathogens viz., Rhizoctonia solani, Sclerotium oryzae and Fusarium oxysporum f.sp. ciceri. Infected plant samples of rice and chickpea were collected from the fields of RARS, Nandyal. Three pathogens viz., Rhizoctonia solani, Sclerotium oryzae and Fusarium oxysporum f.sp. ciceri were isolated from the diseased samples and proved the pathogenicity. Twenty Trichoderma isolates showing high antagonistic activity were collected from different Research stations of ANGRAU, Andhra Pradesh and pure cultures of Trichoderma isolates were maintained in PDA slants. All the twenty Trichoderma isolates were designated based on the location and were evaluated against the three pathogens in vitro. Twenty Trichoderma isolates were tested against R. solani in vitro. The maximum inhibition per cent which was from 72.33 per cent to 33.67 per cent. AT-6 Trichoderma isolate collected from Anakapalli Research station showed highest inhibition of 72.33 per cent followed by AT-1 (67.33%), AT-4 (66.33%) and AT-2 (65.67%) which were statistically on par with each other. The least inhibition was observed with AT-5 isolate with 33.67 per cent. Based on the results from this assay against R. solani, Trichoderma isolates viz., AT-6, AT-1, AT-4, AT-2 were carried forward to test the mechanism of antagonistic activity and their characterization. When twenty Trichoderma isolates were tested against Sclerotium oryzae, the maximum inhibition per cent was from 82.20 per cent to 44.40 per cent. AT-4 isolate showed maximum growth inhibition of Sclerotium oryzae (82.20%) followed by KT-1 (78.86%), AT-6 (77.76%) and AT-1(76.63%) which were on xvii par with each other. The least inhibition was observed in NT-7 isolate (44.40%). Based on the above results, Trichoderma isolates viz., AT-4, KT-1, AT-6 and AT-1 were carried forward to test the mechanism of antagonistic activity and their characterization. When twenty Trichoderma isolates were tested for their antagonistic potential against Fusarium oxysporum f.sp. ciceri, the maximum inhibition per cent was from 60.17 to 33.33 per cent. Maximum per cent inhibition of 60.17% per cent was observed with AT-6 isolate, followed by AT-2 (57.57%) and AT-1 (53.70%). Least per cent of inhibition was observed with AT-5 (33.33). Of the twenty Trichoderma isolates were tested against three pathogens, five Trichoderma isolates viz., KT-1, AT-1, AT-2, AT-4, AT-6 were selected based on their performance in dual culture assay and carried forward to test the antagonistic activity and their characterization. Maximum mycelial growth inhibition of R. solani, S. oryzae, Fusarium oxysporum f.sp. ciceri was due to production of volatile compounds by AT-6, AT-4, AT-6 Trichoderma isolates respectively. The effect of non-volatile compounds produced by potential Trichoderma isolates against R. solani was similar in all the three concentrations viz., 50, 30 and 10 per cent with the highest mycelial growth inhibition of R. solani by AT-6, S. oryzae by AT-4, Fusarium oxysporum f.sp. ciceri by AT-6 isolates respectively. Morphological characters of all five potential Trichoderma isolates viz., KT-1, AT-1, AT-2, AT-4, AT-6 like branching of conidiophores, shape and size of phialides and conidia were studied. KT-1 and AT-2 showed Sigmoid or hooked phialide shape and the size ranged in between 4.5-12.5 × 2.5-3.5 µm, conidia were globose to ovoid and size between 3.6-4.8 × 3.5-4 µm. AT-1 isolate showed ampulliform to lageniform phialides shape and size between 4.7–7.9 × 2.3–3.5 µm, conidia were subglobose to ovoid and the size was between 2.5–3.2 × 2.2–2.8 µm. AT-4 and AT-6 isolates showed bottle shaped phialides and the size ranged in between 6–11.5 × 2.5–2.9µm, conidia were ellipsoidal, subglobose shaped and size ranged between 4–6 × 3.0–4.0 µm. Tests for hydrolytic enzyme production viz., cellulases, proteases, amylases were performed. Of the five potential Trichoderma isolates KT-1, AT-4, AT-6 were positive for cellulase, AT-1, AT-4 and AT-6 isolates were positive for amylase and KT-1 isolate was found positive and the remaining isolates were found negative for protease production. AT-4, AT-6, KT-1, AT-2 isolates were positive for ammonia production. AT-1, AT-4, AT-6 isolates were positive for HCN production. All the five isolates produced siderophores. Molecular characterization of potential Trichoderma isolates viz., KT-1, AT-1, AT-2, AT-4, AT-6 was done by using ITS-1 and ITS-4 primers. Amplification of the 18S rDNA region from Trichoderma isolates with primers ITS 1 and ITS 4 yielded products of approximately 600 bp. BLAST analysis (BLAST) results showed that KT-1 and AT-2 isolates showed more per cent identity with T. viride, AT-1 with T. harzianum and AT-4, AT-6 with T. longibrachiatumThesisItem Open Access MOLECULAR CHARACTERIZATION OF VIRUS ASSOCIATED WITH YELLOW MOSAIC DISEASE IN HORSE GRAM(Acharya N G Ranga Agricultural University, 2024-05-06) BODELA SUSHMA; Dr. PRADEEP MANYAMIn this study, begomovirus associated with YMD of horsegram in Andhra Pradesh was studied based on diseased samples collected from Anantapuramu, Chittoor and YSR Kadapa districts. Based on PCR amplification and sequencing analysis, it was confirmed that all five samples infected with HgYMV indicating its predominance in horse gram growing areas of AP. Whole genome was determined for all the five isolates using overlapping primers for amplification of DNA-A and DNA-B components of HgYMV. The size of DNA-A in five isolates ranged from 2733-2736 nucleotides whereas for DNA-B, it was found to be 2670-2726 nucleotides in length. Complete genome analysis and sequence identity of HgYMV DNA-A and DNA-B of five isolates shared maximum nucleotide identity ranged from 95.5-98.7% for DNA-A and 94-98.2% for DNA-B with other HgYMV infecting pulses from different places. Among DNA-A and DNA-B components shared more than 94% identity among themselves, thus provining five isolates of HgYMV belong to same variant of the HgYMV. The recombination analysis revealed that DNA-A and DNA-B of HgYMV under present study is a recombinant, which is a derivative of known virus. The sequence analysis of IR region of HgYMV DNA-A and HgYMV DNA-B yielded broad range of identity (50.8-98.8% and 27.4-98.7% respectively) with HgYMV infecting other legumes. The IR region of all five isolates contains conserved TATA box, Nanomer and Ori sites. Nucleotide analysis of six ORFs of HgYMV DNA-A component with other begomoviruses was attempted. ORFAV1 and ORFAV2 shared 95.3 to 100% and 81.8 to 100% identity respectively with compared HgYMVs different isolates of HgYMV. A high similarity was also observed for other ORFs AC1 (95.0-100%), AC2 (80.7-100%), AC3 (83.5-99.2%) and AC4 xviii (92.8-100%). When compared with other begomovirus the closest association was found for MYMIV (80.6-86.6%), MYMV (82.2-84.5%) for DNA-A and MYMIV (60.3-68.4%), MYMV (60.5-68.3%) for DNA-B and less similarity was observed for DoYMV, VbGMV and FbLCV. The nucleotide analysis of ORFs of DNA-B component showed that high similarity (94.1-100%) was observed for BV1than BC1 (77.8-100%) which indicates BC1 is a divergent (KDP and TPT isolates). Bemisia tabaci populations were collected from four districts of Andhra Pradesh (YSR, Anantapuramu, Chittoor, Nellore) for identification biotypes and genetic groups. The existence of two genetic groups was revealed based on partial mtCOI gene sequence analysis. KDP and NLR belong to Asia-II-1 genetic group. Asia-II-8 genetic group was 1st time reported in AP identified in ATP and TPT B. tabaci population. The association of secondary bacterial endosymbionts with Bemesia tabaci populations was studied using16S rRNA/23S rRNA gene sequences. Wolbachia, a s-endosymbiont was identified in all four isolates which belongs to super group B. Whereas the association of Cardinium and Arsenophonus was observed from Kadapa B. tabaci population. The phylogenetic analysis identified Cardinium connected to C2 subgroup and Arsenophonus to A2 subgroup. Rickettesia was absent in all B. tabaci populations. Thus, Asia -II-1 genetic group from KDP was found in association with Wolbachia, Cardinium and Arsenophonus, while Asia-II-8 genetic group associated with only Wolbachia. A total of 37 Horse gram genotypes were screened for identifying resistance against Horse gram yellow mosaic virus. The PDI values of 37 genotypes ranged from 0-97.2%. Eighteen genotypes were found resistant under natural disease screening methods. Eight genotypes exhibited higher degrees of susceptibility (30.85-97.2%). The apparent rate of infection which depicts disease progression indicated that slow progress in resistant type genotypes (BSP21-3, r:0.20), whereas faster rate of spread disease in susceptible genotypes Indira Kulthi (r:0.45) and BSP21-5 (r:0.454).ThesisItem Open Access MOLECULAR CHARACTERIZATION OF SESAME PHYLLODY PHYTOPLASMA AND ITS EPIDEMIOLOGY IN ANDHRA PRADESH(Acharya N G Ranga Agricultural University, 2024-05-06) SANDHYA GOPISETTY; Dr. M. GURIVI REDDYAn investigation was carried out to identify and characterize the phytoplasma strains associated with the sesamum phyllody disease showing symptoms of phyllody, floral virescence and yellowing in Andhra Pradesh. A roving survey was conducted in Chittoor, Kadapa districts in kharif season and Chittoor, Kadapa, Vishakapatnam, Vizianagaram and Srikakulam districts of Andhra Pradesh in late rabi during 2021-22. The disease etiology was confirmed by performing nested PCR assays using universal primer pairs P1/P7 followed by R16F2n/R16R2, which amplified ~1.8 and ~1.25 kb product of 16S rRNA gene. The results of phytoplasma identification in the infected samples were further validated by using secA multilocus gene which yielded an expected amplicon sizes of ~840bp by utilizing primer pairs SecAfor1/SecArev3 BLAST and phylogenetic analysis of 16S rDNA and secA genes revealed that phytoplasma associated with sesame phyllody disease in kharif season belonged to Ca. Phytoplasma australasia (16SrII) group whereas in late rabi season it belonged to Ca. Phytoplasma asteris (16SrI) group. Virtual RFLP analysis was performed to further confirm phytoplasma at the subgroup level which classified the kharif isolates under the 16SrII-D subgroup and late rabi isolates under the 16SrI-B subgroup. Symptomatic weeds, other host plants and insect vectors feeding on infected sesame plants were collected from in and around infected sesame fields. Out of them four weed species: Parthenium hysterophorus, Celosia argentea, Cleome viscosa, Tephrosia purpurea; two other host plants, sun hemp (Crotalaria juncea), redgram (Cajanus cajan) were tested positive for phytoplasma utilizing similar set of primer pairs of 16S rRNA and secA xix genes. Hishimonus phycitis collected from infected sesame fields of Chittoor district also tested positive for Ca. Phytoplasma australasia 16SrII-D subgroup phytoplasma which was identified as a potential putative vector for the sesame phyllody phytoplasma. The effects of sowing dates, vector population and weather parameters on sesame phyllody disease incidence were studied during kharif and late rabi seasons. The lowest disease incidence of 62% was observed in August sown crops and the highest disease incidence of 81.87% was observed in June sown crops in kharif season. During late rabi season less or negligible per cent of disease incidence was observed compared to kharif season. The vector population and all the weather parameters except rainfall were significantly correlated with disease incidence on all sowing datesThesisItem Open Access CHARACTERIZATION OF BANDED LEAF AND SHEATH BLIGHT PATHOGEN AND ITS MANAGEMENT IN BARNYARD MILLET(Acharya N G Ranga Agricultural University, 2024-05-06) PALLAVI TATINENI; Dr. T. S. S. K. PATROIn the present investigation on “Characterization of banded leaf and sheath blight pathogen and its management in barnyard millet”, the banded leaf and sheath blight (BLSB) affected leaf samples were collected from different millet growing regions of India and the pathogen was isolated. Initially, seven different media were used to study their effects on morpho-cultural characteristics of the pathogen among which Potato Dextrose Agar (PDA) was found to support best radial growth of the pathogen in addition to production of highest number of sclerotial bodies and hence was used to carry out further morpho-cultural characterization studies for all the isolates. Morpho-cultural characterization studies revealed that, there was considerable variation among the isolates in various morpho-cultural characters like radial growth, colony colour, colony texture, hyphal width, sclerotia size, sclerotia weight, distribution of sclerotia, pattern of arrangement of sclerotia, sclerotia texture and sclerotia colour. Molecular characterization using ITS1/ITS4 primers revealed that all the isolates belong to AG1-IA group of Rhizoctonia solani and there was no much variability among the isolates collected from different geographical locations which depicts the genetic flexibility and adaptability of the pathogen to spread to new ecological niches. Pathogenic variability was studied for all the 10 isolates and the incubation period varied from 4 to 8 days. The isolate, RAP-2 was more virulent. Correlation analysis between different morpho-cultural characters and virulence of the isolates revealed that isolates with higher radial growth were more virulent and also there exists a significant positive correlation between sclerotia size and sclerotia number, hyphal width. Yield loss assessment studies revealed that the potential yield loss caused by the pathogen ranged from 54% to 62%. Integrated management studies include screening for host resistance, evaluation of different treatments viz., chemicals viz., propiconazole @ 0.1%, tebuconazole + trifloxystrobin @ 0.05%, biocontrol agents viz., Trichoderma asperellum, Pseudomonas xvii fluorescens, Bacillus subtilis, biorational viz., panchagavya against banded leaf and sheath blight disease. The study identified the genotypes, VBBC-340, VB 19-3, VB-19-4, as resistant and seed treatment and foliar spray with tebuconazole + trifloxystrobin @ 0.05% as the most effective among the treatments tested.ThesisItem Open Access STUDIES ON BIOLOGICAL CONTROL POTENTIAL OF NATIVE BACILLUS SPP. AGAINST RHIZOCTONIA SOLANI KUHN. CAUSING RICE SHEATH BLIGHT(Acharya N G Ranga Agricultural University, 2024-05-06) PAGIDIRAI KALAVATHI; Dr. M.K. JYOSTHNAA roving survey was conducted during, rabi, 2020-2021 in Chittoor and Nellore districts of Andhra Pradesh to assess the disease severity of sheath blight disease in rice. The disease severity ranged from 6.11 to 13.44%. Rice sheath blight pathogen R. solani was isolated from the diseased samples obtained during survey. Its pathogenicity was proved by using mycelial ball insertion technique. A total of 26 native Bacillus spp were isolated from the rhizoplane soils of rice crop of Chittoor and Nellore districts and their antagonistic efficiency was tested using dual culture technique. Among the isolates, NB13 showed maximum antifungal efficiency with 86.15% followed by CB10 (81.60%) and CB4 (75 %). Maximum inhibition of sclerotial germination was observed in CB4 (98.42%) followed by NB13 (97.2%) and CB10 (96.36%) and maximum per cent of lysis of sclerotia was observed in CB10 isolate (100%) followed by CB4 (98.14%) and NB13 (95.55%). Those isolates CB4, CB10, NB13 recorded maximum mycelial inhibition, sclerotial inhibition and sclerotia lysis which are significantly on par. Cultural characters viz., colony shape, colour, size, surface, margin, elevation and time of colony appearance of the potential Bacillus isolates were recorded. Among all isolates NB4, NB13, CB10 isolates produced irregular, white, large colonies with rough surface, lobate margins, flat elevation and formed colonies with 48h after inoculation. CB4 produced irregular, white, large colonies with rough surface, filamentous margins and formed colonies with 48h after inoculation. Out of ten potential isolates tested for biochemical tests, all isolates showed positive reaction to gram staining, endospore staining, motility test and catalase test, whereas only seven isolates showed positive reaction to anaerobic growth, six isolates showed positive reaction to oxidase test and three isolates showed positive reaction to nitrate reduction test. xvi 16S r DNA sequence analysis revealed that the NB4, NB13, CB4 and CB10 have close similarity with Bacillus subtilis. Out of the 10 potential isolates maximum chitinase activity (maximum halo zone diameter (2.6 cm) and chitinolytic index (3.13) and oxalate oxidase enzyme activity (maximum halo zone diameter 2.35cm) was observed in isolate CB10. A total of ten potential isolates were screened for PGPR characteristics. All the isolates were positive to siderophore production, phosphate solubilization activity, of which CB10 isolate recorded highest siderophore index, maximum zinc carbonate solubilization index and efficiency and NB13 recorded maximum IAA production, PSI and PSE% and also produced maximum ZSI and ZSE % for zinc phosphate, CB4 recorded highest potassium solubilizing index and efficiency and five isolates were positive for HCN production, four isolates for organic acid production, while isolate CB10 was produced maximum ACC (58nm-α-ketobutyrate mg-1h -1 ). All the ten potential isolates significantly increased seed germination, seedling growth (root &shoot length) and vigor index of rice seedlings when compared to control by paper towel method. Among these highest vigor index was recorded NB13 (2683.66), followed by CB10 (2380.70), CB4 (2214.83) which are significantly on par.
