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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 MOLECULAR CHARACTERIZATION AND DETECTION OF PHYTOPLASMA INFECTING PULSES(Acharya N.G. Ranga Agricultural University, Guntur, 2015) VIJAY KUMAR NAIK, D; SAILAJA RANI, JThe present study was carried out for molecular characterization phytoplasmas infecting pulses and studies on their detection and host range. Phytoplasma infected samples of blackgram, greengram, pigeonpea, chickpea, cowpea and fieldbean were collected from Chittoor and Kurnool districts. DNA from plant sample was isolated following CTAB method. The isolated DNA was successfully amplified by nested PCR with phytoplasma specific primers P1/P7 and R16F2n/R16R2. The resulting amplicons of six isolates were cloned, sequenced and data was assembled. The amplicon was determined as 1250bp. Sequence analysis revealed that blackgram phyllody phytoplasma shared highest identity of 98% with ‘Candidatus Phytoplasma australasiae’ (Ca. P. australasiae) 16S rDNA II-D followed by sesame phyllody 16S rDNA II-D (98%) whereas greengram phyllody and cowpea phytoplasma shared maximum identity of 99.9% with sesame phyllody 16S rDNA II-D, ‘Ca. P. australasiae’ 16S rDNA II-D and papaya mosaic phytoplasma (Y10096). Chickpea phytoplasma showed highest sequence identity (99.4%) with sesame phyllody 16S rDNA II-D, ‘Ca. P. australasiae’ 16S rDNA II-D and papaya mosaic phytoplasma (Y10096). Fieldbean bud proliferation phytoplasma had shown highest identity of 99.5% with sesame phyllody 16S rDNA II-D, ‘Ca. P. australasiae’ 16S rDNA II-D and papaya mosaic phytoplasma (Y10096) and pigeonpea little leaf phytoplasma shared maximum identity of 100% with sesame phyllody 16S rDNA II-D, ‘Ca. P. australasiae’ 16S rDNA II-D and papaya mosaic phytoplasma (Y10096). The important finding of the work was identification of the 16S rDNA-II phytoplasma with fieldbean, cowpea and pigeonpea for the first time from India. The present results with partial 16S rDNA gene sequence alignment and construction of phylogenetic tree using 16S rDNA gene sequences had clearly established that the phytoplasma infecting blackgram, greengram, redgram, cowpea, chickpea and fieldbean belongs to ‘Candidatus phytoplasma aurantifolia’ (16S rDNA-II) in Andhra Pradesh. Totally 32 other crop plants and weed hosts were collected for host range studies of phytoplasma. The DNA was isolated from 32 weeds and other crops showing phytoplasma disease symptoms and subjected to PCR amplification with phytoplasma specific primers R16F2n/R16R2. The result shows that R16F2n/R16R2 primer amplified 1250bp product in 19 weeds and other crop species. They are Cleome gynendra, Solanum duclamara, Portulaca oleracea, Pergularia daemia, Aerva lanata, Celosia argentea, Parthenium hysterophorus, Tephrosia purpurea, Solanum melongena, Solanum lycopersicum, Sesamum indicum, Cleome viscosa, Croton bonplandianum, Saccharum officinarum, Citrullus lanatus, Capsicum annuum, Borreria hispida, Cassia auriculata and Arachis hypogaea. The notable contribution in the present study was identification of six new hosts for phytoplasma for the first time in the Andhra Pradesh. They are Cleome gynendra, Solanum duclamara, Portulaca oleracea, Aerva lanata, Celosia argentea and Pergularia daemia in Andhra Pradesh. The above results indicate that phytoplasma have wide host range. Greengram variety LGG-460 was used to detect the phytoplasma by PCR at different stages of crop growth. Phytoplasma infected three greengram plants were collected for DNA isolation at 30, 45, 60 and 75 DAS from the same plants and performed PCR with R16F2n/R16R2 primers. Samples collected at 30 and 45 DAS gave good amplification of expected product size in PCR with R16F2n/R16R2 primers, but weak bands were observed in samples collected from 60 and 75 DAS, thus indicating that the optimum age for the detection of phytoplasma in greengram is 3045 DAS. The present result shows that the PCR techniques described here allows rapid, sensitive and accurate detection of phytoplasma in plants that are showing typical phytoplasma disease symptoms.ThesisItem Open Access BIOLOGY, EPIDEMIOLOGY AND MANAGEMENT OF Alternaria spp. CAUSING EARLY BLIGHT OF TOMATO (Lycopersicon esculentum Mill.)(Acharya N.G. Ranga Agricultural University, Guntur, 2015) RAMA DEVI, P; KRISHNA PRASADJI, JThe present investigation on the biology, epidemiology and management of early blight of tomato caused by Alternaria spp. was carried out in the Horticultural Research Station, Dr. Y. S. R. Horticultural University, Venkataramannagudem, West Godavari district of Andhra Pradesh during 2010-11 to 2013-14. Early blight symptoms on tomato leaves were observed as irregular to regular brown necrotic spots with obscured concentric rings and as brown almost circular necrotic spots with characteristic concentric rings. A. alternata from samples showing first type symptoms and A. solani from samples with second type of symptoms were isolated and pathogenicity of the two Alternaria spp. was proved. The disease incidence was found to range from 31.76 to 70.56% and severity from 20.06 to 54.43%, with highest mean incidence (52.47%) and severity (34.27%) in West Godavari district. Variety of the crop plant, soil type and pH were not found to greatly influence early blight incidence and severity. However, age of the crop was found to have a positively significant correlation with per cent disease incidence and disease severity with r values of 0.79 to 0.87 and 0.62 to 0.85, respectively in the districts surveyed. Colonies of most A. alternata isolates were light grayish to brown while that of A. solani were mostly light grayish brown on potato carrot agar. Differences in radial growth (6.48 to 8.98 cm), time for sporulation (8.00 to 12.23 days), sporulation (9.56 x 104 to 32.44 x 104/ml) and conidial dimensions (27.54 to 59.99 µm length; 9.41 and 18.29 µm breadth and 3.56 to 22.76 µm beak length) among A. alternata isolates were noticed. Such differences were also observed among A. solani isolates (6.89 to 8.08 cm in radial growth; 16.17 to 18 days for sporulation and 0.67 to 2.15 x 104/ml in number of spores). A. solani isolates’ spores were longer (99.89 to 172.35 µm) than A. alternata spores with beak length being the primary determinant of spore length. Incubation period among A. alternata (4.0 to 5.33 days) and A. solani (4.33 to 5.0 days) isolates did not differ significantly. Isolates also exhibited wide and significant differences in the number of spots produced, total spotted area and disease ratings. The twenty isolates i.e., 16 of A. alternata and four of A. solani were grouped into five clusters by Ward’s minimum variance dendrogram using Mahalanobis-Euclidean (D2) distance statistic. The chief characters viz., number of spots produced, per cent spotted area and conidial beak length that contributed the maximum to clustering of isolates were identified by Wilks’ test. Isolates were found to cluster based on the morphological and pathogenicity characters but not on the basis of geographical relationships. The apparent rate of infection (r) varied in both the seasons. The r values ranged between a maximum of 0.440 during 66 and 70 DAT and a minimum 0.006 during 96 and 100 DAT with a mean of 0.075 units/day in 2010-11 crop season. In 2012-13, r values were between a maximum of 0.290 and a minimum of 0.025 with a mean of 0.068 units/day. Regression analysis of PDI with DAT revealed that the age of the plant was an important factor explaining disease development up to 98 to 99%. Maximum temperature ranging between 25.50 C and 32.750 C and morning relative humidity ranging between 68 and 95% were found to be significantly positively correlated (r =0.35 and 0.39, respectively). A regression equation with the data sets of weather and PDI for the two seasons was constructed which revealed that maximum temperature and morning relative humidity would influence early blight development in tomato up to 46%. Y = -239.67 + 5.88 (max temp*) – 3.28 (min temp*) + 1.92 (RH 0800*) N = 46 R2 = 0.46 F value = 12.04 Standard error = 16.30 * significant at 5% Alternaria spp. were isolated from both surface sterilized and unsterilized seeds following blotter paper and agar plate methods indicating both externally and internally seed borne nature of the pathogen. The pathogen was found to exhibit greater survival at deeper depths in soil as isolation frequency of the pathogen from samples stored at different depths (0 to 120 cm) increased from 5.31 to 20.63%. Stemphylium botryosum was found more aggressive in interaction with A. alternata by producing significantly more number of spots. Salicylic acid was not found effective at concentrations between 100 and 500 ppm as a systemic acquired resistance (SAR) elicitor in reducing the severity of early blight. However, significant reduction in number of spots over unsprayed check (35.33/leaf) was recorded in plants treated with Pseudomonas fluorescens (24.50/leaf) and Trichoderma asperellum (27.17/leaf). Tebuconazole, copper oxychloride, chlorothalonil, dimethomorph, mancozeb and azoxystrobin in that order significantly inhibited the radial growth, sporulation and spore germination of A. alternata in vitro. Tebuconazole seed treatment followed by eight foliar sprays of tebuconazole and copper oxychloride alternated with each other recorded the lowest terminal disease severity (PDI=35.39%) that was lesser by 53.17% than that recorded in check (75.57%) and gave the maximum yield (25.71 t/ha) with 86.47% increase over control and with a benefit : cost ratio of 1.60. Significantly higher yield (19.38 t/ha) was also realized with the treatment with P. fluorescens as four foliar sprays preceding four sprays of tebuconazole and copper oxychloride alternated with each other that had significantly decreased disease severity.ThesisItem Open Access EPIDEMIOLOGY AND MANAGEMENT OF BUD NECROSIS AND STEM NECROSIS DISEASES AFFECTING GROUNDNUT (Arachis hypogaea L.)(Acharya N.G. Ranga Agricultural University, Guntur, 2015) SOWMYA LAKSHMI, G; Dr. V. MANOJ KUMARThe investigation on the “Epidemiology and management of bud necrosis and stem necrosis diseases affecting groundnut (Arachis hypogaea L.) was carried out in the Agricultural College, Bapatla, Guntur district, Andhra Pradesh during 2013-14. Surveys conducted in two major groundnut growing districts viz., Guntur and Prakasam of Andhra Pradesh during rabi 2013-14 revealed the incidence of groundnut bud necrosis disease (GBND) caused by GBNV in the range of 0.75-16.75% and 2.25-14.25%, respectively. Per cent incidence of peanut stem necrosis disease (PSND) caused by TSV was recorded in the range of 0-3.75% and 0-2.25% in Guntur and Prakasam districts, respectively. DAC-ELISA tests of samples indicated high prevalence of GBNV compared to TSV. Mixed infections of GBNV and TSV were also noticed. Groundnut bud necrosis disease symptoms appeared as either mild chlorotic mottle or spots, which gradually transformed to chlorotic rings and finally as necrotic spots on young quadrifoliate leaves of groundnut. Necrotic symptoms on leaves extended to petioles, terminal buds and finally to stem leading to proliferation of axillary shoots resulting in stunting. Peanut stem necrosis disease showed localized necrotic spots and veinal necrosis on young leaves, that spread to petioles, buds and stem as continuous necrotic streaks and even on pods and kernels and finally resulted in death of the plant. Mechanical sap inoculations on cowpea cv. C-152 with GBND sample produced chlorotic local lesions seven days after inoculation while TSV produced chlorotic to necrotic lesions four days after inoculation. Bud necrosis and stem necrosis diseases showed significant positive correlation with thrips population (r=0.677 and r=0.772), maximum temperature (r=0.775 and r=0.746), minimum temperature (r=0.803 and r=0.755) and significant negative correlation with morning relative humidity (r =-0.777 and r =-0.778) and evening relative humidity (r=-0.593and r=-0.564). Regression analyses for per cent incidence of diseases with thrips and weather factors revealed that maximum temperature and thrips population per plant would influence development of bud and stem necrosis diseases in groundnut up to 86.5% and 87.8%, respectively. Fifteen genotypes of groundnut screened against bud and stem necrosis diseases under field conditions with Narayani as susceptible check showed varied per cent incidences. The genotypes K3 and R8808 showed resistant reactions whereas GPBD-4 and ICGS-44 were moderately resistant while other genotypes were moderately susceptible to GBND. However K3 and R8808 genotypes showed resistant reactions to PSND while all other genotypes recorded moderately susceptible. Insecticidal spray with imidacloprid SL @ 0.0053% at 45 DAS, fipronil SC @ 5% at 45 DAS resulted in effective control of both GBND and PSND through vector control. It also improved shoot length, dry pod weight, number of pods per plant, 100 seeds weight, shelling percentage and it was found economical.ThesisItem Open Access STUDIES ON ALTERNARIA FRUIT ROT OF CHILLI(Acharya N.G. Ranga Agricultural University, Guntur, 2015) USHAM SUDHEINA SINGH; Dr. J. KRISHNA PRASADJIAlternaria fruit rot of chilli caused by Alternaria alternata (Fr.) Keissler is prevalent in most of the chilli growing regions of Guntur district of Andhra Pradesh, India. The incidence and severity (PDI) of Alternaria fruit rot were in the range of 2.19 to 10.49% and 0.83 to 8.42, respectively, while the corresponding incidence and severity of Colletotrichum fruit rot were 3.41 to 14.17% and 1.26 to 8.96%, respectively in 25 locations on nine chilli varieties during Kharif 2013-14 in Guntur district. Symptoms were found to be distinct for both Colletotrichum fruit rot and Alternaria fruit rot. Generally one or occasionally two to three elliptical spots surrounded by bleached tissue was characteristic of Colletotrichum fruit rot. One to three generally circular spots without bleached tissues were found to be the typical symptoms of Alternaria fruit rot. None of the fruits was found infected by both pathogens at any stage of investigation. Both the pathogens were also found to be both externally and internally seed borne in almost all the varieties and in all mandals of the district surveyed. Association of A. alternata with chilli seeds ranged from 0% to 47.00% (mean, 20.08%) as externally seed borne and 0% to 25.00% (mean, 8.20%) as internally seed borne while that of C. capsici varied from 0% to 67.00% (mean, 30.00%) as externally seed borne and 0% to 45.00% (mean, 17.84%) as internally seed borne. Other fungal flora infesting chilli seeds were Fusarium spp., Aspergillus spp. and Curvularia spp. at very low frequency. The seed mycoflora of chilli exhibited different distribution pattern as externally and internally seed borne and among which Colletotrichum and Alternaria had higher colonizing frequency (CF) and isolation recovery (IR) irrespective of location and variety. For externally seed borne mycoflora the highest Simpsion’s diversity index (DI=0.585) and Shannon-Wiener diversity index (H’=1.040) were in seed samples from Thullur mandal and Sattenapalli mandal, respectively. The species richness was the greatest in seeds from Amravati mandal (0.516) but more uniform in seed samples from Sattenapalli mandal with the highest species evenness (0.646). Among varieties the highest DI (0.614) and H’ (1.100) were in seeds from Byadagi variety while the greatest species richness (0.763) and species evenness (0.683) were in varieties LCA-577 and Byadagi, respectively. The highest diversity of internally seed borne fungi was in seeds from Piduguralla mandal with the highest DI (0.519) and H’ (0.853) values while the greatest species richness (1.508) and evenness (0.530) were in seeds from Amaravati mandal and Piduguralla mandal, respectively. Among varieties, mycofloral diversity in Avatar variety was the highest in terms of DI (0.531) while the highest H’ (0.875) was in Byadagi variety while species richness was the highest in Sarada variety (1.768) and evenness in Byadagi variety (0.544). Studies corroborated the seed borne nature of both fruit rot pathogens despite encountering competition from other saprophytes associated with chilli seed. In vitro study of interaction between A. alternata and C. capsici on detached matured transition stage chilli fruits revealed dominance of A. alternata over C. capsici which accounted to its greater necrotrophic nature of nutrition and preference of senescing and injured tissues than C. capsici. Colletotrichum fruit rot incidence increased with age of the crop and was in the range of 19.98 to 35.80% at 187 DAT. Based on incidence three genotypes viz., LCA 334, LCA 436 and G4 were categorized as moderately resistant. However, based on severity all the genotypes were grouped under the moderately resistant category. Progress of Alternaria fruit rot incidence was similar but started later to Colletotrichum fruit rot and ranged from 34.13 to 69.68% at 194 DAT. Severity of Alternaria fruit rot in terms of PDI was between 31.93 and 58.24 based on which all the genotypes were categorized as either susceptible or highly susceptible. Among the various biochemical and nutrient content of chilli fruits only total phenol and calcium content showed significant negative correlation with severity (PDI) of Alternaria fruit rot of chilli. Benomyl (0.05%) either alone or in combination with either Trichoderma harzianum (108 spores/ml) or gingelly oil (0.5%) significantly reduced incidence and severity of post harvest Alternaria fruit rot of chilli. Benomyl reduced incidence by 70.58% and severity by 83.02%.ThesisItem Open Access STUDIES ON VIRAL DISEASES OF URDBEAN [Vigna mungo (L.) HEPPER](Acharya N.G. Ranga Agricultural University, Guntur, 2015) JANAKI RATNAM, J; Dr. V. MANOJ KUMARThe investigation on the “Studies on viral diseases of urdbean [Vigna mungo (L.) Hepper] was carried out at Agricultural College, Bapatla, Guntur district, Andhra Pradesh during 2013-14. Survey conducted in Guntur district of Andhra Pradesh during rabi 2013-14 revealed the incidence and severity of mungbean yellow mosaic disease caused by MYMV in the range of 4-36% and 1.78-38.22%, respectively. Per cent incidence of leaf curl disease caused by GBNV and leaf crinkle disease caused by urdbean leaf crinkle virus were in the range of 6-18% and 11-25%, respectively. DAC-ELISA tests of leaf curl infected samples confirmed the prevalence of GBNV. Mungbean yellow mosaic disease symptoms appeared as yellow diffused spots scattered on leaf lamina and rapidly expanded. Very soon, each leaf showed yellow patches alternating with green colour. The affected leaves were reduced in size and later turned completely yellow. Leaves with severe symptoms turned necrotic. Leaf curl disease showed veinal discoloration. These veins later became necrotic resulting in downward curling of leaves. On the surface of the infected leaves, chlorotic lesions turning necrotic were observed. Leaf necrosis lead to the death of growing bud. Early infection caused the death of the plant. Urdbean leaf crinkle virus caused systemic infection in blackgram. The characteristic symptoms associated with the disease were puckering, crinkling and curling of leaves, reduction in petiole length, malformation of flowers and stunted growth. Mechanical sap inoculation of cowpea cv. C-152 with GBNV infected leaf sample produced chlorotic lesions five to seven days after inoculation which later turned necrotic. ULCV sap inoculation on blackgram (LBG 623) produced disease symptoms eight to ten days after inoculation, inoculated leaves showed upward curling, foamy texture, pale green, severe crinkling and were reduced in size compared to normal leaves. During kharif 2013, MYMV incidence revealed a significant positive correlation with relative humidity (8:30 AM) and evening relative humidity (5:30 PM) whereas during rabi 2013-14, whitefly population per trifoliate leaf, maximum temperature and minimum temperature showed positive significant correlation, relative humidity at 8:30 AM showed significant negative correlation. Leaf curl incidence showed positive significant correlation with relative humidity at 8:30 AM and relative humidity at 5:30 PM during kharif 2013 whereas maximum temperature and minimum temperature showed significant positive correlation, relative humidity at 8:30 AM showed significant negative correlation during rabi 2013-14. Leaf crinkle incidence showed positive significant correlation with relative humidity at 5:30 PM during kharif 2013 whereas during rabi leaf crinkle incidence had significant positive correlation with maximum and minimum temp and significant negative correlation with relative humidity at 8:30 AM. Eighty-five genotypes of urdbean screened against virus diseases under field conditions with LBG 623 as susceptible check showed varied per cent incidence. Seventy-three genotypes showed resistant reaction whereas eight genotypes were moderately resistant to MYMV, three genotypes were immune and 18 genotypes were highly resistant to leaf curl disease. Thirty-seven genotypes were immune and 28 were highly resistant to ULCV while all other genotypes showed moderately resistant to immune reaction. 91.7% of MYMV resistant, 70.58% of leaf curl resistant and 94.5 %, of leaf crinkle immune genotypes exhibited dense pubescence. MYMV resistant genotypes, leaf curl resistant genotypes and leaf crinkle immune genotypes showed highest wax content in the range of 0.417 to 0.653 mg dm-2. Seed treatment with imidacloprid @ 5g/kg seed and insecticidal spray with thiamethoxam @ 0.2 g / l at 30 DAS resulted in significant control of virus diseases through vector control. It also improved shoot length, number of primary branches per plant, number of pods per plant, 100 seed weight, seed yield and it was found economical.ThesisItem Open Access EFFECT OF GRAIN DISCOLOURATION DISEASE COMPLEX ON RICE SEED QUALITY AND ITS MANAGEMENT(Acharya N.G. Ranga Agricultural University, Guntur, 2015) DIVYA, M; Dr. V. PRASANNA KUMARIThe investigation on the “Effect of grain discolouration disease complex on rice seed quality and its management” was carried out in the Agricultural College, Bapatla, Guntur district, Andhra Pradesh during 2013-14. Grain discolouration was recorded in all the samples collected from the selected major rice growing districts of Andhra Pradesh. Rice grains obtained from four different rice growing areas showed considerable and varied levels of grain discolouration both on weight and number basis in all the four major rice growing districts of Andhra Pradesh. Discolouration level was found to increase with increase in the storage period irrespective of the variety and location of sample. Grain discolouration which was 10.80% initially, increased to 50.84% after four months of storage across samples from all the four districts. Mycoflora well known to be associated with discoloured grains were recovered from discoloured grain samples in this investigation also. Curvularia sp. (31.65% in glumes and 31.89% in kernals) Helminthosporium sp. (32.67% in glumes and 30.15% in kernals), Alternaria sp. (14.77% in glumes and 21.15% in kernals), Fusarium sp. (17.64% in glumes and 12.40% in kernals) and Aspergillus sp. (2.91% in glumes and 4.45% in kernals). The three most predominant fungi viz., Curvularia sp., Helminthosporium sp. and Alternaria sp. were found to cause grain discolouration upon individual and combined inoculations. However, combined inoculations of these fungi resulted in enhanced discolouration. Seed germination and seedling vigour decreased significantly with increase in the grade of discolouration and storage period. Seed germination was 88.40 to 92.20% in seeds with 1-5% discolouration from the four districts and was found to be lesser; 85.80 to 89.40% in seeds with 6-25% discolouration, 81.60 to 86.20% in seeds with 25-50% discolouration and 79.40 to 80.80% in seeds with more than 50% discolouration in the first month of collection of samples. Seed germination decreased as an obvious consequence of increased discolouration with increasing storage period; four months after storage seed germination in seeds with 1-5% discolouration was 84 to 86.60% and in seeds with more than 50% discolouration it was 64.60 to 69.4 %. Seedling vigour index was found to be in the trend as that of seed germination i.e., an inverse relationship with level of grain discolouration and storage period. Significantly higher concentration of starch, total sugar, reducing and non reducing sugars and lower concentrations of total phenols were observed in healthy grains than in discoloured grains. Changes in biochemical constituents between healthy and discoloured grains were significant for starch, total phenols, total sugars, reducing sugars, and non significant for non reducing sugars. Curvularia sp., Helminthosporium sp. and Alternaria sp. isolated from discoloured grains were found to be sensitive to mancozeb at higher concentration (250 ppm) and to propiconazole at lower concentration (100 ppm) in vitro. The lowest narrow brown leaf spot severity (PDI) was recorded with mancozeb 0.25% and validamycin 0.2% spray (4.07). Propiconazole 1.0% (18.51), hexaconazole 0.2% (20.48), mancozeb 0.25% (20.85) and tricyclazole 0.06% (22.99) significantly reduced brown spot severity than unsprayed check. No significant difference was observed among the fungicides tested in controlling sheath rot and false smut. The lowest grain discolouration (11.93%) was recorded with mancozeb 0.25% compared to other fungicides. Number of grains per panicle and grain yield did not differ significantly with fungicidal treatments, as the fungicidal treatments were imposed only after panicle initiation and that could not significantly influence the number of grains per panicle. However, highest grain yield (39.58 q ha -1) was obtained in hexaconazole treated plots. Varieties were evaluated for their reaction to grain discolouration and other diseases and their possible correlation with grain discolouration. Leaf blast severity was low and ranged between nil (MTU-1010, NLR-3041 and MTU-1064) and 11.11 (RGL-2537). Similarly, narrow brown leaf spot severity was also low and the highest PDI was recorded in BPT -2411 (12.78) and the lowest was in MTU-1075 (2.22). The highest brown spot severity was recorded in MTU 1075 (PDI=35.94). During the season, varieties like MTU-1010, BPT-3291, BPT-1768, BPT-2270, RGL-2537 and MTU-1064 were free from sheath rot and likewise, in five varieties viz., MTU-1010, BPT-3291, BPT-2295, BPT-1768 and MTU-3626 false smut was not recorded. Though panicle mite incidence was observed in all the varieties the differences in incidence did not differ significantly. Grain discolouration was significantly varied among the rice varieties with the highest in NLR 34449 (40.68%) and the lowest in MTU 1010 (14.78%). Correlation between grain discolouration and other diseases and panicle mite revealed a non significant positive correlation with leaf blast, NBLS, sheath rot and highly significant positive correlation with brown spot and panicle mite. Panicle mite infestation might have predisposed the grains in their formative stage to fungi causing discolouration.ThesisItem Open Access STUDIES ON VARIABILITY AND MANAGEMENT OF Sarocladium oryzae (Sawada) Gams and Hawksworth, CAUSING SHEATH ROT OF RICE(Acharya N.G. Ranga Agricultural University, Guntur, 2015) SUNIL KUMAR, Y; ANIL KUMAR, PThe present investigation on “Studies on variability and management of Sarocladium oryzae (Sawada) Gams and Hawksworth, causing sheath rot of rice” was carried out in order to assess the prevalence of sheath rot in major rice growing mandals of Nellore and Chittoor districts of Andhra Pradesh, to find variability in vitro among the ten sympatric isolates of S. oryzae and to evaluate rice based fungicides, plant extracts and bio control agents against sheath rot in vitro and in vivo. Survey conducted during late kharif and rabi 2014-15 revealed that incidence of sheath rot was more in Nellore district (49.82%) than that in Chittoor district (29.16%). Sheath rot incidence was also found to be more in late kharif than in rabi. Over all the mandals surveyed during kharif 2014-15 in Nellore district, Indukurpeta mandal (59.6%) recorded highest sheath rot incidence and Pellakur mandal (28.4%) recorded the least. In Chittoor district Vadamalapeta mandal recorded highest disease incidence (36.6%) and Srikalahasthi mandal (9.3%) recorded the least. Over all the villages surveyed in Nellore and Chittoor districts during kharif 2014-15, maximum disease incidence was recorded in Indukurpeta village (65.5%) of Indukurpeta mandal of Nellore district while least disease incidence was recorded in Mannavaram village (7.4%) of Srikalahasthi mandal, Chittoor district. Over all the mandals surveyed in Nellore and Chittoor district during rabi 2014-15, maximum disease incidence was recorded in Doravarisatram mandal of Nellore district and least in Srikalahasthi mandal of Chittoor district. Over all the villages surveyed in Nellore and Chittoor districts, maximum disease incidence was recorded in Ayyapalem village (45.1%) of Doravarisatram mandal and least in Mannavaram village (7.4%) of Srikalahasthi mandal Ten sympatric isolates were collected, five from each of the two districts surveyed and assessed for the variability. Rice Leaf Extract Agar (RLEA) and Potato Dextrose Agar (PDA) were the best solid media utilized by S. oryzae as carbon source. Isolate So DVS had least growth (1.2cm) and isolate So SKL (1.7cm), So PTR (1.7cm) had maximum radial growth. RLEB was the best liquid media utilized by S. oryzae (0.82g). Least mycelial dry weight was observed on OMB (0.25g). Isolate So SKL showed highest dry weight of mycelial mat (0.55g) and isolate So RCP recorded least mycelial dry weight (0.2g). Conidiation was highest on OMA (49.2 X 106/sq cm) and least on RLEA (22.3 X 106/sq cm). The conidiation was highest with isolate So IDP (68.6 X 106/sq cm), while it was least with isolate So SKL (24.7 X 106/sq cm). Over all the isolates tested maximum length of conidiophore was recorded on RLEA (95.5µm), while least length of conidiophore was recorded on PSA (81.2µm). Maximum mean length of conidiophore was recorded in isolate So RCP (101.2µm), while the least length of conidiophore was recorded in isolate So IDP (66.6µm). Over all the media, isolate So DVS (9.3µm) recorded longest conidia. Isolate So VMP (5.9µm) recorded least conidial length. Over all isolates tested, highest length of conidia was recorded on CDA (8.6µm), while least length of conidia was recorded in RLEA (5.9µm) Isolate So NDP gave maximum lesion length of 1.5cm, while So PTR gave the least lesion length measuring 0.6cm. Isolate So RCP failed to show any symptoms in vitro. Carbendazim, hexaconazole, mancozeb and tebuconazole + trifloxistrobin recorded 100% inhibition in the growth of S. oryzae NLR at all the five concentrations tested in vitro. Among the six plant extracts tested, bulb extract of Allium sativum was found to be the most effective in inhibiting the growth of S. oryzae (63.4%). None of the seven isolates of Trichoderma and eight isolates of Pseudomonas fluorescens were found effective on the growth of S. oryzae. In field experiment, two sprays of tebuconazole+trifloxistrobin resulted in least disease incidence (13.3%) equivalent to 40.1% disease reduction over control (22.2%). During rabi 2014-15, least disease incidence was observed with two sprays of garlic extract (43.7% with disease reduction equivalent to 30.6%) and with tebuconazole + trifloxistrobin (44.7% with disease reduction equivalent to 29.1%). No correlation was obtained between amount of disease and yield as the reduction in disease due to fungicidal spray was not substantial.ThesisItem Open Access MANAGEMENT OF GROUNDNUT STEM ROT PATHOGEN Sclerotium rolfsii Sacc. USING ROOT ENDOPHYTES(Acharya N.G. Ranga Agricultural University, Guntur, 2015) SHAHEDA NASREEN, S; ANIL KUMAR, PIn the present investigation seven endophytic Trichoderma spp., seven rhizosphere Trichoderma spp., six isolates of Pseudomonas fluorescens and eight isolates of endophytic bacteria were isolated, screened for their biocontrol potential against groundnut stem rot pathogen Sclerotium rolfsii in vitro and the selected potential isolates were further assessed in vivo in pot culture against ground stem rot. The data obtained was summarized herewith. The groundnut stem rot affected plants showed yellowing and drying of leaves, collar rot and wilting of plants, and association of white mycelial threads along with brown mustard seed like sclerotial bodies on the affected groundnut plant parts. The white mycelial cottony growth of the pathogen S. rolfsii took four days to attain 9.0 cm diameter on PDA at 28±2°C and produced 108-132 sclerotial bodies with 0.9 to 1.2mm dia after 10 days of incubation. On liquid potato dextrose medium, the mycelial dry weight was measured to be 0.8 to 1.0g and the sclerotial number was 98 to 110 with 10 days of incubation at 28±2°C. Variation existed between the cultivars of groundnut in terms of susceptibility to S. rolfsii. Groundnut cv. Narayani was more susceptible to S. rolfsii with seed rot as the major symptom while cv. TMV-2 had less of seed rot and there by more of seedling rot and collar rot. With cv. TMV-2, the inoculum threshold level was found to be 4g/kg soil of S. rolfsii inoculum mass multiplied on sterilized sorghum grains. As the dose of inoculum per kg soil increased, the disease incidence or plant mortality also increased. Based on morphological features, the seven endophytic Trichoderma isolates were identified as T. flavofuscum (designated as ET-1 and ET-3), T. harzianum (ET-2), T. viride (ET-4 and ET-5) and T. longibrachiatum (ET-6 and ET-7). The seven rhizosphere Trichoderma isolates were identified as T. aureoviride (designated as RT-1), T. fertile (RT-2), T. hamatum (RT-3), T. polysporum (RT-4), T. koningii (RT-5 and RT-6) and T. harzianum (RT-7). The six endophytic isolates obtained on fluorescent Pseudomonas selective medium were designated as PF-1 to PF-6 while the eight endophytic isolates obtained on nutrient agar with no fluorescence were designated as EB-1 to EB-8. Variation existed in the initial growth of the 14 test Trichoderma isolates in their growth on PDA. Isolate ET-1 among the endophytic Trichoderma spp., and RT-4 and RT-6 among the rhizosphere Trichoderma spp. were considered relatively fast growing. Dual culture interactions revealed that among the isolates of endophytic Trichoderma ET-1, Et-2, ET-3 and ET-7, and among rhizosphere Trichoderma RT-5 and RT-6 could cause lysis and then could overgrow on S. rolfsii. In other interactions where in zone of inhibition was not formed, S. rolfsii could over grow on Trichoderma. Microscopic studies revealed no mycoparasitic signs but Trichoderma hyphae interwoven with S. rolfsii mycelia and hyphal strands, bulging and deformation S. rolfsii hyphae and sclerotial initials were observed. Among the endophytic bacterial isolates, PF-1 was found better with consistent inhibition in the growth of S. rolfsii. Based on growth in monoculture and dual culture studies in vitro, isolate ET-1, RT-6 and PF-1 were selected for further studies in vitro and in vivo. In vitro antibiosis assays revealed that the volatiles produced by ET-1 were more effective in inhibiting the growth of S. rolfsii compared to the volatiles of RT-6 and PF-1. On the other hand, culture filtrates of RT-6 and PF-1 had higher inhibitory effect than that of ET-1. Among the fungicides tested, viz., carboxin+thiram (combination product), tebuconazole, thiram and mancozeb showed 100 per cent inhibition in the growth of S. rolfsii in vitro. Carbendazim was found ineffective against S. rolfsii. Further, isolates ET-1 and RT-6 were found incompatible with the four fungicides that were also found effective against S. rolfsii. However, under high nutrient conditions of PDA, ET-1 was found compatible with carboxin+thiram. Rhizosphere isolate RT-6 was found more tolerant to mancozeb than endophytic ET-1. Compatibility studies in vitro using dual culture method reveled that RT-6 and PF-1 were not compatible resulting in formation of inhibition zone. Pot culture studies revealed that seed treatment with endophytic isolates ET-1 or PF-1 was better than that with rhizosphere isolate RT-6 in reducing groundnut stem rot. However, soil application of RT-6, ET-1 and PF-1 were on par in reducing stem rot of groundnut. All the treatments tested proved better in reducing stem rot of groundnut in comparison to pathogen inoculated check excepting combination of PF-1 and RT-6 which were incompatible with each other. No additional benefit could be derived by combination treatments. All the effective treatments were on par with the seed treatment of carboxin+thiram combination product indicating that biocontrol can successfully be substituted for fungicidal treatment. Application of biocontrol agents significantly improved the vigour index of groundnut plants by decreasing loss in germination due to S. rolfsii and increasing root and shoot length.ThesisItem Open Access CHARACTERIZATION AND RHIZOSPHERE COMPETENCE OF TRICHODERMA SPP. FROM DIFFERENT CROPPING SYSTEMS IN CHITTOOR DIST(Acharya N.G. Ranga Agricultural University, Guntur, 2015) RANGA RANI, ATLA; KHAYUM AHAMMED, SNine Trichoderma isolates were obtained from 27 rhizosphere samples collected from groundnut, redgram and tomato. Five isolates from groundnut rhizosphere soils, two isolates from redgram and two isolates from tomato crop grown in Chittoor dist. All isolates were grouped based on growth rate, isolates GRT-2, GRT-3, RRT-2 and TRT-2 were categorized as very fast growing, GRT-1, RRT-1 and TRT-1 as fast growing and GRT-4, GRT-5 as medium growing. Based on characters observed in cultural and microscopic studies, Trichoderma spp. was identified up to species level. Isolates GRT-2, GRT-4, GRT-5 identified as Trichoderma virens, RRT-1 and GRT-3 as Trichoderma harzianum. TRT-2 and RRT-2 as Trichoderma asperillum. Isolates GRT-1 and TRT-1 as Trichoderma longibrachiatum and Trichoderma pseudokoningii respectively. In dual culture studies against major soil borne plant pathogens viz., Sclerotium rolfsii, Aspergillus niger, Rhizoctonia solani, Macrophomina phaseolina, Fusarium oxysporum showed that GRT-3 isolate was found to be effective against Aspergillus niger and Fusarium oxysporum. Isolate TRT-1 was found to be effective against Scerotium rolfsii and TRT-2 was effective against Rhizoctonia solani and Macrophomina phaseolina. Among nine isolates of Trichoderma spp. isolate GRT-3 recorded highest optical density of 0.290, 0.130, 0.260 in terms of production of chitinase, β-1,3 glucanase and cellulase. Molecular characterization for all isolates by PCR- RAPD showed that, out of 15 primers from OPA and OPM series 9 primers were gave reproducible and scorable band with high percentage of polymorphism. A total of 207 amplification products were obtained, out of which 196 were polymorphic. The maximum polymorphism was observed in PCR reaction with OPA-01, OPA-03, OPA-05, OPA-09, OPA-10, OPM-04 and OPM-20. These similarity co-efficients were subjected to Unweighted Pair Group Method on Arithmetic average (UPGMA) and a dendrogram was drawn using SPSS package. The prominent outcome of this analysis is that the Trichoderma isolates clustered into two major groups, first group having GRT-4, GRT-5, GRT-3 and TRT-1 in one cluster and remaining isolates GRT-1, GRT-2, RRT-2, TRT-2 and RRT1 in other cluster which in turn grouped into two sub-clusters separating isolates GRT-1, GRT-2 formed one group and RRT-2, TRT-2 and RRT-1 formed another group. Based on characterization and bio-efficacy of all the isolates of Trichoderma spp. GRT-3 was found to be effective and its rhizosphere colonization in soils collected from groundnut, redgram and tomato crops were studied up to 15 days of sowing. Among all crops tested, redgram plant yielded the highest rhizosphere populations of antagonist GRT-3 i.e. 28 and 35 x 108 cfu/g of soil at 15 DAS in both natural and autoclaved soil respectively. The extent of rhizosphere colonized by Trichoderma isolate GRT-3 in other crops in descending order of rhizosphere competence was 25 and 31 x 108 cfu/g of soil, 22 and 28 x 108 cfu/g of soil in natural and autoclaved soils of tomato and groundnut respectively at 15 DAS. There was less rhizosphere populations of Trichoderma isolate (GRT-3) when it was applied to crops which were grown in natural soil as compared to autoclaved soil.