ThesisItem Open AccessA STUDY ON MARKET OPPORTUNITIES FOR VALUE ADDED MILLET PRODUCTS IN URBAN AREAS OF PRAKASAM DISTRICT OF ANDHRA PRADESH(Acharya NG Ranga Agricultural University, 2024-02-08) PENUGONDA RAMAKRISHNA; P.V. SATHYA GOPALMillets are small-grained cereal food crops with drought, and extreme weather resilience and require minimal chemical inputs such as fertilizers and pesticides to flourish. Millets are also known as "Nutri-cereals" because they contain most nutrients necessary for regular human body function. Millets can bring a dietary advantage to their consumers and help them to tackle many lifestyle diseases. Millets are becoming more essential because of the systemic link between human health and nutritional consumption. The rise in demand for value added millet foods is mainly due to a change in their lifestyle and the resulting diseases like diabetes, obesity, cardiovascular diseases and cancer etc., Commercialization with value addition of the products is the only way to increase the consumption of millets. The objective of the present study was to collect the data on market opportunities for value added millet products in urban areas of Prakasam district of Andhra Pradesh. The study is based on primary data collected from sample of 80 consumers from four urban centres (20 consumers from each urban centre). The data on consumption of millets, consumer preference towards value added millet products was collected with the help of a structured interview schedule developed based on the study objectives. The collected data was processed using Percentages, Frequencies, Mean, Standard Deviation and Garret ranking. Presented in the form of tables to draw valid conclusions. Several factors affect the consumption of millets which resulted in shifting of consumers from fine cereals to millets. Socio-economic factor is one of the major variables which changes the food purchasing behaviour which is unique for each consumer. xiv The education, income and health level of the family are the major factors that were found to influence the consumption of millets. The present study found a positive association between education levels and millet consumption. The millet consumers were more in the higher education level category. Most of the consumers expressed that they could observe an improvement in their health status due to the consumption of millets. Thus, millet consumption was found to be positively associated with health status. Income status too influenced millet consumption. The consumption statistics for value added millet products revealed that they were consumed regularly, either alternate day or weekly once and that they provided personal benefits to the consumers. While majority of consumers preferred to consume instant mixes, RTE foods, and RTC foods to save preparation time, avoids spoilage and wastage. Most of consumers are spending an average high amount on traditional recipes for consuming. The study revealed that nutritional value, price, good flavour and taste, storage and preservability are the major attributes preferred by the consumer. The estimated market potential of value added millet products in Prakasam district, for Traditional recipes was rupees 72.15 crores followed by Pasta products is rupees 21.46 crores, Bakery products is 16.86 crores, Flaked and popped products is rupees 8.29 crores and for Instant food mixes is rupees 4.02 crores (per year) ThesisItem Open AccessSTUDIES ON IDENTIFICATION, CHARACTERIZATION AND EFFECTIVENESS OF Trichoderma spp. AGAINST CHICKPEA SOIL BORNE PATHOGENIC FUNGI(Acharya N G Ranga Agricultural University, 2023-12-26) MADDI SANDHYA; S. KHAYUM AHAMMEDIn the present investigation on “Studies on identification, characterization and effectiveness of Trichoderma spp. against chickpea soil borne pathogenic fungi”, three soil borne pathogenic fungi i.e., Sclerotium rolfsii, Rhizoctonia bataticola and Fusarium oxysporum f. sp. ciceri symptoms were collected from the infected fields of chickpea and were isolated. Thirteen Trichoderma isolates were collected from the Department of Plant Pathology, Agricultural College, Bapatla. Of all the 13 Trichoderma isolates, four isolates were considered as potential isolates and further assessment was made to study their variability in morphological, cultural, biochemical and molecular characters. They were also tested for their sensitivity towards various fungicides and insecticides. Variability studies of thirteen Trichoderma isolates collected were performed using cultural characters such as colony texture, elevation, growth habit, colony margin and mycelial nature. All Trichoderma isolates were grown on PDA to study their morphological and cultural variability and grouped into four categories i.e., very fast, fast, medium and slow based on radial growth. Isolate T 19002 showed fast growth (4.1-6.0 cm) and remaining 12 isolates with medium growth of 2.1 to 4.0 cm range at 1 day after incubation (DAI). At 3 DAI, T 19001 and citrus isolates showed fast growth and remaining 11 isolates showed very fast growth (>6.1 cm) and considered to be having better proliferation and all isolates showed very fast growth by 5 DAI. Observations at 3 DAI indicated that most of the isolates recorded growth rate between 0.5 to 1.0 mm/hr. xvii Based on bioefficacy studies in vitro using dual culture technique against S. rolfsii, R. bataticola and Foc. The present investigation revealed that incubation up to five days was insufficient to categorize an isolate as potential. Hence, based on other qualitative parameters such as zone of inhibition, overgrowth potential, lysis, sporulation in Trichoderma were also considered for screening and selection of potential isolates. Isolates (T 19006, T 19015, T 19002, T 19026) with fast growth, lysing and overgrowing with good sporulation over test pathogen at zone of inhibition (zi), pigmentation were considered as potential isolates against all three test pathogens i.e., S. rolfsii, R. bataticola, Foc and used for further studies. The four potential Trichoderma isolates were assessed for their variabililty in morphological, cultural, biochemical, molecular characterization and their sensitivity in radial growth and spore germination. Based on morphology of conidiophore branching, phialides shapes, the 4 Trichoderma isolates were identified as T. harzianum (T 19006, T 19015), T. asperellum (T 19002), T. aureoviride (T 19026). The four potential Trichoderma isolates were assessed for their variabililty in morphological, cultural, biochemical, molecular characterization and their sensitivity in radial growth and spore germination. Based on morphology of conidiophore branching, phialides shapes, the 4 Trichoderma isolates were identified as T. harzianum (T 19006, T 19015), T. asperellum (T 19002), T. aureoviride (T 19026). Assessment of molecular variability using SSR primers for 4 potential Trichoderma isolates was performed which resulted in 60 bands with polymorphism having band size from 100 to 2000 bp. Where, some of the primer sequence was used to identify Trichoderma genus upto species level and confirmed them as T. asperellum, T. aureoviride and T. harzianum. Dendrogram obtained had 2 clusters (I and II). Cluster I consists of 3 isolates and cluster II contain I isolate (T19002), had a similarity of 53 per cent with each other cluster. Biochemical studies were performed to test their chitinase and β-1,3-glucanase activity, where banana isolate have high enzyme production i.e., 181.54 mg ml-1 and 122.06 μmol min-1 ml-1 respectively. Among six insecticides tested for their sensitivity by poison food technique, spinosad completely inhibited the radial growth of all four Trichoderma isolates at all the three concentrations (R/2, R and 2R respectively). Indoxacarb showed mycelial growth only at R/2 concentration and complete inhibition was observed both at R and 2R concentrations in all Trichoderma isolates. Among six fungicides tested for their sensitivity by using slide germination technique, metalaxyl + mancozeb, azoxystrobin + tebuconazole, carbendazim + mancozeb, azoxystrobin + difenconzole, carboxin + thiram complete inhibition of spore germination in four potential Trichoderma isolates at all the three concentrations (R/2, R and 2R) was observed and tebuconazole+trifloxystrobin showed spore germination with significant difference when compared to control. Among six insecticides tested for their sensitivity, spinosad completely inhibited the spore germination of all Trichoderma isolates followed by profenophos and rynaxypyr at all the three concentrations (R/2, R and 2R respectively). ThesisItem Open AccessETIOLOGY, EPIDEMIOLOGY AND MANAGEMENT OF CHRYSANTHEMUM FLOWER BLIGHT(Acharya N G Ranga Agricultural University, 2023-12-26) A. SNEHALATHA RANI; V. PRASANNA KUMARIThe present investigation entitled “Etiology, epidemiology and management of chrysanthemum flower blight” was carried out to assess the prevalence of the disease and further characterization. Disease dynamics during 2019-21 revealed that it is an important emerging disease both under protected and open filed conditions of Andhra Pradesh. Maximum per cent disease incidence (48.40 %) and severity (28.28 %) was recorded in East Godavari followed by Chittoor and Visakhapatnam districts. Predominant pathogen was Ectophoma multirostrata along with occurrence of Stemphylium lycopersici, Botrytis cinerea, Alternaria alternata, Colletotrichum gloeosporoides and Lasiodiplodia theobroame. Pathogenicity of the six pathogens was proved on chrysanthemum cultivar New Man and twelve isolates of Ectophoma were characterized morphologically and molecularly. Ectophoma culture was greenish grey initially with floccose to felty appearance and later became dark brown or black with appressed texture on potato dextrose agar. It produced dark brown to black, globose or irregular, solitary or aggregated pycnidia that were partly or fully submerged in the media. Conidia were hyaline, single celled, mostly oblong to ellipsoid and guttulate. Pycnidial length and width of population varied between 89.67 and 132.98 μm and from 60.56 to 89.68 μm respectively. Mean conidial length of population was 4.00±0.24 μm and conidial width of population ranged between 1.00 and 2.90 μm. Pathological and morphological characters contributed significantly to study the divergence of isolates when compared to cultural characters. Incubation period (5.33 to 8.33 days) and lesion length (7.67 to 38.33 mm) among the isolates in detached xix leaf assay correlated with the incubation period and disease severity in pot experiment (1.00 to 2.67 days and 17.67 to 65.67 PDI respectively). Based on different characters studied, the multivariate analysis revealed grouping the twelve isolates in to four clusters. Simple sequence repeat (SSR) primer based diversity analysis showed that the Ectophoma isolates, VSPPM3 and VSPPM4 from Visakhapatnam were closely related with 96 per cent similarity whereas VSPPM3 from Visakhapatnam and EGPM3 from East Godavari were distantly related with only fifty per cent similarity. Isolates were grouped irrespective of their geographical region based on clustering by Tocher’s and SSR analysis. The most virulent isolate, EGPM1 was characterized molecularly by sequencing and Phylogenetic trees constructed based on ITS region and actin gene sequences showed 92 to 100 per cent similarity with Ectophoma multirostrata. The ITS sequence of EGPM1 (EGPM19-1) was submitted and obtained NCBI unique accession number, ON819852. Correlation studies between disease parameters of chrysanthemum and weather parameters during 2019-20 and 2020-21 revealed that disease incidence and severity were significantly and negatively correlated with maximum temperature, minimum temperature, morning relative humidity and evaporation during first and second dates of planting. In vitro fungicide assays were conducted with selected fungicides, against the six pathogens isolated where complete inhibition of E. multirostrata, B. cinerea, A. alternata and C. gloeosporoides was observed with difenoconazole while mancozeb completely inhibited S. lycopersici and L. theobromae. Under field conditions two years pooled data revealed that two sprays of difenoconazole @ 0.1 per cent was significantly superior over other treatments with 40.00, 76.67 % disease incidence, 2.17, 7.64 % of disease severity on flowers and 3.52, 4.28 % of disease severity on leaves respectively at five and 15 days after second spray. It was also observed with the highest yield (6.87 kg plot-1; 7.63 t ha-1), highest B: C ratio (2.06) and highest shelf life period of flowers (4.83 days, 10.33 days at room temperature and 4 0C respectively). ThesisItem Open AccessCHARACTERIZATION OF MUNGBEAN GENOTYPES WITH VARIABLE REACTIONS TO MUNGBEAN YELLOW MOSAIC VIRUS INFECTION(Acharya N G Ranga Agricultural University, 2023-12-26) CHALLA SRI PRIYA; G. BINDU MADHAVIThe present investigation on “Characterization of mungbean genotypes with variable reactions to mungbean yellow mosaic virus infection” was carried out at the Regional Agricultural Research Station (RARS), Lam, Guntur, Andhra Pradesh during rabi 2021-22. Mungbean [Vigna radiata (L.) Wilczek] is an important short duration grain legume because of its low water requirement, and as a crop suitable for rotation and nutritional security being a rich dietary source of protein. Biotic stress produced by viruses especially mungbean yellow mosaic virus (MYMV) is the major constraint in its cultivation causing substantial yield losses. Total twenty five mungbean genotypes along with LGG 450 as susceptible check were screened against Mungbean yellow mosaic virus disease under field conditions. Symptoms of MYMV first appeared on young leaves in the form of yellow, diffused, round spots scattered on the leaf lamina. The infected leaves later turned necrotic. The diseased plants matured later and had relatively few flowers with shriveled pods. Disease symptoms first appeared in genotypes LGG 673, LGG 677, LGG 460 and LGG 450 by 20 DAS while in genotypes, LGG 610, LGG 604, LGG 606, LGG 625, LGG 645, IPM 2-14 and Pusa 9072 disease occurred at 60DAS. The data on incidence and severity of yellow mosaic virus was recorded at different intervals i.e., 20, 40 and 60 DAS. The per cent disease incidence of MYMV among 26 mungbean genotypes was varied from 4.25 to 51.76% and disease severity (PDI) ranged from 1.58 to 76.49 % during 60 DAS. Further, tested genotypes were grouped into different categories based on 0-9 disease scale given by AICRP and MULLaRP. Among the 26 genotypes of mungbean, seven were found resistant, 15 genotypes xv were moderately resistant, two were moderately susceptible, three genotypes were susceptible and the check LGG 450 showed highly susceptible reaction to yellow mosaic virus of mungbean. Morphological characters viz., trichome density, leaf thickness, stomatal frequency, leaf epicuticular wax content and leaf colour intensity were evaluated in all 26 mungbean genotypes during 40 and 60 DAS. It was observed that trichome density, leaf epicuticular wax content and leaf colour intensity in MYMV resistant mungbean genotypes were comparatively high to that of susceptible genotypes. Similarly, leaves of MYMV resistant mungbean genotypes were thicker when compared to susceptible genotypes and highly susceptible check. However, stomatal frequency was found maximum in susceptible genotypes than the resistant genotypes. The biochemical parameters viz., total sugars, reducing sugars, total phenols, total protein and total chlorophyll content were studied both at 40 and 60 DAS in all mungbean genotypes. Decreased total sugar content was observed in susceptible entries compared to resistant ones during both periods of observations i.e., 40 and 60 DAS.It was found that total reducing sugar content was maximum in MYMV resistant genotypes followed by moderately resistant genotypes and then susceptible genotypes. The similar trend was followed in total phenols, total proteins and total chlorophyll content in all tested mungbean genotypes. The molecular characterization of yellow mosaic virus (YMV) in infected mungbean genotypes was done by using the coat protein (CP) and movement protein (MP) gene specific primers from isolates collected at RARS, Lam farm to confirm their strain as MYMV or MYMIV.PCR based characterization of strains (MYMV/MYMIV) were carried out using their gene specific primers respectively.Distinct viral gene specific PCR products corresponding to CP ~648 bp, ~704 bp and ~920 bp were obtained for MYMV and MYMIV respectively. The movement protein gene sequence was also successfully amplified with a fragment size of 900 bp using MYMIV- MP gene specific primer.The samples were further confirmed by CP and MP gene sequencing.The obtained sequences were compared with the other selected begomovirus sequences from the NCBI blast database. The full length coat protein and movement protein gene sequences of MYMV and MYMIV isolates along with available corresponding DNA-A and DNA-B sequences of yellow mosaic virus (YMV‟s) infecting mungbean genotypes when subjected to phylogenetic analysis formed two major clusters. Results were found to show more sequence homology with MYMIV isolates from South India confirming that the begomovirus causing yellow mosaic disease in mungbean is explored to be as strain of MYMIV and not as MYMV. ThesisItem Open AccessISOLATION OF Pseudomonas fluorescens AND PINK PIGMENTED FACULTATIVE METHYLOTROPHS FOR MANAGEMENT OF URDBEAN FUNGAL FOLIAR DISEASES(Acharya N G Ranga Agricultural University, 2023-12-26) DASARI MANIKANTHA; V. MANOJ KUMARA total of 40 isolates, 20 of Pseudomonas fluorescens and 20 methylotrophic bacteria were isolated from the blackgram phyllosphere and their biochemical studies revealed that all the P. fluorescens isolates tested to be positive for Catalase, Amylase, Urease and Protease activity. 17 out of 20 isolates had Siderophore production and only two isolates has HCN production. Only one isolate had shown positive for indole production. All the PPFM isolates were found positive for Catalase and Urease activity and negative for HCN production. Fourteen out of 20 PPFM isolates had shown Amylase activity, only one isolate shown positive for Protease activity and two had shown positive for Siderophore production. Testing for PGP traits revealed that 15 P. fluorescens isolates had shown Psolubilization, six isolate had shown IAA production and five isolates had shown Ksolubilization. Eleven PPFM isolates had shown positive for P- solubilization and only one isolate had shown positive fir IAA production and all the PPFM isolates had shown negative for K- solubilization. In vitro dual culture studies revealed that, among 20 P. fluorescens isolates tested, two isolates viz., CBP- 05 and PPP-01 were found to be the most promising isolates with maximum antagonistic potential against Corynespora cassiicola (66.51% and 64.99%) and Alternaria alternata (60.43% and 60.43%). Two methylotroph isolates viz., PPM-01 and ABM-04 exhibited maximum antagonistic potential against C. cassiicola (68.04% and 54.34%) and A. alternata (34.55% and 34.55%). xvii Intra and inter compatibility studies of four antagonistic bacterial isolates, viz., two Pseudomonas (CBP-05, PPP-01) and two methylotrophs (PPM-01 and ABM-04) revealed that all the isolates were compatible with each other under in vitro conditions which was tested through cross streak method. Based on 16S rRNA gene sequencing the Pseudomonas isolate PPP-01 and CBP-05 was found closely related with Pseudomonas fluorescens. However, the methylotroph PPM-01 grouped with Methylobacterium indicum and ABM-04 grouped with Hyphomicrobium facile. The pathogens Corynespora grouped with Corynespora cassiicola isolate while Alternaria was related with Alternaria alternata isolate. Under field conditions, Fungicidal check had shown lowest PDI and AUDPC against Corynespora leaf spot (28.11% and 501.10 respectively) and Powdery mildew (0.00% and 0.02 respectively) and there was a significant increase in yield (1130.40 kg ha-1), number of pods per plant (20.10), no. of seeds per pod (5.63) and test weight of 3.85g. Among the antagonist treated plots, foliar spray of consortium of CBP-05, PPP- 01, PPP-01 and ABM-04 @ 108 CFU ml-1 has recorded the lowest PDI against Corynespora leaf spot (36.37%) and Powdery mildew (38.17%) and minimum area under disease progress curve for both Corynespora leaf spot (639.03) and Powdery mildew (644.33). It was also observed to significantly increase the number of pods per plant (19.50), No. of seeds per pod (5.43) and the highest test weight of 3.77g, yield of 1080.25 kg ha-1. However, the benefit cost ratio (BCR) of the different treatments varied from 0.99 to 1.70 with the highest BC ratio was recorded with Treatment T7 (CBP-05, PPP- 01, PPP-01 and ABM-04 (FS)) (1.70) and the fungicide treatment having BC ratio of 1.55 which represents, the combination treatment is a potential alternative to fungicides ThesisItem Open AccessSTUDIES ON DIVERSITY OF Rhizoctonia solani Kuhn INFECTING RICE IN GODAVARI ZONE OF ANDHRA PRADESH AND ITS MANAGEMENT(Acharya N G Ranga Agricultural University, 2023-12-26) VUNDAVALLI SWETHA BINDU; M. RAMABHADRA RAJUIn the present study, on “Studies on diversity of Rhizoctonia solani Kuhn infecting rice in Godavari zone of Andhra Pradesh and its management” survey during kharif 2021 in ten villages from each district of West and East Godavari district. Survey revealed that the sheath blight disease severity was recorded highest in Maruteru (45%) and lowest in Seethanagaram (34%). Studies on cultural and morphological variability of twenty Rhizoctonia spp. isolates obtained from West and East Godavari districts of A.P. indicated that maximum radial growth was observed in WSB21-1 (9.00 cm) with high growth rate of (1.25 mm h-1). Colony colour varied from White (8/1 7.5YR), light brown (6/3 7.5YR), pale brown (6/3 10YR), brownish yellow (6/6 10YR), light yellowish brown (6/3 2.5Y). Six types of growth patterns were observed. Variation in sclerotia colour was observed viz., light brown, dark brown, brown and black brown. Different patterns of sclerotia were observed. Three different types of sclerotia distribution was observed i.e., aerial, surface and surface and aerial. Two types of sclerotia texture were observed i.e., rough and smooth. Time taken for sclerotial formation varied from three to seven days. Sclerotia number varied from 0 to 60. xiv Sclerotial width among isolates ranged from 1.56 to 2.63 mm (ESB21-3). Hyphal width varied from 3.82 (ESB21-4) to 14.68 μm (ESB21-3). Molecular variability was done for all twenty isolates by using ITS and Rhizoctonia specific primers. Among twenty isolates, twelve isolates amplified for Rs2.1 primer indicating that the isolates belong to AG2-1 and AG-8. One isolate was amplified using RoGr-1 primer indicating that isolate as R. oryzae. One isolate amplified by Rs8 primer indicating WSB21-2 belongs to AG-8. In vitro studies of fungicides revealed that Hexaconazole 5% SC, Thifluzamide 24% SC and Carbendazim 50%WP were found superior in inhibiting the R. solani at all concentrations i.e., upto R/5 (200 ppm). In vitro studies of organic extracts revealed that vitex leaf extract was effective against both mycelial growth and sclerotial production of R. solani, whereas, Dried ginger buttermilk extract was effective against only on sclerotial production of R. solani, however, Cow dung + Urine + Asafoetida was found effective against only on mycelial growth of R. solani. Jeevamrutham was found effective at lower concentrations viz., R/4 (2500 ppm) and R/5 (2000 ppm), whereas Bael leaf extract was found siginificantly superior upto R/2 (5000 ppm) in case of filter sterilized extracts on mycelial growth of R. solani. Pot culture studies of fungicides revealed that azoxystrobin 11%+ tebuconazole 18.3% found effective against sheath blight followed by thifluzamide 24% SC and hexaconazole 5% SC. Among the organic extracts, Sour buttermilk followed by Beejamruth, Cow dung + Urine + Asafoetida whereas, treated check carbendazim 75% WP also found effective with highest per cent inhibition. ThesisItem Open AccessVARIABILITY IN RICE BLAST PATHOGEN (Pyricularia oryzae B.C. Couch) AND MOLECULAR PROFILING OF BLAST RESISTANCE GENES IN RICE GENOTYPES(Acharya N G Ranga Agricultural University, 2023-12-26) NARRA NEERAJA; V. BhuvaneswariThe present investigation was undertaken with an aim to know the variability between leaf blast and neck blast pathogen populations. Studies carried out on the variability of isolates using morphological and molecular characteristics. In another study efforts were made to identify the blast resistance genes in rice genotypes. Survey was conducted during rabi, 2021-22 in five different mandals of West Godavari district of Andhra Pradesh for the collection of blast diseased samples and to assess the severity of the disease. The highest mean leaf blast Per cent Disease Index (PDI) 38.48% was recorded in Bhimadolu mandal and the lowest was recorded in Palakollu mandal (18.31%). Among the five mandals, highest neck blast incidence was recorded in Bhimadolu (8.74%). A total of 10 monoconidial isolates of Pyricularia oryzae were established. Out of ten isolates, five were leaf blast (WLB-1 to WLB-5) and five were neck blast isolates (WNB-1 to WNB-5.) The variability in radial growth, colony colour, growth pattern, elevation was studied among the isolates of P. oryzae. Variation existed among the isolates in their conidial dimensions. The longest conidia were observed in the isolate WNB-4 (24.44±0.90) and the shortest conidia in the isolate WLB-1 (18.04±1.58). The broadest conidia were observed in WNB-4 (8.50±1.06) and the narrowest in WNB-5 (6.70±0.96). Molecular identification of P. oryzae isolates with ITS4 and ITS5 universal primers were used in order to support the morphological identification of P. oryzae isolates. All the isolates were appeared as identical by producing the amplified fragment of 560 bp. These results further confirmed the identification of the isolates as P. oryzae. The genetic diversity of P. oryzae isolates was studied using a total of 5 SSR markers. The PIC values ranged from 0.68 to 0.84 with average of 0.78 per marker. The SSR analysis formed two main clusters (I–II) at the Dice similarity coefficient of 0.63. This grouping revealed that, all the isolates were clustered in accordance of leaf blast and neck blast isolates, but not in the specificity of geographical location. A set of 48 genotypes were screened against leaf blast and neck blast during rabi, 2021-22. The same set of genotypes were also profiled for blast resistance genes by using 10 SSR markers. From the phenotypic data 14 genotypes were found as resistant genotypes for both diseases. Eight genotypes viz., LRP 276, Pusa 1882-12-111-7, Pusa Basmati -1, Pusa 1886-13-91-26-9, CR 4156-1-506-2-24, RYT 3437, NLR 20104 and NLR 145 with major R genes i.e., Pi1, Pi2, Pi54, Pita and Pikh combinations were identified as promising lines for rice blast resistance. ThesisItem Open AccessSTUDIES ON PROGRESS AND MANAGEMENT OF CORYNESPORA LEAF SPOT OF COTTON UNDER HIGH DENSITY PLANTING SYSTEM(Acharya N G Ranga Agricultural University, 2023-12-18) PULLURI MOUNIKA; B. SREE LAKSHMIThe present investigation was undertaken to study the progress and management of C orynespora leaf spot of cotton under High Density Planting System. On infected cotton leaves initially, minute pinhead size light orange to brick red minute spots appeared that gradually enlarged and became circular to oval or irregular concentric spots with tan to light brown centre with yellow halo around the margin. These spots enlarged and concentric zonations were formed resulting in target board symptom. When a roving survey was conducted in cotton growing areas of Guntur district at square initiation stage, boll initiation stage and boll maturity stage for occurrence of C orynespora leaf spot mean PDI was recorded as 13.33 at square initiation stage, 20.23 at boll initiation stage and 25.25 at boll maturity stage. At RARS, Lam, Guntur highest PDI was noticed in cotton cultivar L 1060 at boll formation and boll development stage i.e., 41.25. Multiple regression analysis of Corynespora leaf spot PDI data with weather parameters during kharif 2020-21 revealed that in all the four different spacings of HDPS tested, significant negative correlation was observed between disease severity and RH II, WS and Evap. Area under disease progress curve (AUDPC) was assessed for different spacings. Among the four spacings highest AUDPC was found in 60 cm X 30 cm (645) while the least AUDPC was observed in 75 cm X 45 cm spacing at boll maturity and bursting stage (585). When 150 cotton germplasm lines were screened for resistance against Corynespora leaf spot, 69 entries scoring less than 10% at boll formation and boll development stage were considered resistant. Among the eleven fungicides tested in vitro, the fungicides hexaconazole @ 0.2%, carbendazim @ 0.1%, fluxapyroxad + pyraclostrobin @ 0.06% and metiram + pyraclostrobin @ 0.3% completely inhibited the growth of the pathogen with maximum inhibition of mycelial growth (100%) and significantly superior over all other treatments. Propiconazole @ 0.1% also significantly reduced the radial growth (0.9 cm). Under field conditions all the test fungicides significantly reduced the disease in all spacings when compared to control. After final spray maximum reduction of disease was recorded with fluxapyroxad + pyraclostrobin @ 0.06% (14.3 mean PDI) when compared to control (34.1 PDI) while highest mean PDI was recorded in carbendazim @ 0.1% (22.3). Highest benefit:cost ratio was obtained with propiconazole @ 0.1% i.e., 3.00. ThesisItem Open AccessISOLATION AND EVALUATION OF Bacillus AND Pseudomonas SPECIES FOR PLANT GROWTH PROMOTING AND PATHOGEN SUPPRESSING TRAITS IN SUGARCANE(Acharya N G Ranga Agricultural University, 2023-12-18) CHETAN K.K.; P. KISHORE VARMAThe present study on “Isolation and evaluation of Bacillus and Pseudomonas species for plant growth promoting and pathogen suppressing traits in sugarcane” was conducted at RARS, Anakapalle during 2021-22, where 40 isolates of Bacillus and Pseudomonas species were isolated on specific media with selective supplements from rhizoplane of different sugarcane genotypes. Twenty each of Gram-positive and Gram-negative isolates were further identified as Bacillus and Pseudomonas species respectively by PCR amplification with Bacillus (BCF1 and BCR2) and Pseudomonas (Psmn289 and Psmn1258) specific primers. Morphologically most of the colonies formed by Bacillus isolates were round in shape with even margins, flat, opaque and smooth textured with creamy to milky white pigmentation with few exceptions. In case of Pseudomonas many of the isolates have round or irregular, flat, opaque, smooth textured and creamy to milky whitish colonies with undulated margin with few exceptions. All the 40 isolates were tested for their antagonistic activity against Colletotrichum falcatum and Fusarium sacchari through dual culture assay. Among them six isolates viz., SRB2 (65.74%), SRB4 (54.81%), SRB20 (80.37%), SRP3 (44.26%), SRP19 (80.78%) and SRP20 (69.81%) had significantly inhibited the growth of C. falcatum and five isolates viz., SRB2, SRB20, SRP3, SRP19 and SRP20 have shown inhibition of 52.30, 35.00, 30.93, 46.30 and 39.30% against Fusarium sacchari respectively. The observations at interaction zone revealed variation in growth pattern of the test fungus with hyphal thinning, wrinkling, hyphal tip shearing, protoplasm disintegration, clustering of hyphae and formation of intercellular and terminal chlamydospores. The volatile and non-volatile compounds from the potential isolates substantially reduced the radial growth of C. falcatum and F. sacchari. xvi The highly potential antagonistic isolates (SRB2, SRB20, SRP19 and SRP20) were identified as Bacillus inaquosorum, Bacillus vallismortis, Pseudomonas chlororaphis subsp. aurantiaca and Pseudomonas aeruginosa respectively by partial sequencing of 16S-23S intergenic region amplified by 16F945 and 23R458 primers. All the isolates were qualitatively tested for plant growth promoting and pathogen suppressing traits like, P solubilization (60% of the total isolates), IAA production (30%), protease activity (57.5%), cellulase activity (17.5%), chitinase activity (12.5%), HCN production (10%), siderophore production (27.5%), pyocyanin and fluorescein production (15 and 20% of Pseudomonas isolates respectively) and Antimicrobial peptide (AMP) genes like, fenD (60%), bmyB (50%), spaS (30%) and ituC (30%) for Bacillus isolates and phlD (20%), prnD (20%), phz (15%) and pltC (10%) for Pseudomonas isolates. Sett bacterization had positive impact on sett germination with negligible to very low increase in shoot length and low to higher increase in seedling vigour ranging from 23.85 (SRB1) to 92.91% (SRB11) and 8.80 (SRP14) to 98.73% (SRP17) of increase over control in Bacillus and Pseudomonas treated trays respectively. Sett treatment with potential antagonistic isolates revealed that four (SRB2, SRB20, SRP19 and SRP20) out of six isolates were found effective in controlling pre-emergence and post emergence seedling mortality in C. falcatum and F. sacchari inoculated pots under greenhouse conditions. The isolates SRP19 (Pseudomonas chlororaphis subsp. aurantiaca) and SRB20 (Bacillus vallismortis) were considered to be the most promising isolates in improving plant health as evident by their performance in PGP and disease suppressing activity.