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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Alginate based consortial formulation of native microbial fertilizers(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2019) Alfiya Beegum, A; KAU; Surendra Gopal, KAt present, the available biofertilizers are bulky and have short shelf life due to contamination problem. Hence, a suitable formulation needs to be developed which is less bulky and has increased shelf life. Alginate is one of the most commonly used polymers for microbial encapsulation. It is commercially extracted from seaweeds like Macrocystis pyrifera, Ascophyllum nodosum, Laminaria etc. The present study was undertaken in the Department of Agricultural Microbiology, College of Horticulture, Vellanikkara to develop an alginate based formulation of nitrogen, phosphorus, and potash biofertilizers consortia and evaluate for growth enhancement using tomato as the test crop. Five isolates each of nitrogen fixers, phosphorus and potassium solubilizers from Wayanad district were obtained from the repository maintained in the Department of Agricultural Microbiology, COH, Vellanikkara. The bacterial isolates were screened for nitrogen fixation, phosphorus and potash solubilization along with indole acetic acid production. Amount of nitrogen fixed (22.63 mg of N g -1 sucrose utilized) and indole acetic acid production (6 μg ml-1) were highest for Microbacterium arborescence. Similarly, Burkholderia cepacia recorded the highest amount of phosphorus solubilization (64.83 μg ml-1) and indole acetic acid production (8.67 μg ml-1). Among the potassium solubilizers, Acinetobacter calcoaceticus solubilized the highest amount of potassium (41.63 μg ml-1) under in vitro conditions. Microbacterium arborescence, Microbacterium testaceum and Nguyenibacter vanlangensis were selected as the three most promising nitrogen fixers. Similarly, the phosphorus solubilizers selected were Burkholderia cepacia, Bacillus subtilis (KASB5) and Bacillus subtilis (H4). The potassium solubilizers selected were Acinetobacter calcoaceticus, Burkholderia sp. and Brevibacterium sp. Compatibility studies were conducted among the selected bacterial isolates using cross streak method which showed no inhibition at the intersection of two bacterial isolates. The compatible isolate was further confirmed by dual culture method. The efficient isolates selected for consortia preparation were Microbacterium arborescence + Burkholderia cepacia + Acinetobacter calcoaceticus (N1P1K1), Microbacterium arborescence + Bacillus subtilis (KASB5) + Acinetobacter calcoaceticus (N2P2K2) and Microbacterium testaceum + Burkholderia cepacia + Burkholderia sp. (N3P3K3). In order to prepare a sterile and uniform sized alginate beads, a protocol was standardized for temperature, time and concentration of sodium alginate solution with calcium chloride solution. The optimum concentration of sodium alginate solution and temperature required for alginate beads preparation was 3% and 95 oC for 15 minutes. The diameter of alginate beads ranged between 2 mm – 2.7 mm. The rate of release of nitrogen fixers from alginate based consortia-1 during the initial 24 hours was high (41.67 x 106 cfu -1 g of beads) which reached to a population of 21 x 106 cfu -1 g of beads at 90th day. Population of nitrogen fixers, phosphorus solubilizers and potassium solubilizers decreased towards the 90th day when compared with the initial count of bacteria released from the alginate beads. A pot culture experiment using tomato as a test crop was conducted under sterile and unsterile potting mixture separately to evaluate Alginate based consortia (T1, T2 and T3), combination (T1 + T2 + T3), Talc based consortia (T5, T6 and T7) and POP (T8), Organic POP (T9) and Absolute control (T10). In sterile soil, the population of nitrogen fixers were higher for all the treatments receiving bacterial consortia. The population of P-solubilizers were higher in alginate based consortium-1 (13.0 x 106 cfu g-1) while the population of K-solubilizers were higher in treatments with combined application of alginate based consortia. Under unsterile soil, the population of nitrogen fixers were found to be higher in treatments with alginate and talc based consortia. The population of potassium solubilizers was higher in treatment with combined application of alginate based consortia. Treatments with alginate based consortium showed a higher population of phosphorus solubilizers compared with talc based consortia in unsterile soil. However, the population of N fixers, P and K solubilizers decreased with time in all treatments. Compared to initial soil status, application of alginate based bacterial consortium-1 resulted in a significant increase in available nutrient content among treatments receiving bacterial consortia in sterile soil conditions. Yield and yield attributes were higher in the alginate based bacterial consortia-1(897.0 g/plant) under sterile condition. However, yield was higher in treatment based on POP under unsterile soil conditions (845.0 g/plant). Among alginate based treatments, alginate based consortium-1 recorded a higher yield (707.33g/plant) under unsterile condition also. The present studies indicated that the alginate based consortium could be a potential microbial inoculant formulation which is less bulky, free from contamination, biodegradable and non-toxic. Encapsulation enables slow and controlled release of cells and thus, maintains a uniform bacterial population. However, further studies are required to study its shelf life, its performance under field condition before commercialization and develop a suitable protocol for large scale production.ThesisItem Open Access Soil microclimatic parameters and microbial activities on the population and diverisity of aqrbuscular mycorrhizal fungi(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2019) Anusha, K; KAU; Surendra Gopal, KArbuscular mycorrhizal fungi (AMF) are ubiquitous, which promote the plant growth by assisting in nutrient uptake and also mitigate several biotic and abiotic stresses in plants. Soil temperature, soil moisture, soil pH and nutrient availability are the major factors that affect the diversity, distribution and activity of AMF. The arbscular mycorrhizal fungi are obligate symbiont and require a host plant to complete its life cycle. Solenostemon rotundifolius or Chinese potato is one of the important minor tuber crop of Kerala, which is rich in starch, proteins, vitamins and minerals, with 70- 90% mycorrhizal colonization. The present study was undertaken to assess the effect of soil microclimatic parameters and microbial activities on the population and diversity of AMF and also evaluate the influence of AMF on the growth and yield of Solenostemon rotundifolius. The field experiment was conducted in a randomized complete block design (RCBD) with nine treatments and three replications at Agronomy farm, College of Horticulture, Vellanikkara during 2017 to 2019. The treatments consisted of five AMF species viz., Rhizophagus fasciculatus (T1), Funneliformis mosseae (T2), Glomus etunicatum (T3), Acaulospora sp. (T4), and Gigaspora sp. (T5), consortium of AMF (T6), POP recommendations of KAU, 2016 (T7), Organic POP of KAU, 2017 (T8) and absolute control (T9). Per cent AMF root colonization was higher (93.33%) in Rhizophagus fasciculatus (T1), Funneliformis mosseae (T2), Acaulospora sp. (T4) and T6 (T1 +T2 +T3 +T4 +T5). Spore population varied between the months, but highest spore population were recorded at 30 DAP and 120 DAP, whereas lowest was at 60 DAP. However, AMF spore diversity was highest in T6 (T1 +T2 +T3 +T4 +T5) throughout the experiment. AMF spore count and per cent root colonization increased with soil temperature but, not affected by soil moisture and soil pH. However, AMF spore diversity decreased with soil pH. Funneliformis mosseae (T2) and consortium of AMF (T6) recorded highest dehydrogenase activity throughout the experiment. Carbon dioxide evolution was highest at 120 DAP, in Gigaspora sp. (T5), which was on par with Acaulospora sp. (T4) and Funneliformis mosseae (T2). Acid phosphatase activity was highest in Funneliformis mosseae (T2) followed by Acaulospora sp. (T4). Per cent root colonization by AMF was positively correlated with dehydrogenase activity, CO2 evolution and acid phosphatase activity. AMF spore population was positively correlated with dehydrogenase activity and CO2 evolution. AMF spore diversity was positively correlated with CO2 evolution and acid phosphatase activity. Funneliformis mosseae (T2) showed better performance with respect to biometric characters (plant height, root biomass and dry weight) of the plant. AMF consortium (T6) treated plants recorded highest (16.98 t ha-1) tuber yield, which was also on par with T1 (Rhizophagus fasciculatus), T2 (Funneliformis mosseae), T4 (Acaulospora sp.) and T7 (POP recommendations of KAU, 2016). Phosphorus uptake by Chinese potato plants were highest (60.06 kg ha-1) in T2 (Funneliformis mosseae) and lowest in absolute control. Plant biometric characters, tuber yield and P uptake in Chinese potato were enhanced with AMF root colonization. Consortium of AMF (T6), Rhizophagus fasciculatus (T1) and Acaulospora sp. (T4) treated plots were recorded with less nematode population (506.67 to 559 nematodes per 250 g soil). The present study indicated that soil temperature affected AMF root colonization and spore count. Increase in soil microbial activities (dehydrogenase activity, CO2 evolution and acid phosphatase activity) showed increased root colonization, spore count and spore diversity. AMF root colonization enhanced growth, phosphorus uptake and yield of plant. Funneliformis mosseae (T2) was the most promising AMF for improving the growth, yield and phosphorus uptake in Solenostemon rotundifolius. However, extensive field studies are needed under different seasons and agro ecological zones, in order to develop an abiotic stress tolerant AMF for Chinese potato plant.ThesisItem Open Access Growth Promotion in Chilli on Inoculation with Pseudomonas Fluorescens and Piriformosporaa(Department of Agricultural Microbiology, College of Agriculture,Vellayani, 2019) Nandana, M S; KAU; Anith, K NThe study entitled “Growth promotion in chilli (Capsicum annuum L.) on inoculation with Pseudomonas fluorescens and Piriformospora indica” was undertaken during 2017-2019, in the Department of Agricultural Microbiology, College of Agriculture, Vellayani, Thiruvananthapuram, with the objective to assess the compatibility of the root endophytic fungus Piriformospora indica and two Pseudomonas fluorescens strains, and to evaluate their effect on growth promotion in chilli variety Vellayani Athulya. The Pseudomonad strains used were Pseudomonas fluorescens PN026 and Pseudomonas fluorescens AMB8. Experiments comprised both in vitro and in vivo studies. For in vitro study a dual culture plate assay was done in potato dextrose agar (PDA) and coconut water agar (CWA) with the fungal and bacterial endophytes to evaluate the direct antagonism. Both Pseudomonas fluorescens PN026 and Pseudomonas fluorescens AMB8 showed antagonism to the root endophyte Piriformospora indica in PDA whereas in CWA, Pseudomonas fluorescens PN026 did not show any antagonistic effect and Pseudomonas fluorescens AMB8 showed a reduced antagonism to Piriformospora indica compaired to that in PDA. Indirect antagonism was evaluated through agar well diffusion method and paper disc diffusion method using culture filtrate of the bacterial strains and the culture filtrate from both the bacterial strains showed antagonism against Piriformospora indica in which the maximum zone of inhibition was observed in culture filtrate of Pseudomonas fluorescens AMB8. A Co-culture experiment involving P.indica and Pseudomonas strains using a single fermentation system was attempted in two different media; potato dextrose broth (PDB) and autoclaved coconut water (ACW). The flasks were incubated under agitation for 48 h and the population of the bacteria was determined at 24 h intervals by dilution plating in Kings B agar medium and it was observed that, when 10 day old cultures of the fungus in ACW and PDB were inoculated with the bacteria, ACW supported the growth of the bacteria similarly to fungus free ACW and KB medium. Co-cultivation in PDB led to a decline in bacterial population and the autoclaved coconut water can be suggested as a better medium for coculturing of P. indica and Pseudomonas fluorescens strains. A pot culture experiment was undertaken to study the effect of the different treatments on growth promotion of chilli. The experiment was laid out in CRD with six treatments and three replications and observation was taken in 15 days. The treatments comprised fungal and bacterial endophytes along with combinations of both fungal and bacterial endophytes and an uninoculated control. Different parameters like plant height, number of leaves, number of branches, number of fruits/plant, fresh fruit yield, fresh shoot weight, dry shoot weight, fresh root weight, dry root weight, days to flowering, days to fruit set and percentage root colonisation by Piriformospora indica were evaluated. Maximum plant height was recorded in the treatment with mixed inoculation of Piriformospora indica and Pseudomonas fluorescens PN026 without any significance in statistical data. A significantly increasing trend was observed in number of leaves with mixed inoculation of Piriformospora indica and Pseudomonas fluorescens PN026 from 45th day after transplanting and it was statistically on par with the treatment consisting of Piriformospora indica alone. Number of branches were found to be higher with mixed inoculation of Pirifomospora indica and Pseudomonas fluorescens PN026. There was no significant difference in the fresh weight and dry weight of shoot, whereas the fresh and dry weight of root (21.13 g and 8.26g respectively) were significantly higher in the plants treated with P. indica along with Pseudomonas fluorescens PN026. Number of fruits per plant (10.25/plant) and fresh fruit yield per plant (37.95g/plant) were recorded significantly higher with mixed inoculation of Piriformospora indica and Pseudomonas fluorescens PN026. The in vivo study disclosed that plants treated with Piriformospora indica along with Pseudomonas fluorescens PN026 were found to perform better than all other treatments. The mixed inoculation of Pseudomonas fluorescens AMB8 and P. indica had no additional advantage in plant growth in chilli. Piriformospora indica was able to successfully colonize in the plant roots applied with the bacterial endophyte. The present study revealed that plant growth promoting rhizobacteria, Pseudomonas fluorescens PN026 can be used along with Piriformospora indica, the root endophyte, for enhancing plant growth in chilli.ThesisItem Open Access Management of bacterial wilt disease of tomato by the root endophytic fungus piriformospora indica, rhizobacteria and bacterial endophytes(Department of Agricultural Microbiology, College of Agriculture, Vellayani,Thiruvananthapuram, 2018) Athira, S; KAU; Anith, K NThe study entitled “Management of bacterial wilt disease of tomato by the root endophytic fungus Piriformospora indica, rhizobacteria and bacterial endophytes” was conducted during 2016-2018 at Department of Agricultural Microbiology, College of Agriculture, Vellayani with the objective of assessing the potential of root endophytic fungus Piriformospora indica, plant growth-promoting rhizobacteria and bacterial endophytes in suppressing bacterial wilt incidence in tomato. The bacterial wilt pathogen, Ralstonia solanacearum was isolated from infected tomato plants on Semi selective medium from South Africa (SMSA). Koch’s postulates were proved by artificial inoculation of tomato seedlings. A functional relationship between population and optical density of the broth culture was worked out and was used for determining the inoculum density for challenge inoculation in the biocontrol experiment. In vitro antagonistic interaction between the bioagents and the pathogen was worked out both by direct and indirect assays. In all direct assays which involved cross streak plating, agar plug diffusion technique, disc diffusion and spot on lawn method, it was found that Bacillus amyloliquefaciens VLY24, Bacillus velezensis PCSE10 and Streptomyces leeuwenhoekii KBT004 exhibited antagonism against Ralstonia solanacearum. Indirect antagonism was checked by agar well diffusion and disc diffusion methods using culture filtrate. Out of the eight bacterial bioagents tested, only two i.e., Bacillus velezensis PCSE10 and Bacillus amyloliquefaciensVLY24 had inhibitory effect on the pathogen. Dual culture plate assay on PDA has shown that three bacterial bioagents, Rhizobium radiobacter PCRE10, Bacillus megaterium NAT001 and Streptomyces leeuwenhoekii KBT004 were compatible with Piriformospora indica. However, when the compatible bacteria were co-cultured in a single fermentor system along with Piriformospora indica it was observed that Bacillus megaterium NAT001 failed to grow along with the fungal endophyte. Suppression of bacterial wilt incidence by the individual and combined application of bacterial bioagents and fungal endophytes were tested with the wilt susceptible tomato variety Naveen (Indo-American hybrid seeds Pvt. Ltd, Bengaluru) and the moderately tolerant KAU variety Vellayani Vijay. Bioagents were applied during the nursery production of seedlings and the 21 days old seedlings were transplanted to pots filled with unsterile garden soil. Challenge inoculation with the pathogen was done five days after transplanting by drenching the pots with 10 ml each of the bacterial suspension (107cfu/ml). The disease incidence was scored at weekly intervals for 21 days. When the bioagents were tested individually for the suppression of bacterial wilt incidence in the hybrid variety Naveen, maximum disease suppression was observed in plants treated with Rhizobium radiobacter PCRE10 (15 percent) after 21 days. The disease suppressive ability of Bacillus velezensis PCSE10 (25 percent) was also significantly superior to all other treatments. Selection of bacterial bioagents for combined application with Piriformospora indica was done based on compatibility with the fungal endophyte and inhibitory action against Ralstonia solanacearum. Combined application of the fungal endophyte and Bacillus amyloliquefaciens VLY24 suppressed the wilt incidence to the highest extent (40 percent). When bacterial wilt suppression in Vellayani Vijay was tested by the individual application of bacterial bioagents, maximum disease suppression was recorded in plants treated with Streptomyces leeuwenhoekii KBT004 (30 percent), when observed 21 days after challenge inoculation. The combination of Piriformospora indica with Rhizobium radiobacter PCRE10 (50 percent) and Bacillus velezensis PCSE10 (50 percent) showed significantly lower disease incidence compared to the rest of the treatments. In the plant growth promotion experiment done with the variety Vellayani Vijay in the nursery stage, maximum plant height was observed in plants treated with Rhizobium radiobacter PCRE10 (14.49cm). However, those plants treated with Bacillus pumilus VLY17 had the highest number of leaves per plant (4.58). Combined inoculation of Piriformospora indica and Bacillus amyloliquefaciens VLY24 resulted in improved shoot fresh weight (2.08 g per plant) which was on a par with the plants treated with Bacillus velezensis PCSE10 (1.95 g plant-1). However, shoot weight on dry weight basis was the maximum for plants treated with Bacillus velezensis PCSE10 (122.55 mg plant-1) which was at par with those treated with combination of Piriformospora indica and Bacillus amyloliquefaciens VLY24 (104.78 mg plant-1). The present study revealed that biological management of bacterial wilt in tomato could be a feasible strategy under controlled conditions. The same has to be validated under field conditions before making any recommendations.ThesisItem Open Access Microbial inoculants for enhancing degradation of biosolid waste in aerobic composting(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2019) Shilpa, P; KAU; Girija, DSolid waste management is a major challenge throughout the world, especially in urban areas, due to the rapid growth of population along with urbanization. Earlier, centralized management of biosolid waste was being practiced. However, due to problems in transportation and segregation, management at source is being promoted. Aerobic composting has been practiced from time immemorial for recycling of biosolid waste, using various processes and containers. Recently, more importance is being given to bio- composting, considering the efficiency of microorganisms in enhancing degradation of organic substrates by their multiple mode of action. Hence, this study was taken up to explore microorganisms which can enhance the process of aerobic composting of biosolid waste. Isolation of potential decomposing microorganisms was attempted from different compost samples including coir pith compost, kitchen waste compost and Oushadhi ayurvedic compost. A total of 14 isolates were obtained from different compost samples. All the isolates were assigned names depending upon the type of microorganism and the source from which they were isolated. Based on the ability to degrade the chemical components in selective medium, four isolates (BaBc-1, BaCp-1, BaOu-1 and AcOu-1) and four reference cultures (Bacillus subtilis, Bacillus niabensis, Gongronella butleri and Trichoderma asperellum) were selected for quantitative assay. Enzyme assay was carried out for selected isolates and the isolate G. butleri exhibited highest cellulase activity. BaBc-1, B. subtilis and BaOu-1 recorded significantly higher β- 1, 3 glucanase activity. Glucosidase activity was found to be significantly high in G. butleri, T. asperellum, BaBc-1 and B. subtilis. Significantly higher laccase, amylase and pectinase activity was recorded in BaOu-1, BaBc-1 and AcOu-1 respectively. Maximum protease activity was recorded in fungal isolates G. butleri and T. asperellum. Potential isolates were further subjected to cultural, morphological, biochemical and molecular characterization. The isolate BaBc-1 showed maximum homology to Bacillus subtilis, BaCp-1 to Bacillus cereus, BaOu-1 to Bacillus sp. and the actinomycete isolate AcOu-1 to Streptomyces roseofulvus. The compatible combinations of selected isolates with high enzyme activity were selected for formulation of microbial consortia and the consortia were evaluated for degrading vegetable waste under in vitro condition. All the inoculated treatments showed faster degradation compared to uninoculated control. Based on visual observations, per cent weight reduction, enzyme activity and microbial population on 21 DAI in flask culture, consortium II (B. subtilis BaBc-1+ T.asperellum+ Bacillus sp. BaOu-1) and consortium IV (B. subtilis+ G. butleri +B. subtilis BaBc-1) were selected for pilot scale experiment. The efficiency of selected consortia was evaluated in KAU smart biobin along with cow dung slurry and uninoculated treatment. In T1 (B. subtilis BaBc-1+ T.asperellum+ Bacillus sp. BaOu-1) compost formation was initiated within 17 days after inoculation. Based on the volume reduction, duration of composting process, yield of compost, microbial population and phytotoxicity of compost, consortium I (B. subtilis BaBc-1+ T.asperellum+ Bacillus sp. BaOu-1) was selected as best performing consortium in KAU smart biobin. Hence, this consortial formulation was selected for large scale experiment in Thumburmuzhi composting units. Cow dung was used as inoculum in positive control and uninoculated treatment served as negative control. The treatment T1 (B. subtilis BaBc-1+ T.asperellum+ Bacillus sp. BaOu-1) recorded maximum temperature (640C) during composting period, faster volume reduction and maximum microbial population in compost. Based on these results, T1 was found to be the best treatment in Thumburmuzhi composting unit. The study revealed that, consortial formulation of B. subtilis BaBc-1, T. asperellum and Bacillus sp. BaOu-1 could be exploited for enhancing degradation of biosolid waste in aerobic composting. This can be used in future for the management of agricultural and municipal solid waste. The plant growth promoting (PGP) activities of these isolates could be an added advantage in improving the growth and yield of plants.ThesisItem Open Access Assessment of soil temperature and soil parameters on the population and functional efficiency of pseudomonas fluorescens in the rhizosphere of Pokkali rice (Oryza Sative L.)(Department of Agricultural Microbiology, College of Agriculture, Vellayani, 2018) Reshma Francis; KAU; Surendra Gopal, KPokkali is a umque variety of rice that is cultivated organically in coastal wetlands of Kerala. Pokkali fields are situated close to the sea and therefore prone to flooding and salinity. Pokkali rice has enormous potential for tolerating most of the abiotic stresses. It is the only economic crop which can be grown in waterlogged environment while tolerating salinity. The present study on “Assessment of soil temperature and soil parameters on the population and functional efficiency of Pseudomonas fluorescens in the rhizosphere of Pokkali rice (Oryza sativa L.)”, was conducted in Rice Research Station, Vyttila, under Kerala Agricultural University during 2016 to 2018. Two plots (40 m2) were used for the study. One of the plots was maintained as control (without application of Pseudomonas fluorescens) and another plot with rice was treated with P. fluorescens. P. fluorescens (KAU) was applied as seed treatment (10g kg-1) just before sowing and soil application (2.5 kg ha-1) at 1 week after dismantling. The main objectives were to study the effect of soil temperature and soil parameters on the population and functional efficiency of P. fluorescens / fluorescent Pseudomonas in Pokkali rice. The rhizosphere soils of Pokkali rice were collected at monthly interval from June, 2017 to October, 2017. The population of fluorescent Pseudomonas sp. in the rhizosphere soils of Pokkali rice were recorded at monthly interval. The population was absent before the start of the experiment in treated plot. However, the highest population 3.3x102 cfu g-l) was recorded at 90 DAS (August, 2017). However, the lowest population was recorded at 60 DAS (July, 2017). The population was not found at 30 DAS (June, 2017), 120 DAS (September, 2017) and 150 DAS (October, 2017). In the case of control plot, population of fluorescent Pseudomonas was absent before the start of experiment. At 30 DAS (June, 2017) population of fluorescent Pseudomonas was 3.3 x 102 cfu g-1. However, no fluorescent Pseudomonas were found at 60 DAS (July, 2017), 90 DAS (August, 2017), 120 DAS (September, 2017) and 150 DAS (October, 2017). Out of the six isolates (VPJU, VPJL, VPAU1, VPAU2, VPAU3 and VPAU4) of fluorescent Pseudomonas obtained, all the isolates produced IAA and ammonia with varied intensity. Three isolates (VPAU1, VPAU3 and VPAU4) produced HCN and none of the isolates showed siderophore production. The correlation studies between soil temperature, soil pH, EC and C02 evolution with population, revealed that the population of fluorescent Pseudomonas was affected by soil pH and soil EC. However, soil temperature and C02 evolution did not affect the population of fluorescent Pseudomonas. The functional efficiency of the fluorescent Pseudomonas were correlated with soil temperature, soil pH, EC and C02 evolution It was found that soil temperature, soil pH, EC and C02 evolution did not affect the functional efficiency of fluorescent Pseudomonas. All the six isolates obtained m the study were identified and confirmed through 168 rDNA sequencing. The isolates VPAJU, VPAU1 and VPAU2 were identified as Pseudomonas sp. and VPAJL, VPAU3 and VPAU4 isolates were found to be Pseudomonas aeruginosa. The present studies indicated that the inoculated P.fluorescens did not survive in Pokkali fields. The population of fluorescent Pseudomonas showed negative correlation with soil pH and EC. However, soil temperature and C02 evolution did not had any effect on population. The functional efficiency of fluorescent Pseudomonas was not affected by soil temperature, soil pH, EC and C02 evolution. However, further studies on influence of soil edaphic factors and weather variables on host plant and P. fluorescens needs to be studied and develop a suitable PGPR for Pokkali rice.ThesisItem Open Access Standardization of liquid formulation of PGPR MIX-1 and its evaluation for plant growth promotion in amaranthus(amaranthus tricolor L.)(Department of Agricultural Microbiology,College of Agriculture, Vellayani,Thiruvananthapuram, 2018) Gokul, K Gopi; KAU; Meenakumari, K SThe study entitled “Standardization of liquid formulation of PGPR mix–I and its evaluation for plant growth promotion in Amaranthus (Amaranthus tricolor L.)” was conducted in the Department of Agricultural Microbiology, College of Agriculture, Vellayani during the period 2016-2018. The main objectives of the study were standardization of liquid formulation of PGPR mix–I and its evaluation for plant growth promotion along with saving of chemical fertilizers in amaranthus. The component cultures of PGPR mix-I, Azospirillum lipoferum, Azotobacter chroococcum, Bacillus megaterium and Bacillus sporothermodurans were procured from the Department of Agricultural Microbiology, College of Agriculture, Vellayani. All the isolates produced significant quantity of IAA under in vitro conditions. The nitrogen (N) fixers, Azospirillum lipoferum and Azotobacter chroococcum produced 40.31 and 36.43 ppm of IAA respectively, whereas Bacillus megaterium and Bacillus sporothermodurans produced 1.28 ppm and 3.36 ppm of IAA respectively. The in vitro estimation of N fixation by N fixing organisms namely, Azospirillum lipoferum and Azotobacter chroococcum recorded a significant quantity of 21 and 14 mg N g-1 of carbon source respectively. Quantitative assessment of solubilization of phosphorus (P) by Bacillus megaterium present in PGPR mix–I under in vitro conditions recorded 69.36 ppm, whereas qualitative assessment recorded a clearing zone of 8 mm and 12 mm diameter in NBRIP and Pikovaskayaˈs medium respectively. Similarly, in vitro assessment of K solubilization by Bacillus sporothermodurans recorded 12.18 ppm of potassium (K) and a clearing zone of 18 mm diameter in Glucose Yeast Agar medium. Morphological and biochemical characterization of the isolates supported the genus level identification of the isolates. An experiment was carried out to standardize the protocol for the preparation of liquid formulation of PGPR mix–I in completely randomized design with different treatments such as 2% Glycerol, 2% Polyvinylpyrrolidone (PVP), 15mM Trehalose, 1% Glycerol + 1% PVP, Glycerol (2%) + Trehalose (1%) + Yeast extract (1%) + PVP (1%) + Proline (1%) and control without any additives in four replications. Talc based formulation was kept as a standard. In spite of inconsistent viable count recorded in different treatments till eighth month, from ninth month onwards, formulation amended with 15mM Trehalose exhibited maximum viable count until fourteenth month. A significant decline of total viable population in talc based formulation was observed in each month compared to 15mM Trehalose amended formulation. Based on the population study, 15mM Trehalose amended formulation was adjudged as the best liquid biofertilizer formulation. Even after fourteenth month significant population was observed in 15mM Trehalose amended formulation and hence the shelf life studies of the same have to be continued. A pot culture experiment was conducted in completely randomized design using sterilized soil under glass house conditions to test the efficacy of the best treatment ( liquid formulation amended with 15mM Trehalose ) with amaranthus as the test crop The seven treatments included 100% NPK as per KAU recommendation as chemical fertilizer alone, talc based or liquid formulation of PGPR mix–I each alone and with 100% and 50% NPK, control with additives without PGPR microorganisms and absolute control in three replications. Roots of seedlings were dipped in 2 per cent of the freshly prepared liquid formulation at the time of transplanting and 50 ml of 2 per cent liquid was drenched in the soil in each pot two weeks after transplanting. The results indicated that the treatment T6- liquid formulation of PGPR mix–I+ 100% NPK recorded, maximum plant height of 37.54 cm, leaf number of 44.44 and leaf area index of 4.97 at harvest, but was on par with T3- talc based formulation of PGPR mix–I+ 100% NPK. The treatment T6 also recorded maximum fresh and dry weight of shoot (55.41 and 4.97 g plant-1 respectively) and fresh and dry weight of root (6.6 and 0.56 g plant-1 respectively). However, the treatment T6 was found to be on par with T3 in these characters also. But T6 recorded the least oxalate content of 0.39 per cent as well. The treatment liquid formulation of PGPR mix–I + 50% NPK (T7) was found to be statistically on par with chemical fertilizer @ 100% NPK (T1) in parameters such as plant height, number of leaves, leaf area index, fresh and dry weight of shoot and root and oxalate content. Application of treatments had significant effect on the soil available NPK content. Analysis of rhizosphere population after application of PGPR mix-I revealed successful colonization of organisms of PGPR mix-I in the rhizosphere of amaranthus. The present investigation could standardize the protocol for liquid formulation of PGPR mix-I with 15 mM Trehalose as the best amendment. The study revealed that liquid formulation of PGPR mix–I is equally effective as talc based formulation of PGPR mix–I along with 100% NPK chemical fertilizers in enhancing yield and other biometric parameters of amaranthus. Compared to talc based formulation, the liquid formulation of PGPR mix–I showed higher shelf life beyond fourteenth month. The study also indicated that liquid formulation of PGPR mix–I + 50% NPK as chemical fertilizers was on par with chemical fertilizer @ 100% NPK and hence a saving of 50 per cent of chemical fertilizers could be advocated after confirmatory field trials.ThesisItem Open Access Evaluation of biofilm based microbial antagonists for the management of soil borne diseases and growth promotion in cowpea (Vigna unguiculata L. Walp)(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2018) Vinay Kumar, B; KAU; Surendra Gopal, KThe biocontrol agents play an important role in the plant disease management and growth promotion. They are eco-friendly and low cost agricultural inputs. One of the major constraints in the use of biocontrol agents, is the survivability of inoculated cultures till the end of the crop period. So, there is a need to enhance the survivability of the biocontrol agents for the management of soil borne pathogens and growth promotion. Trichoderma and Bacillus sp. are two well-known biocontrol agents for plant disease management and growth promotion. Cowpea is one of the most popular, protein rich legume crop of Kerala. One of the major constraints in the cowpea production is the diseases like collar- rot (Rhizoctonia solani) and root rot (Pythium aphanidermatum) which have become a serious threat. Since, no studies have been conducted in Kerala on the biofilm based inoculants, an attempt was made to increase the survivability of Trichoderma and Bacillus through biofilm based inoculants for the management of two major soil borne diseases and growth promotion in cowpea. Rhizosphere soil samples were collected from ten different cowpea growing areas of Thrissur district. The maximum population of Trichoderma sp. (4.8 × 103 cfu g-1) and Bacillus sp. (4.48 × 105 cfu g-1) were recorded in Chellakara and Mala, respectively. A total of nine Trichoderma sp. and five Bacillus sp. were obtained. They were screened for plant growth promoting and antagonistic activities. Among Trichoderma sp., maximum IAA production (24.03 μg ml-1) was recorded by TCK- 2 (Chalakudy) followed by TML (Mala) (14.77 μg ml-1). TML (Mala) isolate was the most efficient P solubilizer (147.2 μg/ml). Among Bacillus sp., maximum IAA production (6.20 μg ml-1) and maximum P solubilization (151.3 μg ml-1) were recorded by BCH (Chellakara) isolate. Among Trichoderma sp., TCH-1 (Chellakara) and TMT (Mttathur) were positive for HCN production and TCH-1, TMT, TMS, TPZ and TCK-1 were positive for ammonia production. Among Bacillus sp., BCH (Chellakara) and BMT (Mattathur) were positive for HCN production and all five isolates (BCH, BML, BMS, BPN and BMT) were positive for ammonia production. Both Trichoderma sp. and Bacillus sp. were screened in vitro for their antagonistic activity against Rhizoctonia solani and Pythium aphanidermatum. Among Trichoderma sp., TCH-1 (Chellakara) isolate recorded maximum inhibition (51.1%) against Rhizoctonia solani and Pythium aphanidermatum (57.7%). Bacillus sp. isolates were screened for biofilm production and highest biofilm production was recorded by BCH (Chellakara) (0.060) followed by BPN (Pazhayanur) (0.058) isolates. Based on the PGPR traits, per cent inhibition and biofilm production under in vitro, three most promising Trichoderma sp. (TCH, TMT, TPZ) and Bacillus sp. (BCH, BPN, BML) were subjected for mutual compatibility studies. All the selected Trichoderma sp. and Bacillus sp. were mutually compatible with each other. The isolates of TCH (Chellakara) + BCH (Chellakara), TPZ (Pazhayanur) + BPN (Pazhayanur) and TMT (Mattathur) + BML (Mala) were selected for the biofilm based inoculant production. Among the different carrier materials for biofilm based inoculant production talc powder was the most promising carrier material due to highest population of isolates at 90 DAI. Biofilm based inoculants were evaluated under pot culture for the management of collar rot (Rhizoctonia solani) and root rot (Pythium aphanidermatum) in cowpea under two separate experiments. Based on the biometric parameters, collar rot and root rot disease management and yield parameters, biofilm based formulation of TCH (Chellakara)+BCH (Chellakara) (T2) was the most promising treatment for the management of collar rot disease and growth promotion in cowpea, which was on par with the PGPR Mix- II (T9). Population of inoculated Trichoderma sp., Bacillus sp. and Rhizobium sp. indicated declining trend till the final harvest of the crop. The population decreased from 108 cfu ml-1 to 104 cfu ml-1. However, biofilm based inoculant showed highest population of Trichoderma sp. and Bacillus sp. at the time of harvest. The three best promising Bacillus sp. isolates were identified through 16S rRNA sequencing and identified BCH isolate as Bacillus subtilis, BPN as Bacillus velezensis and BML as Bacillus megaterium.ThesisItem Open Access Isolation and characterization of pink pigmented facultative methylotrophs (PPFMs) associated with paddy(Department of Agricultural Microbiology, College of Agriculture, Vellayani, 2018) Nysanth, N S; KAU; Meenakumari, K SThe study entitled “Isolation and characterization of Pink Pigmented Facultative Methylotrophs (PPFMs) associated with paddy” was conducted in the Department of Agricultural Microbiology, College of Agriculture, Vellayani during the period 2015-2017. The main objectives of the study were isolation, characterization and evaluation of Pink-Pigmented Facultative Methylotrophs (PPFMs) associated with paddy for antagonistic efficiency, seed germination, seedling growth and yield of paddy. . The pink pigmented facultative methylobacteria (PPFM) were isolated from phyllosphere of paddy collected from different locations of Kerala by leaf imprint method on Ammonium Mineral Salt (AMS) agar medium supplemented with 0.5% methanol and cycloheximide. Forty six isolates were obtained from different locations and code numbers were allotted for each of the isolate. They were tentatively identified as PPFMs based on the characteristic pink pigmented colonies on AMS agar supplemented with 0.5% methanol as sole source of carbon and energy. The product developed by Tamil Nadu Agricultural University was taken as the reference culture. Indole Acetic Acid production by the different isolates of PPFM showed wide variations ranging from 9.27 to 68.65 μg mL-1 of culture filtrate. Maximum IAA production of 68.65μg mL-1 of culture filtrate was recorded by PPFM35. The reference culture produced 57.39 μg mL-1 of IAA. All the isolates were found to produce carotenoid pigment in varied quantity ranging from 0.07 to 1.74 μg mL-1. Among these isolates, the highest carotenoid production was recorded in PPFM16 (1.74 μg mL-1). The reference culture recorded a total carotenoid production of 0.64 μg mL-1. The antagonistic efficiency of all forty seven PPFM isolates including reference culture was assessed against two important fungal pathogens of paddy namely, Rhizoctonia solani, Pyricularia oryzae and one bacterial pathogen, Xanthomonas oryzae pv. oryzae following dual culture method. Six out of forty seven isolates tested inhibited Rhizoctonia solani. The results revealed that the isolate PPFM 10 exhibited the maximum zone of inhibition (ZOI) of 12.72 mm. The reference culture inhibited Rhizoctonia solani and produced a ZOI of 9.07mm. Four out of forty seven isolates tested showed antagonistic activity against Pyricularia oryzae with PPFM24 producing the maximum zone of inhibition of 10.00 mm. Four out of forty seven isolates tested inhibited Xanthomonas oryzae pv. oryzae and PPFM5 produced the maximum ZOI of 9.80 mm diameter. In the study on the effect of PPFM isolates on seed germination and seedling growth both treated and uninoculated control seeds germinated on the second day of seed treatment. Maximum germination percentage of 100 was recorded in seeds treated with PPFM35. Treatment with PPFM30 recorded the maximum shoot length of 26.38 cm and maximum root length of 24.20 cm was obtained in seeds treated with PPFM22 and same isolate recorded the highest seedling vigour index of 4756.35 over the control (3037.91). The root shoot ratio of seedlings showed significant increase when seeds were treated with PPFM isolates. Maximum root shoot ratio of 0.62 was observed when seeds were treated with PPFM26 and PPFM35 compared to control (0.33). A pot culture experiment was conducted using variety Jyothi (Ptb-39)) in completely randomized design using wetland soil. Seedlings were dipped in 2 per cent of liquid culture of the PPFM isolates before transplanting. One per cent foliar spray of the liquid culture of respective isolates was given 15 and 30 days after transplanting. Appropriate control treatments and replications were maintained. Application of PPFM isolates significantly increased growth and biomass production. Also the yield of paddy was significantly increased. PPFM11 recorded the highest grain yield of 46.30 g hill-1 whereas the control recorded a grain yield of 33.65 g hill-1 only. The reference culture recorded a grain yield of 38.40 g hill-1. Physiological characterization of plants revealed significant influence of PPFM isolates on chlorophyll content, cell membrane stability and proline content of the plant compared to untreated plants. The isolates PPFM11, PPFM16, PPF19, PPFM22 and PPFM35 were adjudged as superior isolates based on maximum germination percentage, seedling vigour index, growth promotion efficacy and grain yield of paddy. These five isolates were identified as Methylobacterium spp. based on morphological, biochemical and molecular characteristics.
