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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 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 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.ThesisItem Open Access Impact of weather variables on the functional efficiency of beneficial microflora in the rhizosphere of black pepper (piper nigrum L.)(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2017) Manju Mohan, E; KAU; Surendra Gopal, KBlack pepper has been reported to be the most vulnerable spice crop to climate change. The beneficial microorganisms in the rhizosphere of black pepper can reduce the impact of abiotic stress due to changes in the weather variables. However, the soil microbial community are also influenced by changes in weather and microclimatic parameters. A study was undertaken on the “Impact of weather variables on the functional efficiency of beneficial microflora in the rhizosphere of black pepper”. The main objectives were to study the effect of weather and microclimatic parameters on the population and functional efficiency of beneficial microflora namely; Azospirillum, phosphate solubilizing bacteria (PSB), Pseudomonas fluorescens and Trichoderma sp. The rhizosphere soil samples from black pepper were collected at monthly interval for a period of one year from Pepper Unit, Kerala Agricultural University (KAU), Vellanikkara. The selected beneficial microorganisms were enumerated and in vitro screening was done at monthly interval for IAA, ammonia, HCN, siderophore production, phosphate solubilization and antagonistic activity against Phytophthora capsici. Simultaneously, the weather and microclimatic parameters were also recorded. The Azospirillum and PSB were not obtained throughout the study period from July, 2015 to June, 2016. The population of fluorescent pseudomonads was highest in September, 2015 and was absent in March, 2016 and April, 2016. Trichoderma sp. recorded the highest population in July, 2015 and lowest in June, 2016. A total of 31 isolates of fluorescent pseudomonads and 3 isolates of Trichoderma sp. were obtained during the entire study period. Out of 31 isolates of fluorescent pseudomonads, 29 isolates produced ammonia with different concentrations. Fifteen isolates produced HCN and only ten isolates showed siderophore production as their antagonistic mechanism. Only 5 isolates were phosphate solubilizers and 4 isolates were antagonistic to Phytophthora capsici. However, in the case of Trichoderma sp. two isolates produced ammonia, one isolate was HCN producer, two produced siderophore and two isolates showed antagonistic activity against Phytophthora capsici. Considering the correlation studies between weather, microclimatic parameters and population of isolates obtained, it was found that the population of fluorescent pseudomonads were positively correlated with rainfall and soil moisture whereas negatively correlated with air temperature, sunshine hours and soil temperature. However, the population of Trichoderma sp. was positively correlated with rainfall, relative humidity and soil moisture whereas it was negatively correlated with air temperature, sunshine hours and soil temperature. The study indicated that rainfall (200 to 500 mm) and soil moisture (15 to 20%) favoured fluorescent pseudomonads and Trichoderma population. The functional efficiency of the isolates were also correlated with the weather and microclimatic parameters. In case of fluorescent pseudomonads, the weather and microclimatic parameters had no significant effect on its ammonia and HCN production. However, significant effect on the siderophore production was noticed. In the case of Trichoderma, weather and microclimatic parameters had no significant effect on ammonia, HCN and siderophore production. The present studies clearly indicated that the weather and microclimatic parameters affected the siderophore production in the case of fluorescent pseudomonads but, there was no effect on functional efficiency of Trichoderma sp. However, mitigation strategies have to be studied in the case of fluorescent pseudomonads to overcome the effect of weather and microclimatic variables on functional efficiency.ThesisItem Open Access Evaluation of abiotic stress tolernant PGPR and trichoderma sp. for growth and disease management in black pepper (piper nigrum L.)(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2017) Sri Vithya, R; KAU; Surendra Gopal, KA study was conducted on the “Evaluation of abiotic stress tolerant PGPR and Trichoderma sp. for growth and disease management in black pepper (Piper nigrum L.)” at the Department of Agricultural Microbiology, College of Horticulture, Vellanikkara during May 2015 to July 2016. The objective of the study were to screen Azospirillum sp., Micrococcus sp., Burkholderia sp., Pseudomonas fluorescens and Trichoderma sp., for abiotic stress tolerance under in vitro and also evaluate the abiotic stress tolerant isolates for growth and disease management in black pepper under stress (polyhouse) and without stress (natural) conditions. Rhizosphere soil samples were collected from ten different black pepper growing areas of Thrissur district for isolation of Azospirillum sp., Micrococcus sp., Burkholderia sp., Pseudomonas fluorescens and Trichoderma sp. The isolates obtained were screened for PGPR activities, abiotic stress tolerance and screening for antagonistic activity against P. capsici. The most promising isolate from each type of microorganism were selected for pot culture experiment to evaluate the selected abiotic stress tolerant isolates for growth promotion and disease management in black pepper. Azopsirillum sp. was not recorded in the black pepper rhizosphere soil collected from Thrissur district. In the case of Micrococcus sp., the highest population was recorded in Pazhayannur (45×104 cfu g-1). In the case of Burkholderia sp., was highest in Kannara (116.5×104 cfu g-1). In the case of Fluorescent pseudomonads, the highest population was recorded in Chellakkara (55×104 cfu g-1). And Trichoderma sp., was highest in Mupliyam (96.5×103 cfu g-1). A total of 34 obtained different microbial isolates were screened for PGPR activities (IAA production, % P - solubilisation, Ammonia production and HCN production) and abiotic stress tolerance (temperature tolerance 280C, 370C, 410C and 500C, acidity tolerance and drought tolerance). Based on the PGPR activities and abiotic stress tolerance, the most promising isolates selected for pot culture experiment were Micrococcus sp. - VKM isolate (410C, pH 5.5 and -0.15 M Pa osmotic stress) Burkholderia sp. - PAB isolate (410C, pH 5.5 and -0.15 M Pa osmotic stress), fluorescent pseudomonads - PAP isolate (410C, pH 5.5 and -0.15 M Pa osmotic stress) and Trichoderma sp. - CKT isolate (370C, pH 5.5 and -0.15 M Pa osmotic stress). The maximum Per cent inhibition (64.75 %) was recorded in the case of Burkholderia sp. (KKB) and in the case Trichoderma sp. the maximum per cent inhibition (66.95 %) was recorded with CKT isolate. The isolates were further screened under pot culture experiment. There were two pot culture experiments with polyhouse condition (with elevated temperature as stress) and natural condition (without stress). Under polyhouse condition (with elevated temperature as stress), T5 (Trichoderma sp. - CKT isolate) and T6 was the most efficient isolates for enhancing the growth of black pepper. However, T4 (Pseudomonas fluorescens - PAP isolate) and T5 (Trichoderma sp. - CKT isolate) were the most promising treatments for Phytophthora disease management. Under natural condition (without stress), T8 (PGPR Mix - II - KAU ref. culture) and T4 (Pseudomonas fluorescens - PAP isolate) were the most efficient isolates for enhancing the growth of black pepper under natural condition (without stress). However, T3 (Burkholderia sp. - PAB isolate), T4 (Pseudomonas fluorescens - PAP isolate) and T5 (Trichoderma sp. - CKT isolate) were the most promising isolates for Phytophthora disease management. Among the isolates obtained in the present studies, the most promising abiotic stress tolerant isolate for growth promotion and disease management in black pepper under polyhouse condition was Trichoderma harzianum (T5 - CKT isolate), whereas Pseudomonas fluorescens (T4 - PAP isolate) was the most promising abiotic stress tolerant isolate under natural conditions. Most promising abiotic stress tolerant isolate for abiotic stress tolerance, growth promotion and Phytophthora disease management in black pepper nursery under both polyhouse and natural conditions was Trichoderma harzianum (T5 - CKT isolate). However, further studies are needed to confirm the results.ThesisItem Open Access Biocontrol potential of plant associated bacteria from piper spp. against phytophthora capsici infecting black pepper(Department of Agricultural Microbiology, College of Agriculture, Vellayani, 2017) Nadiya Kollakkodan; KAU; Anith, K NThe study entitled “Biocontrol potential of plant associated bacteria from Piper spp. against Phytophthora capsici infecting black pepper” was conducted at the Department of Agricultural Microbiology, College of Agriculture, Vellayani and Coconut Research Station, Balaramapuram during 2015-2017 with the objective to study the antagonistic effect of plant associated bacteria from Piper colubrinum and Piper nigrum, and their potential for the biological control of Phytophthora capsici induced foliar infection in black pepper in the nursery. Plant associated bacteria were isolated from phylloplane, stem surface and within the leaves, stem and roots of P. colubrinum and P. nigrum on different bacteriological media. A total of 70 isolates were obtained, out of which 39 were from P. colubrinum and 31 from P. nigrum. The isolates were grouped based on cultural and morphological characters. In the initial in vitro screening using dual culture plate assay, it was found that out of the 70 isolates obtained, 16 isolates showed inhibitory effect against P. capsici. The results revealed that the isolates PCSE8 and PCSE10 had the maximum zone of inhibition. The dual culture plate assay was followed by a detached leaf assay using the 16 isolates showing inhibition. It was found that minimum lesion size was observed in leaves sprayed with isolate PCSE10 which caused 79.02% disease suppression over the control, which was on par with leaves sprayed with PCSE5. Biochemical characterization of the selected isolates were carried out using biochemical kits and a tentative genus level identification was done. Molecular level characterization was done and the plant associated bacteria from Piper spp. having biocontrol potential against P. capsici were identified as Burkholderia cenocepacia, Acinetobacter sp, Staphylococcus epidermidis, Streptomyces deccanensis, Bacillus sp, Rhizobium sp, Pantoea dispersa, Bacillus velezensis, Enterobacter sp, Acinetobacter baumannii and Bacillus subtilis. A greenhouse experiment was carried out at Coconut Research Station, Balaramapuram, to study the effect of selected isolates on plant growth promotion and suppression of P. capsici induced foliar infection in the black pepper var. Karimunda. Suppression of foliar infection was studied by challenge inoculation with the pathogen on the foliage. Following artificial inoculation with the pathogen, the lowest lesion size was observed in plants treated with Rhizobium sp PCRE10 (1.18 cm) which caused 75.05% disease suppression over the pathogen control with the lowest disease index of 0.2. The isolate B. velezensis PCSE10 resulted in 53.69% disease suppression over pathogen control with a disease index of 0.32. The plant growth promotion aspects of the plant associated bacteria were studied by analysing the biometric characters of rooted cuttings of black pepper var. Karimunda at 70 DAP. Maximum leaf number was observed in plants treated with B. velezensis PCSE10 (2.25). The treatments had significant effect on the rooting of the cuttings. The highest root number was observed in plants treated with isolate Rhizobium sp PCRE10 (12.33) followed by S. deccanensis PCRE1 (10.92). A similar trend was observed in root fresh weight and root dry weight. The shoot dry weight was highest in plants treated with B. velezensis PCSE10 followed by plants treated with B. velezensis PCSE8. The study revealed that wild relative of black pepper, P. colubrinum is a good source for isolation of antagonistic bacteria against P. capsici. Bacterization with endophytes improved the plant growth characteristics and helped in better establishment of plants. Treatment with plant associated bacteria from P. colubrinum and P. nigrum suppressed the development of foliar infection of P. capsici. The endophytes of P. colubrinum, Rhizobium sp PCRE10 and B. velezensis PCSE10 were selected as best candidates when both disease suppression and plant growth promotion were considered..ThesisItem Open Access Evaluation of bacillus thuringiensis isolates against diaphania indica (saund.) (Lepidoptera:pyralidae)(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2017) Janish Rose, Jacob; KAU; Girija, DChemical pesticides provide significant benefit by controlling pests of agricultural crops. However, their use has increased at an alarming rate, along with proportionate increase in their adverse effect on the environment. In recent years, several insects have developed resistance towards a few pesticides due to their indiscriminate use. Several microbial agents have been used as an alternative for chemical pesticides and Bacillus thuringiensis is one among them. B. thuringiensis is a sporulating, Gram positive, facultative anaerobic soil bacterium, capable of synthesizing δ-endotoxins or Cry proteins during sporulation. Due to the insecticidal properties of these proteins, the bacterium is used against insect species of the orders Lepidoptera, Coleoptera and Diptera. More than 500 isolates of B. thuringiensis obtained from the Western Ghats of Kerala, in a DBT funded project, are being maintained in the repository of the Department of Agricultural Microbiology, College of Horticulture, Thrissur. Several microbial inoculants such as Pseudomonas fluorescens, Trichoderma viride, Beauvaria bassiana, Lecanicillium lecanii have been developed by Kerala Agricultural University but there is no formulation of B. thuringiensis. A study was conducted to develop a commercial formulation of B. thuringiensis and to evaluate its bio-efficacy against the pumpkin caterpillar, Diaphania indica (Saund.). Twenty native isolates with cent per cent mortality in previous studies were selected from the repository of the Department of Agricultural Microbiology. Morphological, biochemical and molecular characterisation of these native B. thuringiensis were carried out. The isolates showed only very slight variations in their cultural characteristics. Colonies appeared circular, creamy white with entire to undulate margin and flat elevation. The isolates showed positive reaction to starch and esculin hydrolysis, sucrose fermentation test and negative to Voges-Proskauer test. The isolates were screened for the presence of lepidopteran specific insecticidal genes, using PCR. Among the 20 native B. thuringiensis isolates, seven isolates yielded cry1 gene amplicons. None of the isolates produced cry2 and cry9 amplicons. The cry1 amplicons were further sequenced and when subjected to Blastn analysis showed homology towards cry1, cry1A, cry1Aa and cry1Ac. All the isolates have shown identity in the range of 93-96 per cent to the known cry1 genes. Thus, the presence of cry1 gene was confirmed. Based on the abundance of crystal protein and cry1 gene, three native isolates (KAU-11, KAU-474 and KAU-2189) were further selected for laboratory bioassay against the lepidopteran pest, D. indica. Among the native isolates, KAU-2189 showed highest per cent morality and was further selected for liquid formulation studies. Suitability of three media (soy flour broth, coconut water broth and T3 broth) was assessed based on the population and spore count at 0 h, 72 h and 96 h after inoculation. Coconut water yielded higher population than the standard medium (T3 broth). Spore count of B. thuringiensis in coconut water and T3 were statistically on par. Thus, coconut water served as the best among the tested substrates for B. thuringiensis production and this was further used for the liquid formulation. Bio-efficacy of the liquid formulation was evaluated in pot culture experiment against D. indica using little gourd (Coccinia indica) as the test crop. Btk (ABTEC), a commercial formulation was used as standard. The higher per cent mortality was recorded for the formulations containing KAU-2189 in coconut water broth and HD-1 in coconut water broth and both were statistically on par with each other. Minimum leaf damage was also recorded in treatments with these formulations and was statistically on par with each other. Shelf life studies of liquid formulations indicated that both population and spore count decreased from fourth month onwards. The study revealed that the native isolates have the potential to be developed into a biopesticide. Coconut water could be used as an ingredient for low cost liquid formulation. Further evaluation under field conditions is required to confirm the efficiency of KAU-2189 as a biopesticide.