Browsing by Author "Surendra Gopal, K"

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Agrobacterium rhizogenes mediated in vitro multiplication of AMF(Glomus intraradices) in Artemisia annua L.
(Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara, 2010) Thiagarajan, K; Surendra Gopal, K
Arbuscular mycorrhizal fungi (AMF) are an important biofertiliser and biocontrol agent for agricultural crops. It plays an important role in phosphorous uptake and imparts stress tolerance in plants. At present, large scale multiplication of AMF is done in pots using a suitable host. However, it is difficult to maintain pure culture of AMF in pot culture. Moreover, in vitro multiplication on artificial media is not possible due to its obligate symbiotic nature. One of the recent approaches for the mass multiplication of AMF is the Ri-T-DNA hairy root technique. AMF, if colonised on hairy roots, can be a novel technique for its in vitro mass multiplication. Hence, a study was undertaken to multiply AMF (Glomus intraradices) in the hairy roots of Artemisia annua under in vitro conditions. The studies on the effect of G. intraradices on Artemisia confirmed root colonisation and spores in rhizosphere. Among the two strains of Agrobacterium rhizogenes used for hairy root induction in Artemisia, MTCC 532 was selected and was found to be superior to MTCC 2364. Hairy roots were induced on A. annua as per the procedure already standardised. The cellulase enzyme (0.16 mg l-1) in water agar media enhanced G. intraradices spore germination for inoculation on hairy roots. Normal procedures carried out to infect hairy roots of Artemisia with normal and germinated spores of AMF did not yield positive results. The hairy roots failed to proliferate further and the AMF inoculum also did not survive even after repeated attempts in different culture conditions (solid, liquid static and shaking). However, the possibility of using A. annua as a host for AMF (G. intraradices) was confirmed through pot culture experiments. A. annua based inoculum was found superior to maize based inoculum and it recorded maximum survival per cent, number of leaves, plant height (cm), number of tillers, plant fresh weight and dry weight in pot culture experiment using tissue culture (TC) derived ginger plants. The present study revealed the possibility of using A. annua as a host for multiplication of AMF. However, no root colonisation was observed on hairy roots of A. annua. Microbial contamination during AMF spore inoculation was the main limiting factor for proliferation. Thus, the procedure for in vitro inoculation of AMF spores in hairy roots of A. annua, are yet to be standardised. A suitable medium that will allow survival and proliferation of hairy roots and AMF together also needs to be standardised.
Alginate based consortial formulation of native microbial fertilizers
(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2019) Alfiya Beegum, A; Surendra Gopal, K
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; Surendra Gopal, K
Pokkali 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.
Biocontrol of bacterial wilt in tomato using arbuscular myaorrhizal fungi
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2003) Nandakumar, A; Surendra Gopal, K
Bioefficacy of endophytic actinomycetes on plant growth promotion and management of bacterial wilt in tomato.
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2011) Sreeja, S J; Surendra Gopal, K
Biofertilizer technology for spices:Technical Bulletin 01
(Department of Agricultural Microbiology, College of Agriculture, KAU,Vellanikkara, 2020) Girija, D; Surendra Gopal, K; Santosh Ranjan, Mohanty
Development of a native microbialconsortium of biofertilizers for plant growth promotion in nutmeg (Myrstica fragrans Houtt)
(Department of Agricultural Microbiology, College of Agriculture, Vellanikkara, 2025-08-12) Salitha; Surendra Gopal, K
Biofertilizers are the living microorganisms that promote plant growth by increasing nutrient availability in soil. They are renewable, ecofriendly and reduce dependency on chemical fertilizers. The consortium of biofertilizers is a combination of various microorganisms which act together as a community that contributes to plant growth. Nutmeg, an important spice crop of India, is widely cultivated in Kerala. The nutrient exhaustive crop is used in this study to reduce the dependency on chemical fertilizers. Wayanad, an agrarian district, is known for its organic production of spices. The present investigation titled “Development of a native microbial consortium of biofertilizers for plant growth promotion in nutmeg” was carried out with the objective of isolation of native nitrogen fixers, phosphate solubilizers, and potassium solubilizers from the rhizosphere soils of nutmeg of Wayanad district and to develop microbial consortia and evaluate microbial consortium for plant growth promotion of nutmeg under pot culture and field evaluation in the Wayanad district. Nutmeg rhizosphere soil samples were collected from 10 different locations of Wayanad district in Kerala. A total of 55 isolates were obtained comprising of 21 nitrogen fixing bacteria, 18 phosphorus solubilizing bacteria and 16 potassium solubilizing bacteria. These beneficial bacterial isolates were screened for plant growth promoting activities viz., nitrogen fixation, phosphorus solubilization, potassium solubilization and IAA production under in vitro condition. The nitrogen fixation by the bacterial isolates ranged from 0.70 to 4.90 mg g-1 of carbon source. The phosphorus solubilization ranged from 12.98 µg P ml-1 to 71.65 µg P ml-1. The potassium solubilization values by the bacterial isolates ranged from 6.66 mg K ml 1 to 8.30 mg K ml-1. IAA production was qualitatively and quantitatively estimated for all 55 bacterial isolates. IAA production of nitrogen fixing bacteria ranged from 0.46 µg ml-1 to 11.09 µg ml-1. IAA production of phosphorus solubilizing bacteria ranged from 0.07 µg ml-1 to 1.85 µg ml-1. IAA production of potassium solubilizing bacterial isolates ranged from 0.63 µg ml-1 to 9.77 µg ml-1. Based on their functional efficiency, 15 most promising bacterial isolates were characterized for the morphological, cultural, and biochemical characters. Ten of the bacterial isolates were Gram positive and five identified as Gram negative. Ten of the isolates were rod shaped while the other five cocci shaped. Fifteen isolates were further screened for abiotic stress tolerance. The moisture stress tolerance was studied at 10 %, 20 %, 30 %, and 40 % using PEG 6000 in Tryptone Soy broth for 48 h at 28 ± 2 ℃. Similarly, temperature stress tolerance was screened at temperatures of 30 ℃, 35 ℃, 40 ℃ and 45 ℃ for 48 h. All the 15 bacterial isolates were found to be tolerant to the maximum stress of 40 % moisture stress and 45 ℃ temperature stress. Compatibility of the most promising 15 isolates were assessed. All 14 bacterial isolates were compatible among themselves. One potassium solubilizing bacterial isolate viz., KKK 2 was incompatible with 5 bacterial isolates (nitrogen fixing bacteria, phosphorus solubilizing bacteria). Based on the plant growth promoting activities, abiotic stress tolerance and compatibility studies, 9 most promising bacterial isolates were selected. Molecular characterization of the nine bacterial isolates were done using 16S rRNA gene sequencing and identified as Staphylococcus equorum VTN 2, Staphylococcus equorum KPN 3, Enterobacter sp. KPN 1, Staphylococcus pasteuri PPP, Bacillus velezensis KKP 1, Pseudomonas aeruginosa MKP 2, Sphingobacteriumanhuiense MPK, Staphylococcus epidermidis NMK 2 and Pseudomonas veronii MHK. Based on the ranking of the bacterial isolates, the 3 best nitrogen fixing bacteria (Staphylococcus equorum VTN 2, Staphylococcus equorum KPN 3 and Enterobacter sp. KPN 1), 3 phosphorus solubilizing bacteria (Staphylococcus pasteuri PPP, Bacillus velezensis KKP 1, and Pseudomonas aeruginosa MKP 2) and 3 potassium solubilizing bacteria (Sphingobacteriumanhuiense MPK, Staphylococcus epidermidis NMK 2 and Pseudomonas veronii MHK) were selected for developing 3 distinct formulations of liquid biofertilizer consortia. The liquid biofertilizer consortia was evaluated under pot culture at Block 10, RARS, Ambalavayal, Wayanad with 6-month-old nutmeg seedlings. Combined application of liquid biofertilizer with 2 levels (50 % and 75 % of N, P, K) of recommended dose of fertilizers, commercial formulation PGPR Mix 1, inorganic POP, organic POP, control were the treatments. Pot culture evaluation results revealed that liquid biofertilizer consortium C2 (Staphylococcus equorum KPN 3 + Bacillus velezensis KKP 1 + Staphylococcus epidermidis NMK 2) with 50 % RDF was the most promising among the treatments, resulting in 50% reduction of chemical fertilizer dependency. Based on the plant growth parameters, the 2 best consortia (Consortium 2 (Staphylococcus equorum KPN 3 + Bacillus velezensis KKP 1 + Staphylococcus epidermidis NMK 2) and Consortium 1 (Staphylococcus equorum VTN2, Staphylococcus pasteuri PPP, Sphingobacteriumanhuiense MPK)) were selected for further field evaluation. The 2 best biofertilizer consortia obtained from pot culture experiment in Wayanad district were evaluated under field condition at Block 5, RARS, Ambalavayal, Wayanad. Plant growth parameters revealed that application of consortium 2 (Staphylococcus equorum KPN 3 + Bacillus velezensis KKP 1 + Staphylococcus epidermidis NMK 2) with 50 % RDF was the most promising treatment. Metagenomics analysis of the soil samples before and after application of biofertilizer consortia revealed that there was no change in the predominant phyla level classification, except for its composition percentage. Proteobacteria, Actinobacteria and Acidobacteria dominated at the phylum level composition. There were changes at the species level. At the species level composition, Aciditerrimonasferrireducens (12.94 %) dominated in the initial soil sample and Sphingomonaslimnosediminicola (31.18 %) dominated in the case of the best biofertilizer consortia application (Staphylococcus equorum KPN 3 + Bacillus velezensis KKP 1 + Staphylococcus epidermidis NMK 2 + 50 % RDF of N, P, K). Field level application of liquid biofertilizer consortia has resulted in changes to the rhizosphere bacteria of nutmeg plants, which in turn has enhanced their growth and development. Hence, it can be concluded that liquid biofertilizer consortium 2 (Staphylococcus equorum KPN 3 + Bacillus velezensis KKP 1 + Staphylococcus epidermidis NMK 2) increased nutrient availability to the plants and promoted nutmeg growth. Native biofertilizer consortia reduced 50 % dependency of chemical fertilizers and increased nutmeg seedling growth. These results indicated the importance of exploiting native bacterial isolates rather than a non-native consortium. It is an ecofriendly, cost effective and sustainable method compared to synthetic fertilizers. Multilocation trials and risk assessment of the biofertilizer need to be assessed before commercialization of the liquid biofertilizer consortium.
Evaluation of abiotic stress tolerant 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; Surendra Gopal, K
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; Surendra Gopal, K
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; Surendra Gopal, K
Evaluation of bioinoculant consortia for organic cultivation of ginger
(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2015) Haritha, T R; Surendra Gopal, K
Evaluation of drought and acid tolerant actinomycetes for rice (Oryza sativa L.)
(Department of Agricultural Microbiology, College of Agriculture, Vellanikkara, 2022) Gokul Vigneshwaran, P; Surendra Gopal, K
Rice (Oryza sativa L). is one of the world's most significant cereal crops. It is widely cultivated food crop in the world, providing staple food to 2.7 billion people. Rice cultivation is facing many challenges due to abiotic stresses like drought, acidity, flood and high temperature. Among the major yield-limiting biotic factors, disease management is one of the most important problems in paddy cultivation. Among the several diseases in rice, sheath blight (Rhizoctonia solani) is a fungal disease that has a high impact on the rice crop from tillering to the heading stage. Rhizospheric microbes, particularly actinomycetes have gained attention due to their ability to promote plant growth, control diseases and reduce harm to the environment. The use of actinomycetes as bio-control agents is sustainable and complementary in improving crop yield and protection that is affordable to farmers. Actinomycetes have been used to mitigate drought and acidic stress. Hence, the present study was carried out on “Evaluation of drought and acid-tolerant actinomycetes for rice (Oryza sativa L).” with the objective of plant growth-promotion and Rhizoctonia solani management under pot culture studies. Ten rhizospheric soil samples were collected from drought and acidic rice-growing areas of the Thrissur and Palakkad districts. All the actinomycetes isolates were subjected to morphological, cultural, and biochemical characterization. The actinomycetes isolates showed gram-positive reaction and varied in spore chain morphology viz., filamentous, spiral and closed spiral. In vitro screening of actinomycetes isolates for plant growth-promoting traits showed that all the actinomycetes isolates were positive for indole acetic acid production. Out of ten isolates, seven isolates were positive for the production of IAA and two isolates viz., MNT7 and CHT-1 were high indole acetic acid producers. IAA production by actinomycetes isolates ranged from 4.41 (μg/ml) to 5.99 (μg/ml). The MNT-7 (Streptomyces spinoverrucosus) isolate showed the highest IAA production (5.99 μg/ml) followed by CHT1 (5.43 μg/ml) and PTK-4 (Streptomyces spp.) (5.23 μg/ml). All the isolates fixed atmospheric nitrogen which ranged from 2.80 μg/ml to 10.50 μg/ml. The MNT-7 (Streptomyces spinoverrucosus (10.50 μg/ml), VLK-2 (9.10 μg/ml) and VER-4 (Streptomyces cellulosae) (7.70 μg/ml) isolates were the most efficient nitrogen-fixing isolates. The amount of phosphate solubilization varied between 3.28 μg/ml to 57.56 μg/ml. nine isolates showed potassium solubilization in the range of 1.86 μg/ml to 5.07 μg/ml. 134 In vitro screening of actinomycetes for antagonistic properties did not show ammonia and siderophore production. Among the ten actinomycetes isolates, MNT-7 (Streptomyces spinoverrucosus) and PTK-4 (Streptomyces spp.) isolates produced hydrogen cyanide. Only MNT-7 (Streptomyces spinoverrucosus) (71.23%) and PTK-4 (Streptomyces spp) (68.82%) isolates inhibited the growth of Rhizoctonia solani indicating their biocontrol potential. In vitro screening of actinomycetes for acidic pH and water stress tolerance showed that MNT-7 (Streptomyces spinoverrucosus) isolate was tolerant to acidic pH upto pH 3.5 and MNT-7 (Streptomyces spinoverrucosus) and PTK-4 (Streptomyces spp.)isolates were water stress tolerant upto 20 % PEG. The three most promising (MNT-7, PTK-4 and VER-4) actinomycetes were identified as Streptomyces spinoverrucosus, Streptomyces spp., Streptomyces cellulosae respectively. On the basis of the plant growth-promoting activities, acidic pH and water stress tolerance, native actinomycetes isolates of Streptomyces spinoverrucosus (MNT-7), Streptomyces spp. (PTK-4) and Streptomyces cellulosae (VER-4) evaluated under pot culture. MNT-7 (Streptomyces spinoverrucosus) significantly increased all the growth parameters and yield also recorded the minimum sheath blight percent disease incidence of 6.79 under pot culture studies. The present study revealed that Streptomyces spinoverrucosus (MNT-7) was the most promising PGPR for plant growth promotion and sheath blight disease management. To, the best of knowledge, Streptomyces spinoverrucosus is the first report of PGPR tolerant to drought and acidic pH. However, further evaluation field is needed to confirm the findings.
Evaluation of native rhizosphere microflora for plant growth promotion and management of fusarium yellows in ginger
(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2016) Rekha, K G; Surendra Gopal, K
Evaluation of plant growth promoting rhizobacteria for pokkali rice
(Department of Agricultural Microbiology, College of Agriculture,Vellanikkara, 2023-02-17) Bony Cyriac.; Surendra Gopal, K
Pokkali rice farming is a time-honoured, environmentally beneficial, traditional and organic method of growing rice. Neither chemical fertilizers nor plant protection agents are used on the crop in this conventional rice farming technique. The present study was undertaken to evaluate a native plant growth promoting rhizobacteria (PGPR) consortia with an objective to screen PGPR for functional efficiency under in vitro and evaluate for plant growth promotion in Pokkali rice. Isolation, characterization and screening of plant growth promoting rhizobacteria such as nitrogen fixers, phosphate solubilizers, potassium solubilizers, fluorescent pseudomonads and Bacillus sp. were carried out from three Pokkali rice growing regions of Ernakulam district (Vytilla, Varapuzha and Kadamakudy). Maximum population of 4 x 103 , 4.66 x 103 and 16.67 x 103 cfu per g of soil were recorded for nitrogen fixers, phosphate solubilizers and Bacillus sp. respectively and fluorescent pseudomonads and potassium solubilizers were absent. A total of 25 predominant isolates were obtained of which 17 isolates belonged to Bacillus sp. and remaining 4 isolates each were nitrogen fixers and phosphate solubilizers. Cultural, morphological and biochemical characters of all the 25 isolates of rhizobacteria showed varied colony morphology and Gram reaction. These isolates were evaluated under in vitro for plant growth promotion activities (production of indole acetic acid, nitrogen fixation, phosphate and potassium solubilization), antagonistic mechanisms (NH3, HCN and siderophore production) and its activities against Xanthomonas oryzae. Quantity of IAA produced by rhizobacterial isolates ranged from 0.46 to 31.27 μg ml-1. Quantity of nitrogen fixed and phosphate solubilized by rhizobacterial isolates varied from 5.72 to 25.21 mg of N g-1 sucrose utilized and 1.98 to 53.19 μg ml-1, respectively. There was no significant difference between potassium solubilized by isolates. Among the rhizobacterial isolates all Bacillus sp. isolates and two isolates each of nitrogen fixers and phosphate solubilizers were found positive for ammonia production. In case of screening of isolates for siderophore production, isolate VYP1 produced moderate orange halo zone on CAS agar media. Isolates VYN1, VYN2, VRB1 and VRB3 recorded poor siderophore activity. Remaining all isolates in the study screened negative for siderophore production. All isolates in the study were found negative for HCN production. Antagonistic activities of isolates to inhibit the rice pathogen Xanthomonas oryzae was evaluated and twenty one isolates screened exhibited antagonistic response against pathogen in which Bacillus isolates KDB4 and KDB5 exhibited excellent antagonism against pathogen. Based on the plant growth promotion activities and antagonistic activities, four most efficient isolates each of nitrogen fixers, phosphate solubilizers and Bacillus sp. were selected for salinity tolerance studies. Among the isolates, nitrogen fixers and Bacillus sp. exhibited maximum salinity tolerance of 12% whereas, phosphate solubilizers exhibited salinity tolerance up to 4% salt concentration. After salinity tolerance studies, three most tolerant nitrogen fixers (VYN2, KDN1 and KDN2), phosphate solubilizers (VYP1, VRP1 and KDP1), and Bacillus sp. (VYB3, VYB6 and KDB1) were selected for compatibility studies. Three most promising PGPR based consortia, PGPR consortia1 (KDN2 + KDP1 + VYB6), PGPR consortia-2 (KDN1 + KDP1 + VYB6) and PGPR consortia-3 (KDN2 + VYP1 + KDB1) were formulated. The three most promising consortia were evaluated under pot culture experiment, along with KAU commercial formulation (PGPR Mix-1) and Organic Package of Practices Recommendations of KAU (2017), at RRS, Vytilla, with Pokkali rice (variety Vytilla-6) as the test crop. All the three native PGPR consortia (T1, T2 and T3) exhibited significant increase in plant height and plants treated with T1 (PGPR consortia 1- KDN2 + KDP1 + VYB6) and T2 (PGPR consortia 2 - KDN1 + KDP1 + VYB6) recorded significantly higher results. Higher number of grains per panicle, grain yield (g per pot) and theoretical grain yield (kg ha-1) were observed in PGPR consortia 1 consisting of isolates KDN2 (N-fixer) + KDP1 (P- solubilizer) + VYB6 (Bacillus sp.). Significantly higher test weight of seeds were observed in T1, T2 and T3 inoculated with native PGPR consortia compared to other treatments. However, the treatments did not have any significant effect on number of tillers, number of panicles per plant and the percentage of chaffy grains produced. The present study indicated that saline tolerant PGPR consortia-1 consisting of Enterobacter cloacae strain KDN2 (N-fixer) + Bacillus subtilis strain KDP1 (Psolubilizer) + Bacillus altitudinis strain VYB1 (Bacillus sp.) was the most promising biofertilizer in enhancing the production of Pokkali rice of Kerala. However, further evaluation of the most promising consortia needs to be done under field conditions to confirm the results.
Field evaluation of abiotic stress tolerant strains of trichoderma harzianum and pseudomonas fluorescens for phytophthora disease management in black paper (Piper nigrum L.)
(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2020) Rima, K R; Surendra Gopal, K
Black pepper (Piper nigrum L.), known as “the king of spices” is an important spice commodity of commerce and trade in India since pre-historic period. It is highly sensitive to abiotic stresses like climate changes. The abiotic stresses in plants can be overcome by the use of beneficial microorganisms. However, the microorganisms themselves are vulnerable to abiotic and biotic stresses. Therefore, abiotic stress tolerant strains of beneficial microorganisms have to be developed for black pepper to overcome changes due to micro-climatic variables and soil parameters. In an earlier study in the Department of Agricultural Microbiology, College of Horticulture, native abiotic stress tolerant isolates of Trichoderma harzianum (CKT isolate) and Pseudomonas fluorescens (PAP isolate) were identified for growth promotion and disease management in black pepper (Piper nigrum L.) under pot culture studies. As the performance of these strains varies under field conditions, a study on “Field evaluation of abiotic stress tolerant strains of Trichoderma harzianum and Pseudomonas fluorescens for Phytophthora disease management in black pepper (Piper nigrum L.)” was undertaken with an objective to study the effect of micro- climatic and soil parameters on abiotic stress tolerant strains under field conditions. Before field evaluation, pot culture experiment was conducted to evaluate the efficiency of the abiotic stress tolerant Trichoderma harzianum (CKT) and Pseudomonas fluorescens (PAP) for growth promotion and Phytophthora disease management in black pepper during April – October, 2017. T. harzianum (CKT) was the most promising isolate for growth promotion and disease management based on biometric (number of leaves, plant height, number of lateral branches, number of nodes, intermodal length), biological and disease management characters under pot culture studies. It was found that population of Trichoderma harzianum (CKT), Pseudomonas fluorescens (PAP), Trichoderma viride (KAU reference culture) and Pseudomonas fluorescens (KAU reference culture) was negatively correlated with soil temperature and positively correlated with soil moisture. There was no significant correlation between the population of microbes and soil pH and soil respiration. Field evaluation revealed that Trichoderma harzianum (CKT) + KAU POP was the most promising treatment for growth promotion under field conditions based on biometric and biological characters. The population of Trichoderma harzianum (CKT), Pseudomonas fluorescens (PAP), Trichoderma viride (KAU reference culture) and Pseudomonas fluorescens (KAU reference culture) were negatively correlated with soil temperature and positively correlated with soil moisture content. However, soil pH and soil respiration did not have any correlation with the population of Trichoderma sp. and Pseudomonas fluorescens. Micro-climatic and soil parameters did not show any effect on the production of ammonia, HCN and siderophore but had significant effect on production of IAA in Trichoderma sp. and Pseudomonas fluorescens. Soil temperature (26.8 to 30.6 °C), soil moisture content (14 to 17.6 %), soil pH (5.7 to 6.1) and soil respiration (8.1 to 9.8 mg CO2 g-1 day-1) were found to be the optimum micro-climatic and soil parameters for IAA production. Trichoderma harzianum (CKT) was the most promising isolate for growth promotion under field conditions. However, multilocational field trials at different agro- ecological zones of Kerala need to be conducted before commercialization of Trichoderma harzianum (CKT).
Growth enhancement and management of Phytophthora - Rot in Vanilla Nurseries using microbial inoculants
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2007) Shahida, K; Surendra Gopal, K
A study on “Growth enhancement and management of Phytophthora rot in vanilla nurseries using microbial inoculants” was carried out in the Department of Plant Pathology, College of Horticulture, Vellanikkara. The salient findings are abstracted below: The study revealed that Phytophthora meadii Mc. Rac.was the pathogen causing Phytophthora rot in vanilla nurseries. Even though, the treatments did not influence growth characters significantly, AMF (Perumbavoor) and Azospirillum (Mazhuvannur) were the most effective AMF and Azospirillum isolates for enhancement of growth and nutrient content in vanilla. In vitro screening of antagonists against P. meadii revealed that Trichoderma (Vellanikkara) and rhizobacteria ( Mazhuvannur) were very effective against the pathogen. The effective microbial isolates obtained were identified. Among the fungicides tested, Bordeaux mixture, copper hydroxide and copper oxychloride (at all concentrations) and potassium phosphonate (at higher concentrations) completely inhibited the growth of the pathogen. Compatibility studies revealed that potassium phosphonate was compatible with antagonists, while copper fungicides were not compatible with antagonists. Results on compatibility between Trichoderma and antagonistic bacteria showed that Trichoderma was compatible with antagonistic rhizobacteria as well as Azospirillum. The experiment on growth enhancement and Phytophthora rot management in vanilla revealed that all the microbial isolates gave early sprouting. Azospirillum (MVR) gave maximum length. AMF (PBR) and P. fluorescens (commercial) were found to be effective against Phytophthora rot in artificially inoculated vanilla cuttings. Among chemicals tested, potassium phosphonate gave best control against Phytophthora rot.
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; Surendra Gopal, K
Induction of growth promotion in vanilla through plant growth promoting microorganisms consortia
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2007) Dhanya, V; Surendra Gopal, K
A study on “Induction of growth promotion in vanilla through plant growth promoting microorganisms consortia” was carried out in the Department of Plant Pathology, College of Horticulture, Vellanikkara. The salient findings are abstracted below: Isolates of Pseudomonas spp., Bacillus spp. and Trichoderma spp.were evaluated for its efficiency in production of growth promoting substances like IAA and salicylic acid and observed that Pseudomonas sp. was most efficient. Results on compatibility between selected PGPM like Pseudomonas sp., Bacillus sp. and Trichoderma sp. showed that all isolates were compatible with each other under in vitro condition. In the case of Pseudomonas sp, all the selected fungicides and insecticides at all concentrations completely inhibited their growth and among Bacillus isolates, all the selected fungicides and insecticides at all concentrations completely inhibited their growth except carbaryl which was compatible with isolates B1 , B2 and B3 at all concentration .Similarly, in the case of Trichoderma isolates, all the selected fungicides and insecticides at all concentrations completely inhibited their growth. In the present study, most of the growth parameters of vanilla in the nursery experiment was maximum with individual treatments especially Bacillus sp., which performed better than consortia treatments. The use of individual PGPM namely; Pseudomonas sp., Bacillus sp. and Trichoderma sp. and their consortia exerted better growth characteristics in vanilla than untreated control.
Microbial biosorption of heavy metals
(Department of Agricultural Microbiology, College of Agriculture, Vellanikkara, 2020) Bony, Cyriac; Surendra Gopal, K
Screening of acid-tolerant consortia of azospirillum and phosphate solubilizing bacteria from lateritic soils
(Department of Agricultural Microbiology, College of Horticulture,Vellanikkara, 2014) Athulya, M M; Surendra Gopal, K
A study was undertaken on “Screening of acid-tolerant consortia of Azospirillum and phosphate solubilizing bacteria from lateritic soils”. The main objective was to develop an acid-tolerant and efficient consortium of Azospirillum and phosphate solubilizing bacteria (PSB) for acidic soils of Kerala. Lateritic soils with acidic pH were collected from ten different locations of Thrissur district for the isolation of Azospirillum and phosphate solubilizing bacteria. The pH of the soil ranged from 5.22 (Vellanikkara) to 6.51 (Madakkathara). The highest population of Azospirillum was recorded in soils of Madakkathara (MD) and Mulayam (MU) (1.1x105 MPN g-1). However, Chelakkara (CH), Elanad (EL) and Perumpilavu (PV) recorded least population (0.9x104 MPN g-1). Highest population of PSB was obtained from Mulayam (12.7x106 cfu g-1) and least PSB population was obtained from Perumpilavu (PV) (1.0x105 cfu g-1). The population of both Azospirillum and phosphate solubilizing bacteria were higher in rhizosphere soil than non-rhizosphere soil. A total of six isolates of Azospirillum and 35 isolates of PSB were obtained. The isolates AND-4 (Azospirillum from Nadavarambu) and AMU-2 (Azospirillum from Mulayam) were acid-tolerant upto pH 4.5. Similarly, PMD-7 (PSB from Madakkathara) and POL-1 (PSB from Ollur) were also tolerant upto pH 4.5. The AND-4 isolate of Azospirillum sp. fixed highest amount of nitrogen (17.94 mg of N g-1 of malate) followed by AMU-2 isolate (14.58 mg of N g-1 of malate). The isolate AMU-2 showed maximum IAA production (51.95 µg ml-1) followed by AND-4 (30.53 µg ml-1). The PMD-7 was the most efficient P-solubilizer (207.22 µg ml-1) followed by POL-1(187.78 µg ml-1). The PMD-7 isolate produced maximum IAA (33.07 µg ml-1). Sixteen combinations of Azospirillum and PSB were compatible. The three consortia selected based on acid tolerance, efficiency and compatibility were AND-4 (Azospirillum sp.) + PMD-7 (Acinetobacter sp.), AMU-2 (Azospirillum sp.) + PMD-7 (Acinetobacter sp.) and AND-4 (Azospirillum sp.) + POL-1 (Bacillus megaterium). Among the consortia, Azospirillum sp. + Bacillus megaterium (T4) was found to be the most efficient in enhancing the growth of okra under acidic pH based on biometric and yield parameters. However, the POP recommendation (T1) recorded maximum plant height, maximum number of fruits, fruit yield and minimum days for flowering. The population of Azospirillum and PSB increased at the time of harvest in all the treatments except in T7 (Absolute control). The population of Azospirillum was highest in T3 (Azospirillum sp. + Acinetobacter sp.) (23.38x103 MPN g-1) and minimum in T7 (Absolute control) (7.73x103 MPN g-1). The population of PSB was highest in T3 (Azospirillum sp. + Acinetobacter sp.) (6.43x105 cfu g-1) and minimum in T7 (Absolute control) (2.08x105 cfu g-1). The maximum nitrogen uptake was recorded in T1 (KAU POP recommendation) (0.99 g plant-1). Among the consortia, T4 (Azospirillum sp. + Bacillus megaterium) (0.81 g plant-1) and T3 (Azospirillum sp. + Acinetobacter sp.) (0.80 g plant-1) recorded highest nitrogen uptake. The maximum uptake of phosphorus was noticed in T1 (KAU POP recommendation) (0.41 g plant-1) followed by T4 (Azospirillum sp. + Bacillus megaterium) (0.36 g plant-1). The most efficient isolates AND-4 and AMU-2 were identified as Azospirillum sp. The most efficient PSB isolates POL-1 and PMD-7 were identified as Bacillus megaterium and Acinetobacter sp. respectively. The present studies clearly showed that the acid-tolerant and efficient consortium of Azospirillum + Bacillus megaterium (T4 treatment) performed better under pot culture studies, which was on par with chemical fertilizer. However, further studies are needed to evaluate its efficiency under field conditions.