1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Bioefficacy and soil health impact of flucetosulfuron in wet seeded rice (Oryza sativa L.)(Department of Agronomy, College of Agriculture, Vellayani, 2018) Arya, S R; Elizabeth K SyriacItem Herbicide mixtures for weed management in direct seeded puddled rice (Oryza sativa L.)(Department of Agronomy,College of Agriculture, Vellayani, 2016) Sheeja K Raj; Elizabeth K SyriacItem Development of inoculant cultures of zinc solubilizing microorganisms(Department of Agricultural Microbiology, Vellayani, 2016) Aathira S Kumar; Anith, K NItem Validation of identified genes for water stress in rice (Oryza sativa L.) mediated by Pseudomonas fluorescens(Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara, 2016) Saakre Manjesh; Abida, P SRice is the staple food for an expansive part of the world, particularly Asia. It is grown under diverse water regimes ranging from poorly drained waterlogged situations to well drain or water stressed upland conditions. Drought is one of the major abiotic stresses that adversely affect crop plants limiting their growth and yield potential. It disrupts the ionic and osmotic equilibrium of the cell. Susceptibility to water stress in rice is more pronounced at the reproductive stage and causes the greatest reduction in yield when stress coincides with the irreversible reproductive processes. Transcriptome analysis was carried out in Matta Triveni (PTB 45) to understand the influence of PGPR under water stress tolerance. Matta Triveni is a popular short duration (100-105 days) rice variety of Kerala, recommended for rainfed ecosystem especially in lowlands during the first crop and irrigated conditions during summers (third crop). With growing emphasis on expanding area under upland rice in the state, the need for an early, profusely tillering, drought tolerant variety is on the rise. Matta Triveni though high yielding is found to be adversely affected by drought. Hence, the present study was performed to assess the impact of application of Pseudomonas fluorescens in inducing tolerance to drought in variety Matta Triveni. In the present study the already identified differentially expressed genes such as Cytochrome oxidase subunit I (CO I), Protein kinase domain protein (PKDP), bZIPl (basic Leucine Zipper), AP2-EREBP (APETALA2 and ethylene-responsive element binding protein), Hsp20 (Heat shock protein 20) and COC1 (Circadian oscillator component) which are involved in ABA dependent and independent signal transduction pathways under water stress were validated using real-time PCR. Seedlings of rice variety Matta Triveni were given three treatments. Unstressed plants were maintained as absolute control. Water was withheld in second treatment and in the third treatment water was withheld in plants for which Pseudomonas fluorescens Pf1(KAU strain) was applied. Plants were given two applications of Pseudomonas fluorescens(pf) i.e., seed treatment and foliar spray. Water was withheld continuously for 15 days during reproductive stage (panicle initiation stage) after foliar spray. Plants exhibited leaf rolling which was scored as per IRRI, SES and was used for total RNA isolation. Biometric parameters were recorded after harvest. Total RNA was isolated from 65 days old rice plants after drought induction using TRIzol reagent. The first strand cDNA was synthesized by reverse transcriptase PCR from the above RNA samples. The cDNA was normalized using actin, which is a housekeeping gene. The real-time PCR primers were designed for six differentially expressed genes such as COI, PKDP, bZIPl, AP2-EREBP, Hsp20 and COC1 using IDT PrimerQuest software and the designed primers were validated using IDT OligoAnalyzer 3.1 tool. The target genes were analyzed by keeping actin as endogenous control. Comparative Δ Ct method was used to analyze the expression levels of genes. Results revealed that all these genes were upregulated in water stressed + Pf treated plants. COI,PKDP, bZIPl, AP2-EREBP, Hsp20 and COC1 genes were found to have 2.3, 2, 6, 2.8, 4.5 and 4 fold increases in relative expression levels respectively in the same treatment as compared to control. In-silico analysis was performed to identify the Transcription Factor Binding Sites (TFBSs) and combinatorial cis-regulatory elements for COI, PKDP, bZIP, AP2- EREBP, Hsp20 and MYB genes which are expressed in treatments. TFBSs were identified by AthaMap database, a genome-wide map of TFBSs in Arabidopsis thaliana, and STIFDB2 database which is a comprehensive collection of biotic and abiotic stress responsive genes in Arabidopsis and Oryza sativa. The significant TFBSs were analyzed based on the parameters provided by databases and were cross validated. The results revealed that the WRKY, MYB, HSF, bZIP, ARF, AP2/EREBP, bHLH, Trihelix and ABI3/VP1 TF families and their respective regulatory elements were predicted as functionally significant. The combinatorial cis- regulatory elements for three genes viz, CO 7, AP2-EREBP and Hsp20 were also identified. The transcription factors belonging to MYB, WRKY, bHLH and Trihelix families which are mainly responsible for drought stress signals and were predicted as co-associated. The study had shown that gene expression in plants lacking adequate water can be remarkably influenced by microbial colonization. The activation of the ABA dependent signaling pathway induced by colonization of P. fluorescens might be a key element for induced systemic tolerance. The predicted TFBSs and combinatorial cis-regulatory elements would be responsible for the upregulation of genes under water stress.Item 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, 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.Item Characterization, host range and management of papaya ringspot virus (PRSV)(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2018) Atheena Harish; Anita Cherian, KItem Standardisation of nursery management practices in pachotti (Symplocos cochinchinensis (Lour.) S. Moore)(Department of Plantation Crops and Spices, College of Agriculture, Vellayani, 2018) Ajil, M S; Deepa S NairThe study entitled “Standardisation of nursery management practices in pachotti (Symplocos cochinchinennsis (Lour.) S. Moore)” was carried out in the Department of Plantation Crops and spices, College of Agriculture, Vellayani durng 2017-18. The objective of the study was to evaluate the propagation efficiency of different propagules viz., seeds, stem cuttings and root cuttings and to standardise the potting media for the nursery plants of pachotti. The propagules viz., seeds, stem cuttings and root cuttings for the study were sourced form Jawaharlal Nehru tropical Botanical Gardens and Research Institute, Palode, Thiruvananthapuram and from Wayanad district. The seeds were subjected to in vivo and in vitro germination studies. In in vivo study, among the pretreatments tried, viz., physical treatments, chemical priming and bio priming, only physical treatment of scarification (with sand paper) responded with a very low germination of 2 per cent. The germination commenced after two months of the treatment. Other in vivo pretreatments as well as in vitro treatments did not give any germination. In vegetative propagation, stem cuttings were exposed dto hormone/chemicals (auxins, phloroglucinol and salicylic acid (SA) pretreatments for two hours before planting. When pretreated with SA @ 10 and 20 mg L -1, at three months after planting, the hardwood cuttings responded with 30 pere cent survival, whith a shoot length of 2.99 mcm and 3.62cm, respectively. The semihardwood cuttings pretreated with SA@ 20 mg L-1 responded with 23.33 per cent survival with a higher shoot length of 3.72 cm. Both the hardwood and semi hardwood cuttings pretreated with SA 20 mgL-1 had on par values with respect to shoot length. Root cuttings were pretreated with different concentrations of various types of auxins. Root cuttings pretreated with IAA @ 250 mg L -1, after three months of planting responded with 33.33 per cent survival with a shoot length of 5.73 cm. Though root cuttings had slightly higher survival percent and shoot length, hardwood cuttings were selected for the valuation of potting media due to better availability and ease in procurement. The three month old hardwood cuttings pretreated with SA @ mgL-1 were then transplanted to ten different potting media comprising of two basal media viz., soil:coipith compost :cowdung (1:1:1) (B1) and soil : soirpith compost : vermicompost (1:1:1) (B2), and each in combination with biofertilisers @ 5g plant -1 viz., PGPR (Plant Growth Promotng Rhizobacteria) Mix I, Azospirillum, PSB (Phosphorus Solubilising Bacteria ) and AMF (Arbuscular Mycorrhizal Fungi). At fourth month after transplanting, B2 in combination with biofertilisers were found to be significantly superior to B2, B1 and B1 in combination with biofertilisers with respect to morphological parameters. B2 +PGPR Mix I recorded highest shoot length (11.50 cm) and number of leaves (10.50) which was on par with B2+Azospirillum, B2+PSB and B2+AMF; the highest number of branches (1.92) was observed in B2+ Azospiriillum which was on par with the treatments , B2+ PGPR Mix I, B2+PSB and B2+AMF. The fresh and dry weight of shoots were the highest (21.35 g and 4.78 g respectively) in B2 +PGPR Mix I which was on par with B2+ AMF. B2+ AMF recorded highest values (4.77 cm, 0.30 mm, 3.28 g and 0.0092 g, respectively) with respect to root growth parameters viz., root length, root girth , fresh and dry weight of roots. The physiological parameters, leaf area index (1.36) and leaf area duration (34.63 days) were the highest in B2+ PGPR Mix I which was on par with B2 in combination with other biofertilisers. The phytochemical analysis indicated that carbohydrate content (80.9 mg g-1) of plant tissue was the highest in B2+PGPR Mix 1, which was on par with B2+PSB, B2+Azospirrillum and B2+AMF. Chlorophyll content was found to the highest (1.20 mg g-1) in B2+ Azospirillum which was on par with B2+PGPR Mix I. The same treatment recorded the highest soluble protein content (20.31mg g-1) and it was on par with B2 in combination other biofertilisers. The nutrient analysis of plant tissue showed that nitrogen (2.22 percent ) and potassium (2.15 per cent ) content was significantly higher in B2+ Azospirillum. B2+PSB Recorded higher phosphorus content (0.26 per cent) among the treatments. The study indicated that nursery plants in the potting media B2 in combination with biofertilizers gave better performance with respect to morphological parmeters, physiological parameters, phytochemicals and plant nutrients. Among the various potting media tried, B2+AMF recorded significantly higher plant growth potential (0.522) followed by B2 + PGPR Mix I (0.428). In the study, hardwood cuttings were identified as the preferred planting material for the nursery establishment of pachotti. The cuttings could be treated with salicylic acid @ 20 mg L-1 for initial establishment of nursery plants. The preferred potting media for transplanting the established cuttings for raising the nursery plants of pachotti is Soil : Coirpith compost : Vermicompost (1:1:1) +AMF (5g/plant).Item Impact of foliar application of nutrients and growth promoters on seed yield and quality of okra(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2018) Nishidha, C T; Rose Mary FranciesItem Impact of pre-storage seed invigoration in ash gourd (benincasa hispida (thunb.) cogn.)(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2018) Athmaja, S; Rose Mary FranciesA study to elucidate the effect of seed invigoration on viability and quality of seeds in ash gourd variety KAU Local was conducted at College of Horticulture, Vellanikkara, Thrissur, during 2016-2018. The impact of seed invigoration on seed viability and seed quality parameters under ambient (S1) and refrigerated storage (S2) was assessed following a completely randomized design with seven invigoration treatments (I1 to I7) and three replications. Seeds were separately invigorated using CaCl2 (50 m M) for 12h (I1), CaCl2 (50 mM) for 24h (I2), kinetin (10 ppm) for 12h (I3), kinetin (10 ppm) for 24h (I4), KH2PO4 (10-1 M) for 24h (I5), Pseudomonas fluorescens (1x106 cfu.ml-1) for 12h (I6). Untreated seeds (I7) served as control. Both treated and untreated seeds were dried to < 8 per cent moisture content and packed in polythene bags (700 gauge). The seed quality parameters were recorded immediately after treatment and subsequently at monthly intervals for a period of 10 months, while, germination of stored seeds was assessed up to 14 months after storage (MAS). At bimonthly intervals, quantification of lipid peroxidation, sugar and amino acids leached out from the seeds and the seed micro flora infection was also done. Seed quality during storage and seed longevity were found to be significantly influenced by storage environment, invigoration treatment and their interaction throughout the storage period. The results revealed that germination and other seed quality parameters such as germination index, coefficient of velocity of germination, energy of germination, vigour indices I and II, in both treated and untreated seeds decreased progressively over the storage period. However, there was an increase in mean time to germination, time taken for 50 per cent germination, allometric index, electrical conductivity of seed leachate, seed infection per cent, leachate of sugar, amino acid and lipid peroxidation, towards the end of storage period. Germination of seeds stored under the refrigerated storage was lower than that under ambient storage in the initial storage period (upto 3 MAS). Henceforth, refrigerated seeds exhibited significant superior germination than that under ambient storage till the end of storage period (14 MAS). Germination of seeds under refrigeration was retained above 60 per cent (the minimum seed certification standards required for ash gourd) for 13 MAS compared to 5 MAS in ambient stored seeds. The study thus revealed that irrespective of seed invigoration treatments, to prolong seed longevity and maintain seed quality, storing seeds under refrigeration is advantageous over ambient storage. Irrespective of storage environment, priming induced early germination. The seed quality parameters of the invigorated seeds before storage were found to be superior to untreated seeds. The invigorated seeds had also exhibited a germination per cent above 80 at 1 MAS, while, the germination in untreated control (I7) during the corresponding period was below the MSCS. Seeds invigoration with calcium chloride for 12h (I1) and 24h (I2) recorded significantly high germination and other seed quality parameters during the storage period of ten months. Owing to the significant superiority of seeds invigorated with I1 (CaCl2 50mM 12h) and I2 (CaCl2 50mM 24h) with respect to germination in the initial period of storage (up to 4 MAS), superior seed qualities during storage as well as retention of germination above MSCS for 8 MAS, seed invigoration with CaCl2 50mM before storage can be advocated to help retain seed qualities and prolonging seed longevity during storage. The interaction between storage condition and invigoration treatment on germination and other seed indices pointed out that it was most advantageous to treat seeds with CaCl2 50mM for 12h (I1) before storing under ambient conditions. If provision for refrigerated storage is available, bio-priming with Pf 1x10-6 cfu.ml-1 for 12h (S2I6) or priming with CaCl2 50mM for 24h (I2), kinetin 10 ppm for 12h (I3) or kinetin 10 ppm for 24h (I4) or KH2PO4 10-1 M for 24h (I5) would be most advantageous. Analysis of the impact of pre-storage seed invigoration treatment on seed longevity subsequent to retrieval of seeds from refrigerated storage revealed that, irrespective of the storage period under refrigeration, the seeds were found to retain viability above MSCS for a minimum period of one month after retrieval from refrigerated storage. Viability retention of invigorated and untreated seeds during further periods of thawing was unpredictable. It was also evident that none of the treatments could help retain seed viability above MSCS for five months after retrieval from refrigeration. Results also revealed that seed invigoration with CaCl2 50mM 12h (I1) is advantageous, if one or two months of ambient storage after retrieval from cold storage is unavoidable. Hence, considering the impact of storage environment, invigoration treatment and their interaction on seed longevity and quality, as well as their influence on seed longevity during thawing, it can be summarised that seed invigoration with CaCl2 50mM for 12h (I1) or 24h (I2) would be beneficial.Item Management of cercospora leaf spot of vegetable cowpea (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt.)(Department of Plant Pathology, College of Agriculture, Vellayani, 2017) Chinnu Ravi; Radhakrishnan, N V