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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 Characterization and integrated management of Fusarium oxysporum f.sp. cubense (E.F. Smith) synder and hansen causing fusarium wilt disease of banana(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2020) Lishma, N P; KAU; Anita Cherian, KFusarium wilt of banana caused by the soil borne fungus Fusarium oxysporum f. sp. cubense (Foc) is a serious constraint to banana cultivation in Kerala. The fungal species constitute four pathogenic races, of which Race 1 is the prevalent one in our country and Race 4 is one of the emerging threats, though not reported from Kerala yet. The present study was undertaken to characterize the associated pathogenic races and to develop an integrated package for the disease management. The project initiated with purposive sampling surveys in various districts viz., Thiruvananthapuram, Ernakulam, Thrissur, Palakkad, Kozhikode and Wayanad representing different agroclimatic zones of Kerala. The per cent disease incidence (PDI) and the per cent disease severity (PDS) ranged from 1.52 to 43.65 per cent and 20.34 to 49.57 per cent. The correlation analysis of PDI with weather parameters showed a positive correlation with rainfall. However, it was negatively correlated with temperature. The study on symptoms under natural as well as artificial conditions showed characteristic external and internal symptoms. The number of days taken for complete wilting under artificial inoculation was 29.67 in Rasthali (AAB), 47.99 in Njalipoovan (AB), 31 in Kadali (AA) and 37.67 in Chenkadali (AAA). Among the thirty isolates of the Foc collected, twenty three isolates were from Rasthali variety, four isolates from Kadali, two isolates from Njalipoovan and one from Chenkadali. Studies on identification of Foc races with the differential host assay revealed that the varieties such as Cavendish (assay host to Race 4), Nendran (assay host to Race 4), Heliconia sp. (assay to Race 3) and Monthan (assay to Race 2) did not produce any type of symptoms whereas, all the isolates produced symptoms on Rasthali (assay host to Race 1) variety. A non polymerase chain reaction (PCR) based quick molecular diagnostic technique with loop mediated isothermal amplification (LAMP) assay was developed for the detection of Races of the pathogen. All isolates showed positive reaction to the LAMP assay for Race 1 and negative for Race 4. A PCR was also standardised for the confirmation of the races. It is concluded that all the isolates collected from different agroclimatic zones belonged to the Race 1 category of the pathogen only. Cultural and morphological characterization of the isolates revealed white coloured aerial mycelium with pink pigmentation and cottony and fluffy mycelial mat. The mycelial growth rate in half strength potato dextrose agar (PDA) medium ranged from 0.83 to 2.40 cm/day and the length and breadth of macroconidia and microconidia measured about 15.01 - 20.20 μm x 2.14 - 5.07 μm and 4.49 - 7.42 μm x 1.35 - 3.13 μm respectively. The inter-septal length and breadth of hyphae ranged from 16.14 to 22.94 μm and 4.22 to 6.57 μm respectively and the size of chlamydospores varied from 5.68 to 9.58 μm in diameter. The PCR based molecular characterization of isolates using ITS (internal transcribed spacer) primers produced single bands of size approximately 580 bp. In silico analysis of the sequences showed 96 to 100 per cent homology to Foc. Based on cultural, morphological and molecular characters, the pathogen was identified as Fusarium oxysporum f. sp. cubense. The screening of accessions maintained in the germplasm of Banana Research Station (BRS), Kannara was done to assess their disease resistance to Foc Race 1 and were grouped into six categories. Fifteen immune varieties viz., Attunendran, Zanzibar, Big Ebanga, Nedunendran, Nendran, BRS II, Thiruvananthapuram, Pachanadan I, Cultivar Rose, Pisang Lilin, Pisang Jari Buaya, Yangambi Km5, Grand Naine, Chinese Cavendish and Nendran Hybrid and four highly susceptible varieties viz., Cheriya Poovan, Valiya Poovan, Kadali and Rasakadali were identified. The estimation of biochemical parameters for the assessment of host plant disease resistance against Foc Race 1 revealed that the activity of total phenols and defense related enzymes was more in resistant varieties compared to susceptible varieties and the activity of reducing and non reducing sugars was more in susceptible varieties. An in vitro experiment was conducted for the evaluation of chemical fungicides, biocontrol agents and botanicals for control of the pathogen. The effective treatments from in vitro evaluation were carried over to pot culture and field experiments for the disease management. Among the various treatments, an integrated package comprising of Pseudomonas fluorescens + arbuscular mycorrhizal fungi and Trichoderma enriched cow dung + tebuconazole (T6) was proved to be the best for yield and disease management. It is concluded that the present study has enlightened our knowledge on characterization, race identification and management of Fusarium wilt pathogen infecting banana.ThesisItem Open Access Management of early blight disease of tomato (Solanum lycopersicum L.) under protected cultivation(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2020) Sumbula, V; KAU; Sainamole Kurian, PTomato (Solanum lycopersicum L.) is one of the most remunerative and widely grown vegetables all over the world. With the coordinated efforts of central and state governments, protected cultivation of tomato is now gaining popularity in Kerala. Despite being a versatile crop adapted to various agroclimatic regions and seasons, cultivation of tomato is constrained by various fungal, bacterial and viral diseases. Among the fungal diseases, early blight caused by Alternaria solani is the most common, destructive and widespread in all the tomato growing tracts. Fungicides and bioagents are commonly used to manage plant pathogens. But little is known about their effects on the non-target microbial communities that inhabit inside and outside the plant. Hence, it has become necessary to consider the effect of different fungicidal and bioagent treatments on target and non-target microbial communities while formulating disease management strategies. So, the present investigation was carried out with the objectives to formulate suitable management strategies against early blight disease of tomato under protected cultivation and to assess their impact on culturable and non-culturable microflora associated with the plant. Isolation of the pathogen from infected tomato leaf samples revealed the association of the fungus, Alternaria sp. and its pathogenicity was established by inoculating on threemonth- old tomato seedlings. Symptoms observed on leaves, shoot and fruits were almost same under both natural and artificial conditions. Cultural and morphological characters of pathogen was studied on potato dextrose agar (PDA). Initially, pathogen produced greenish brown mycelium and later turned to grey colour. Hyphae are septate and the colony has aerial topography and irregular rough growth patterns with concentric zonation. Sporulation was observed after six days of incubation and conidiophores were straight or flexuous brown to olivaceous brown in colour. The conidia are solitary straight or muriform or oblong, pale or olivaceous brown, length 40-110 μm and 7-15 μm thick with 2-8 transverse and 0-3 longitudinal septa. The cultural and morphological characters of the pathogen completely fit into the description of Alternaria solani by Alexopoulos et al. (1996). Hence, it is confirmed that the symptom observed on tomato leaves are those of early blight disease caused by A. solani. In vitro evaluation of fungicides and bioagents showed complete inhibition of the pathogen with propineb (0.1%, 0.2% & 0.3%), hexaconazole (0.05%, 0.1% & 0.15%), iprodione + carbendazim (0.1%, 0.2% & 0.3%), difenoconazole (0.075%), Trichoderma viride (KAU), T. viride (PGPM mix), T. harzianum (PGPM mix) and plant growth promoting microbial consortium (PGPM mix of KAU). Among the bacterial antagonists, Bacillus subtilis (endophyte from cocoa) showed maximum growth inhibition of the pathogen. All the three bioagents recorded earliness in seed germination and enhanced seedling vigour compared to the fungicidal treatments and control. The results of field experiment under polyhouse and rain shelter conditions showed that all the treatments are superior to control in early blight disease management, of which, spraying of iprodione + carbendazim (0.2%) and propineb (0.2%) were the best among fungicides and PGPM mix application was the most efficient among bioagents. Moreover, the highest yield was recorded from iprodione + carbendazim treated plants. Biocontrol treated plants showed better performance in overall plant vigour of which PGPM mix application was the most effective. Residue analysis showed that degradation rate of fungicides was more under polyhouse condition. Analysis of population of phylloplane and endophytic microflora proved that there was drastic reduction in microbial population after spraying with chemical fungicides whereas population increased after bioagent application. The study on survival of bioagents on tomato phylloplane revealed that both Pseudomonas fluorescens and T. viride, survived on leaf surface up to 15 days after foliar application. Analysis of fungicidal residue on tomato fruits revealed that, the degradation of fungicides was faster in polyhouse compared to rain shelter. Metagenomic analysis of microbial diversity on tomato leaves revealed that spraying of chemical fungicides reduces microbial population and diversity while bioagent application enhances the same. However, microbial community structure was changed in both cases. This study also enlightened the new mode of action for fungicides and bioagents besides their direct effect that is shifting the microbial community structure so that it provides greater resistance against the pathogen. Interestingly, metagenomic results also showed association of Cladosporium, Corynespora, Pseudocercospora along with early blight pathogen Alternaria on tomato leaves that otherwise remain undetected. Another important observation was Clostridium in tomato leaf samples except in PGPM mix treatment, suggesting the possibility of plants as alternate host for major human and animal bacterial pathogens. Hence, considering the effects of treatments on per cent disease severity both under polyhouse and rain shelter condition, residue analysis, phylloplane and endophytic microbial enumeration study and metagenomics analysis of microbial diversity, the present study recommends spraying of propineb (0.2%) as the best treatment among the tested fungicides and spraying of PGPM mix among biocontrol agents for the management of early blight disease of tomato under protected cultivation. Further system-level analysis of the complex interaction that governs outcomes among community members in the context of the plant host is required, in order to identify microbial interaction and selection processes for beneficial communities at different concentrations of fungicides and pathogen pressures.ThesisItem Open Access Integrated management of foliar fungal disease of culinary melon (Cucumis meloL. var. acidulus Naudin)(Department of Plant Pathology, College of Agriculture, Vellayani, 2016) Narmadhavathy, S; KAU; Kamala NayarThe project entitled “Integrated management of foliar fungal disease of culinary melon (Cucumis melo L. var. acidulus Naudin)” was undertaken with the objective of making a comparative evaluation of the efficacy of foliar application of fertilizers, micronutrients, bio-control agents and newer fungicide for the management of Colletotrichum leaf spot (Colletotrichum sp.) disease of culinary melon. Surveys conducted during September 2013 to December 2013, in ten culinary melon fields located at Instructional Farm (IF), College of Agriculture (CoA), Vellayani as well as in farmers’ fields near, CoA, Vellayani, in order to assess the prevalence of major diseases such as Colletotrichum leaf spot and downy mildew disease affecting the crop. Highest disease incidence (DI) and percentage disease index (PDI) of Colletotrichum leaf spot were observed, 75 days after sowing, at Chavadinada (70.00 per cent and 64.44 per cent respectively). Incidence and index of downy mildew disease were recorded in four out of the ten locations surveyed (Palapoor, Papanchani, Kalliyoor and Punjakari). Maximum disease incidence and percentage disease index of downy mildew disease (36 per cent and 33.33 per cent respectively) were observed at Papanchani. The most virulent isolate of anthracnose leaf spot pathogen (IF, Vellayani isolate), obtained during the survey was identified as Colletotrichum fructicola by molecular characterization. The treatment NPK 19:19:19 (0.5 per cent) combined with the fungicide mancozeb (0.4 per cent) and adjuvant was most effective in inhibiting the mycelia growth of the pathogen C. fructicola, in vitro, (100 per cent) over control as well as in suppressing artificially induced anthracnose disease and improving the growth parameters of the plants, in the two greenhouse experiments conducted at the CoA, Vellayani during March to June 2014 and August to October, 2014. Results of two field trials conducted at CoA, Vellayani, during January to March, 2015 and April to June, 2015 for testing four most effective treatments screened from the greenhouse experiments, indicated that NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant (DI 40.00 and PDI 13.05 respectively) and NPK 19:19:19 (0.5 per cent) + mancozeb (0.4 per cent) + adjuvant (DI 40.00 and PDI 13.47 respectively) were most effective in managing the disease and also increasing total yield of plants, when compared to the remaining treatments. Trials were conducted in farmers’ fields at three locations (Venganoor, Vavamoola and Venjaramoodu) for confirming the efficacy of the two most effective treatments screened from the field trials conducted at CoA, Vellayani and pooled analysis of the results indicated that the lowest PDI (12.22) and DI (28.50) were obtained in plants treated with NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15ml/l) + adjuvant, which was significantly superior to the other treatments. Results of the microbial studies indicated that there was decline in fungal flora of the plants treated with foliar fertilizer NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant, days after application of treatments whereas bacterial population was higher in plants applied with the same treatment when compared to the application of combination of foliar fertilizer NPK 19:19:19 (0.5 per cent) + mancozeb (0.4 per cent) + adjuvant. There was indication of higher induction of systemic resistance in plants treated with NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant due to the higher activity of defense related enzymes, such as phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenol oxidase (PPO), β-1,3glucanase, super oxide dismutase (SOD) and the compound phenol, all of which, reached maximum level on the 15th day after treatment. Leaf samples obtained from plants treated with foliar fertilizer NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant indicated highest nutrient use efficiency in all three locations of the confirmation trials while highest pigment status due to this treatment was observed in the trial conducted at Venganoor. Relative water content was generally high in leaf samples collected from all plants irrespective of the treatments, although it was comparatively low, in leaf samples obtained from plants of absolute control plot. Epicuticular wax content was slightly lower in the plants treated with combination of the foliar fertilizer NPK 19:19:19 (0.5 per cent) and fungicides, either azoxystrobin (0.15 ml/l) or mancozeb (0.4 per cent) + adjuvant. Stomatal frequency on the upper and lower surfaces of leaves was not much affected by application of foliar fertilizer NPK 19:19:19 (0.5 per cent) combined with the fungicides. B:C estimated ratio revealed that the highest returns were obtained from the plants treated with foliar spray of NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant, in all three locations of the farmers’ field trials. This study presents the first report of the pathogen Colletotrichum fructicola causing anthracnose leaf spot disease of culinary melon in India. In field conditions, combination of the foliar fertilizer NPK 19:19:19 (0.5%) and azoxystrobin (0.15 ml/l) along with adjuvant applied twice at 15 days’ interval was most effective in controlling anthracnose leaf spot disease of culinary melon and also increasing the yield of the crop.ThesisItem Open Access Strain improvement of oyster mushrooms- pleurotus cystidiosus O.K. Mill and pleurotus opuntiae (Durieu and LEV.) SACC.(Department of Plant Pathology, College of Agriculture, Vellayani, 2018) Krishnapriya, P J; KAU; Geetha, DThe present study entitled “Strain improvement of oyster mushrooms: Pleurotus cystidiosus O.K.Mill and Pleurotus opuntiae (Durieu and Lev.) Sacc.” was carried out in College of Agriculture, Vellayani during 2015-2018, with the objective to standardize the techniques for production of oyster mushrooms: P. cystidiosus and P. opuntiae; and to study their morphological, physiological and cultural characteristics as well as nutritional and organoleptic qualities; and to undertake genetic improvement by protoplast fusion. The mushrooms were collected from two locations of Thiruvananthapuram and three fast growing isolates of Pleurotus spp. viz., PC2 (Vellayani), PNC1 (Chirayinkeezhu) and PO1 (Vellayani) were selected for the study. These isolates were identified as P. cystidiosus subsp. abalonus, P. cystidiosus and P. opuntiae using internal transcribed spacer (ITS) primers and subsequent sequencing; and registered at Genbank database with accession numbers KY214254, KY887023 and KY214255 respectively. The fast growing isolates of P. cystidiosus (coremial), P. cystidiosus (non-coremial) and P. opuntiae recorded maximum growth on PDPA amended with one per cent yeast under dark condition. The optimum temperatures for the growth were 30 0C, 25 to 30 0C and 25 0C respectively whereas, the optimum pH were 8, 8 and 7 to 8 respectively. Studies with different substrates and amendments for spawn production revealed that sorghum with one per cent yeast was the best for P. cystidiosus (coremial) and P. opuntiae whereas, paddy grains with one per cent yeast for P. cystidiosus (non-coremial). Experiments with different substrates and amendments for mushroom production revealed that rubber wood sawdust sprayed with 2.5 per cent of 1 M potassium dihydrogen phosphate recorded the maximum BE for P. cystidiosus (non-coremial) (192.76 per cent). P. opuntiae recorded the maximum BE in rubber wood sawdust amended either with 4 per cent neem cake (91.38 per cent) or wheat bran (91.37 per cent). Major insect pests observed in the beds of Pleurotus spp. were phorid flies, spring tails, black ants and staphylinid beetles. The competitor moulds observed were different species of Coprinus, Aspergillus, Penicillium and Trichoderma. Sporocarps soaked in one per cent CA for 15 minutes followed by mechanical drying and powdering was the best post harvest treatment for both P. cystidiosus (non-coremial) and P. opuntiae. Mycelium of P. cystidiosus (coremial) showed black coremial structures, representing its asexual stage (Antromycopsis broussonetiae Pat. & Trab.). The coremia comprised of elliptical (16.31 µm x 7.48 µm) and round conidia (8.06 to 8.49 µm). The black colour of coremia was due to melanin which was extracted (255.56 mg l-1) and characterized. The performance of long duration P. cystidiosus (non-coremial) and short duration P. opuntiae was compared with two ruling mushrooms of Kerala viz., long duration P. florida (Mont.) Singer and short duration P. eous (Berk.) Sacc. The study revealed that P. cystidiosus (non-coremial) and P. opuntiae showed higher BE compared to P. florida and P. eous, respectively. P. cystidiosus (non-coremial) recorded maximum moisture (94.05 per cent), starch (200.55 mg g-1), protein (30.2 mg g-1), fat (4.25 per cent), antioxidants (485.45 μg equivalent gram of ascorbic acid-1), beta-carotene (25.69 µg 100 mg-1), polyphenols (7.55 mg g-1) and energy (359.45 Kcal) compared to other Pleurotus spp. Sensory evaluation of mushroom products made from the species of Pleurotus was done and masala curry prepared from P. cystidiosus (non-coremial) scored the maximum value for overall acceptability. Shelf life of P. cystidiosus (non-coremial) was higher (5 days) compared to P. opuntiae, P. florida and P. eous (3 days each) in perforated poly propylene covers stored under refrigeration. Vanillin (0.05 per cent) and carbendazim (1 mM) were selected as dual biochemical markers for the PEG mediated protoplast fusion. Three days old P. cystidiosus (non-coremial) and four days old P. opuntiae recorded the maximum protoplast yield at five and four hours after incubation respectively with 0.6 M KCl and 30 mg ml-1 of enzyme consortium. Eight fusant lines with varied mycelial characters were obtained. Among fusants, F6 and F8 did not segregate in the second generation whereas, F4 segregated. F6 and F8 recorded higher BE of 168.05 and 99.95 per cent respectively compared to the parental lines and other fusants. Sporocarp of F6 and F8 was morphologically similar to P. cystidiosus (non-coremial) and P. opuntiae respectively; and F8 also exhibited low temperature adaptability. The present investigation indicated the exploitability of two promising isolates viz. P. opuntiae for tropical areas and P. cystidiosus (non-coremial) for cooler regions of Kerala using locally available materials and the standardized cultivation practices. The present study also standardized the protoplast fusion technique between P. cystidiosus (non-coremial) and P. opuntiae; and two fusant lines (F6 and F8) recorded higher BE which can be used for future breeding programmes.ThesisItem Open Access Strain evaluation and production technology of shittake mushroom ( Lentinula edodes ( Berk. ) pegler)(Department of Plant Pathology, College of Agriculture, Vellayani, 2016) Deepa Rani, C V; KAU; Lulu DasThe present investigation on "Strain evaluation and production technology of Shiitake mushroom (Lentinula edodes (Berk.) Pegler' was conducted at Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvananthapuram during the period 2012-2015. The aim of the experiment was to exploit various strains of Lentinula spp. for novel production technology and their phylogeny analysis through physiological and molecular studies. Surveys were collected during pre and post monsoon periods of May to December from different parts of Thiruvananthapuram, Kollam, Wayanad, Idukki, Pathanamthitta, Kannur and Kasargode districts. Six isolates of sp. (VLYN- 1 to VLYN-13) obtained during the survey were identified and compared with procured reference strains of Lentinula edodes (LE-1 to LE-5 from GB Pant University of Agricultural and Technology, Pantnagar, Uttarakhand) and LE-6 strain (Maharana Pratap University of Agriculture and Technology, Udaipur) . Morphologically the native isolates of Lentinus spp. had concave, funnel and convex pileus with varying colors and were leathery in nature.L. edodes strains in contrast had convex pileus with chocolate brown and golden yellow sporocarps which were fleshy and edible. Phylogenetic analysis of all six strains of L. edodes using RAPD markers confirmed the variability between the strains. Maximum similarity coefficient of 74.10 per cent was observed between LE-2 and LE-6 strains while LE-2 and LE-4 strains showed a minimum similarity coefficient of 35.70 per cent. Further studies by ITS sequencing showed that all the L. edodes strains tested in the study showed 99- 100 per cent similarity with the known sequences off L. edodes available in NCBI database while that of native isolates showed 99- 100 per cent similarity to Lentinus tuber-regium and Lentinus connatus thus confirming the variability between Lentinus and Lentinula sp. All the six strains of L. edodes, showed maximum mycelial growth in malt extract peptone dextrose agar in solid and oat meal broth in liquid medium. L. edodes strains preferred temperature of 20 °C with an acidic pH of 6. Dark and ambient light conditions favored maximum mycelial growth and biomass production for L. edodes culture. Although a minimum period of 16.33 days was required for full mycelial run in maize grains but due to comparatively less contamination rate in paddy grains which took 18.33 days for completion of mycelial run were selected as best substrate for further studies. Different substrates were evaluated for the development of a cultivation package for shiitake mushroom. Results showed that LE-1 strain took minimum of 71.00 days for initiation of sporocarp in sawdust supplemented with 20 per cent wheat bran. Hard wood sawdust especially of teakwood was used in the study. The substrate based on paddy straw and banana pseudo stem were not found effective for pinhead initiation and thus failed to produce sporocarps. LE-1 produced maximum sporocarp (11.33) in sawdust + 20 per cent wheat bran which was followed by LE-3 (10.63) in sawdust + 20 per cent rice bran. Maximum yield of 290.66 g/ 500 g substrate was obtained in sawdust + 20 per cent wheat bran by LE-6 strain. Maximum biological efficiency of 58.13 per cent was also recorded in LE-6 in sawdust supplemented with 20 per cent wheat bran substrate. Substrates like paddy straw and sawdust amended with 20 per cent wheat bran substrates were evaluated for the development of native isolates of Lentinus tuberregium and Lentinus connatus . Results showed that maximum biological efficiency of 58.00 per cent was obtained by Lentinus tuber-regium whereas 36.60per cent biological efficiency by Lentinus connatus in sawdust amended with 20 per cent wheat bran substrate. Nutrient analysis of all the six strains showed that carbohydrate content ranged between 35.29 per cent to 40.23 per cent, protein 18.33 per cent to 21.66 per cent, crude fibre 22.33 per cent to 27.33 per cent, Vitamin- C 2.53 per cent to 3.50 per cent, ash 2.70 per cent to 4.40 per cent and lipid 2.46 per cent to 3.60 per cent. Mineral content of L. edodes included Ca (11.00 mg to 19.00 mg/ 100 g), Mg (0.46 to 1.10 mg/ 100 g), Fe (1.36 mg to 1.80 mg/ 100 g), Mn (1.53 mg to 2.63 mg), P (1.65 mg to 2.87 mg), K (16.33 mg to 25.20 mg), Na (13.00 mg to 23.66 mg) and Zn (19.66 mg to 28.33 mg/ 100 g). Sensory evaluation of mushroom products made from L. edodes was carried out by a panel of judges for various characters of which mushroom masala scored maximum for texture, taste, flavor and overall acceptability when compared to other recipes like mushroom cutlet, scramble, soup, baji and biscuit. As part of the study, paddy grain was found to be the most suitable substrate for spawn production of L. edodes and teakwood sawdust amended with 20 per cent wheat bran was the most efficient bed substrate. LE-6 strain was superior in terms of yield and biological efficiency. Therefore findings of the above investigation recommends the adoption of a suitable cultivation package for shiitake mushroom by using low cost substrates (hardwood sawdust) available in Kerala in plains and hilly regions.ThesisItem Open Access Integrated management of viral diseases of bittergourd (momordica charantia L.)(Department of Plant Pathology, College of Agriculture, Vellayani, 2018) Radhika, N S; KAU; Umamaheswaran, KThe present research work entitled ‘Integrated management of viral diseases of bitter gourd (Momordica charantia L.) was carried out in the College of Agriculture, Vellayani during 2014-2017, with the objectives to study the occurrence and distribution of viruses in bitter gourd in Thiruvananthapuram, Idukki and Palakkad, immunomolecular characterization of the viruses, and screening of antiviral chemicals, antiviral principles of animal, plant and microbial origin for the management of the disease. In the suvey conducted at five locations in Thiruvanaanthapuram district, Pappanchani area recorded highest incidence of viral disease (60%) while highest Vulnerability Index (V.I) was recorded from Vellayani (56.00). In Idukki district, six major bitter gourd cultivating areas were surveyed among which Rajakumary area recorded the highest disease incidence (100%) and V.I (82.00). In Palakkad district, five locations were surveyed, among which panackatri and Thekkepotta recorded highest disease incidence of 88% and highest V.I (69.00). The major insects associated with the crop were whitefly (Bemisia tabaci (Genadius) with an incidence of 10-25%, aphids (Aphis gossypii glover) with an incidence of 10-40%, Jassids (Empoasca (Empoasca) motti Pruthi) with an incidence of 10-30% and mites with an incidence of 10-50%. Phyllody and little leaf symtoms (20% incidence) were also recorded in bittetgourd form Rajakumary and Rajakkad areas in Idukki. Flat limb and multiple proliferation of shoot tip were observed at many fields in Idukki. Symptoms associated with the disease include yellow mottle, mosaic,blistering, leaf curl and reduction in leaf size. Yellow mosaic and blistering is seen in severe infection finally leading to stunting of the plant, reduced flowering an fruiting and hairyness on stem. Mechanical transmission of the virus on Datura stramonium produced yellow lacal lesions indicating the presenceof Bean Golden mosaic virus (Begomo) in the infected leaf extract. This leaf extract also produced local lesions on othe indicator hosts like Chenopodium amaranticolor and Gomphrena globosa indicating the presence of Cucumber mosaic virus (CMV) or Potato virus Y (PVY). The viruses were transmitted by whiteflies (20%) and aphids (30%) from infected bittetgourd plants to healthy seedlings. Whiteflies (Bemisia tabaci Gennadius)) and aphids (Aphis gossypii Glover) are the vectors of the respective viruses Wedge grafting diseases scion on to 3-5 leaf stage healthy seedling of bittergourd produced symptoms of infection within ten days. KAU varieties Preethi and Priyanka were found to be susceptible to infection with preethi expressing a V.I of 70.80 and Priyanka expressing a V.I of 62.50 respectively. Ensyme linked immunosorbent assay (ELISA) and Dot immunobinding assay (DIBA) revealed the presence of three viruses belonging to Begomo, CMV and PVY group causing an mixed infection in bittergourd. The presence of all the three viruses were also confirmed in electron micrograph, Begomovirus as twin particles of size 18-20 X 30nm,CMVas single particles of 18nm and PVY as lonog flexuous rod of size 750nm. PCR amplification of coat protein gene (cp gene) of virus isolates from all the three districts yielded an amplicon of size approximately equal to 570 bp. Idukki and Palakkad isolates showed 94% identity to Tomato leaf Curl Virus isolate TNUDU BGI Coat Protein (AVI) gene while Trivandrum isolate showed 95% identity to Tomato leaf Curl Virus isolate TNPDU BG4 Coat Protein (AV1) gene . Phylogenetic tree constructed using multiple sequence alignment programme showed close relation between Begomo viruses identified in bittergourd from different districts. Studies on defense related enzymes such as peroxidase (PO), polyphenol oxidase (PPO) and phenyl alanine ammonialyase PAL) showed significant activity of PO and PPO in diseased plants than in healthy plants and the activity was on par in healthy and diseased for PAL. Protien profile of healthy and diseased at different days after virus inoculation through grafting indicated the production of novel proteins in diseased. There was no difference in the native profile of peroxidase in healthy and diseased at 15 days after virus inoculation. An additional isozyme band with a Rm value of 0.5 was observed in diseased at 45 days after virus inoculation. Management of the disease with antiviral chemicals and antiviral principles of plant, animal and microbial origin was undertaken as pot culture studies with pre and post inoculation of treatments. Twelve treatments with three replications each were laid out in completely randomized design for the evaluation. The treatments included Aspirin at two levels of 100 and 150 ppm, Salicylic acid (SA) at two levels of 100 and 150 ppm and Acibenzolar S methyl (ASM) at 50 and 75 ppm concentration, and two commercial formulations viz., Perfect and virus –Ex at 0.5 and 1.0 ml concentrations. The treatments were applied three times at 10 days interval. Pre application of thrice sprapying of Acibenzolar S methyl (ASM), 75 ppm concentration (V.I-35.00) at ten days interval was statistically significant over other treatments followed by ASM-50 ppm (V.I-41.33). Post application of antiviral chemicals also showed a statistically significant effect of three times spraying ASM-50 ppm(V.I-25.00) at ten days interval followed by spraying of Virus Ex 1ml L-1 (VThe best eight treatments with control was laid out as Randomised Block Design at the Instructional Farm, College of Agriculture, Vellayani during February to May 2017 as a field trial to study the effect of treatments on natural incidence of the viruses in the susceptible variety Preethi. The treatment, three sprays of ASM-50 ppm (V.I-28.33) at ten days interval ws on par with buttermilk (Three times dilution of curd) (V.I-39.16). Yield was also significantly high in ASM-50 ppm (437g plant-1) followed by Pseudomonas fluorescens talc based formulation (2%) (233 g plant-1)among the treatments.ThesisItem Open Access Identification of graft transmissible resistant factors and development of si RNA mediated resistance in cassava against cassava mosaic geminivirus(Department of Plant Pathology, College of Agriculture, Vellayani, 2017) Asha, B Nair; KAU; Umamaheswaran, KThe present study entitled ‘Identification of graft transmissible resistant factors and development of siRNA mediated resistance in Cassava against Cassava mosaic virus’ was carried out during the period 2012-2017 at the Department of Plant Pathology, College of Agriculture, Vellayani. The study was carried out with the objective of identification of transferability of resistance factor from resistant cassava, Sree Padmanabha to susceptible, Vellayani Hraswa by grafting and to develop siRNA mediated technology for the development of cassava plant resistant to Cassava mosaic geminivirus. Grafting experiments were conducted using resistant Sree Padmanabha as root stock and susceptible Vellayani Hraswa as scion. Symptoms like leaf mosaic, chlorotic spots, reduction in leaflet size and stunting of plants were noticed in susceptible variety. Virus concentration was found to be less in grafted plants. Grafting experiments showed the expression of an extra protein by SDS-PAGE and Coomassie staining in grafted plants which is around 38 kDa. Molecular weight of the new protein revealed the presence of extracellular protein in grafted samples. The extra proteins found in the grafted plants are assumed to be transferred from Sree Padmanabha to Vellayani Hraswa by the process of grafting. The study also involved the development of an intron hairpin RNA vector against replicase gene of SriLankan cassava mosaic virus and introduction of this construct into embryogenic cells via Agrobacterium mediated transformation. A protocol for somatic embryogenesis in cassava variety, Vellayani Hraswa was developed by using immature leaf lobes as explants. The young leaf lobes from tissue culture plantlets produced through meristem culture was used for embryogenic callus formation. Cremish white calli was initiated in Murashige and Skooge (MS) medium supplemented with picloram 12 mg L-1 in dark. For embryogenesis, the calli were transferred to MS medium supplemented with BA 2µM and NAA 1µM which resulted in the production of glassy elongated somatic embryos. The germinated cotyledonary embryos were then regenerated into plantlets by culturing in MS medium supplemented with BA 1mg L-1. Effort was taken to construct an intron hairpin RNA vector and the gene targeted for silencing was the replicase gene of SriLankan cassava mosaic virus (SLCMV). Total DNA was extracted from virus infected plants and the whole replicase gene was isolated using gene specific primers. Sequencing of the whole gene was done. BLAST analysis showed 98% similarity to replicase gene of various isolates of SLCMV. The sequence was then subjected to miRNA target prediction and restriction mapping to select suitable region for the construct. Based on this information, a fragment of 397 bp towards the 5’ end was amplified by designing a set of primers with anchored restriction sites. The primers anchored with Xho and Kpn 1sites were used for the amplification of sense strand and the primers anchored with Xba and Cla 1sites were used for amplification of antisense strand. Selected region was amplified to form sense and anti-sense fragments and cloned to pTZ57R/T cloning vector. Inserts were then released from pTZ57R/T using the corresponding restriction enzymes. The sense and anti-sense fragments were then integrated in the primary vector pHANNIBAL on either side of the pdk intron which facilitated the formation of intron hairpin RNA construct. The intron hairpin RNA construct in pHANNIBAL contained CaMV35S promoter, sense strand, pdk intron, antisense strand and OCS terminator in the order with Not 1 restriction sites. After confirmation of integration by restriction digestion, the Not1 fragment with sense and anti-sense strand were released from pHANNIBAL and ligated to the digested Not1 site in the lacZ gene of binary vector pART27 containing antibiotic resistant marker nptII and spec. the binary vector was confirmed for the presence of insert by transferring to DH5α cells and colony selection by blue white screening. Plasmid DNA isolated from transformed colonies grown on Luria agar medium supplemented with 100 mg L -1 spectinomycin were confirmed for the presence of insert. After confirmation of insert in the binary vector, it was transformed to Agrobacterium tumefaciens strain LBA4404 via freeze thaw method. Transformed colonies were selected on kanamycin selection medium at 100 mg L -1 and confirmed for the presence of binary vector and ihpRNA insert using nptII primers and primer for sense and antisense strands by PCR reaction. Cotyledons excised from the somatic embryos were transformed with LBA4404 having pART 27 by co-cultivation and the transformed embryos were selected with antibiotic pressure (Kanamycin 100 mg L-1). DNA was isolated from the transformed somatic embryos and confirmed for the presence of insert using forward primer of sense fragment and reverse primer of antisense fragments. Transformed embryos were subjected to regeneration.ThesisItem Open Access Molecular characterization of virus causing infectious chlorosis disease of banana(Department of Plant Pathology, College of Horticulture Vellanikkara, 2017) Ahamed Mujtaba, V; KAU; Anita Cherian, KThe experiment entitled “Nutrient management in strawberry (Fragaria x ananassa Duch.)” was undertaken at Regional Agricultural Research Station, Ambalavayal, Wayanad during the year 2016-17. Performance of strawberry variety Winter Dawn was evaluated under nine treatments and a control in the open field viz., FYM 10 t ha-1 + NPK 50:20:50 kg ha-1 (T1); FYM 10 t ha-1 + NPK 75:30:75 kg ha-1 (T2 ); FYM 10 t ha-1 + NPK 100:40:100 kg ha-1 (T3); FYM 20 t ha-1 + NPK 50:30:100 kg ha-1 (T4); FYM 20 t ha-1 + NPK 75:40:50 kg ha-1 (T5); FYM 20 t ha-1 + NPK 100:20:75 kg ha-1 (T6); FYM 30 t ha-1 + NPK 50:40:75 kg ha-1 (T7); FYM 30 t ha-1 + NPK 75:20:100 kg ha-1 (T8); FYM 30 t ha-1 + NPK 100:30:50 kg ha-1 (T9) and an absolute control (T10), without any nutrient application. All the treatments were on par and superior over the control (T10) in case of plant height. In case of plant spread, T2, T3, T5, T6, T7, T8 and T9 were on par and superior over the control while T1 and T4 were on par with each other but differs with other treatments. All the treatments except T2 were on par and superior over the control with respect to number of leaves per plant. Application of treatments had no significant effect on days to first flowering. In case of number of flowers and clusters per plant, T1, T2, T3, T5, T6, T7, T8 and T9 were on par and superior over the control while T4 was on par with the control (T10). Days to first harvest was minimum in T6, T7, T8 and T9 which were on par while all other treatments were on par with the control (T10).In case of number of fruits and yield per plant, T7 (FYM 30 t ha-1 + NPK 50:40:75 kg ha-1) and T8 (FYM 30 t ha-1 + NPK 75:20:100 kg ha-1) were on par and superior over other treatments including T1, T2, T3, T4, T5, T6 and T9 which were on par and superior over the control. Average fruit weight recorded under T3, T5, T6, T7, T8 and T9 were on par which was followed by T2 on par with T4 and T1. Days to final harvest was not found to be influenced by the application of different treatments. Biochemical characters of fruits viz., TSS, acidity and TSS/acidity ratio were not having any significant effect due to the application of treatments. In case of total sugars, T3, T7, T8 and T9 were having the highest content and were on par which was followed by T5 on par with T1, T2, T4, T6 and T10. The overall sensory score was highest in T7 followed by T8. Application of different treatments had no significant effect on the shelf life of strawberry fruits. N, P, K and Ca content in the plant were not significantly affected by any treatment while Mg content was found to be on par in all treatments and superior over the control. Soil analysis after the harvest of the crop revealed that the values for soil EC, available P, K, Mg and S were found to be elevated while soil pH, organic carbon and available Ca content were found to be at lower levels than the initial values before planting. It was concluded that among different nutrient combinations evaluated, T7 (FYM 30 t ha-1 + NPK 50:40:75 kg ha-1) with a BC ratio of 3.06 can be recommended for further optimization and refinement.ThesisItem Open Access Enhancement of systemic resistance to soil borne pathogens of ginger by enriched spent mushroom substrate of pleurotus sajor-caju(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2017) Remya, J S; KAU; Beena, SSpent mushroom substrate (SMS) is the composted organic material retained after a crop of mushroom. The world mushroom industry needs to discard more than 50 million tons of SMS every year. The latest research throw light on the efficient use of SMS for the disease management of crop plants. A preliminary study on the use of SMS of Pleurotus spp. as mulch for the management of rhizome rot complex disease of ginger under pot culture condition was carried out in the Department of Plant Pathology, College of Horticulture, Vellanikkara. In this study, among the various SMS used, the paddy straw SMS of P. sajor-caju as mulch recorded the highest biometric characters and least disease incidence compared to control. Hence this project was proposed as the continuation of the above study to evaluate the efficacy of enriched SMS of P. sajor-caju in enhancing growth and systemic resistance for the management of soil borne pathogens of ginger under field conditions. SMS of P. sajor-caju was produced during three different periods viz., March-April, June-July and November-December (2013) at six different locations of Kerala viz., College of Horticulture, Vellanikkara (Thrissur dist.), farmer’s field at Kodakara (Thrissur dist.), Perinjanam (Thrissur dist.), Krishnagiri (Wayanad dist.), Mananthavady (Wayanad dist.) and College of Agriculture, Vellayani (Thiruvananthapuram dist.). Enumeration of microflora of these SMS was carried out and a total of 47 fungal and 45 bacterial isolates were obtained. The antagonistic efficiency of these isolates were evaluated against the five pathogens viz., Pythium aphanidermatum, Fusarium oxysporum, Rhizoctonia solani, Sclerotium rolfsii and Ralstonia solanacearum under in vitro conditions. All the isolates from SMS showed antagonistic property against one or the other soil borne pathogens, with varying degree of inhibition. Mutual compatibility between the most efficient fungal and bacterial antagonists was evaluated to develop an effective microbial consortium for enriching the SMS and could be used against the soil borne diseases of ginger. Biosoftening efficiency of selected fungal and bacterial antagonists on SMS was evaluated. Two separate experiments were carried out with the selected antagonists effective against fungal and bacterial pathogens. For each experiment, five fungal antagonists, five bacterial antagonists and three compatible pairs were selected based on the in vitro evaluation of antagonistic efficiency and mutual compatibility studies. SMS was enriched separately with different antagonists and standardized the period for biosoftening of SMS as mulch for ginger cultivation. A period of 15 days was selected as most suitable for biosoftening the SMS as mulch with optimum antagonistic fungal and bacterial population. Wide range of C:N ratio was recorded by the SMS enriched with each antagonists. By considering the C:N ratio along with external appearance, the treatments having C:N ratio of 30:1 to 45:1 were selected, since it was the most suitable stage to be used as mulch in ginger. The effectiveness of biosoftened SMS against rhizome rot and bacterial wilt diseases of ginger was evaluated in two pot culture experiments. Three fungal and bacterial antagonists each and one compatible pair of antagonists which were selected based on the in vitro evaluation of antagonistic and biosoftening property were used for enriching the SMS. After enrichment, the SMS were kept for 15 days for biosoftening and were applied as mulch in the experiments. Observations on germination percentage and other growth parameters viz., number of tillers/plant, number of leaves/tiller and height of tillers were recorded at one month intervals from two months after planting (MAP). Challenge inoculation of pathogens was done at 45 days after germination and per cent disease incidence was recorded at 7 and 14 days after inoculation (DAI). In the experiment for the management of P. aphanidermatum, the lowest disease incidence was observed in T7 (SMS softened with P1F1+ M1F2) on 14th day after inoculation (DAI). This treatment also recorded the highest number of tillers, number of leaves/ tiller and height of tillers and rhizome yield. In the experiment for the management of R. solanacearum, the treatment T2 (SMS softened with T1F2) was found to be the most efficient one, which recorded the least disease incidence at 14 DAI, whereas the highest values for biometric characters and rhizome yield were recorded by T7 (SMS softened with K1B1 + T2B1). The activity of phenol and defense related enzymes such as peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were estimated by spectroscopy, before challenge inoculation with pathogen and at one, three and five days after the challenge inoculation. For estimation, leaf samples were collected separately from the pot culture experiments I and II for the management of P. aphanidermatum and R. solanacearum respectively. The treatments which recorded less disease incidence in both the pot culture experiments exhibited the highest activity of defense related enzymes and phenol. The highest activity of defense related enzymes and phenol was recorded at 5 DAI. Thus the present study showed that in addition to direct antagonism and plant growth promotion, induction of defense related enzymes was also contributed by SMS to enhance resistance against invasion of soil borne pathogens of ginger. Field evaluation of the selected treatments from pot culture experiments showed the lowest disease incidence in the treatment T2 (SMS softened with T1F2) followed by T5 (SMS softened with P1F1+M1F2). Statistically these were on par with each other. The treatment T5 (SMS softened with P1F1+M1F2) recorded the highest germination percentage, number of tillers, number of leaves/tiller and rhizome yield also. Analysis of primary nutrients viz., nitrogen, phosphorus and potassium in SMS, plant and soil from field experiment was conducted. Among these, SMS softened with P1F1+M1F2 recorded the highest percentage of N, P and K. This treatment recorded the highest nutrient content in ginger rhizome and soil also. Attempts were also made to identify the fungal and bacterial antagonists selected for field experiment. Based on the cultural and morphological characters, the fungal antagonists viz., Kr1F4, T1F2, P1F1 and M1F2 were tentatively identified as Trichoderma viride (Pers.), T. viride (Pers.), T. koningii (Oudem.) and T. harzianum (Rifai) respectively. The identification got confirmed from National Centre for Fungal Taxonomy (NCFT), New Delhi. The bacterial antagonists selected for field experiment were also identified based on cultural, morphological, biochemical and 16s rRNA sequence analysis. The three bacterial antagonists P3B2, T2B1 and K1B1 were identified as Bacillus safensis, B. methylotrophicus and Burkholderia gladioli respectively. Spent mushroom substrate is rich in microflora and these microflora exert antagonistic activities against soil borne pathogens. It stimulates the natural defense system in plants, provide necessary nutrients for plant growth and also improve soil physical condition. From field evaluation it was found that the SMS softened with T. viride recorded the lowest disease incidence and which enhanced systemic resistance to soil borne pathogens of ginger by defense related enzymes and phenol. The results were on par with the SMS softened with consortium of antagonists, T. koningii and T. harzianum (P1F1+M1F2). The highest rhizome yield and other growth parameters were also contributed by the SMS softened with T. koningii and T. harzianum. The content of nitrogen, phosphorus and potassium were also recorded the highest in this SMS. So from the present study it can be concluded that the SMS softened with T. koningii and T. harzianum can be used as mulch in ginger which was found equally effective to induce systemic resistance against soil borne pathogens and to enhance growth parameters and rhizome yield.
