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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 Molecular characterization of promising isolates of trichoderma spp. and their field evaluation against fusarium wilt of vegetable cowpea(Department of plant pathology, college of agriculture,Vellayani, 2023-08-07) Jeevidha, M; KAU; Sible, George VargheseThe present study entitled “Molecular characterization of promising isolates of Trichoderma spp. and their field evaluation against Fusarium wilt of vegetable cowpea” was conducted at the Department of Plant Pathology, College of Agriculture, Vellayani during 2020-2022. The study aimed at molecular characterization of potential Trichoderma isolates and their evaluation against Fusarium wilt of vegetable cowpea under field conditions. Five potent isolates of Trichoderma viz., TRMW-2, TRKR-2, TRPN-3, TRPN-11 and TRPN-17 were obtained from the previous study. The analysis of Trichoderma isolates for cell wall degrading enzymes like chitinase, protease and lipase revealed that TRPN-17 recorded the highest chitinase activity of 88.38 U ml-1 . Protease activity was found to be higher in TRPN-11 (165.86 U ml-1 ) whereas highest lipase activity was exhibited by TRPN-3 (4.86 U ml-1 ). The compatibility test among the five isolates showed that all the combinations exhibited antibiosis, lysis and overgrowth except the isolates TRPN-3 and TRPN-11 which displayed only overgrowth. A mild level of antibiosis and overgrowth was observed in the combination of the isolates TRKR-2 and TRPN-17. Assessment of competitive saprophytic ability of the Trichoderma isolates showed that per cent colonization of TRKR-2 was found to be higher (67.50 %) than other isolates and was followed by TRPN-3 and TRPN-17 (56.25 %) with no significant difference among all five isolates. In vitro screening of Trichoderma isolates by dual culture technique revealed that the per cent inhibition of TRPN-17 (63.71 %) was found to be higher, followed by TRKR-2 (58.76 %) and TRPN-3 (58.21 %). Based on the in vitro studies the effective isolates TRKR-2, TRPN-17, TRPN-3, consortia of isolates TRKR-2 and TRPN-17 and consortia of isolates TRPN-3 and TRPN-17 were selected for the in vivo evaluation against Fusarium wilt of vegetable cowpea. Molecular characterization of the isolates were done using the primers for Internal Transcribed Spacer (ITS) regions 1 and 4. All the five isolates produced a single, intact amplicon of size 600 bp approximately. The nucleotide sequences of all the ITS PCR products obtained from the five isolates were confirmed through bidirectional sequencing using the Sangers DNA sequencing. The best match of the amplified sequences was obtained from the GenBank database using NCBI-BLAST and their phylogenetic positions were explored along with the referral sequences from BLAST analysis. The oligonucleotide set of genus-specific primer TvP was used for genus-specific PCR analysis and an amplicon of approximately 245 bp was obtained. The DNA barcoding of the amplicon confirmed the genus identity of all the isolates as Trichoderma. The species-specific identification tried with translational elongation factor- 1 (tef1) and RNA polymerase II (rpb2) gene specific primers did not yield any amplicon indicating that the isolates did not belong to the species T. virens, T. longibrachiatum, T. harzianum and T. asperellum. Application of talc-based formulations of the isolates TRKR-2, TRPN-3, KAU strain and consortium of TRPN-3 and TRPN-17 as seed treatment @ of 20 g kg-1 of seed followed by soil drenching @ 2 per cent at 20, 40 and 60 DAS effectively reduced the incidence of Fusarium wilt of vegetable cowpea in pot culture study. The application of isolate TRPN-3 produced highest pod number (19) in pot culture experiment and also yield per plant (369.57 g) on par with the yield per plant produced by consortia application of TRPN-3 and TRPN-17 (344.52 g). Under field conditions, the disease was most effectively reduced by isolates TRKR-2, TRPN-3, KAU strain and consortia of TRKR-2 and TRPN-17. Lengthy pods (48.16 cm) and highest number of seeds per pod (21.73) were recorded by the application of consortium of TRPN-3 and TRPN-17 whereas application of TRPN-3 resulted in highest yield (1172.63 g/plant), number of pods per plant (19) and reduced days of flowering. Enumeration of population of Trichoderma spp. from soil in different treatments at 90 DAS revealed that, highest population was in treatment with isolate TRPN 3 under pot culture (7 ×104 cfu g-1 ) and field conditions (4 ×104 cfu g-1 ) . In the present study, Trichoderma isolates TRKR-2, TRPN-3, and consortium of TRPN-3 and TRPN-17 were found effective against Fusarium wilt of vegetable cowpea under field conditions. The genus of the isolates under study was identified as Trichoderma. The efficacy of the isolates against other soil-borne diseases of vegetable cowpea and species level identification need to be exploredThesisItem Open Access Cataloguing and documentation of diseases of sympodial orchids in kerala(Department of plant pathology,Vellanikkara, 2023-07-15) Anjali, P; KAU; Deepa, JamesOrchids are valued for their exotic beauty and long vase life, making them one of the most popular cut flowers and ornamental plants worldwide. Currently, orchids hold sixth position among the top ten cut flowers in the world, among which, sympodial orchids rank higher in the export market. However, orchid cultivation is challenged by many biotic factors especially fungal, bacterial and viral diseases, which reduce production potential and economic value. Hence, the present study, ‘Cataloguing and documentation of diseases of sympodial orchids in Kerala’ was proposed with the objective to document various diseases affecting sympodial orchids in Kerala. A purposive sampling survey in orchid growing areas of three districts viz., Thrissur, Ernakulam and Thiruvananthapuram conducted revealed the incidence of leaf blight, leaf spot, wilt, black rot, soft rot, twig blight, petal blight and flower spot diseases in four different sympodial orchids such as Dendrobium spp., Cattleya spp., Oncidium spp. and Spathoglottis spp. Among the 49 diseased samples collected from eight different locations, 21 diseased samples were obtained from Dendrobium spp., 16 from Oncidium spp., six from Cattleya spp. and six from Spathoglottis spp. PDS and PDI were calculated for each symptom from Dendrobium spp., and the highest PDI and PDS were recorded for VY DLB (76.47 %) and MT DLB1 (36.67 %) respectively. In Cattleya spp. highest PDI and PDS were recorded for VY CLS (70.80 %) and VP CSR (48.5 %) respectively. In Cattleya spp. highest PDI and PDS were recorded for VY CLS (70.80 %) and VP CSR (48.5 %) respectively. In Oncidium spp., the highest PDI and PDS were recorded for VK OLS1 with 76.92 per cent and 46.90 per cent respectively. In Spathoglottis spp., highest PDI (48.0 %) and PDS (29.79 %) were recorded for MT SLB1. From the PDS and PDI data, it was found that, leaf blight symptoms were more common and severe in Dendrobium spp. whereas leaf spot symptoms were more severe in Oncidium spp. In Cattleya spp., leaf spot symptoms were most frequently noticed, and soft rot symptom showed highest disease severity. In Spathoglottis spp., leaf blight symptoms were most frequent and severe. PDS and PDI values were correlated with light intensity at different survey locations, and a negative correlation was observed. Isolation of pathogens from diseased samples yielded 52 fungal isolates and one bacterial isolate from different sympodial orchids. A total of 21 fungal isolates were obtained from Dendrobium spp.,18 fungal isolates from Oncidium spp., five fungal isolates and one bacterial isolate from Cattleya spp. and nine fungal isolates from Spathoglottis spp. All the isolates showed different symptoms upon artificial inoculation and these isolates could be reisolated and confirmed as pathogens. The pathogens were identified at generic level based on cultural and morphological characteristics. Different fungal isolates, such as Fusarium spp. (9 nos.), Colletotrichum spp. (6 nos.), Alternaria spp. (2 nos.), Sclerotium spp. (2 nos.), Phytophthora sp. (1 no.) and Curvularia sp. (1 no.) were obtained from various symptoms collected from Dendrobium spp. The pathogens isolated from Oncidium spp. were Colletotrichum spp. (11 nos.), Diplodia sp. (1 no.), Diaporthe sp. (1 no.), Pestalotia sp. (1 no.), Alternaria sp. (2 nos.), Phytophthora sp. (1 no.) and Fusarium sp. (1 no.). Fungal isolates such as Colletotrichum spp. (2 nos.), Fusarium sp. (1 no.), Lasiodiplodia sp. (1 no.), and a bacterial isolate, Pectobacterium sp. were isolated from Cattleya spp, and Colletotrichum spp. (7 nos.), Fusarium sp. (1 no.) and an unidentified fungal culture were obtained from Spathoglottis spp. Molecular characterisation of major pathogens from Dendrobium spp., Oncidium spp., Cattleya spp. and Spathoglottis spp. was done for species level identification. Leaf blight pathogens, VL DF1, VY DF, IK DF1 and MT DF1 were identified as Colletotrichum boninense, Fusarium proliferatum, Fusarium oxysporum and Sclerotium rolfsii respectively, and the leaf spot pathogen, VP DF1 was identified as Alternaria alternata. The leaf spot pathogens, VK OF3 and IK OF1 from Oncidium were identified as Colletotrichum sp. and Diaporthe tulliensis respectively. The isolate, VY CF2 causing leaf spot disease in Cattleya was identified as Lasiodiplodia theobromae and the fungus MT SF1, causing leaf blight symptom in Spathoglottis was identified as Colletotrichum gloeosporioides. The bacteria (VP CB) causing soft rot symptom in Cattleya was identified as Pectobacterium aroidearum. In vitro studies were carried out using chemicals and biocontrol agents against seven fungal pathogens and one bacterial pathogen. Based on the data, hexaconazole was the most effective among the systemic fungicides, which showed 100 per cent inhibition of Colletotrichum boninense (VT DF1), Fusarium proliferatum (VY DF), Sclerotium rolfsii (MT DF1), Alternaria alternata (VP DF1) and Colletotrichum gloeosporioides (MT SF1) at all three doses. The fungicide also showed 100 per cent inhibition of Lasiodiplodia theobromae (VY CF2) at higher dose, while it was least effective (38.33-79.58 %) against Colletotrichum sp. (VK OF3). Bordeaux mixture (1 %) was found to be the most effective contact fungicide, which showed complete inhibition of all pathogens under study except Alternaria alternata (76.25 %). Among two combination fungicides evaluated, carbendazim 12 % + mancozeb 63 % could inhibit all fungal pathogens except Alternaria alternata (52.91 to 65 %). Among the chemicals evaluated against Pectobacterium aroidearum, copper hydroxide showed a maximum per cent inhibition (25.92 %) followed by 1 % Bordeaux mixture (15.5 %) while streptocycline showed per cent inhibition ranging from 0-16.67 per cent. Among the biocontrol agents evaluated, PGPM showed maximum inhibition per cent against the fungal pathogens (60.41-100 %) followed by PGPR-II (50.41-100 %) and Trichoderma asperellum (20.41-91.16 %), while Pseudomonas fluorescens was found to be least effective. In the case of Pectobacterium aroidearum, no inhibition was found when evaluated with P. fluorescens, PGPR-II and PGPM. However, Trichoderma asperellum exhibited a lower inhibition percentage (26.67 %) against the bacterial pathogen. Bioassay studies revealed that carbendazim 12 % + mancozeb 63 % was highly effective against Colletotrichum boninense (VT DF1), followed by Fusarium proliferatum (VY DF), S. rolfsii (MT DF1) and Colletotrichum sp. (VK OF3), whereas the fungicide was found least effective in controlling Lasiodiplodia theobromae (VY CF2) under in planta condition. Hence the study has thrown light upon the diseases affecting sympodial orchids in Kerala and disease management by chemicals and biocontrol agents under in vitro condition.ThesisItem Open Access Biochemical response of okra to bhendi yellow vein mosaic virus and production of virus free plants(Department of plant pathology,Vellayani, 2023-11-14) Swetha, B Nair.; KAU; Ayisha, R; KAUThe research entitled ‘Biochemical response of okra to Bhendi Yellow Vein Mosaic Virus and production of virus free plants’ was undertaken at the College of Agriculture, Vellayani, Thiruvananthapuram during the years 2021 to 2023 with the objective of host pathogen interaction of Bhendi yellow vein mosaic virus (BYVMV)infecting okra, screening of different genotypes of okra cultivars for disease resistance and production of virus free plants using meristem culture. Purposive sampling survey was done and samples were collected from AEU8 and AEU 10. The disease incidence of virus infected okra plants in surveyed locations ranged from 37 to 100 %. And vulnerability index varied from 23.40 to 85.20. Highest V. I. was observed in Arka Anamika (85.2) followed by varieties, Varsha Uphar(80) and Anakomban (83.53). The okra variety, Anjitha, recorded lowest disease incidence of 37.20 per cent and vulnerability index of 23.40. Disease incidence was observed to be high at the flowering and fruiting stage. The virus causing BYVMD was serologically detected using ELISA and DIBA and found that BYVMV isolate have close relationship with tomato leaf curl New Delhi virus. The molecular detection of virus was done using PCR and an expected amplicon of size 520 bp was obtained using Deng primer. The BLAST analysis of the sequence of amplicon from okra with vein clearing symptom and enation symptom showed 96.27 % and 96.67 % similarity with DNA-A segment of bhendi yellow vein mosaic virus isolate. Out of 286seeds collected from infected plants seeds sown, only 57.14 % germination was observed. None of the seedlings established symptoms till flowering stage. Molecular analysis of random samples taken from asymptomatic leaves of grow out plants also showed negative reaction to the virus. ELISA also showed negative results confirming absence of seed transmission. But, presence of virus was detected molecularly on whole seeds taken randomly from the seeds collected from infected plants. Out of 20 seeds examined only four seeds showed positive reaction. The presence of virus was also not detected on any of the seed parts examined. Hence it can be inferred that the virus is present on seed samples but there is no seed transmission. On screening of 15varieties, Phule Vimukta variety (V.I.-13.34) was found to be moderately resistant to BYVMD and Anjitha variety (V. I.- 38.30) was moderately susceptible to BYVMD. Arka Anamika, Anakomban, Arka Nikitha and ten NBPGR accessions studied were found to be highly susceptible to BYVMD.(IC 052303, IC 00780, IC 588166, IC 002134, IC 006101,IC 002024, IC 043279, IC 093771, IC 093688, IC 045820)Defense-related enzymes activities varied with genotypes and also with the growth stages of the crop. Tolerant varieties were found to possess the highest content of defence enzymes compared to susceptible varieties. PO activity of moderately resistant variety Phule Vimukta was observed with 270.29 % and 35.02 % more enzyme activity than the susceptible variety, Anakomban at 90 days after sowing and 45 days after graft inoculation respectively. PO and PPO activity showed an increasing trend on inoculation with virus while PAL showed a decreasing trend. Standardisation of production of virus free plants using meristem culture was done. Meristem culture can be successfully done using MS media with BAP (0.5µM), NAA(0.1 µM) and GA3(0.1µM). Virus indexing of meristem cultured plants by PCR confirmed the absence of virus in regenerated plants. Based on the present study, the virus causing BYMD showing symptoms of vein clearing and enation was found to be BYVMV. Presence of virus was detected on seed (20 %) but seed transmission was not observed in grow out test. Breakdown of resistance was observed in Varsha Uphar and Arka Anamika which were earlier reported as resistant. The variety Phule Vimukta, with disease resistance and high defense related enzyme activity can be used for breeding purposes for the development of disease resistant varieties. Meristem culture can be successfully used for the production of disease-free planting materials and production of quality seeds.ThesisItem Open Access Etiology of bud proliferation in vegetable cowpea(Department of Plant Pathology, College of Agriculture, Vellayani, 2022) Devika, S; KAU; Radhika, N SThe study entitled „Etiology of bud proliferation in vegetable cowpea‟ was conducted at Department of Plant Pathology, College of Agriculture, Vellayani during 2019-2021 with an objective of studying the symptomatology, immuno-molecular detection and characterization of incitant/(s) of bud proliferation in vegetable cowpea. Bud proliferation disease of cowpea has been observed in different varieties in different locations. Purposive sampling was carried out in different locations of Thiruvananthapuram, Kollam, Alappuzha and Thrissur and collected symptoms were used for further studies. The characteristic symptom of the disease is the abnormal proliferation of bud which showed an increase in number of buds up to 16-35. The proliferated buds also showed pinkish- brown patches in it. Noticeable symptoms were also seen in the leaves of the diseased plant. They were smaller, crinkled and unusually dark in colour. The fasciation of stem has also been observed in the fields of Onattukara and Chavara. The infected plants were stunted and completely sterile. The highest disease incidence was found to be in the variety Bhagyalakshmy cultivated in Mannuthy (6.57 per cent). The population of hoppers was observed in the field and the insects identified were Exitanus sp., Balclutha sp., Nilaparvata lugens, Ptoleria sp., Nisia nervosa. The weeds Phyllanthus, Neer-grampu and Jack bean were found to be showing similar symptoms near the diseased cowpea fields. The graft transmission was successful from cowpea to periwinkle with 40 per cent efficiency. The leaves of the graft inoculated periwinkle plants showed severe interveinal chlorosis and later on yellowing. Graft transmission was unsuccessful from cowpea to cowpea. The transmission studies for viruses from cowpea to cowpea and cowpea to Chenopodium revealed the absence of viruses. The DAPI staining of diseased and healthy plants affirmed the presence of phytoplasma in the diseased samples. Small fluorescent-coloured bodies were seen in the stem and leaf of infected plants compared to healthy. The hormonal analysis of the symptomatic plants compared to the healthy ones showed significant difference. The GA content in diseased leaf and bud was increased by 20.88 and 17.46 per cent respectively. The IAA content in diseased leaf (older) and bud was increased by 61.55 and 46.52 per cent respectively. The serological detection for viruses using monoclonal antibodies of CABMV and BICMV and polyclonal antibodies of TSWV and WSMoV divulged the absence of viruses in the diseased samples. The graft inoculated periwinkle plants also showed no presence of viruses. The molecular detection of phytoplasma with nested PCR was carried out. The first primers P1/P7 amplified a 1.8kb fragment and the second set of primers; R16F2n/R16R2 amplified a 1.2kb fragment, giving positive results. The final amplified product was sequenced and by BLAST analysis it was found that the 16S rDNA sequence shared 99.80 per cent similarity with that of the „Candidatus Phytoplasma asteris‟ reference strain (GenBank accession: M30790). Hence the phytoplasma under study is a „Candidatus Phytoplasma asteris‟-related strain. The virtual RFLP pattern derived from the query 16S rDNA F2nR2 fragment was identical (similarity coefficient 1.00) to the reference pattern of 16Sr group I, subgroup B (GenBank accession: AP006628). The phytoplasma under study was found to be a member of 16SrI-B.ThesisItem Embargo Prevalence of sesamum phyllody in Onattukara tract and evaluation of fungal root endophyte Piriformospora indica for its management(Department of Plant Pathology, College of Agriculture, Vellayani, 2022) Gifty, K J; KAU; KAU; Radhika N SThe research work entitled ‘Prevalence of sesamum phyllody in Onattukara tract and evaluation of fungal root endophyte Piriformospora indica for its management’ was conducted during 2019-21 at Department of Plant Pathology, College of Agriculture, Vellayani and Onattukara Regional Agricultural Research Station with the objectives to study the symptomatology, molecular detection and characterization of phytoplasma inciting sesamum phyllody disease in AEU 3 (Onattukara tract); and evaluation of fungal root endophyte P. indica for its management. Phytoplasma infected sesamum samples were collected from D and F blocks of Onattukara Regional Agricultural Research Station and Karthikapally. Karthikapally recorded highest disease incidence (39.44 per cent) and vulnerability index (23.75). Chocolate weed, Melochia corchorifolia, was found to be exhibiting symptoms of shoot proliferation. Hoppers collected from the infected fields were identified as Orosius albicintus, Hishimonas phycitis and Nephotettix sp. Disease symptoms were observed at the stage of flowering of sesamum plants in all the sampled locations. The associated symptoms were reduction in internodal length of stem, axillary bud proliferation, thickening of the floral veins, phyllody and floral proliferation. Microtome sections of infected and healthy leaf, stem of sesamum stained with 4,6-diamidino-2-phenylindole (DAPI) stain, and observed under fluorescence microscope emitted diffuse fluorescence from the infected tissues, which was brighter than the one from the parenchymal cells indicating the presence of phytoplasma in the infected tissues. Studies on variations in the level of gibberellic acid (GA) and indole-3-acetic acid (IAA) in phyllody infected and healthy sesamum was undertaken. GA content was increased by 2.25 times and 10.46 times, and IAA content was decreased by 1.25 times and 1.97 times in leaves and flowers of infected samples compared to the healthy samples. Molecular characterization of sesamum phyllody was performed with leaf samples collected from ORARS lowland, ORARS upland, Vellayani and Karthikapally. Amplicons of 1.4kb was obtained by amplifying with universal primers P1/P6 for detection of phytoplasma. The sequences obtained were subjected to BLAST analysis and the 16S rDNA gene sequence showed that all the isolates shared more than 99 per cent similarity with that of the ‘Candidatus phytoplasma aurantifolia’ strains in GenBank data base. In the phylogenetic tree constructed, the sesamum phyllody phytoplasma under study clustered with the 16SrII group (Candidatus Phytoplasma aurantifolia) phytoplasmas causing sesamum phyllody in various regions. The virtual RFLP pattern generated by iPhyClassifier, derived from 16S rDNA fragment was found to be identical to the reference pattern of 16Sr group II, subgroup D (GenBank accession: Y10097). Based on the results obtained from sequence analysis and virtual RFLP pattern, the phytoplasma associated with sesamum phyllody was identified as ‘'Candidatus Phytoplasma aurantifolia”-related strain belonging to subgroup 16SrII-D. P. indica obtained from Department of Plant Pathology, College of Agriculture, Vellayani was mass multiplied in sterilized coir pith: FYM mixture (1:1) amended with 2 per cent gram flour and sesamum seeds were sown. Colonization was observed seven days after germination. Wedge grafting was standardized in sesamum at 30 days after germination. Pot culture experiment was conducted to evaluate the effect of P. indica against phytoplasma causing sesamum phyllody, by grafting the colonized and non-colonized plants with infected scion. P. indica colonization could significantly reduce the incidence and severity of infection. After 30 and 45 days of grafting, an incidence of 20 and 60 per cent, and severity of 5 and 50 were recorded in the colonized plants grafted with infected scion, whereas an incidence of 60 and 80 per cent and severity of 45 and 75 were recorded in non-colonized plants grafted with infected scion. In colonized plants, enhanced shoot and root length at 30 and 55 days after germination were recorded and also earliness in flowering compared to noncolonized plants. Hence the associated symptoms of phytoplasma infection in sesamum are virescence, thickening of floral veins, phyllody and floral proliferation. The study revealed the association of Candidatus phytoplasma aurantifolia group with sesamum phyllody prevalent in Onattukara tract. The evaluation of beneficial fungal root endophyte P. indica against phytoplasma revealed delayed expression of symptoms in the colonized plants.ThesisItem Open Access Evaluation of beneficial fungal root endophytes against fusarium rot in small cardamom(Department of Plant Pathology, College of Agriculture,Vellayani, 2022-04-02) Aishwarya, Manoharan.; KAU; Dhanya, M KThe study entitled “Evaluation of beneficial fungal root endophytes against Fusarium rot in small cardamom” was conducted at College of Agriculture, Vellayani and Cardamom Research Station, Pampadumpara during 2020-21 to evaluate the colonisation and interaction of two beneficial fungi, Piriformospora indica and Glomus fasciculatum, in cardamom and their potential to manage Fusarium rot disease of cardamom and elucidation of the role of gibberellic acid in the endophytic fungimediated disease tolerance. Fusarium infection in small cardamom is characterised by root rotting, eye shaped lesion on pseudostem and panicle rot. Fusarium oxysporum Schledt was isolated from the infected roots of the farmer’s field of Pampadumpara in Idukki district. Koch’s postulate was proved by inoculation of the pseudostem of one year plants using pinprick method where the isolate produced the typical eye shaped lesion within two weeks. A pot culture experiment was conducted at CRS, Pampadumpara to assess the interactive effect of the fungal root endophytes P. indica and G. fasciculatum on the vegetative growth of small cardamom seedlings and suckers using four treatments and five replications. Both individual and combinatorial effects of the endophytes on the vegetative characters like plants height, number of leaves, leaf length, leaf width, root parameters, biomass etc. were evaluated. Successful root colonization was observed in P. indica and G. fasciculatum treated roots at six and seven days after their inoculation respectively. This is the first report of colonization of P. indica in small cardamom. The study revealed that the endophytes inoculated plants were superior to control plants in which maximum shoot growth was shown by the dually colonized plants followed by the P. indica-colonized which was then followed by G. fasciculatum colonised plants. The root parameters were higher for P. indica-colonized plants compared to the combined or G. fasciculatum colonized plants in cardamom seedlings whereas dually colonized plants had better root growth in cardamom suckers. P and K analysis of the whole plant clearly indicated the enhanced nutrient uptake to root, shoot and leaf in the endophytes-colonized plants. The IAA analysis of root samples also revealed a higher IAA content in the endophytes colonized seedlings compared to the control seedlings with P. indica colonized plants recording the maximum value of 83.80 µg g-1 in seedlings and 94.30 µg g-1 in suckers; and least value being observed in control plants recording 44.80 µg g-1 in seedlings and 94.30 µg g-1 in suckers. This study stipulate a scope of better establishment of cardamom in field especially in the case of seedlings during transplantation due to well established root system. There was also a reduction in nursery period by two months in the P. indica and G. fasciculatum dually colonized seedlings compared to the non-colonized seedlings. In vitro evaluation of P. indica against F. oxysporum and in vivo evaluation of both the bioagents against F. oxysporum in small cardamom was carried out to appraise the effect of bioagents in the management of Fusarium rot disease of cardamom. In in vitro evaluation, dual culture assay of P. indica with F. oxysporum was performed in PDA in which a percent inhibition of 64.4 (%), antagonism index of 20.53 and an obscure lysis zone was observed. There wasn’t any presence of inhibition zone, antibiosis, coiling, overgrowth, sporulation etc. In in vivo evaluation, a pot culture experiment was laid out at CRS, Pampadumpara with seven treatments and three replications including a bio agent check of 2% Pseudomonas fluorescens and chemical check of 2 % carbendazim as basal drench. The study revealed that the beneficial interaction with bioagent successively decreased the disease severity and lesion size, among which P. indica treated plants showed the best result having the least disease severity of 38.07 (%) and 31.48 (%) in seedlings and suckers respectively. The disease severity of the control plants were the highest, recording 86.62 (%) and 76.77 (%) in seedlings and suckers respectively. Combinatorial and P. fluorescens treatments were the other treatments showing promising results in disease management. Total Gibberellic acid was estimated from leaf samples of challenge inoculated experimental plants to elucidate the role of GA in endophyte mediated disease tolerance and the authors couldn’t interpret any role of GA in disease development. Moreover, the GA content was higher in P. indica colonised recording 18.60 µg g-1 and 10.65 in µg g-1 in seedlings and suckers respectively; and dually colonised plants recording 18.00 µg g-1 and 9.71 µg g-1 in seedlings and suckers respectively. Thus, the present study proclaims a very pronounced plant growth promotion in cardamom seedlings and suckers by the beneficial fungal root endophytes viz., P. indica and G. fasciculatum just before transplanting to the field and therein advocating better development and establishment in the field condition. Furthermore, the results also indicates an effective management of the destructive Fusarium rot disease in small cardamom using endophyte colonization especially in P. indica colonized and dually colonized plants.ThesisItem Open Access Management of a major fungal disease in black pepper (Piper nigrum L.)(Department of Plant Pathology, College of Agriculture,Padanakkad, 2022-04-11) Pranavya, A P; KAU; Sajeesh, P KBlack pepper (Piper nigrum L.) is one of the major spice crops and plantation crops that grow as the sole crop or intercrop in Kerala. In nurseries of black pepper major biotic stress are caused by bacteria, fungus, virus and nematode, out of this fungal infection are the leading one. The seedling blight, anthracnose and collar rot were found to be more severe in the nursery. With this background, the present study was conducted to identify the major fungal pathogen associated with black pepper nursery and formulate disease management strategies against that pathogen. A survey was carried out in black pepper growing nurseries to record the different diseases. Seedling blight, anthracnose and collar rot were observed. The fungal isolates associated with seedling blight in nurseries at Padannakkad and Kanakappalli were designated as Pc1 and Pc2 respectively. Anthracnose affected seedlings were collected from Padannkkad, Balal, Panniyur and Periya black pepper nurseries and the fungal isolates associated were designated as Cg1, Cg2, Cg3 and Cg4 respectively. The collar rot samples were collected from Padannakkad, Periya and Panniyur and isolates were designated as Sr1, Sr2 and Sr3. In the case of seedling blight infection, highest disease incidence (DI) (74%) was recorded in Pc1. The highest percent disease index (PDI) in case seedling blight (32%) was recorded in Pc1 as compared to Pc2 isolate. In the case of anthracnose, higher DI (30%) and PDI (25%) were recorded in Cg1 in comparison with Cg2, Cg3 and Cg4. In case of collar rot, higher DI (20%) was recorded in case of Sr1 isolate. All the isolates were tested for its pathogenicity; in case of seedling blight, the isolate Pc1 recorded higher radial growth (7.90 cm) and recorded lesser time (2days) for the symptom development as compared to Pc2 isolate. In case of anthracnose, isolate Cg1 recorded higher radial growth (8.0 cm) and took lesser time (5days) for the symptom development in comparison with Cg2, Cg3 and Cg4. In case of collar rot isolate Sr1 recorded higher radial growth (8.96 cm) and recorded lesser time (2days) for the symptom development as compared to Sr2 and Sr3. A trial was laid out to identify the most susceptible variety of black pepper as well as the most virulent strain of the pathogen among different isolates on pepper varieties viz., Panniyur (P) 1-6, P8, P9, Vijay and Karimunda. Panniyur 2 was identified as most susceptible variety and Pc1 was the virulent isolate. Based on cultural and morphological characters and molecular characterization, Pc1 was identified as Phytophthora capsici. In vitro evaluation of biocontrol agents, chemical fungicides and organic preparations were carried out to study the efficacy against P. capsici. Under in vitro conditions biocontrol agent T. harzianum (2%) exhibited maximum inhibition (55.56%) followed by P. fluorescens (53.33%). Among the chemical fungicides copper oxychloride (0.3%) and metalaxyl (8%) + mancozeb (64%) at 0.3 percent recorded 100 per cent inhibition. Among the organic preparations, ready to use neem oil garlic soap (3%) and garlic extract at 0.3 percent recorded maximum inhibition 31.11% percent and 28.88% percent respectively in the mycelial growth of the pathogen. The best-performing treatments from the in vitro evaluation were selected for pot culture experiment on variety Panniyur 2. After 7 days of inoculation, the least PDI (0.00 %) as well as the least lesion development (0.00%) was recorded in case of metalaxyl (8%) + mancozeb (64%) at 0.6 per cent. The higher PDI (86.66%), as well as maximum lesion development (46.66%), was recorded in ready to use neem oil garlic soap (3%). The study reveals that, the seedling blight caused by Phytophthora capsici can be effectively managed with the foliar application of metalaxyl (8%) + mancozeb (64%) at 0.6 per cent.ThesisItem Open Access Comparative evaluation of different species of oyster mushroom suitable to Kerala(Department of Plant Pathology, College of Agriculture, Padannakkad, 2022-03-11) Akhil, G L; KAU; Susha S, Tharahe present study entitiled “Comparative evaluation of different species of Oyster mushroom suitable to Kerala” was carried out in the College of Agriculture, Padannakkad during 2019-2021 with the objective to identify the oyster mushroom species best suitable for cultivation under five agro-ecological zones of Kerala. Five species of Oyster mushrooms were selected for the study viz., Pleurotus florida, P. djamor, Hypsizygus ulmarius, P. sajor-caju and P. citrinopileatus. To evaluate the yield performance, five species were cultivated in farmer’s field of five agroecological zones of Kerala. The study also aims to evaluate the proximate constituents and medicinal components present in oyster mushrooms. Sensory evaluation and shelf life studies were also carried out. The sporocarps of five species of oyster mushrooms were studied for their morphological characters. P. florida produced white, delicate and fleshy sporocarp with an average weight of 11.71 g. P. djamor produced pinkish white leathery sporocarps with smaller pileus having very short stipe (0.8 cm). H. ulmarius produced creamy white fleshy sporocarps with significantly large pileus having average size of 7.0 cm x 7.52 cm. P. sajor-caju produced greyish white leathery sporocarp. P. citrinopileatus produced golden yellow delicate sporocarp with comparatively short stipe. The average size of pileus was 5.45 cm x 6.17 cm. Microscopic observations of hyphae and spores of five species of oyster mushrooms shows that hyphae of all the five species were septate, branched and hyaline with clamp connections. The width of the hyphae of all the five species ranged from 1.5- 4.5 μm. Basidiospores of P. florida and P. djamor recorded 7-12 μm in length and 2-5 μm in width whereas, H. ulmarius and P. sajor-caju produced spores with dimension of 8-12 μm× 3-6 μm. P. citrinopileatus produced spores with dimension of 7-10 μm× 2-3 μm. 141 Two substrates namely paddy straw and rubber sawdust were evaluated for the cultivation of five species of oyster mushrooms. Total yield from three harvests were significantly less in paddy straw, (954.66 g) compared to rubber sawdust which has given a yield of 1306.40 g. The yield recorded was highest for H. ulmarius cultivated on both paddy straw and rubber sawdust (1233 g kg-1 and 1611 g kg-1 respectively) which was followed by P. florida (1148.30 g kg-1 and 1582.66 g kg-1 respectively). It has been evident that selection of substrate significantly affected time taken for complete spawn run, time taken for pin-head formation, time taken for first harvest, total crop period and total yield from three harvests. The present study revealed that both the substrates viz., paddy straw and rubber sawdust were suitable for the cultivation of oyster mushrooms. So, both the substrates can be selected for cultivation based on the ease of availability and cost. In the present study, the suitability of five species of oyster mushrooms in five agro-ecological zones of Kerala were evaluated by cultivating the mushroom species at coastal plains, midland laterites, foothills, high hills and Palakkad plains. H. ulmarius was found to be the best suited oyster mushroom species for cultivation in coastal plains (102.99 % BE), foot hills (92.73 % BE) and high hills (123.30 % BE). In midland laterites and Palakkad plains, highest BE of 82.70 (%) and 103.80 (%) respectively were obtained from P. djamor. P. djamor, although reported to be performing well under warm conditions, yielded well under midland laterites and Palakkad plains. This may be due to low relative humidity and comparatively higher temperature in these zones. Earliness in primordial initiation (14-19 days) and extremely fast growth also make this species promising for cultivation in Kerala especially during dry months. The proximate analysis of five species of oyster mushrooms was carried out and it revealed that mushrooms are rich source of proteins, carbohydrates, fibres, amino acids, vitamins and minerals with less fat content. The protein content was highest in P. sajorcaju (26.02 %) and the fibre content was highest in P. florida (26.20 %). Fat content was the least in H. ulmarius with 1.70 per cent on dry weight basis. H. ulmarius (31.27 %) recorded the highest carbohydrate content among the five species of oyster mushrooms. 142 P. florida recorded the maximum moisture content (90.97 %). Highest amino acid content of 19.40 per cent was recorded from P. sajor-caju Analysis of mineral components revealed that highest content of sodium (965 ppm) and potassium (7175 ppm) was present in P. djamor. P. florida recorded highest content of calcium (1000 ppm) and magnesium (4025 ppm) which supports healthy immune system and keep bones strong. Medicinal analysis confirmed that these mushrooms were rich in bioactive components. P. djamor recorded highest content of β-glucan (30.25 g per 100g) having antitumour and immunomodulation activities, β-carotene (3.70 μg per 100g) having antioxidant properties and lovastatin (370.75 μg per 100g) which reduce blood cholesterol. P. sajor-caju recorded highest glycoprotein (435.00 μg per 100g) and terpenoid (1.26 %) content. Sensory evaluation of five species of oyster mushrooms was done using sauteed mushroom recipe to evaluate the quality attributes and consumability of the species. H. ulmarius recorded highest scores for appearance (8.83), colour (8.75), texture (8.66), flavour (8.58) and taste (8.83) on a maximum score of 9. H. ulmarius scored 8.80 in terms of overall acceptability followed by P. florida (7.60). Overall, from this study it was found that oyster mushrooms, especially H. ulmarius and P. florida are highly favoured for consumption. Shelf life of five species of oyster mushrooms were undertaken both in room temperature (26±20C) and in refrigerated conditions (150C). In the present study, comparatively higher shelf life was observed on P. djamor and P. sajor-caju which could be stored for two days after harvesting in room temperature and three days in refrigerated conditions. The present study demonstrated the exploitability of five species of oyster mushrooms in Kerala conditions. All the five species can be cultivated under the five agro-ecological zones of Kerala but H. ulmarius, P. florida and P. djamor yielded well compared to P. citrinopileatus and P. sajor-caju. H. ulmarius was found to be the best 143 suited oyster mushroom species for cultivation in coastal plains, foot hills and high hills. In midland laterites and Palakkad plains, highest yields were obtained from P. djamor can be economically cultivated regarding the yield and earliness in fruiting.ThesisItem Open Access Prevalence of sesamum phyllody in Onattukara tract and evaluation of fungal root endophyte Piriformospora indica for its management(Department of Plant Pathology, College of Agriculture, Vellayani, 2022) Gifty, K J; KAU; Radhika, N SThe research work entitled ‘Prevalence of sesamum phyllody in Onattukara tract and evaluation of fungal root endophyte Piriformospora indica for its management’ was conducted during 2019-21 at Department of Plant Pathology, College of Agriculture, Vellayani and Onattukara Regional Agricultural Research Station with the objectives to study the symptomatology, molecular detection and characterization of phytoplasma inciting sesamum phyllody disease in AEU 3 (Onattukara tract); and evaluation of fungal root endophyte P. indica for its management. Phytoplasma infected sesamum samples were collected from D and F blocks of Onattukara Regional Agricultural Research Station and Karthikapally. Karthikapally recorded highest disease incidence (39.44 per cent) and vulnerability index (23.75). Chocolate weed, Melochia corchorifolia, was found to be exhibiting symptoms of shoot proliferation. Hoppers collected from the infected fields were identified as Orosius albicintus, Hishimonas phycitis and Nephotettix sp. Disease symptoms were observed at the stage of flowering of sesamum plants in all the sampled locations. The associated symptoms were reduction in internodal length of stem, axillary bud proliferation, thickening of the floral veins, phyllody and floral proliferation. Microtome sections of infected and healthy leaf, stem of sesamum stained with 4,6-diamidino-2-phenylindole (DAPI) stain, and observed under fluorescence microscope emitted diffuse fluorescence from the infected tissues, which was brighter than the one from the parenchymal cells indicating the presence of phytoplasma in the infected tissues. Studies on variations in the level of gibberellic acid (GA) and indole-3-acetic acid (IAA) in phyllody infected and healthy sesamum was undertaken. GA content was increased by 2.25 times and 10.46 times, and IAA content was decreased by 1.25 times and 1.97 times in leaves and flowers of infected samples compared to the healthy samples. Molecular characterization of sesamum phyllody was performed with leaf samples collected from ORARS lowland, ORARS upland, Vellayani and Karthikapally. Amplicons of 1.4kb was obtained by amplifying with universal primers P1/P6 for detection of phytoplasma. The sequences obtained were subjected to BLAST analysis and the 16S rDNA gene sequence showed that all the isolates shared more than 99 per cent similarity with that of the ‘Candidatus phytoplasma aurantifolia’ strains in GenBank data base. In the phylogenetic tree constructed, the sesamum phyllody phytoplasma under study clustered with the 16SrII group (Candidatus Phytoplasma aurantifolia) phytoplasmas causing sesamum phyllody in various regions. The virtual RFLP pattern generated by iPhyClassifier, derived from 16S rDNA fragment was found to be identical to the reference pattern of 16Sr group II, subgroup D (GenBank accession: Y10097). Based on the results obtained from sequence analysis and virtual RFLP pattern, the phytoplasma associated with sesamum phyllody was identified as ‘'Candidatus Phytoplasma aurantifolia”-related strain belonging to subgroup 16SrII-D. P. indica obtained from Department of Plant Pathology, College of Agriculture, Vellayani was mass multiplied in sterilized coir pith: FYM mixture (1:1) amended with 2 per cent gram flour and sesamum seeds were sown. Colonization was observed seven days after germination. Wedge grafting was standardized in sesamum at 30 days after germination. Pot culture experiment was conducted to evaluate the effect of P. indica against phytoplasma causing sesamum phyllody, by grafting the colonized and non-colonized plants with infected scion. P. indica colonization could significantly reduce the incidence and severity of infection. After 30 and 45 days of grafting, an incidence of 20 and 60 per cent, and severity of 5 and 50 were recorded in the colonized plants grafted with infected scion, whereas an incidence of 60 and 80 per cent and severity of 45 and 75 were recorded in non-colonized plants grafted with infected scion. In colonized plants, enhanced shoot and root length at 30 and 55 days after germination were recorded and also earliness in flowering compared to noncolonized plants. Hence the associated symptoms of phytoplasma infection in sesamum are virescence, thickening of floral veins, phyllody and floral proliferation. The study revealed the association of Candidatus phytoplasma aurantifolia group with sesamum phyllody prevalent in Onattukara tract. The evaluation of beneficial fungal root endophyte P. indica against phytoplasma revealed delayed expression of symptoms in the colonized plants.