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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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Subject: Plant Pathology × Author: Anjali, V A × End date: 2019 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Characterisation of Ralstonia solanacearum (Smith) Yabuuchi et al. infecting solanaceous vegetables in relation to Physico-chemical and Biological properties of soil
    (Department of Plant Pathology, College of Horticulture, Vellanikkara, 2019) Anjali, V A; KAU; Sainamole Kurian, P
    Ralstonia solanacearum, the causal agent of vascular wilt disease of crop plants has been ranked as the second most important bacterial pathogen in the world next to Pseudomonas syringae. The high diversity exhibited by the pathogen hampers the breeding for resistance, consequently the resistant varieties developed may not express uniform level of resistance in different geographical locations. Being a soil inhabitant, the survival of R. solanacearum is influenced by physico-chemical and biological properties of soil. Considering these facts, present investigation was carried out with the objective of characterisation of R. solanacearum from different agro ecological units (AEUs) of Kerala and to determine the effect of soil physical, chemical and biological properties on the pathogen. Purposive sampling survey was conducted in four AEUs of Kerala viz., North Central laterite (NCL), Marayur hills (MH), Southern laterite (SL) and Palakkad central plains (PCP) from March to September 2018. Two locations from each AEUs were selected for the survey. The per cent incidence in different locations ranged from 20 to 88 per cent. The pathogen was isolated from infected plant samples collected during the survey on triphenyl tetrazolium chloride (TZC) agar and pathogenicity was proved by inoculation on respective hosts. The rhizosphere soil samples of healthy and diseased plants were collected from each location. The population of the pathogen present in the soil was quantified and it ranged from 20.66 x 104 cfu g-1of soil to 137.66 x 104 cfu g-1 of soil. A strong positive correlation was observed between pathogen density in soil and per cent disease incidence (PDI). A total of eight isolates were collected, purified and maintained for all the experiments. The colony characters of different isolates on TZC agar showed considerable variation and the morphology of the bacterial cells was studied using scanning electron microscopy. Typical rod shaped cells with size 0.3-0.5 µm x 1.2-1.7 µm were observed. The molecular characterization of the isolates was done by PCR amplification and sequencing of 16S rRNA. The sequences were subjected to in-silico analysis which confirmed the identity of all isolates as R. solanacearum (Smith) Yabuuchi et al. The phylogenetic analysis revealed that the eight isolates collected from different AEUs clustered on different branches of the tree while those from the same AEUs clustered together. This indicates considerable variation among the isolates in accordance with location which can be attributed to the difference soil parameters in these locations. The isolates of the pathogen were further categorized into races and biovars based on pathogenicity on differential hosts and utilization of disaccharides and hexose-alcohols respectively. The results revealed that two isolates from Marayur hills (MH 1 and MH 2) belong to race 3, biovar II whereas two from Palakkad central plains (PCP 1 and PCP 2) belong to race 1 biovar III A. The other four isolates collected from Northern central laterite (NCL 1 and NCL 2) and Southern laterite (SL 1 and SL 2) were identified as race 1, biovar III. The physico-chemical and biological properties of the soil samples collected during the survey were analysed using standard protocols. The statistical analysis using paired sample t-test revealed significantly higher soil pH, organic carbon, available K, Ca and Fe content and soil microflora in rhizosphere soil of healthy plant compared to diseased. A significant positive correlation was observed between PDI and soil parameters viz., water holding capacity and bulk density whereas soil pH and available Ca content exhibited a negative correlation with PDI. A similar trend was observed in the case of pathogen population also. Further, multiple regression analysis was performed to assess the extent of variation contributed by different soil parameters on PDI and pathogen population. The results indicate that 96.8 per cent variation in the bacterial wilt incidence is explained by soil pH and available Ca content in the rhizosphere soil with negative correlation whereas bulk density and Ca content contributed 92.2 per cent in the build-up of population of Ralstonia solanacearum in soil. The study revealed the influence of soil factors on bacterial wilt disease incidence, population of R. solanacearum and pathogen variability. Hence, it is concluded that, manipulation of soil factors can play a major role in integrated management of the disease. Furthermore, the variability of pathogen according to geographical region, may be considered while planning resistance breeding programmes against bacterial wilt disease.