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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Open Access
Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii(Burgess) (Diptera:Agromyzidae)
(Department of agricultural entomology, College of horticulture, Vellanikkara, 2014) Jyothi Sara, Jacob; KAU; Maicykutty P, Mathew
A study on “Biotic agents for the management of American serpentine leaf miner, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae)” was carried out at the Department of Agricultural Entomology, College of Horticulture, K.A.U., Vellanikkara during 2011-2013 with the objectives of collection and identification of indigenous natural enemies and to assess the pathogenicity of the entomopathogens to explore the feasibility of utilizing them for its management. Surveys were conducted in the vegetable fields for the collection and identification of natural enemies associated with L. trifolii in three districts, namely, Thrissur, Ernakulam and Kottayam from January to March, 2011. The surveys revealed the occurrence of nine species of hymenopteran parasitoids. The per cent parasitism varied from 10.96 to 58.99 per cent among the crops surveyed. Three species of eulophids, namely, Cirrospilus acadius Narendran, C. brevicorpus Shafee & Rizvi and Aprostocetus sp. as well as the braconid, Toxares sp. are new reports for India. Among the parasitoids, Closterocerus spp. were the dominant group followed by Chrysonotomyia sp. All parasitoids were solitary, larval endoparasitoids except Toxares sp. which was larval-pupal in nature. One species each of small ants (Formicidae) and a dipteran fly (Dolichopodidae) were observed as predators on L. trifolii. In the study, no entomopathogens were observed from L. trifolii. Considering the level of pesticide consumption in vegetable crops that undermine the potential of insect parasitoids and also that no entomopathogens could be observed during the survey, it was decided to evaluate entomopathogenic nematodes (EPNs) as biocontrol agents against L. trifolii. Isolation of EPNs from 72 soil samples from Thrissur, Ernakulam and Kottayam districts yielded four isolates of Steinernema carpocapsae. Bioefficacy studies carried out on these four isolates along with Steinernema bicornutum and Heterorhabditis indica showed that S. carpocapsae Isolate - 1 had the lowest LC 50 , LC 90 and LT values indicating their higher effectiveness against the maggots of the pest. 50 Pot culture study conducted to compare the potential of S. carpocapsae Isolate - 1 with other treatments showed that azadirachtin 1 EC at 0.005% was the most effective causing 84.51 per cent mortality to the maggots of L. trifolii. This was followed by the foliar application of H. indica at 32 infective juveniles (IJs)/ maggot which caused 18.98 per cent mortality. Application of Beauveria bassiana at 1×10 7 spores/ ml was not effective. In the field evaluation, fipronil 5 SC at 0.002% was found to be the most effective treatment for controlling L. trifolii followed by azadirachtin 1 EC at 0.005%. Compatibility of the IJs of the S. carpocapsae Isolate - 1, S. bicornutum and H. indica was studied with ten commonly used insecticides in the laboratory by direct exposure method. Chlorantraniliprole 18.5 SC at 0.005% was found to be the most compatible insecticide with S. carpocapsae isolate - 1 causing only 0.17 per cent mortality to IJs at 72 hours after treatment (HAT). Quinalphos 25 EC at 0.05% and chlorpyriphos20 EC at 0.05% were highly incompatible, causing 96.17 and 92.87 per cent mortality of the nematodes. Dimethoate 30 EC at 0.04% was the most compatible insecticide with S. bicornutum and caused only 0.60 per cent mortality at 72 HAT and was followed by azadirachtin 1 EC at 0.005% with 0.78 per cent mortality to the IJs. Quinalphos 25 EC at 0.05% caused 99.93 per cent mortality at 72 HAT. Heterorhabditis indica was compatible with all insecticides except quinalphos 25 EC at 0.05% which was moderately toxic resulting in 39.6 per cent mortality. The virulence, pathogenicity and multiplication of the survived IJs were not affected by the insecticide treatments. Parasitoids and EPNs were observed as potential candidates for the management of L. trifolii. Hence future studies on the bio-ecology and mass production of dominant parasitoids and standardization of methods to improve the efficacy of EPNs are suggested for the successful control of L. trifolii in polyhouses as well as in the field.
Open Access
Characteization and evaluation of nutmeg (Myristica fragrans Houtt.) accessions
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 2016) Vikram, H C; KAU; Mini Raj, N
Nutmeg (Myristica fragrans Houtt.) is an introduced crop to India. There exists tremendous variability in the nutmeg population in Kerala, which is the major nutmeg growing state in the country. Assessment of the existing variability is a prerequisite for taking up successful crop improvement programmes, which is very much limited in this tree spice. In this context, the present study entitled “Characterization and evaluation of nutmeg (Myristica fragrans Houtt.) accessions” was taken up exclusively with the specific objectives to characterize nutmeg accessions based on morphological, biochemical and molecular parameters so as to scale the variability in a multidimensional way. Select fifty nutmeg accessions from a core germplasm collected and maintained in a private plantation in the Chalakudy river basin, belonging to age of fifteen years, formed the material for the study. Among the select fifty accessions, forty two were females, four monoecious and four males. In the morphological characterization, 51 qualitative and 38 quantitative characters were recorded from two trees per accession. Biochemical characterization was done in the select seventeen distinct accessions. GC-MS profiling was done in kernel and mace oils. Biochemical constituents of fresh pericarp were estimated. Isozyme profiling was done for peroxidase and polyphenol oxidase enzymes. The molecular characterization was attempted with 21 RAPD and 12 ISSR primers after screening. A key for identification of an elite nutmeg tree was developed. A descriptor for nutmeg with a set of 51 qualitative and 38 quantitative parameters and descriptor states for each of these characters was developed as the first step. This is the first study of its kind to develop a minimal descriptor for nutmeg. The descriptor developed from the present study was simultaneously utilised for morphological characterization and evaluation of the accessions. Wide variability was noticed among the accessions for 47 out of 51 qualitative characters. Four characters viz., leaf margin, fruit pubescence, grooves on nut and nature of fruit dehiscence were noted as non variable characters and hence, these were not included for further analysis. Based on the qualitative characters, accessions were classified into 11 clusters at 66 per cent similarity level. Accessions differed significantly for all the quantitative characters except shelling percentage. Performance evaluation of the accessions brought out the superiority of accession 8, 9 and 22 for yield. The accessions showed high GCV, PCV, h2 and genetic gain for most of the characters. Number of fruits per tree, fruit set percentage, number of fruits per m2, fresh and dry weight of mace, mace volume as well ratio of nut to mace exhibited high genetic gain. Hence, selection programme based on these characters will be very effective in improving the base populations. Based on Mahalanobis D2 analysis, accessions were grouped into 10 clusters. Wide range of variation was observed in contents of volatile oil, oleoresin and fixed oil of kernel and mace. Based on these constituents accessions were grouped into 26 clusters, which indicated their distinct quality. Based on the results of the morphological characterization, seventeen distinct accessions were selected for further biochemical and molecular analysis. GC-MS analysis of kernel and mace oils exhibited 20 and 24 constituents respectively. Volatile oil composition exhibited wide variability for the major constituents viz., myristicin, elemicin, safrole and sabinene apart from the presence of some unique compounds. Grouping of the accessions was done based on the per cent content of these important compounds. Two accessions recorded high contents of both myristicin and elemicin whereas another two accessions were in the complimentary; belonging to low myristicin group. High sabinene combined with low myristicin was the intrinsic quality attribute of one of the accessions. Change, as well as addition/deletion of specific constituents was also noticed in the volatile oils after storage for one year. Accessions exhibited wide range of variation in the biochemical constituents of pericarp, a valuable information for the value addition of pericarp. Total phenol and tannins exhibited high variation. The accessions were ranked based on the content of biochemical constituents. Isozyme profiling using peroxidase enzyme produced four bands and that based on polyphenol oxidase exhibited three bands. Molecular markers could assess the variability among the accessions. The selected 21 RAPD primers produced a total of 164 amplicons of which 63.21 per cent were polymorphic. The 12 ISSR primers selected produced a total of 87 amplicons of which 69.44 per cent were polymorphic. Few unique bands were detected for specific characters. Inter cluster association of each of the qualitative clusters with other clustering patterns was worked out. The results indicated the differences as well as similarities of the qualitative clusters with other clustering patterns. Finally, key quantitative characters were identified based on their direct and indirect effect on yield as also economic importance. The statistical key thus developed using 13 key quantitative characters will serve as a preliminary tool for identification of an elite nutmeg tree.
Open Access
Groundwater irrigation: management, adaptation and economic costs under declining resource conditions
(Department of Agricultural Economics, College of Horticulture, Vellanikkara, 2017) Seenath Peedikakandi; KAU; Indira Devi, P
Groundwater is the major source of domestic use and irrigation in Kerala, accounting for 39 per cent of net irrigated area. Irrigated agriculture in the state shows continuous increase over years. At the same time Kerala is reported as third among the states with highest depletion of groundwater. This situation poses challenges in agricultural production. The study ‘Groundwater irrigation: Management, adaptation and economic costs under declining resource conditions’ was undertaken, in this background. The objectives of the study were to analyse the extent of decline in groundwater resources and farmers’ understanding of the same, to analyse the extraction practices, management and economic efficiency of groundwater irrigation and coping (short term) and adaptation (long term) strategies towards management of groundwater decline and the economic cost of adaptation strategies. The study was conducted in Palakkad district of Kerala. Based on the stage of ground water development, three Block Panchayats viz., Chittur (over exploited), Malampuzha (critical) and Pattambi (semi-critical) were selected for the study. 50 Open Well (OW) irrigated and 50 Bore Well (BW) irrigated farms from each BP were randomly selected from the Grama Panchayats (GPs) where observational wells of the GWD (Ground Water Department- Kerala) are situated. Primary data was collected from the sample farms through field visits using pre-tested structured interview schedule and through direct observation. PRA (Participatory Rural Appraisal) was also conducted in each BP to draw the time line of changes in ground water status and social perceptions. Secondary data on monthly water levels of Groundwater Monitoring Wells (GMWs) maintained by GWD (Palakkad),rainfall data and published reports were used for the study. Statistical tools like descriptive analysis, regression and Stochastic Frontier Function were employed for analysis of the data. In most of the GMWs in the study area, the Water Level from Ground (WLG) has been declining over the years. The trend was more predominant during early summer (Dec.–Jan.) in Chittur and Malampuzha and in late summer in Pattambi BP. Regression analysis showed that WLG was significantly influenced by one year lagged rainfall in Chittur and current year rainfall in Malampuzha and Pattambi. The average well density was 205/km2 with highest in Pattambi. Density of defunct wells was highest (45/km2) and the average functional age of bore wells was lowest (7 years) in Chittur. The depth of well was highest in Chittur where bore well depth (136 mbgl- meters below ground level) was double than that of Pattambi. Coconut based cropping system was prevalent in most of the farms except in Malampuzha where paddy was the major crop. Flood, basin and sprinkler irrigations were found to be more common in Malampuzha and Pattambi BPs, while drip irrigation was prevalent in Chittur. Cost of irrigation in Chittur was about Rs. 29,000/ha/year which accounted for 37 per cent of cost of cultivation. Annual net return per ha. of farm was lowest (Rs. 17,640/-) in Chittur due to low cropping intensity. Stochastic Frontier Analysis indicated that mean economic efficiency was high (99.9%) in Chittur as most of the farms were functioning along the cost frontier. The variability among the farms in Chittur was low. Respondents opined that groundwater is declining over the years irrespective of the region. It has been so, for more than a decade in Chittur affecting socio-economic well-being of farmers. They attributed intensive extraction through bore wells and low rainfall as the major reasons for the decline. Farm level adaptations to water scarcity are classified under ‘supply management’ (methods that facilitated increase in quantity of water available for irrigation) and ‘demand management’ (methods that tried to use the water effectively through minimizing the use) strategies. The supply management strategies were mainly exploitative in nature which included digging new bore well (52-58%), improved draft technology with compressor pumps (58%), taking pits for water conservation (7%), coconut husk burial (12%), coconut leaf mulching (18%) and dependence on water markets (8%). Digging new bore well was the most common supply management strategy in Chittur which is highly capital intensive. The average cost amounted to Rs. 8,520/ha/year. Intensive extraction was done by excessive use of subsidized electricity. Adoption of drip irrigation (60%) was the most widely practiced demand management strategy which cost about Rs. 22,000/ha/year. Cropping pattern change from paddy and sugarcane to coconut was also observed. About 18 per cent of the land area in Chittur was kept fallow due to water scarcity. The study brings out results that suggest policy interventions in regulating bore well digging and revisiting the power subsidy system. In Chittur area, where the rainfall is scanty, extension of the Right Bank Canal of the Chittur River irrigation project is the most feasible solution. Taking up on-farm research trials in the area to suggest efficient farming systems and practices may also be done. Simultaneously water resource conservation strategies are to be popularized through awareness creation, capacity building programmes and subsidy support.
Open Access
Development of F1 hybrids of indeterminate tomato (Solanum lycopersicum L.) for protected cultivation
(Department of Olericulture, College of Agriculture, Vellayani, 2015) Lekshmi, S L; KAU; Celine, V A
The present investigation entitled “Development of F1 hybrids of indeterminate tomato (Solanum lycopersicum L.) for protected cultivation” was conducted at the Department of Olericulture, College of Agriculture, Vellayani, from 2013 to 2015 with the objectives of identifying superior varieties and developing F1 hybrids of indeterminate tomato suited for protected cultivation. The study consisted of two experiments conducted in the naturally ventilated polyhouse of size 50 m x 20 m located at the Instructional Farm, Vellayani. In the first part of the first experiment, 40 tomato genotypes were evaluated for two consecutive years in an RBD with three replications. As the second part, 12 commercial hybrids were evaluated. The second experiment consisted of a 9 x 9 half diallel analysis laid out in an RBD with three replications. Analysis of variance showed significant differences between the genotypes for all the characters for two crops. Pooled analysis revealed that, LE 1 recorded the highest yield (2443.43 g) and fruit weight (108.13 g) followed by LE 7. LE 53 had maximum number of fruits per plant (65.00). In the present study, genotypes had wide variation for quality parameters. Fruits of LE 14 recorded highest TSS with a mean of 5.74 ºBrix. LE 7 had maximum ascorbic acid (30.13 mg/100g) and lycopene content (13.09 mg/100g). Beta carotene value was maximum in LE 16 (184.15 mg/100g). There was minimum incidence of pests, diseases and physiological disorders under protected conditions. Among the 12 hybrids evaluated, INDAM 9802 was the highest yielder (1444.40 g) followed by F1 T 30 (1412.22 g). F1 T 30 recorded maximum fruits per plant (35.66) which was on par with F1 Queen (35.55). Genetic parameters like phenotypic and genotypic coefficients of variation, heritability and genetic advance were studied to assess the genetic variability among the genotypes. High heritability coupled with high genetic advance were observed for characters like truss per plant, fruits per truss, fruit weight, fruits per plant, yield per plant and yield per plot. Path analysis revealed highest positive direct effect for fruit weight (0.3956), truss per plant (0.3558) and fruits per plant (0.3381). Based on D2 analysis the 40 genotypes were grouped into eight clusters. Cluster I was the largest with twenty four genotypes followed by cluster II with ten genotypes. Diallel analysis was carried out using nine parents selected based on genetic divergence and per se performance. The parents were crossed in a diallel fashion excluding reciprocals to obtain 36 F1 hybrids. The study revealed that P5 x P9 had the highest yield (3114.03 g) which was on par with P6 x P8 (3074.37 g) and P1 x P5 (3077.58 g). P1 x P5 had the maximum fruits per plant (103.93). The magnitude of relative heterosis, heterobeltiosis and standard heterosis varied considerably. For yield, relative heterosis ranged from -32.40 to 92.72, heterobeltiosis from -47.14 to 89.54 and standard heterosis from 2.91 to 160.95. The σ2gca and σ2sca ratio indicated that non-additive gene action was predominant for all traits. Among the nine parents, P9 (LE 1), P5 (LE 20) P1 (LE 2), and P2 (LE 7) were superior for yield and yield attributes. The estimates of sca effects indicated that P5 x P9 (LE 20 x LE 1), P6 x P8 (LE 39 x LE 38) and P1 x P5 (LE 2 x LE 20) were the most promising hybrids for protected cultivation. The present study revealed that the genotypes LE 1 and LE 7 and the hybrids INDAM 9802 and F1 T 30 were superior for yield and yield attributes under protection. Based on the mean performance, standard heterosis and sca effects the three potential crosses viz., P5 x P9, P6 x P8 and P1 x P5 could be adjudged as suitable indeterminate tomato hybrids for protected cultivation.
Open Access
Economic valuation of mangrove ecosystems in Kerala
(Department of Agricultural Economics, College of Horticulture, Vellanikkara, 2013) Hema, M; KAU; Indira Devi, P.
Mangroves are invaluable treasure o f our biodiversity with immense ecological and economic significance. But mangroves wealth of the world is depleting at an annual rate of -0. 34 per cent. Mangroves in Kerala, constitute 0.3 per cent o f that in India, is reported to be high in species diversity. The available reports indicate the depleting status o f the ecosystem in Kerala too. The socio-economic and ecological significance o f this ecosystem is to be studied in detail for assisting policy decisions when confronted with the conservation-development debate. This study was undertaken in this background. The study identified the stakeholders o f mangrove ecosystems o f Kerala and quantified the level o f dependence o f local communities for their livelihood and estimated the aggregate demand for products and services. Further, it identified and quantified the relative influence o f socioeconomic, institutional, climatic and anthropogenic forces on the destruction of mangroves and finally assessed the Total Economic Value (TEV) o f mangrove system and suggested policy prescriptions for the conservation and management of mangroves in Kerala. The study was conducted in the mangrove areas o f Emakulam and Kannur districts of Kerala. These two districts accounted for nearly 65 per cent o f the mangroves o f the state. The study was based on primary and secondary data. The primary data was gathered from 480 respondents belonging to four identified stakeholder groups (residents, fishermen, paddy farmers and general public), selected through simple random sampling method. Data was collected through personal interview using structured pretested interview schedule along with direct observation. The major tools of data analysis were Contingent Valuation Method (CVM) and Choice experiment. The data collection was conducted during June 2012 to January 2013. I Four stakeholder groups o f the mangrove ecosystem in the study area were residents living close to mangroves (<1 km from mangroves), fishermen (inland fishermen and women, engaged in shell mining and clam collection, shrimp farmers), paddy farmers (Pokkali and Kaippad) and general public (resides away from the mangroves). The residents were depending on the mangroves for extraction o f fuel wood, fodder and poles. On an average the level o f extraction was 307 kg o f fuel wood, 1024 kg of fodder and 14(no.) o f poles per year valued at X 4628/household. This amounted to 3 per cent o f their annual household income. The major species o f fish catch by the fishermen were Etroplus, shrimp, crab and Tilapia which was quantified at 1553 kg/ year valued at X 1,41,045. Shell mining which was found to be a major economic activity in Kannur region could generate an income of X 30,000/annum through the extraction and sale o f 7500 kg o f shells. Clam collected was quantified at 225 kg/year valued at X 5625. Thus, the average gross income from these activities was estimated at X 1,77,164 per year which was the main source o f income for the household. About 8 per cent of the fishermen were involved in shrimp farming and were mainly from Kannur district. The size o f the farm varied from 0.4 to 2 ha. The input cost/ha was X 2.8 lakhs which includes cost o f seed, feed, lime and water management. Labour cost was estimated at X 77,000. Hence total cost and returns o f shrimp farming/ha was X 3.27 and 4.75 lakhs respectively with net income o f ? 1.48 lakhs. Pokkali and Kaippad agricultural systems are proved to be closely interconnected with the:.mangrove ecosystem and the per hectare gross returns was X 60,007 and X 40,935 respectively. This amounted to average 30 per cent o f their household income. The respondents’ perception on the pattern of change and the major factors that effected the change in mangrove ecosystem was studied based on their responses. 46 per cent o f the respondents were o f the opinion that the mangrove ecosystem has declined over years and facing threat. The major factors responsible for the same were reported as anthropogenic, climatic forces and status o f property rights. The 11 developmental interventions like LNG Petronet Terminal, Puthuvypeen and ICTT Vallarpadam has resulted in large scale conversion o f mangrove areas. The contradictory forces o f development and conservation led to destruction of mangrove ecosystem. One fifth respondents opined that climatic factors were responsible for the decline. Nearly 85 per cent of the mangroves in the state were reported to be under private ownership and rest under public. The property right status along with economic status influences the rate o f depletion. The legal interventions and community and institutional efforts also influence the status of mangroves, most often positively. The economic valuation of ecological benefits o f mangroves was attempted employing the Contingent Valuation Method. The respondents expressed their willingness to contribute towards conservation both in cash and kind (cash payment and manual participation as labour and as volunteer in awareness programmes) and in combination. The average WTP expressed by the respondents was f 2308/annum the range being ? 50-28,870. The TEV of the mangrove ecosystem of the state was thus ? 1,17,947 million, which was 0.14 per cent ofthe GSDP (2011-12). A socially preferred management plan was identified among a set of alternatives, employing the choice experiment method. Among the management options given, the stakeholders preferred community management (41.6%) followed by public management (29.2%) and status quo (21.4%). The community management of the mangrove ecosystem provides opportunity for the local community to participate in management decision process. At the same time, the importance o f public funding for such activities is revealed in the analysis. The study suggests initiating scientific attempts on realistic area estimation and mapping o f the mangrove resources in the state. There should be attempts to identify and classify the species and document the traditional wisdom associated with them. Region specific studies are needed to establish and quantify the extent of association between mangrove ecosystem and the livelihood activities of local communities. The TEV justifies the increased resources allocation for the conservation efforts. Further, the implementation of community management system as institutional form for mangrove management in the state is suggested.
Open Access
Integrated culture of fish with micropropagated plants in a recirculatory system
(Department of Aquaculture, College of Fisheries,Panangad, 2012) Navya, R; KAU; Devika Pillai
An experiment was designed to study an integrated recirculatory sytem with micropropagated aquarium plants, fish and indigenous filter materials like coir, vetiver and bamboo as the filter media. The plants selected for the study were Bacopa caroliniana, Anubias minima, Aponogeton ulvaceus, Rotala rotundifolia and Nymphoides cristata. The first part of the work was to standardise the micropropagation techniques for the above said plants. Murashige and Skoog medium (half and full strength) was used as the basal medium for the establishment of cultures. The explants varied from nodal segments, rhizome buds, leaf petioles and lateral buds. Surface sterilization was carried out with a range of sterilants like mercuric chloride solution, ethyl alcohol, sodium hypochlorite solution etc. for varying durations and concentrations depending on the type of explant. Effect of growth regulators on explants were studied using auxin IAA and cytokinins, BA and Kn. A liquid culture media with 1.5mg l-1 BA and 0.1mg l-1 Kn concentrations was the best medium for Bacopa caroliniana. A combination of auxin cytokinin like 1.5 mg l-1 BA and 1.0 mg l-1 IAA in liquid culture was the best medium for Rotala rotundifolia. In Nymphoides cristata, hormone concentration of 1.0 mg l-1 each of BA and IAA in liquid culture gave the best results. In Anubias minima, a full MS solid medium with 6.0 mg l-1 of BA gave better results compared to lower levels of BA. In vitro trials for Aponogeton ulvaceus was not successful due to the exudation of phenolic extracts in all the treatments which eventually lead to the death of the tissues. Hardening success was 90 percent, 100 percent, 70 percent, 100 percent in the case of Anubias minima, Nymphoides cristata, Rotala rotundifolia and Bacopa caroliniana respectively. The micropropagated plants were incorporated in the recirculatory system along with fish and three different biofilter materials like coir, vetiver and bamboo splits. The study focused mainly on the filtering efficiency of the three filters based on the nitrification curves. The plants were included in the system to be a part of biofilter and their exclusive role in nitrification was not studied since this is a preliminary work. A nitification graph was plotted with the observed values of ammonia, nitrite and nitrate in the three different biofilter systems and compared with a control. It was inferred that coir fibres were the best of filter materials tried in nitrification followed by bamboo and vetiver. The control system took more time (45 days) in stabilizing ammonia levels due to lack of a substratum for growing nitrifying bacteria.
Open Access
Biochemical and molecular studies on post-harvest physiological deterioration of cassava (Manihot esculenta crantz)
(Department of plant physiology, College of agriculture,Vellayani, 2015) Saravanan, R; KAU; Roy Stephen
The project entitled “Biochemical and molecular studies on post-harvest physiological deterioration of cassava (Manihot esculenta Crantz)” was conducted at the Dept of Plant Physiology, College of Agriculture, Vellayani and at ICAR-CTCRI, Thiruvananthapuram during 2013 to 2015. The main objective of the work was to analyse the physiological biochemical and molecular mechanisms associated with post harvest physiological deterioration (PPD) and develop methods to delay the PPD in cassava. The initial screening of the cassava genotypes for their performance of PPD was done with 61 different genotypes including some released varieties. Significant differences were observed for PPD development and shelf-life of harvested roots. Cassava genotypes such as IMS2-8, 9S-172, 11S-53, IRS 2-10 and 9S-286 started showing the visible discolouration in the parenchyma tissue earlier (less than 3 days of storage). Genotypes such as 9S-7, 9S-98, 11S-31, 11S-86, 11S-14, CE63-3, CI43-2, CR43-2, CR54-A5, CR59-8R, Sree Athulya and Kalpaka showed low PPD scores and better shelf-life. Tissue imprinting for peroxidase enzyme showed that there was a remarkable increase in peroxidase activity in the root tissues with increasing PPD symptoms. There was no correlation between the root morphological traits and PPD severity. Carotene and starch content of root did not influence the PPD in the genotypes studied. Chemotypic profile of roots with PPD symptoms was used to classify the genotypes based on PPD. To develop an objective screening tool, Near Infrared Spectroscopy (NIRS) was utilized to analyse root samples for PPD. Principal component analysis (PCA) and chemometric tools clearly grouped the different PPD category in root tissues. Various stains such as saffranin, aniline blue, erythrocin, fast green and phloroglucinol stained the tissue specifically at vascular tissues and other cell components and were not suitable for detecting PPD. Storage techniques such as storing the harvested roots in de-aerated bags, wax coating and burying the roots under the soil were employed with selected cassava varieties like Sree Athulya, Sree Jaya, Vellayani Hrashwa, Kalpaka and Sree Padmanabha to delay PPD. Wax coating was suitable to reduce PPD for few weeks. Effect of different storage temperature on PPD was studied for five cassava varieties. Root respiratory flux was higher in roots stored at ambient conditions compared to high (40o C) or low temperature (4o C) storage. There were significant positive correlation between root respiratory flux at 3 and 9 days of storage to the CAT and POX activities studied in different cassava varieties. Roots were treated with various food preservatives at two different concentrations (0.5 and 1%). There was a weak, but significant reduction in symptom development in butylated hydroxy touline – (BHT, at 0.5 and 1% level) treated roots compared to other treatments. Nearly three folds increase in total phenol content was noticed in BHT and butylated hydroxy anisole (BHA) treated roots. The plant hormones related to wound response such as Salicylic acid and jasmonic acid were used to study the PPD response in roots under storage. The roots did not show marked influence to hormone application. Significant genetic variation was observed for PPD. The low PPD type genotypes such as 9S-7, 9S-98, 11S-31, 11S-86, 11S-14, CE63-3, CI43-2, CR43-2, CR54-A5, Sree Athulya and Kalpaka can be utilized for breeding programmes. High temperature storage of cassava at 40 oC resulted in reduced respiratory rate and increased antioxidant scavenging enzyme activity and also reduced the PPD. Differentiation of cassava roots at the metabolites level corresponding to visual symptoms and chemotypic profile of PPD and NIR spectroscopy offer a rapid screening tools. Among the different storage treatments, wax coating with antiseptic pre-treatment is most suitable and economical for increasing shelf-life of roots. Food preservatives like BHT and BHA have a significant, albeit marginal influence on PPD symptom development in cassava.
Open Access
Efficiency of vermiconversion and decomposition of farm residues on soil health, yield and quality of banana (Musa spp.)
(Department of Science and Agricultural Chemistry, College of Horticulture,Vellanikkara, 2016) Mayadevi, M R; KAU; Sushama
An investigation entitled “Efficiency of vermiconversion and decomposition of farm residues on soil health, yield and quality of banana (Musa spp.)” was undertaken at College of Horticulture and Banana Research Station, Kannara during 2013-2015. The objectives of the study were to compare the efficiency of native and exotic earthworms on vermiconversion of farm residues and the effects of different modes of vermicomposting on soil health, yield and quality of banana and to evaluate the in situ decomposition of banana crop residues An experiment with seven treatments and three replications was laid out in randomized block design to assess the composting efficiency of native and exotic earthworms. Seven treatments included absolute control as soil (S), ex-situ compost in silpaulin vermibed without earthworms (Ex-C), ex-situ vermicompost in silpaulin vermibed using Perionyx excavatus (Ex-P), ex-situ vermicompost in silpaulin vermibed using Eisenia foetida (Ex-E), in-situ vermicompost in banana planting pits using Perionyx excavatus (In-P), in-situ vermicompost in banana planting pits using Eisenia foetida (In-E), in-situ compost in banana planting pits without earthworms (In-C). In the next study, the prepared composts were tested along with recommended doses of fertilizers and FYM to assess their effects on growth, yield and crop quality of banana var. Nendran in RBD with seven treatments replicated thrice. The treatments were absolute control (S), 300:115:450g N:P2O5:K2O plant-1 + FYM at the rate of 20 kg plant-1 (POP) , exsitu vermicompost in silpaulin vermibeds with Perionyx excavatus at the rate of 20 kg plant -1 (Ex–P), ex-situ vermicompost in silpaulin vermibeds with Eisenia foetida at the rate of 20 kg plant -1 (Ex–E) , in-situ vermicompost in crop pits with Perionyx excavatus at the rate of 20 kg plant -1 (In-P), in-situ vermicompost in crop pits with Eisenia foetida at the rate of 20 kg plant -1 (In-E), in -situ compost at the rate of 20 kg plant -1 (In-C). After the harvest of the crop, the entire residues from each plant was incorporated in the respective crop pits and the insitu degradation of the banana residues was monitored. The salient findings are summarized as follows In the first trial, the composting efficiency of native and exotic earthworms under different modes of composting was compared. Chemical properties of compost like pH, electrical conductivity, and content of primary nutrients were significantly affected by modes of composting. Exotic earthworms like Eisenia foetida produced higher auxin content in the compost whereas Perionyx excavatus registered higher dehydrogenase activity under ex-situ mode of composting. The total microbial load was recorded in the compost prepared without earthworms under both modes of composting. Compost yield was more in ex-situ composting methods and Eisenia foetida was more efficient in composting as compared to Perionyx excavatus. Humic acid characterization by Fourier Transform Infra-Red spectroscopy revealed a similar spectra from different treatments and were found to be characterized by aromatic rings and triple bonded skeleton. Presence of relatively higher quantity of polysaccharide like substances was observed in insitu mode of composting. The spectra of humic acids for ex-situ composts prepared using Perionyx excavatus revealed a nitrate band of characteristic shape appearing prominently. Perionyx excavatus produced humic acids with high aromaticity both under ex-situ and in-situ mode of composting. Scanning electron microscopy revealed neo-formed CaCO3 nodules embedded in humic acids in the ex-situ vermicompost produced by Eisenia foetida. Transmission Electron Microscopy of humic acids indicated a globular structure for vermicompost prepared by Perionyx excavatus and a lamellar structure with voids for vermicompost prepared using Eisenia foetida. On field experimentation with different treatments using Nendran banana as the test crop, the highest yield was obtained for combined application of fertilizers and farm yard manure as per POP. Number of fingers per hand and number of functional leaves were found to influence the yield, irrespective of treatments. The number of days to bunching and harvest was significantly reduced for banana under in-situ composting. Higher content of total, reducing and non-reducing sugars were observed for in-situ composting treatments. On the contrary, higher titratable acidity was recorded for the control treatment. Both vitamin C content and sensory parameters were complimentary for POP treatment. Increased absorption and translocation of nutrients such as N, P, K and Mg in fruits were observed under organic nutrition using Perionyx excavatus. For the next study, the residues of banana were added to the respective pits for monitoring the carbon and nitrogen mineralization. The carbon mineralization with respect to time was fitted to single pool exponential model to derive the rate of mineralization and half-life. It revealed crop residues pre-treated with vermicompost using exotic earthworms had a higher rate of C cumulative mineralization. Nitrogen addition by both exotic and native species of earthworms were almost similar under in-situ conditions. The banana residue decomposition by Eisenia foetida was about 3.5 times higher than that of Perionyx excavatus. Calcium content of Perionyx excavatus pre-treated residues added the maximum calcium to the soil.
Open Access
Silicon availability of tropical soils with respect to rice nutrition
(Department of Soil Science and Agricultrural Chemistry, College of Horticulture,Vellanikkara, 2016) Arya Lekshmi, v; KAU; Jayasree Sankar, s
Silicon (Si) is the second most abundant element in soil. The amount of silicon in soil depends on parent material, soil type, pedogenic process and landscape. In soil solution, Si is present as monosilicic acid which is the only form that the plant can absorb from soil. The productivity of rice is comparatively low in soils of Kerala. As a ̳Si – accumulator‘, rice can benefit from Si nutrition. The application of Si can enhance growth and yield of rice. With this background, studies were conducted to categorize major rice growing soils of Kerala according to plant available silicon and to evaluate the efficacy of different sources of silicon including rice straw in wetland rice. The release of silicon from different soils added with various silicon sources under different water regimes was also monitored. Soil samples were collected from five different locations representing major rice growing regions of Kerala viz., Kuttanad, Kole land, Pokkali, sandy and lateritic to categorize them according to plant available silicon. The available Si ranged from 7.70 mg kg -1 (sandy soil) to 34.91 mg kg -1 (Kole land soil) in the order Kole land > Pokkali > lateritic > Kuttanad > sandy soil. All the soils under study were categorized as low in available Si. The available Si had positive correlation with organic carbon, available N, Ca, Mg, Fe, Mn, Zn, exchangeable K, Ca, Mg and CEC and negative correlation with available boron, AEC and silica-sesquioxide ratio. These soils were subjected to fractionation of silicon. The major fractions of Si were mobile, adsorbed, organic, occluded, amorphous and residual Si. The percentage distribution of fractions of Si in these soils were in the order; residual Si > amorphous Si > occluded Si > organic Si > mobile Si > adsorbed Si. Quantity – intensity relationship of five major rice growing soils at two temperatures viz. 25 0 C and 40 0 C were studied. The highest buffer power was indicated by Kuttanad soil followed by Pokkali and sandy soils at 25 0 C. It clearly indicated that these soils have a higher power to retain Si on solid phase and replenish its concentration in soil solution as and when it is depleted through plant uptake or leaching. The equilibrium Si concentration and the amount of Si adsorbed by each soil were used to test the fitness of data to the adsorption isotherms viz., Langmuir, Freundlich and Temkin. The data obtained from the adsorption experiments fitted into Freundlich and Temkin equations, but not to Langmuir equation at 25 0 C. At 40 0 C no adsorption equations were obtained for any soil.An incubation study was conducted to know the extent of release of Si on addition of different sources of silicon such as rice husk ash, biodecomposed rice husk, calcium silicate and sodium silicate in five rice growing soils under submerged water regime (SWR) and field capacity water regime (FCWR). Addition of Si significantly increased the release of available Si in all soils except Kole land soil after a month. Kole land soil showed higher release of available Si after two months. The highest release of available Si was at SWR in case of Kole land and Kuttanad soil, where as Pokkali, sandy and lateritic soils showed more release of available Si at FCWR. Irrespective of soils, treatment with sodium silicate showed higher release of available Si. Total Si showed a decreasing trend over the period of incubation for three months in all the soils. A field experiment was conducted at Agronomic Research Station, Chalakudy to evaluate the efficacy of different sources of silicon including rice straw in wetland rice. Rice husk ash, biodecomposed rice husk, calcium silicate and sodium silicate were used as source of Si along with fertilizers as per package of practice recommendation (NPK alone). The maximum number of panicles per hill, number of spikelets per panicle, thousand grain weights and minimum number of unfilled grains per panicle were recorded in treatment with calcium silicate application. The maximum grain yield of 6.90 t ha -1 was recorded in treatment T 5 (T 2 + Calcium silicate) and significantly superior (fig.54) over all other treatments. This increase in yield may be due to the effect of application of Si on soil fertility, nutrient uptake, and plant growth. The direct effect of Si fertilization on increased number panicle per hill, number of spikelets per panicle, and thousand grain weight and decreased number of unfilled grains per panicle might be the reason for increased grain and straw yield in treatment with calcium silicate. The treatment with POP + sodium silicate showed the highest uptake of Si by grain and straw of rice. The sources of Si had no residual effect on grain and straw yield of succeeding rice crop. In general, sandy soil low in available Si had a high response to applied Si in achieving higher grain yield.

Kerala Agricultural University, Thrissur

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