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Open Access
Nutrient Management for yield and quality improvement in Kacholam
(Department of Agronomy, College of Horticulture, Vellanikkara, 2012) Kavitha, P R; KAU; Meera, Menon V
Kacholam (Kaempferia galanga L.) is an important medicinal and aromatic plant of the Zingiberaceae family. In India, kacholam is cultivated throughout the plains for the rhizomes. The economic produce of kacholam is the chopped and dried rhizomes of 6-7 months maturity. Dried rhizomes are used in bulk quantities in ayurvedic medicine and in the cosmetic industry. It is used for curing inflammatory wounds, skin disorders, piles, oedema, fever, epilepsy, splenic disorders and asthma. The constituents of the rhizome oil include para methoxy ethyl cinnamate (60.24 % of the oil), ethyl cinnamate (20.66%), cineol, borneol, 3-carene, camphene, kaempferol, kaempferide and cinnamaldehyde. There is immense scope for cultivation of kacholam in Kerala, as the climatic and soil conditions are optimally suited to its growth and development. Kacholam can be grown as an intercrop in coconut gardens and it has attained the status of a cash crop of homesteads. Though there is an approved ad hoc recommendation of organic manures as well as N, P and K for kacholam, there are reports that the K dose is inadequate. Also, considering the low availability and high cost, the present organic manure recommendation of 20 tonnes ha-1 is rather unaffordable. There are also reports about the inadequacy in the availability of secondary nutrients viz., S, Ca and Mg, which may affect yield and quality of kacholam. A field experiment was conducted during 2011-2012 in the coconut garden of Water Management Research Unit, Vellanikkara to evaluate the effect of varying doses of K and secondary nutrients on yield and quality of kacholam. There were 12 treatments with 3 replications each. Treatments consisted of package of practices (POP) recommendation of 20 tonnes farmyard manure along with 50:50:50 kg N, P and K ha-1 and combinations with S, Ca, Mg and extra dose of K applied as first and second top dressing. Rhizomes were planted at a spacing of 20 x 15 cm and planting was done on 3/ 06/ 2011. Harvesting was done seven months after planting. Observations included biometric observations taken at monthly intervals, nutrient contents at 2 ½ and 5 months after planting, and at harvest. Nutrient uptakes was also worked out. Essential oil and oleoresin in rhizomes were also analysed. The soil pH and chemical parameters were analysed before and after the experiment. There were significant differences among treatments with respect to yield, essential oil, oleoresin, nutrient contents and nutrient uptake. With respect to yield, the treatment receiving S applied either at first top dressing or at second top dressing and that with S, Ca and Mg recorded highest yields as compared to other treatments. Essential oil content also showed the same trend as that of yield. But in case of oleoresin, the content was more only in the treatments receiving S as first and second top dressing. This treatment resulted in highest uptake of all nutrients except Ca at harvest. Application of the secondary nutrients thus had a direct positive effect on yield and quality. Changing the N:K ratio of present NPK recommendation resulted in reduction of yield and other quality parameters. The yield and quality parameters with the reduced organic manure dose were found similar to the present POP. Increased phosphorus content of soil observed after experimentation indicated the possibility of reducing the recommended phosphorus dose. Supplementing S, Ca and Mg with a reduced organic manure dose is also to be tested.
Open Access
Identification of paprika (Capsicum annuum L) genotype(s) for yield and quality characters
(Department of Olericulture, College of Agriculture,Vellayani, 2012) Lekshmi, S L; KAU; Sreelathakumary, I
The experiment entitled “Identification of paprika (Capsicum annuum L.) genotype(s) for yield and quality characters” was conducted at the Department of Olericultue, College of Agriculture, Vellayani, during the period 2011-2012. The study envisaged assessment of genetic variability in paprika and to study the influence of harvest maturity on quality parameters. Fifty three accessions of paprika were collected from different parts of country and grown in the field in RBD with three replications. The analysis of variance revealed highly significant differences among the 53 accessions of paprika for all the characters studied viz., plant height, primary branches, days to flowering, days to maturity, node to first flower, height of node to first flower, fruit length, fruit girth, fruit weight, fruits per plant, yield per plant, pedicel length, fruit: pedicel ratio, flesh thickness, seeds per fruit, flesh: seed ratio, driage, oleoresin, colour, ascorbic acid, capsaicin, bacterial wilt and leaf curl virus incidence. Among the accessions CA 6 recorded highest yield per plant (776.12 g) and CA 12 recorded maximum number of fruits (265.33). Fruit weight was highest in CA 47 (13.43 g). High phenotypic coefficient of variation and genotypic coefficient of variation were observed for yield per plant, fruits per plant, fruit weight and primary branches per plant. High heritability and high genetic advance also observed for these characters. The path analysis revealed that fruit weight, fruits per plant, plant height and primary branches had direct effect on yield per plant. Correlation and path analysis revealed that fruits per plant is the primary component as evident from the positive correlation as well as high direct and indirect effect on yield. Maximum oleoresin content was observed in CA 7 followed by CA 29 and CA 37. CA 2 recorded a high color value with pungency and CA 37 recorded a high colour with low pungency. CA 38 recorded maximum ascorbic acid content. CA 34 and CA 40 had the minimum pungency and CA 10 recorded the maximum pungency. Bacterial wilt and leaf curl virus incidence among the 53 accessions were studied. CA 33, CA 34, CA 35 and CA 47 recorded less incidence of both diseases. Based on Mahalanobis D2 analysis the current genotypes were grouped into four clusters. Cluster I was the largest with 34 accessions, followed by cluster IV with 15 accessions and cluster II with three accessions. Cluster III had only one accession. In the present study maximum divergence was observed between clusters II and IV as shown by their high intercluster distance. The minimum intercluster distance observed between the clusters I and II indicated a close relationship among the accessions. Based on selection index including both quantitative and qualitative characters CA 34 (Local, Dharwad) was ranked first followed by CA 7, CA 6, CA 33 and CA 35. The accessions were genetically catalogued and the result revealed distinct variations among the accessions for vegetative, inflorescence, fruit, seed and quality characters. Quality characters showed significant differences among the accessions and harvest maturity stages. Oleoresin, colour and capsaicin content in the paprika fruits were found to increase as the age of the fruits increased. Ascorbic acid content in the fruits increased from turning stage to red ripe and then declined. On the basis of the present study the high yielding accessions can be grouped into low pungent and pungent paprika. Among the low pungent, high yielding accessions CA 34, CA 33 and CA 35 recorded high colour value also. CA 6 and CA 7 are promising high yielding pungent paprika accessions. These accessions can be utilized for further crop improvement programmes.
Open Access
Wood quality evaluation of tree species raised in research trials of the Kerala forest department at various localities
(Department of wood Science, College of Forestry, Vellanikkara, 2012) Sindhumathi, .C.R.; KAU; Anoop, E.V
A study entitled “Wood quality evaluation of tree species raised in research trials of the Kerala Forest Department at various localities” was conducted in the College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur during the period 2010-2012. The objective of the study was to evaluate the wood quality of Pterocarpus dalbergioides Roxb., Swietinia macrophylla King. and Pericopsis mooniana (Thwaites) Thwaites, raised in research trials of the Kerala forest department at three localities, viz., Mananthavady research range at Wayanad, Olavakkode research range at Palakkad and Nilambur north research range at Nilambur districts, Kerala. Increment core samples and wooden blocks were collected at breast height from trees, selected at random for each species. These samples were subject to intensive investigations to explore the radial variation in anatomical properties as well as variation between species. The study revealed that most of the anatomical properties varied significantly within species and between species. Tree species were also felled to assess the strength characteristics as well as to study the various physical properties. Specific gravity was higher in P. mooniana, the other two species showing similar values. Heartwood – sapwood ratio showed significantly higher value in S. macrophylla, whereas the other two species were at par. Tangential shrinkage showed higher value compared to radial shrinkage in all the three species. Results revealed that P. mooniana exhibited better strength properties which was almost similar or even better than teak as reported by Sekhar (1988). P. dalbergioides showed lower values for strength properties when compared to natural grown P. dalbergioides (Limaye, 1933). Even though P. mooniana showed higher strength properties compared to the two species, overall results revealed that all the three species has good potential for being used as various solid wood purposes. Regression analysis revealed that P. mooniana and P. dalbergioides showed linear relationship between specific gravity and anatomical properties. The present results on wood quality can be used as a baseline data for future tree improvement aspects of these species with reference to wood quality and bring out their potential utility for future afforestation programmes and various end uses.
Open Access
Evaluation of ornamental flowering shrubes for tropical landscapes
(Department of Pomology and Floriculture, Colege of Horticulture, Vellanikkara, 2012) Najeeb, Naduthodi; KAU; Valsalakumari, P.K.
The present study entitled “Evaluation of ornamental flowering shrubs for tropical landscapes” was carried out at the Department of Pomology and Floriculture, College of Horticulture, Vellanikkara from Jan. 2011 to Dec. 2011. The objectives were to evaluate ornamental flowering shrubs for suitability to various landscaping uses and to compute Air Pollution Tolerance Index. The study involved evaluation of 30 tropical ornamental flowering shrub species or varieties. The selected shrubs were four years old, maintained in the shrubbery of the Department of Pomology and Floriculture. The experiment was laid out in CRD with three replications. Various vegetative and floral characters were recorded and data analysed and correlation studies were made with weather parameters. Shrubs selected for the study were described based on morphological characters. Growth of shrubs was measured in terms of height and spread. Based on the manageable height, they were classified into three groups, i.e. Tall (height above 2 m), Medium (height 1m- 2m) and Dwarf (height below 1m). Among the 30 shrubs evaluated, the maximum height was observed for Calliandra haematocephala (319.4 cm) and the minimum for Lonicera japonica (49.9 cm). Plant spread varied from 43.4 cm in Wrightia antidysenterica to 269.7 cm in Calliandra haematocephala. Regression equation of height for predicting spread was formulated using the monthly data on height and spread. Foliage characters like leaf length, leaf area, petiole length, girth and internodal length were measured. Based on leaf area, plants were categorized into medium coarse, medium, medium fine and fine textured. Qualitative characters of the foliage like shape of leaf, base, tip, margin and colour of leaf were observed and used for plant description as well as categorizing them into different texture classes. Shrub canopy shape (silhouette) was observed and used for making schematic diagram. Qualitative characters of flowers like type of inflorescence, position of inflorescence, colour and fragrance were observed. Time taken to open up the inflorescence from bud stage, persistence of single flower as well as the inflorescence were also observed. Quantitative characters like inflorescence diameter, single flower length and diameter and number of flowers per inflorescence were also recorded. Flowering seasons of the shrubs were observed and accordingly they were categorized into four different phenological phases i.e. Dec-Feb, Mar-May, June- Aug and Sep-Nov. Sideruns were observed and phenological configurations were made. Air Pollution Tolerance Indices of the shrubs were calculated. Calliandra haematocephala (31.7) showed the highest APTI value and the minimum value was observed for Allamanda cathartica ‘Dwarf’ (9.2). Shrubs were categorized into sensitive (value ≤14), intermediate (15- 19), medium tolerant (20-24) and tolerant (> 24) groups based on their APTI values. Based on the different characters studied, shrubs were classified into different landscape utility groups such as, accent plant, foundation planting, screening and privacy, hedges and topiary, shrub border, background planting, corner planting, Shrub group and mass planting, Pot and Container planting, fragrant garden, moon garden, xeriscaping, rock garden, covering sloppy banks and butterfly garden. Shrubs were observed for pest and disease incidence. Major pests were leaf eating caterpillars in Mussaenda erythropylla, Nerium indicum, Calliandra haematocephala and Ixora coccinea, flower bud borer in Wrightia antidysenterica, mealy bug and scales. Shrubs were not severely affected by diseases. Minor leaf spots were observed in certain shrubs. In the present study, shrubs were recommended for various functional uses in the landscapes based on their growth, flowering and morphological characters. Based on flowering season, they were categorized into four phenological phases. Side-runs were observed and phenological configurations were made. Air Pollution Tolerance Indices of the shrubs were also computed and the plants were categorized according to their APTI values.
Open Access
Crop weather relationship in cauliflower (Brassica oleracea var.botrytis L.)
(Department of Agricultural Meteorology, College of Horticulture, Vellanikkara, 2012) Karthika, V P; KAU; Prasada Rao, G S L H V
A field experiment was conducted during 2010-11 and 2011-12 at the Department of Agricultural Meteorology, College of Horticulture, Vellanikkara with the objectives to study the effect of weather on growth and yield of cauliflower and to assess the suitability of cauliflower under various crop growing environments. The study included five planting times at an interval of 15 days (1st November, 15th November, 1st December, 15th December and1st January) and two tropical hybrid varieties (Basant and Pusa Kartik Sankar). The different growth and yield characters like plant height, number of leaves, plant biomass, duration of different growth stages and curd weight were recorded along with monitoring of the incidence of various pests, diseases and physiological disorders. The daily weather parameters like maximum and minimum temperatures, forenoon and afternoon relative humidity, forenoon and afternoon vapour pressure, bright sunshine hours, wind speed, rainfall and rainy days were collected and used in this study. Based on these weather parameters, other important weather variables like mean temperature, diurnal temperature range, forenoon and afternoon vapour pressure deficits and solar radiation were determined. Various heat units like growing degree days, heliothermal units and photothermal units were also worked out. The maximum and mean temperature, diurnal temperature range, forenoon and afternoon relative humidity, forenoon and afternoon vapour pressure deficits, bright sunshine hours and solar radiation were found to be higher in 2010-11 as compared to 2011-12. Plant height, number of leaves and the duration of different growth stages were found to be highly variable among the different planting times in both the years, but when pooled over years, these characters became non-significant (except the duration from curd initiation to harvest) with respect to the planting time as a result of the higher variability between the two years for the different weather parameters. The curd weight and the plant fresh and weights exhibited high significant difference for the different planting times. Duration from transplanting to curd initiation was found to be more critical for the curd yield. To determine the critical weather elements affecting the crop growth, correlation analysis was done and it was observed that the crop duration would increase with increase in the maximum temperature, bright sunshine hours, solar radiation and afternoon vapour pressure deficit whereas, the afternoon relative humidity showed a negative influence on crop duration. The curd yield and plant weight were found to be decreasing with increase in the maximum temperature and sunshine hours. The various heat units exhibited positive correlation with the duration of different growth stages. Based on the weather parameters experienced by the crop during the transplanting to curd initiation period, a regression equation with an R2 value of 0.95 was developed to predict the curd weight. The present study revealed that first fortnight of November is the optimum planting time for tropical cauliflower in Thrissur District, since the maximum curd size was obtained when planted on 1st November in 2011-12. The optimum weather for the planting of tropical cauliflower was observed to be less than 31.2°C of maximum temperature, less than 26.8°C of mean temperature, less than 8.8°C of diurnal temperature range, less than 6.0 hrs of bright sunshine hours and less than 22.3 MJ m-2 of solar radiation, with 22.5°C of minimum temperature. Intermittent rainfall and higher relative humidity observed during the earlier planting times were found to be conducive for the incidence of pests and diseases and the bacterial disease black rot was observed as a serious threat to cauliflower cultivation in this region.
Open Access
Development and evaluation of modified atmosphere packed passion fruit(Passiflora edulis)
(Department of Post harvest technology and agricultural processingKelappaji College of Agricultural Engineering and Technology, Tavanur, 2012) Madhana Supriya, R; KAU; Sudheer, K P
Passion fruit is a tropical fruit which is extensively used in juice processing. The fruit is highly perishable and losses its quality immediately after the second day of harvest. The postharvest loss in quality and commercial value is due to the intense respiratory activity and significant moisture loss. Hence a study was undertaken to develop a wax applicator to extend the shelf life of passion fruit by adopting the postharvest technologies. A simple and efficient wax applicator with a capacity of 250 kg.hr-1 was developed based on the physical properties of the fruits. Various samples of the passion fruits were treated with bee wax and commercial wax packed in LDPE bags of 200 and 400 gauge. The effect on the shelf life extension of fruits was investigated individually and in combination of wax and LDPE bags. In the case of LDPE bags, different levels of perforations such as 0%, 0.5%, 1% and 2% were used. The samples were kept in ambient condition viz., 32 - 35°C and 70 - 80% RH and at cold conditions as 7ºC and 90% RH. The physicochemical characteristics of samples were tested periodically at an interval of 5 and 7 days, under ambient and cold storage conditions, respectively. The results obtained were subjected to statistical analysis. From the results it was revealed that the samples kept in non-perforated polythene covers were found to be better than those kept in perforated bags and in normal atmosphere. A maximum shelf life of 40 days was obtained for passion fruits at 7oC coated with commercial wax emulsion. Thus, commercial wax coating in combination with LDPE bags acted as a barrier against moisture loss and respiration rate of fruits. However, the fruits kept as control had lost consumer acceptability after the tenth day of study at cold condition and within two days at ambient storage conditions.
Open Access
Reproductive biology of water lily (Nymphaea nouchali Burm.f.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2012) Fahida, P K; KAU; Presanna Kumari
Water lilies are a group of fascinating aquatic perennial herb belonging to the genus Nymphaea. Among the different species of Nymphaea, Nymphaea nouchali is one common in south India. This species is commonly known as blue water lily, blue star water lily or star lotus. The plant is historically and functionally significant since it is associated with our culture and tradition. This species which forms an important constituent of aquatic flora possesses immense medicinal and ornamental values. Despite of its immense potentialities, water lily has received very little attention of crop improvement workers. Information on developmental pattern and reproductive biology which is fundamental for crop improvement programmes is lacking in this plant. Hence this investigation entitled ‘Reproductive biology of water lily (Nymphaea nouchali Burm.f.) was under taken up with the objective of elucidating the reproductive biology and developmental pattern of flowers and fruits in Nymphaea nouchali. Two flower colour variants of Nymphaea nouchali- blue and white types maintained in cement tanks were selected for the study. The study was conducted during 2010-2012 in the Department of Plant Breeding and genetics, College of Horticulture, Vellanikkara. The leaves of both the colour variants are simple, orbicular with sub-peltate lamina and deeply cleft near to the petiole base. The petiole of both the type was long, glabrous and brownish in colour with lamina floating on the water surface. The blue type was significantly superior to the white type for mean length of leaf as well as means width of leaf at middle and tip. In both the types it took almost six days for the flower bud to reach the water surface and the flower opening occurred nearly three days after the bud reaching the water surface. Even after the flower opening the pedicel elongation continued in both the types to an extent of 4 cm. Maximum growth rate of the pedicel was observed on the day just prior to the flower opening. The white type produced longer flower bud and thus larger flowers when compared to blue type. However the circumference of the flower bud was more for blue type. The flowers of both the types were faintly fragrant. The flowers opened in morning and closed in the evening hours and again opened on next day. The opening time of the flower varied from 7.30 am to 9.45 am. The closing time varied from 5.15 pm to 6.15 pm. Bright and sunny days favoured early opening of the flower. The blossom life was three days for blue type where as it was four days in white type. The flowers were produced throughout the year on an average of 3 to 4 days interval in both the types. Hence it can be well recommended for water gardens. The flowers were found to be solitary, pedicellate, and complete with various floral whorls in spiral fashion on the floral axis. Significant variability was observed on various floral characters among the two types. Each stamen consisted of a filament, anther and a sterile appendage at the tip. The initiation of dehiscence occurred by the longitudinal splitting of the anthers in both the types. The pollen dehiscence occurred only after complete opening of the flower. The stigma receptivity started 17 hours before flower opening and the receptivity was retained up to 20 hours after flower opening. Honey bees, house flies and weevils were found to be the major insects visiting the flowers. Several dead insects were observed in the stigmatic cup of both the types indicated the insectivorous nature of the flower. The pollen grains were found to be round, yellow in colour and monocolpate with reticulate exine in both the colour variants. No fruit or seed development were observed in both the colour variants. The absence of fruit or seed set can be attributed to very low fertility of the pollen and some incompatibility mechanisms in the flower. The vegetative propagation from leaf was found prominent in both the colour variants under study.
Open Access
Characterization and management of ganoderma lucidum inciting basal stem rot of coconut
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2012) Yunus, C; KAU; Beena, S
The present study on “ Characterization and management of Ganoderma lucidum inciting basal stem rot of coconut ” was undertaken in the Department of Plant Pathology, College of Horticulture, Vellanikkara during 2010-2012 with an aim to isolate the pathogen associated with the disease and to study the cultural, morphological and pathogenic characters of different isolates of the pathogen, symptomatology of the disease, host range and effective management of the pathogen using bio-control agents, phytoextracts and selected fungicides. Purposive sampling surveys were conducted and the occurrence of basal stem rot disease of coconut was observed through out Kerala. The isolation of pathogen from basidiocarps yielded eight isolates of Ganoderma sp. which produced fruiting body in saw dust- rice bran substrate. The pathogenicity of these isolates was tested and observed yellowing, drying and drooping of leaves of coconut seedlings inoculated with all isolates except the isolate GT- from Trivandrum. Basidiocarp formation was noticed only in one seedling inoculated with the isolate GV from Vellayani and reisolation of pathogen was done from this basidiocarp. Symptomatology of the disease under natural and artificial conditions was studied. Under field condition the typical symptom of BSR disease viz., yellowing and drooping of leaves, stem bleeding and basidiocarp formaton were observed in all surveyed areas but all the typical symptoms of disease were not observed under artificial condition. The cultural characters of all the isolates of pathogen were studied on four media viz., Potato dextrose agar, Czapek’s (DOX) agar, Richard’s agar and Soil extract agar media. All isolates produced white mycelial growth on all media but variations in texture, mycelial type, and colour change of mycelium, exudates production and formation of aberrant fruiting body were observed. PDA was found to be the best medium for the growth of pathogen in which all isolates recorded highest growth rate. The pathogen preferred a temperature range of 30-350C and neutral to acid pH of 5-7 for the growth. Slight variation in growth rate was observed under light and darkness. Basidiocarps showed variations in the morphological characters and were stipitate in all isolates except GC from Chirakkacode and GVe from Vettikkal, semicircular to conical shaped, yellowish red to reddish brown with smooth to waved margin, creamy white to brown pore surface, 4.4 – 12.0 x 2.6- 17.0 cm size, 1-10 mm pore length, 139- 254 x 122 – 190 μm pore diameter and 2-10 mm flesh thickness. Basidiospores were brown, ovate to ellipsoidal, truncated apex, double walled with inter wall pillars separating two walls. The size of these basidiospores showed variation in the range of 4.8-13 x 4.5-7.0μm with a spore index of 1.15-1.7. It was trimitic, with generative hyphae hyaline, thin walled, branched, septate and clamped. Reddish brown pigmented skeletal hyphae and colourless binding hyphae were noticed. Based on these observations the eight isolates of the pathogen were identified as Ganoderma lucidum (Leys) Karst. Regarding the in vitro management of the pathogen, two isolates of T. virens and one isolate of T. viride were isolated from rhizophere soil and were proved equally effective with the reference culture, T. viride and T. harzianum in inhibiting the growth of pathogen. Mycoparasitism and production of non volatile metabolites were found to be the mechanisms exhibited by the selected Trichoderma spp. The bacterial antagonists obtained from rhizosphere soil and the reference culture P. fluorescens recorded less than 50 percent inhibition on the growth except in cases of few isolates of the pathogen. It was observed that the selected bacterial antagonists were not much effective in inhibiting the pathogen compared to fungal antagonists. Among the phytoextracts, Azadirachta indica at 20 per cent concentration was found the most effective and recorded more than 50 percent inhibition on the growth of pathogen over control. It was followed by Musa sp. at 10 per cent concentration. The in vitro evaluation of fungicides showed that flusilazole, hexaconazole and iprobenphos at 0.2 per cent concentration were the most effective and recorded cent per cent inhibition on the growth of all isolates of pathogen. The study on the host range of G. lucidium revealed that the seedlings of arecanut, breadfruit, acacia and jack fruit showed yellowing and drooping of leaves and finally wilting of all the seedlings were observed
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.

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