IRSPAS 2017
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Item Formulation and stabilization of Trichoderma spp. in selected carrier materials.(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Botheju, W.S.M.; Hewavitharana, N.,; Kannangara, S.D.P.; Abeywickrama, K.Trichoderma spp. are one of the major biocontrol agents which have the ability to act against large numbers of foliar and soil borne pathogens and are eco-friendly good plant growth promoting agents. Present investigation was carried out with an attempt to determine 1) the best organic carrier material in which the viability and antagonistic activity retain for a sufficient duration and 2) optimum temperature at which the product can be stored without losing the viability and antagonistic activity. In the present study, three Trichoderma spp. (T. asperellum, T. harzianum and T. virens) were formulated in three carrier materials - coir dust, saw dust and waste of polished rice, which were rich in lignocellulosic organic compounds, nitrogen and mineral salts. In the preparation procedure, glucose and starch were added as carbon sources and cow dung was also added as a source of nitrogen as Trichoderma spp. require sufficient amounts of carbon and nitrogen sources for their growth and development. Three Trichoderma spp. were then inoculated separately (ten mycelial blocks with 1cm diameter from 7-day old cultures) into the carrier materials in sterilized polypropylene bags aseptically. Each treatment comprised of six replicates. Shelf life of these formulated products were studied along with viability tests, using spread plate method from which colony forming units were observed at three week intervals. Mean values of measurements were statistically analyzed using ANOVA and Tukey’s pair wise test (Minitab 16). Antagonistic activity of three Trichoderma spp. against three post-harvest pathogens (Colletotrichum musae, Fusarium oxysporum, Pestaliopsis microspora) were monitored using dual culture method at room temperature (30°C) and 4°C where growth inhibition was measured. All three types of carrier materials were good media for the formulation of all three Trichoderma species and when reisolated, the highest Colony Forming Units were observed in waste of polished rice formulations, at 4°C; [T. asperellum (6.23 log CFU/g), T. harzianum (5.92 log CFU/g) and T. virens (6.04 log CFU/g)] compared to other two carrier materials. Optimum temperature for the storage of formulated products was 4°C that maintained the viability and antagonistic activity of Trichoderma propagules for 130 days compared to the storage at room temperature. However, the values for CFUs of all three Trichoderma spp. in three carrier materials were slightly reduced after storage at 4°C which was not significant. The growth of all three post-harvest pathogens were inhibited by the three Trichoderma spp. and the inhibition values ranged from 36.5% – 83.6%. Growth inhibition values obtained at room temperature (30°C) and 4°C were not significantly different. Among the cost effective three carrier materials at two different temperatures, waste of polished rice at 4°C was found to be significantly effective in retaining the viability and antagonistic ability of the tested Trichoderma species. This may be due to the presence of optimum C contents (35%), C:N ratio (28.42) and pH (6.7) which enhance the production of sufficient propagules of three Trichoderma spp.Item Isolation and identification of different Trichoderma species and their effect on plant growth and development.(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Hewavitharana, N.; Kannangara, S.D.P.; Senanayake, R.A.S.P.Trichoderma spp. are fast growing fungi, widely used as bio-control agents for controlling soil borne diseases of plants as well as growth promoters. They are preferred in this aspect due to their ability to enhance growth and development of the plant crop productivity, resistance to abiotic stresses, and uptake and use of nutrients. The present investigation was carried out to isolate different fast growing and efficient Trichoderma spp. from soil and decomposing plant litter materials collected from Sinharaja rain forest and surrounding areas, and to assess their effect on the growth and development of selected crop plants. Using serial dilution spread plate method, several fungal spp. were isolated from the collected samples on to PDA plates. Colony morphology and microscopic features of sporulating structures were compared among the Trichoderma isolates. The growth rate of each Trichoderma isolate on PDA plates were studied. Fast growing Trichoderma spp. were confirmed to species level at the Genentech institute following PCR and sequencing. Selected Trichoderma spp. were mass produced separately, in 250 g of parboiled rice, the selected carrier material. Two inoculum bags (250 g ×2) of Trichoderma spp. were incorporated in to 100 Kg of prepared organic potting media (2:1:1:1 ratio of coir dust, Panicum maximum, Tithonia diversifolia and Mikania scandans) and covered with black polythene for 14 days. Effect of five Trichoderma spp. amended with the selected potting media were evaluated using Basella alba and Amaranthus viridis by measuring several growth parameters 45 days after seeding. The above pot experiments were carried out using a Completely Randomized Design with five replicates of each treatment including controls without Trichoderma amendments. Data obtained were analyzed by one-way ANOVA using MINITAB version 16. Twelve Trichoderma isolates were identified up to generic level using morphological and microscopic characteristics. Among them five Trichoderma isolates were identified as fast growing species based on their growth rates. Following molecular characterization, identities of these five Trichoderma spp. were confirmed as T. viride, T. asperellum, T. virens, T. longibrachiatum and T. harzianum. As per the results obtained for growth and development of B. alba and A. viridis, no significant differences were observed among the five Trichoderma spp. tested. However, B. alba and A. viridis treated with Trichoderma spp. showed significantly higher growth rates along with high foliage quality (disease free) compared to the controls. The highest growth performance of B. alba; (plant height: 16.3 cm, leaf area: 8.5 cm2, number of leaves: 16, fresh weight: 32.3 g and dry weight: 1.8 g) and A. viridis; (plant height: 23.6 cm, leaf area: 10.5 cm2, number of leaves: 11, fresh weight: 8.4 g and dry weight: 1.2 g) were shown in T. asperellum inoculated potting media compared to the potting media amended with other Trichoderma species. Based on the findings of present investigation all five Trichoderma incorporated potting media could be recommended for growing leafy vegetables which are suitable for urban agriculture and home gardening due to cost effectiveness and environment friendly nature.Item Nutrient leaching of selected invasive plant materials.(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Ranasinghe, E.H.A.A.; Jayasekera, L.R.; Kannangara, S.D.P.; Ratnayake, R.M.C.S.Thithonia diversifolia, Sphagneticola trilobata, Mikania scandens, Lantana camara, Chromolaena odorata, Panicum maximum and Mimosa pigra are fast growing invasive plants in Sri Lanka. In this study, the nutrient release potential and the weight loss dynamics during leaching of the above weeds were investigated with a view of utilizing them as sources of organic liquid fertilizers. Fresh leaves and immature shoots of the selected plant species were collected from Gampaha area. Samples were washed twice with distilled water and oven dried at 80 oC to a constant weight. For each species, thirty-six dried- leaves and immature shoots samples of 5 g were placed into 0.18 x 0.18 m2 single layer nylon mesh bags with 2 mm mesh size and submerged separately in 1 L of distilled water in plastic containers at the room temperature with three replicates each. Mesh bags without leaves and shoots submerged in distilled water were used as the control. Three mesh bags of each plant species were randomly collected at weekly intervals for a period of three months and the weight loss of plant material after drying in an oven at 80 oC to a constant weight, electrical conductivity and pH of the leachates were determined over time. At the end of the leaching experiment, nutrient contents of the leachates were determined using the standard methods. Results revealed that mass loss was significantly higher (p< 0.05) for M. scandens (97 %) followed by T. diversifolia (95.8 %) and the lowest for P. maximum (63.7 %). The highest pH and electrical conductivity were observed in L. camara (7.86±0.06) and M. scandens (2139±4.7 μS cm-I) respectively, and the lowest in P. maximum (7.40±0.02, 877±7.6 μS cm-1). Nutrient contents of the leachates of T. diversifolia; (N 160.4±2.1 mg/L, P 8.0±0.5 mg/L, K 349.0±3.0 mg/L), M. scandens; (N 142.8±3.0 mg/L, P 11.1±1.6 mg/L, K 464.3±9.0 mg/L) and C. odorata; (N 190.0±10.0 mg/L, P 9.5±1.5 mg/L, K 338.7±2.5 mg/L) were significantly higher than those of P. maximum (N 71±3.6 mg/L, P 8.3±1.2 mg/L, K 54.0±4.6 mg/L) suggesting that they could be effectively utilized as nutrient-rich sources to formulate environmental friendly organic liquid fertilizers.