Volume 13 - Issue 1

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    Identification of artificial groundwater recharge zones in Vavuniya district using remote sensing and GIS
    (Faculty of Agriculture, Eastern University Sri Lanka, 2019) R. Ramya, A. Nanthakumaran; I. P. Senanayake
    Ground water is a major source for domestic and irrigation purposes in Sri Lanka and plays a crucial role to human life and economic activity. With rapid growth of population and urbanization water requirements for drinking and other purposes are dramatically increasing. The over extraction and unplanned development of ground water resources have led to considerable depletion of water resources. Artificial recharge is the practice of increasing the amount of water that enters groundwater reservoir by artificial means of planned human activity. The distribution and recharge of groundwater in the country varies significantly depending on geology, rainfall and geomorphology. The objective of this study was to identify artificial recharge potential. This study was conducted in Vavuniya district since the water shortage was observed over the years. Geomorphology, geology, soil, land use and stream data along with Landsat 7 ETM+ and DEM images were utilized to develop the relevant thematic layers such as geology, geomorphology, soil, slope, lineament density, land use and stream density by integrating GIS (Geographic Information System) and image processing techniques. The resultant thematic layers were utilized to prepare the groundwater recharge maps of the area through a weighted overlay method in a GIS platform. The results revealed that the artificial recharge was high in Southern part of the study area. Further the area has significant groundwater recharge zones which can be utilized for a sustainable ground water management system.
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    Isolation and characterization of potential probiotic lactic acid bacteria isolated from cow milk and milk products
    (Faculty of Agriculture, Eastern University Sri Lanka, 2019) J. Vanniyasingam, R. Kapilan; S. Vasantharuba
    Probiotics refer to the living microorganisms that exhibit beneficial effect on the health of human by the intestinal microbial balance. Most widely used probiotics are lactic acid bacterial group found in milk and milk products. This study was aimed to characterize the probiotic properties of lactic acid bacterial (LAB) strains isolated from cheddar cheese, yoghurt and cow milk. Bacterial strains naturally grown in milk, cheddar cheese and yoghurt were isolated using De Mann Rogosa Sharpe (MRS) agar medium and incubated at 37oC for 48 h separately under aerobic and anaerobic conditions. There were eight strains grown under aerobic conditions and they were isolated, purified and characterization was done based on the morphological and biochemical analysis such as gram staining, catalase test and motility test. All the eight isolates were either rod or cocci shaped, gram positive, catalase negative, non-motile and non-spore formers. These eight isolated strains were identified as lactic acid bacteria. When screening of the 8 isolates was done to determine their antimicrobial activities against five human pathogenic strains such as E.coli, Klebsiella pneumoniae, Pseudomonas eaeruginosa, Salmonella sp and Staphylococcus aureus, three isolates (M6, C1 and Y1) showed wide spectrum antimicrobial activity. To determine the probiotic properties of these three isolates, different tests such as tolerance to acid, NaCl and bile, lactose utilization and antibiotic resistance were done. Though all the three isolates showed resistance to stomach pH (pH 3.0), the strain C1 showed significantly higher tolerance to stomach pH than the other strains. Though the three isolates grew well in the presence of NaCl and 0.3% bile, the isolate M6 showed significantly higher growth with NaCl and 0.3% bile than the others. Even though all the three isolates had the capacity of utilizing lactose, the isolate M6 showed prominent colour change in the lactose utilization test than the other two strains. When antibiotic susceptibility of the isolated LABs were evaluated using four antibiotics such as Ampicillin, Streptomycin, Bacitracin and Gentamycin, the strain M6 showed significantly higher resistance to Ampicillin and Bacitracin but sensitive to Streptomycin and Gentamycin. Other two isolates (C1 and Y1) were sensitive to all the four antibiotics used. Based on the antibiotic sensitivity tests and the analysis of probiotic properties, the isolated strain M6 was confirmed as a potential probiotic lactic acid bacterium. This strain was identified as Lactobacillus plantarum strain CIP 103151 through16S rDNA sequence analysis.
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    Effect of different concentrations of selected liquid fertilizers on acclimatization of weakly grown in vitro plantlets of Anthurium andraeanum L.var. ‘Lalani’
    (Faculty of Agriculture, Eastern University Sri Lanka, 2019) P. G. S. A. Kumarasinghe, Y. M. U. Anjali; S. Sutharsan, S. Srikrishnah
    An experiment was conducted to evaluate the effects of different concentrations of selected liquid fertilizers on the acclimatization of weakly grown in vitro Anthurium plantlets at the Royal Botanic Gardens, Peradeniya from June to August 2018. Treatments were defined as T1 (1.11g/L Albert’s solution applied as 1st application and 0.55g/L Albert’s solution applied as 2nd application), T2 (1.11g/L Albert’s solution applied in both application), T3 (0.55g/L Albert’s solution applied in both application), T4 (0.625g/L N:P:K (30:10:10) solution applied as 1st application and 0.3125g/L N:P:K (30:10:10) solution applied as 2nd application), T5 (0.625g/L N:P:K (30:10:10) solution applied in both application), T6 (0.3125g/L N:P:K (30:10:10) solution applied in both application), T7 (1.333g/L N:P:K (20:20:20) solution applied as 1st application and 0.666g/L N:P:K (20:20:20) solution applied as 2nd application), T8 (1.333g/L N:P:K (20:20:20) solution applied in both application), T9 (0.666g/L N:P:K (20:20:20) solution applied in both application), T10 – Sterile water (control). First application was done at the time of transplanting and second application was done two weeks after transplanting. Experimental design was Completely Randomized Design with ten replicates for each treatment. Other agronomic practices were followed uniformly for all the treatments. Plant height, Number of roots, Number of leaves and Length of petiole were measured at four weeks after transplanting. Analysis of Variance was performed to determine significant difference among treatments (p < 0.05). Results revealed that better growth performances viz. increase in plant height, leaf number and roots number and length of petiole were observed in plantlets grown exposed to T2. This may be due to optimum amount of nutrients received by the plantlets at T2. Thus it may be concluded that application of Albert’s solution (1.11g/L in two applications at two weeks interval) provide optimum amount of nutrients for acclimatization of weak in vitro Anthurium plantlets.
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    Efficacy of Bio-Intensive integrated pest management against brinjal shoot and fruit borer Leucinides orbonalis (Lepidoptera: Crambidae)
    (Faculty of Agriculture, Eastern University Sri Lanka, 2019) R. F. Niranjana, M. Devi; R. P. Sridhar
    Brinjal (Solanum melongena) plays a vital role in the food of South-Asian people, thus the production of brinjal in these countries is quite high. However the production of brinjal does not satisfy the whole demand of people owing to the severe infestation by L. orbonalis. In order to get maximum yield from the cultivation farmers rely on over and indiscriminate use of chemical insecticides. Due to the side effects of over and indiscriminate use of toxic insecticides, now the trend moves towards Bio-intensive Integrated Pest Management (BIPM). The present study conducted to find the efficacy of BIPM over farmer’s practices and untreated control in controlling the L. orbonalis. The study evidenced the superiority of BIPM in all aspects viz., lesser shoot infestation (15.82 percent), greatest yield (17,170.22 kg/ha) and higher natural enemies activities (5.25 no./10plants), which was equivalent to untreated control. Besides the treatment BIPM proved its efficacy over farmer’s practice and untreated control especially with high percent increase of yield (63.90%), percent reduction of shoot (64.01%) and fruit infestation (80.58%), and less percent reduction of natural enemies’ population (8.70%). Apart from this the benefit cost ratio (BCR) ranked in the order of superiority as BIPM module (1:5.75), which was greater than the farmer practice (1:4.96) on brinjal.
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    Exploring the efficacy of silicon supplementation on control of rice grain discoloration disease
    (Faculty of Agriculture, Eastern University Sri Lanka, 2019) M. F. F. Nasla, K. Prasannath; K. R. D. Gunapala
    Rice is the most important cereal crop in Sri Lanka. Grain discoloration is an emerging disease complex, reducing grain quality of rice crop. Grain discoloration control is, however, mainly focused on fungicide; their use is limited due to perceived environmental problem and health concern. Silicon (Si) application is known as encouraging eco-friendly alternative to fungicide. Foliar applications of Si-based formulations were evaluated to examine their effect on reducing grain discoloration disease. Field experiments were conducted at Rice Research and Development Institute (RRDI), Batalagoda from May to September 2017. After planting, Si was applied as solution at the rate of 1 mL/L at tillering and early flowering stage. Fungicide and control (sterilized water) were applied as treatments at early flowering stage. Treatments were arranged in a randomized complete block design with three replications. Data on plant height, total number of tillers per plant, chlorophyll content, yield, incidence of plant infection and percentage of grain discoloration were recorded. Laboratory study was carried out to isolate and identify the grain discoloration causing pathogens from the infected seeds by using potato dextrose agar plate method. Results revealed that incidence of plant infection and grain discoloration percentage were reduced by foliar application of silicon supplements as same as fungicide application. Among the Si-based formulations tested, Gainexa UPL gave the best result in controlling grain discoloration in rice. These silicon supplements could be used as alternatives to synthetic fungicide and could reduce the amount of fungicide needed during rice crop cultivation. Curvularia lunata and Curvularia pallescence were identified as the causal organisms of rice grain discoloration disease in the study area.