4.Journals Published in Sri Lanka
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Item South American leaf blight - likelyhood behaviour in Sri Lanka and strategies in management(Rubber Research Institute of Sri Lanka. Agalawatta, 1992) Jayasinghe, C.K.Item Changing scene of the disease scenario of the rubber tree in Sri Lanka. history and current status(Rubber Research Institute of Sri Lanka. Agalawatta, 2009) Jayasinghe, C.K.Item Effect of different levels of supplemental nitrogen on CO2 assimilation rates and productivity of Pueraria phaseoloides (Roxb) Benth and Desmodium ovalipolium (prain) wall. ex ridely grown in agalawatta series soil(Rubber Research Institute. Agalawatte, 1985) Nugawela, A.; Jayasinghe, C.K.; Aluthhewage, R.; Wettasinghe, S.Plant dry matter production is linked to CO2 assimilation rates, respiratory losses and total leaf area. Experiments were undertaken to determine the effect of different levels of supplimental nitrogen given to legume cover crops, on their CO2 assimilation rates and productivity. They were found to be highest for Pueraria phaseoloides and Desmodium ovaliforlium when given around 140 and 35 ppm of supplimental nitrogen. Reciprocal of specific leaf area and laef nitrogen content were also determined and they showed a positive linear relationship with supplemental nitrogen levels. How nitrogen could a influence the CO2 assimilation rates of cover crops studies are discussed.Item Nodulation nitrogenase activity and major nutrient constituents of common cover crop legumes during early growth(Rubber Research Institute. Agalawatta, 1989) Jayasinghe, C.K.; Parker, C.A.; Kulasooriya, S.A.Item Seasonal variations in nodule activity of Pueraria phaseoloides (Roxb) Benth(Rubber Research Institute. Agalawatta, 1990) Jayasinghe, C.K.; Parker, C.A.; Kulasooriya, S.A.The age of Pueraria phaseoloides plants had a marked effect upon the rate of acetylene reduction in their nodules. Acetylene reduction activity increased with the age of the plant and maximum efficiency of nodule activity was detected 60 days after sowing, followed by a marked decline on the 120th day and continued at a low rate. Dry matter yield and total nitrogen in plants was more or less constant thrugh out the assay period.Item Effect of combined nitrogen on nodule function of leguminous crops with special reference to tropical soils(Rubber Research Institute. Agalawatta, 1991) Jayasinghe, C.K.The effect of combined nitrogen on nitrogen fixation has been discussed by several investigators and from their findings it could be concluded that inorganic nitrogen may have either stimulatory, neutral of negative effect on nitrogen fixation depending on the type of legome and soil condition. It was reported in some instances that low levels of combined nitrogen especially when applied as a "Starter" fertilizer at germination, stimulates plant growth and enhances nodule mass and nitrogen fixation. On the other hand when most of the legumes are grown in soil high in available nitrogen, the nitrogen fixation rate is severely affected. This phenomenon may become more critical when legumes are grown as cover crops where non legume counterpart is fertilized with nitrogenous fertilizer. The degree of inhibition appears to vary with sevaral factors vis, concentration of combined nitrogen, host species, cultivar, strain of root nodule bacteria, rate of inculation, light intensity and temperature. However, the most critical factor is the concentration of combined nitrogen and it has been shown that very low concentrations such as 240 ppm N reducedItem Effect of combined nitrogen on growth and nodule function or Pueraria phaseoloides(Rubber Research Institute. Agalawatta, 1991) Jayasinghe, C.K.; Wettasinghe, D.S.Nodulation and nitrogen fixation rates of most of the legumes are reported to be severely affected when they are grown in soils high in available nitrogen. Furthermore, this phenomenon may become more critical when legumes are grown in multiple cropping systems like Pueraria phaseoloides in rubber plantatons where ono legume counterpart is fertilized with nitrogenous fertilizer. Results of experiments conducted in seeding agar to find the effect of nitrogen on growth and nodule function of P. phaseoloides showed that nodulation of P. phaphaeoloides was inhibited at a concentration between 24.4 and 44.8 ppm nitrogenItem Susceptibility of Hevea clones to black stripe disease(Rubber Research Institute. Agalawatta, 1997) Jayasinghe, C.K.; Wettasinghe, D.S.Bark rol or black stripe of Hevea brasiliensis caused by Phytophthora spp.is the only economically important disease of the tapping panel.Screening trials were carried out for three consecutive years at four different localities to evalute the inherent susceptibility of thirty three Hevea clones to black stripe disease.The results indicated that the clones commonly grown in the eastern hemisphere or proved to be potential genetic material for future use show a differential inherent susceptibility with RRIC 130 being the most susceptible.Among the other examined RRIC 119.RRIC 133.RRic 110,RRIC 112,RRIC 114,PB 86,RRIC 117,RRIM 600 and RRIC 132 were susceptible while BPM 24,RRIM 717,RRIC 116,PB 260,RRIC 121 and RRIC 100 were resistant.Item Susceptibility of different leaf stages of Hevea to Corynespora cassiicola(Rubber Research Institute. Agalawatta, 2010) Fernando, T.H.P.S.; Jayasinghe, C.K.; Wijesundera, R.L.C.; Siriwardena, D.Item Phytophthora epidemics - possibility of management using resistant clones(Rubber Research Institute of Sri Lanka. Agalawatte, 1996) Jayasinghe, C.K.; Jayaratne, A.H.R.