RRI Publications
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Item A rapid minipreparation method for DNA extraction from Hevea leaf tissue(Rubber Research Institute. Agalawatte, 1996) Herath, S.; Attanayaka, D.P.S.T.G.; Karunanayake, E.H.Use of DNA markers in plant breeding is increasingly becoming popular. A basic requirement in using this technique in plant breeding is the availability of a simple inexpensive method for the isolation of plant DNA from large populations. Here we describe a rapid method of DNA isolation from Hevea leaf tissue. DNA yields obtained by this method were comparable with the yields of the other available methods. The quality of the DNA was tested by digesting with several restriction enzymes and was found to be of adequate purity. Southern blot analysis of this DNA showed its suitability for RFLP analysis of Hevea.Item Seed production of clones PB 86, RRIC 100 and RRIC 121 in three rubber growing areas of Sri Lanka(Rubber Research Institute. Agalawatta, 1997) Seneviratne, P.; Nugawela, A.; Amaratunge, K.A.G.B.; Karunasena, R.P.; Wilbert, S.The rubber seed production in wet rubber growing areas in Sri Lanka has gone to very low levels in the recent past affecting the culling process that should be adopted in establishing rootstock nurseries.From the three rubber growing areas studied satisfacton seed production irrespective of the clone was observed only in Kegalle region.Regional differences may be due to direct or influences of the climate and weather during flowering and pod set. Clonal differences seems to be existing in regions where climate or the weather is favourable for spread of diseases.Further RRIC 100 being a resistant clone for oidum and phytopthora.produced a higher percemage of good quality seeds compared with the other two clones.PB 86 and RRIC 121 which have below average tolerance to these two diseases.However currently country as a whole produces enough seeds to fulfill country's annual seed requirement for the production of rootstocks provided the seeds are collected and transported without delayItem A study of some of the properties of blends of polypropylene and chemical incorporated granular natural rubber(Rubber Research Institute. Agalawatta, 1994) De Silva, K.G.K.; Ranjith, S.L.G.; Warnapura, S.S.Thermoplastic elastormers of plastics natural rubber (TPNR) are generally produced by blending plastics with natural rubber (in bale form) using traditional banbury type internal mixers plastics extruders. This involves high energy consumption also high capital costs of both rubber plastics processing machinery. The production of Thermoplastic elastomers on a continuous basis using extruder blenders has been less applicaple to TPNR blends because natural rubber is not readily or widely available in the required granular form in natural rubber consuming countries. The manufacture of different types of granular rubber in our laboratories has not only made possible the blending of thermoplastics with natural rubber on a continuous basis but also paved the way for producing TPNR blends with improved properties. In this publication the production of different types of granular rubber, the processing characteristics of various compositions of polypropylene natural rubber blends the end product performance of these blends the end product performance of these blends at different temperatures are discussed.Item Role of rock phosphates in the nutrition of immature and mature Hevea(Rubber Research Institute. Agalawatta, 1994) Dissanayake, D.M.A.P. othersCommercially available Eppawela rock phosphate (ERP) was evaluated as a source of P for young rubber plants throughout the period of immaturity. The effects of rock phosphate on yield nutrient composition of leaves soil were also studied on mature rubber.The efficiency of ERP in relation to growth of young plants was similar to that of Imported Rock Phosphate (IRP) Triple Super Phosphate (TSP) when used in soils with a P status less than 37.00 Kg of soils with a soil pH range of 3.6 to 4.2. In these situations it appears that the currently recommended rate of P is unlikely to be sufficient to meet the plant P demand.It is therefore possible to use ERP as a source of P for immature rubber plants growing in areas which are considered low in P for rubber.In contrast, application of rock phosphates did not influence the productivity of the mature rubber tree.plants were able to maintain adequate levels of P in leaves even under no P fertilizer conditions suggesting the effect of residual P in soil that received IRP during the immature phase.Item Factors affecting the budgrafting success and the scion growth of young budding of Hevea(Rubber Research Institute. Agalawatta, 1994) Seneviratne, P.; Nugawela, A.; Samarakoon, S.M.A.The size of the bag in which the stock plant is grown seems to have an effect on the growth of the seedling; from the three bag sizes tested, ie 15 x33 cm, 18 x 38 cm, 23 x 45 cm, it was found that the diameter the number of leaf whorls of the seedling increased with the increase of the bag size.Though the differences are not statistically significant, the budding success too increased in the same pattern. There was no effect of the bag size on the growth of the scion. The two types of buds, axillary scale, showed no difference either on bud grafting success or on the growth of the scion. The growth stage of the top most leaf whorl of the stock plant, either mature or immature, had no effect on the peeling qualities budgrafting success though a little higher budgrafting success was seen when the top flush was immature. There was an effect of the snag, on the scion growth; when the snag was shorter the sprouting took place earlier but, the scion growth was slightly poor as was evident by the diameter the length of the scion. Long snags delayed the sprouting , but the scion growth was better. The best growth of the scion was obtained when the snag was long with a few leaves attached to it.Item Penta chloro phenol - effective and economical fungicide for the management of white root disease caused by Rigidoporus lignosus in Sri Lanka(Rubber Research Institute of Sri Lanka. Agalawatte, 1995) Jayasinghe, C.K.; Jayasuriya, K.E.; Fernando, T.H.P.S.Item The problem of surface sterilization of shoot materials of Hevea(Rubber Research Institute of Sri Lanka. Agalawatte, 1995) Seneviratne, P.; Flegmann, A.W.; Wijesekera, G.A.S.Item The role of snag on the growth of scion in bud grafted plants of Hevea with special reference to young buddings(Rubber Research Institute of Sri Lanka. Agalawatte, 1995) Senaviratne, P.; Nugawela, A.; Samarakoon, S.M.A.Item In vitro antagonism caused by some species of fungi on Rigidoporus lignosus(Rubber Research Institute. Agalawatte, 1996) Jayasuriya, K.E.; Deacon, J.W.; Fernando, T.H.P.S.Fungi potentially antagonistic to rigidoporus lignosus were isolated from a) by placing soil samples on agar plates previously colonized by R.lignosus, or on trichoderma selective agar and b) from basidiomycete fruit bodies in rubber plantations.Modes of action of potential antagonists against R. lignosus were evaluated by in vitro methods viz: production of volatile or non-volatile inhibitory compounds and ability to overgrow colonies of R. lignosus an agar. Some trichoderma spp. were strongly antagonistic to R. lignosus in most of the tests. T. longibrachiatum (isolate DZE10) completely inhibited R. lignosus an agar by producing volatile inhibitory metabolites. Trametes sp. producing volatile inhibitory metabolites. Trametes sp. (isolates ISO16 KIR8) antagonized R. lignosus on dual membered plates.Item Root system of Hevea with special reference to micropropagated plants(Rubber Research Institute of Sri Lanka. Agalawatte, 1995) Seneviratne, P.; Wijesekara, G.A.S.; De Soysa, G.M.