Journal of the Rubber Research Institute of Sri Lanka
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Item Effect of soil moisture on establishment success of different planting techniques in rubber(Rubber Research Institute. Agalawatta, 1993) Samarappuli, L.; Yogaratnam, N.; Hettiarachchi, R.Item Towards shorter immaturity and improved yields by mulching with rice straw(Rubber Research Institute. Agalawatta, 1992) Samarappuli, L.; Yogaratnam, N.; Samarappuli, P.; Mitrasena, U.In this study with immature Hevea brasiliensis, multing with paady straw around the base of the tree was found to be a better agronomic practice than growing leguminous cover crops such as Pueraria phaseoloides and Desmodium ovalifolium or allowing natural vegetation to grow in the inter-row area. Girthing had been much higher with mulching which resulted into reduction of the immature, unproductive period by approximately 18 and 12 month in comparison with naturals and creeping legumes respectively. In addition to early tapping, yield of latex was also higher during the early stages, increases in the region of 33perc. and 40perc. in comparison with creeping legumes and naturals respectively. The present value of the benefit achieved from mulching amount to Rs. 31,088/= per hectare of which Rs. 19,740/= is due to extra yield and the balance of Rs. 11,348/= is saving on inputs as a result of early maturity. Consequently, a net present value (NPV) of Rs. 7.8 million at national level can be achieved with the above practice at 50perc. level of adoptionItem Acclimatization of micropropagated plants of Hevea(Rubber Research Institute. Agalawatta, 1993) Seneviratne, P.; Wijesekera, G.A.S.; De Soysa, G.M.In vitro produced Hevea shoots were successfully acclimatized to outdoor conditions by controlling the ambient conditions, mainly the humidity. Shooots, longer than 5 cm and with some leaves attached performed better. Shoots without roots produced shoots soon after their transfer to soil and the root development and the acclimation succes was better than in the rooted shoots. Use of a concentrated auxin solution, to soak the bases of the shoots or to incoroperate into soil improved root induction. The growth of the aerial part and the root system of the micropropagated plants were comparable to those of embryo cultured plants, up to one year of growth, but the field performance is yet to be monitored.Item Performance of some RRIC 100 series clones under different soil moisture regimes(Rubber Research Institute. Agalawatta, 1992) Samarappuli, L.; Yogaratnam, N.; Hettiarachchi, R.Results obtained on the performance of recently developed RRIC 100 series clones when sujected to water deficit situations are presented in this paper. The plant diameter of RRIC 121 and RRIC 102 was found to be superior to other clones tested such as RRIC 100, RRIC 110 and PB 86 even at the very low soil moisture level of 10% available water. Similar results were recorded in relation to plan height, number of whorls and relative growth rates of clones RRIC 121 and 102 even under low soil moisture conditions. Data obtained also showed that clones RRIC 102 and 121 had the highest plant nitrogen and potassium contents. Moreover, even under very low soil moisture levels plant P content was greater in clones RRIC 121 and 102. Most of the data on growth are also consistat with the physiological parameters such as leaf water protential (LWP) relative water content (RWC), transpiration rate (TR) and leaf diffusive resistance (LDR). It was further noted that the LWP and RWC were highest while TR was lowest in clone RRIC 102. Moreover, the clone RRIC 102 had the highest LDR compared to other clones, confirming the ability of this clone in maintaining a higher water holding capacity under low soil moisture conditions.Item Feasibility of rubber (Hevea brasiliensis Muell.Arg.) cultivation in Eastern province of Sri Lanka with the peasant community(Rubber Research Institute. Agalawatta, 2010) Iqbal, S.M.M.; Rodrigo, V.H.L.; Karunathilake, P.K.W.Item Growth of young budding plants as affected by type and packing density of the potting media(Rubber Research Institute. Agalawatta, 2009) Dharmakeerthi, R.S.; Siriwardana, E.A.D.; Edirimanna, V.U.; Chandrasiri, J.A.S.Item Local knowledge in rubber (Hevea brasiliensis) farming systems in Sri Lanka. applications and constraints(Rubber Research Institute. Agalawatta, 2010) Senevirathna, A.M.W.K.; Pathirana, P.D.; Rodrigo, V.H.L.; Sinclair, F.L.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 Effect of different light regimes on above and below ground development of Hevea brasiliensis during early stage of growth(Rubber Research Institute. Agalawatta, 2009) Senevirathna, A.M.W.K.; Karunatillake, P.K.W.; Pathirana, P.D.; Rodrigo, V.H.L.Item Effect of potassium on growth, yield and mineral composition of young Hevea brasiliensis(Rubber Research Institute of Sri Lanka. Agalawatte, 1995) Iqbal, S.M.M.; Yogaratnam, N.