COCOS - Journal of the Coconut Research Institute of Sri Lanka
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Item Clonal propagation of coconut:improved culture conditions for rhyzogenesis(Coconut Research Institute of Sri Lanka. Lunuwila, 1994-95) Fernando, S.C.; Gamage, C.K.Emphasis has recently been placed on improving culture conditions at the rooting stage of the coconut (cocos nucifera L) cloning procedure. In these experiments shoots for rooting were obtained by culturing shoot apices.Item Effect of N,K, CI on photosynthesis and water relations of open pollinated tall (typica) coconut seedlings(CRI, 1991-93) Jayasekara, C.; Mudallige, R.G.; Ranasinghe, C.S.Item Effect of planting density on the yield of coconut(Coconut Research Institute. Lunuwila, 1996) Fernando, W.M.U.; Bandaranayake, C.K.An analyses is presented of the yield components of coconut established under densities varying from 128 palms/ha to 239 palms/ha from a spacing trial conducted by the Coconut Research Institute. Analysis of yield data during 1976-1980 from 24 palms from 4 replicates analysed for each density treatment revealed significant differences in nuts/palm and copra/palm for the densities tested. The nuts/palm decreased with increasing density but the yield/ha, maximised at a density of 171 palms/ha and decreased beyond 171. Significant differnces were absent inyield of copra/nut for the densities tested. The differences in copra/palm were due to the effect of nut number/palm. At a densityof 179 palms/ha, copra/ha maximised to 2260 kg and decreased beyond 179. The results of the present analysis indicate that a density ranging from 171-179 palms per hectare is the optimum for planting coconut in dry-intermediate zone where the study was conducted.Item Photosynthetic characteristics and productivity of the coconut palm(Coconut Research Institute. Lunuwila, 1996) Jayasekera, C.; Nainayake, N.P.A.D.; Jayasekera, K.S.Among the tree crops in the tropics the coconut palm occupies an important position as a food, oil, and fibre crop. Productivity of crop species depends on the combined effect of their genetic constituion, climate, nutrition and other biotic factors. To increase the productivityof coconut palm it is necessary to have a basic understanding of physiological processes such as assimilation of carbon and growth in relation to climatic factors. In-situ photosynthetic measurement of coconut seedlings using Li-COR 6500 portable photosynthesis system revealed that their maximum photosynthetic capacity is attained at photosynthetic photon flux densities (PPED) ranging from 1400-1700 moles photons m-2 s-1. The rate of apparent photosynthesis (A) of the coconut palm varies between 2-15 m mol CO2 m-2S-1 depending on leaf age, nutritional status and climatic factors. The rate of leaf respiration was closely similar in young and older leaves ranging from - 2 to 1 m mol CO2m-2S-1. The measured light-use efficiency of the coconut palm was found to be 1.2 g MJ-1 and the conversion efficiency of solar energy was approximately 2.4 per cent. Water deficit is the major constraint causing wide fluctuations in photosynthesis. due to height of trees, the leaves in the canopy are exposed to high wind velocity as well as water and thermal stressess. As a result, under soil water defict conditions coconut palm reduce excessive water loss and gaseous echange by mid-day closure of stomata and maintain stomatal conductance at a lower level. However, the rate of apparent photosynthesis and the ratio of intercellular to ambient partial pressure of CO2 (Pi/Pa) are not decreased proportionately with the stomatal conductance.Item Boron deficiency in young coconut (Cocos nucifera L.) in Sri Lanka:symptoms and corrective measures(CRI, 1988) Jayasekara, K.S.; Loganathan, P.Item Population dynamics of the coconut caterpillar, opisina arenosella walker (Lepidoptera:Xyloryctidae), in Sri Lanka(CRI, 1989) Perera, P.A.C.R.; Hassell, M.P.; Godfray, H.C.J.Item Some studies on the use of Metarhizium anisopliae (Metsch.) Sor. for the control of Oryctes rhinoceros in Sri Lanka(Coconut Research Institute of Sri Lanka. Lunuwila, 1994-95) Fernando, L.C.P.; Kanagaratnam, P.; Narangoda, N.K.Black beetle, oryctes rhinocers L. larvae and adults were inoculated in the laboratory with three isolates of the fungus Metarhizium anisopliae (Metsch.) Sor, to screen their virulence against black beetle. ALl the isolates caused 100 per cent mortality of larvae and adults when treated with suspensions of 10(7) conidia/ml. Comparatively the local isolate caused a slow death rate in larvae and adults than the other isolates. Fifty grams of the maize inoculum per 0.008 m2 of breeding medium were sufficient to cause 100 per cent death rate of larvae. In the field, the fungus was capable of disseminating at least 10 m and the impregenation boxes (infection foci) were attractive to black beetle. It is suggested that M.anisopilae could be used as an effective bio-control agent in the intergrated management of black beetle.Item On some hyperparasites of opisina arenosella the black-headed caterpillar pest of coconut in Malabar, India(CRI. Lunuwila, 1985) Ghosh, S.M.; Abdurahiman, U.C.Item On the biology of pediobius imbreus (Hymenoptera:eulophidae), a hyperparasite of opisina arenosella, the black-headed caterpillar of coconut(CRI, 1988) Ghosh, S.M.; Abdurahiman, U.C.Item Metroglyph analysis in coconut (Cocos nucifera L.)(CRI, 1987) Raveendra, T.S.; Ramanathan, T.; Nallathambi, G.; Vijayaraghavan, H.