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Land suitability maps of Awissawella, Panadura-Horana, Aluthgama,Ambalangoda, Galle, Matara and Ambalantota 1" sheet areas,Coconut Research Institute, Lunuwila, Sri Lanka (in preparation)
No full textGenetic control of husked nut weight in coconut (Cocos nucifera)
Get PDFoai:cri.nsf.ac.lk:1/560The genetic control of husked nut weight in coconut (Cocos nucifera) was investigated using a full-diallel cross including eight parents. The parents were selected sample of palms which gave an annual mean yield of 23 kg of copra per palm with 713 gm of husked nut weight over five years. An average of five progenies per cross planted in a fully randomised designed were evaluated for five years. Husked nut weight of five nuts per palm was recorded at each pick. Analysis of variance of mean husked nut weight confirmed the presence of additive and non additive genetic variance to the total phenotypic variance was 0.45. Of the dominance components, directional dominance was non significant. Neither the presence of heterosis nor inbreeding depression was consistent among the selfed and crossed progenies elucidating the fact that not only crossing but selfing could also improve the trait, depending on the genetic constitution of the individual. Reciprocal differences were evident in the crosses suggesting the importance of the direction of cross
Evaluation of cation exchange resin method for determination ofexchangable bases and micro nutrients in low country soils of SriLanka
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Effect of coir dust mulching on weed incidence on pineapple intercropped under coconut in Sri Lanka
No full textPhotosynthetic characteristics and productivity of the coconut palm
Get PDFAmong 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
