Browsing by Author "Perera, L."

Now showing 1 - 11 of 11
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    Coconut
    (2017) Perera, L.; Manimekalai, R.; Sudarsono, S.; Maskromo, I.; lestari, P.
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    Improvement Of Seedling Quality In Polybags Through Manilpulation Of Pottiing Media.
    (1996) Perera, L.; Peries, R.R.A.; Jayatileke, R.
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    In Vitro Characterization of Indigeneous Coconut Varieties (Cocos nucifera L.) of Sri Lanka for Water Stress Tolerance
    (2012) Fernando, S.C.; Santha, E.S.; Perera, S.A.C.N.; Dissanayake, H.D.M.A.C.; Meegahakumbura, M.G.M.K.; Perera, L.
    Coconuts show a remarkable yield drop due to long dry periods caused by global climatic changes.Thus, breeding for drought tolerance has become a priority in coconut breeding in Sri Lanka.Five coconut varieties indigenous to Sri Lanka, namely Ran thembili,Gon thembili, Porapol, Bodiri and Red dwarf were screened for their drought tolerance potential in vitro. Mature zygotic embryos collected from self pollinated nuts of each variety were germinated and developed into plants with one photosynthetic leaf in Y3 medium.Water stress condition was induced by application of Polyethylene Glycol(PEG) into the culture medium.The level of PEG in culture medium was gradually increased from 2% to 7% until the plants showed water stress symptoms in leaves; yellowing and necrosis.More than 75% of zygotic embryos of all tested coconut varieties successfully gemJinated in vitro and developed into plants. Plants of all tested coconut varieties survived water stress caused by 4% to 6% PEG and the percentages of plant survival at different levels of PEG varied among different coconut varieties. Variety Ran thembili showed the highest survival rate(27%) at 6% PEG and overall best plant growth perfomJances at 4% PEG among the five coconut varieties tested. Red dwarf showed the lowest survival rate at 4% to 6% PEG indicating its susceptibility to water stress. Among the coconut varieties tested, zygotic embryos of Ran thembili showed the highest drought tolerance potential.
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    Levels and distribution of genetic diversity of coconut (Cocos nucifera L., var. Typica form typica) from Sri Lanka assessed by microsatellite markers
    (2001) Perera, L.; Russell, J.R.; Provan, J.; Powell, W.
    The coconut variety Typica, formtypica, commonly known as Sri Lanka tall coconuts is the most widely exploited and grown variety in Sri Lanka. Under the coconut bio-diversity conservation programme, several Typica populations have been collected by island-wide surveys and planted ex situ. Thirty-three coconut populations were subjected to microsatellite assay with eight coconut-specific microsatellite primer pairs in order to study the levels and distribution of genetic variation of the collected materials for formulating future collection strategies and selecting parents for the breeding programme. A total of 56 alleles were detected ranging from 3 to 10 alleles per primer pair with an average of 7 alleles per locus. Overall a very high level of genetic diversity was detected (0.999) for all the populations studied ranging from 0.526 for population Debarayaya to 0.683 for population Dickwella. Only four introduced coconut populations, i.e. Clovis, Margeret, Dickwella, Mirishena and an embryo-cultured population were clearly separated from the resulting dendrogram. A very high level of within population variation (99%) accounted for native populations suggests a common history and a restricted genetic base for native Sri Lankan tall coconuts. Categorization of alleles into different classes according to their frequency and distribution confirmed the results of the dedrogram and concluded the adequacy of single large collection from the entire target area to represent the total genetic diversity in Sri Lanka. This study discusses useful information regarding conservation and breeding of coconut in Sri Lanka.
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    Sri Lanka Brown Dwarf (SLBD) coconuts: a potential coconut variety for future breeding
    (2002) Perera, L.; Perles, R.R.A.; Padmasiri, M.H.L.
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    Use of SSR Markers to Determine the anther-derived Homozygous Lines in Coconut
    (Springer-Verlag, 2008-01) Perera, P.I.P.; Perera, L.; Hocher, V.; Verdeil, J.L.; Yakandawala, D.M.D.; Weerakoon, L.K.
    Anther culture was used to obtain dihaploid (DH) coconut plants and their ploidy level was determined by flow cytometric analysis. Simple sequence repeat (SSR) marker analysis was conducted to identify the homozygous diploid individuals. Ploidy analysis showed that 50% of the tested plantlets were haploid and 50% were diploid. Polymorphic fragments of the mother palm and their segregation patterns in anther-derived plantlets were used to determine the origin of the diploid plantlets. Using a diagnostic SSR marker (CNZ43), all the diploid plantlets tested were identified as being derived from microspores (i.e. were homozygous) and were thus candidates for use in coconut breeding programs.
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    Use of SSR markers to determine the anther-derived homozygous lines in coconut
    (2008) Perera, P.I.P.; Verdeil, J.L.; Hocher, V.; Perera, L.; Yakandawala, D.M.D.; Weerakoon, L.K.
    Anther culture was used to obtain dihaploid (DH) coconut plants and their ploidy level was determined by flow cytometric analysis. Simple sequence repeat (SSR) marker analysis was conducted to identify the homozygous diploid individuals. Ploidy analysis showed that 50% of the tested plantlets were haploid and 50% were diploid. Polymorphic fragments of the mother palm and their segregation patterns in anther-derived plantlets were used to determine the origin of the diploid plantlets. Using a diagnostic SSR marker (CNZ43), all the diploid plantlets tested were identified as being derived from microspores (i.e. were homozygous) and were thus candidates for use in coconut breeding programs