Entity

Time filter

Source Type


Ng W.L.,Kyushu University | Ng W.L.,University Putra Malaysia | Onishi Y.,Kyushu University | Onishi Y.,Osaka University | And 8 more authors.
Conservation Genetics | Year: 2014

Members of the mangrove genus Rhizophora represent the most commonly occurring and highly valued species in the Indo-West Pacific region. However, to date, few studies have been directed towards the understanding of their genetic variation. The levels and patterns of genetic variation at chloroplast and nuclear gene regions were studied in R. apiculata, R. mucronata, and R. stylosa sampled from Southeast Asia and Japan. All three species were characterized by low intraspecific genetic variation and a deficiency of heterozygotes in populations within the region, consistent with findings in studies on other mangrove species. Rhizophora mucronata and R. stylosa were also found to be more closely related than any of them with R. apiculata. During the Last Glacial Maximum, sea levels dropped to 120 m below the current levels, exposing part of the Sunda Shelf that became a barrier that limited gene flow between marine species living in the Pacific and Indian Oceans. Today, the Malay Peninsula is thought to still serve as a barrier to gene flow between populations occurring on its coasts. The pattern of genetic differentiation of R. apiculata supports the hypothesis of the land barrier effect of the Malay Peninsula, but such patterns were not found in R. mucronata and R. stylosa. Our findings suggest that R. apiculata, R. mucronata, and R. stylosa have different demographic histories despite being closely related and having sympatric distributions today. Furthermore, all three species appear to have high levels of inbreeding due to limited pollen and propagule dispersal, and that both these factors contributed to population differentiation. © 2014, Springer Science+Business Media Dordrecht. Source


Ng W.L.,Kyushu University | Ng W.L.,University Putra Malaysia | Onishi Y.,Kyushu University | Onishi Y.,Osaka University | And 8 more authors.
Conservation Genetics | Year: 2014

Members of the mangrove genus Rhizophora represent the most commonly occurring and highly valued species in the Indo-West Pacific region. However, to date, few studies have been directed towards the understanding of their genetic variation. The levels and patterns of genetic variation at chloroplast and nuclear gene regions were studied in R. apiculata, R. mucronata, and R. stylosa sampled from Southeast Asia and Japan. All three species were characterized by low intraspecific genetic variation and a deficiency of heterozygotes in populations within the region, consistent with findings in studies on other mangrove species. Rhizophora mucronata and R. stylosa were also found to be more closely related than any of them with R. apiculata. During the Last Glacial Maximum, sea levels dropped to 120 m below the current levels, exposing part of the Sunda Shelf that became a barrier that limited gene flow between marine species living in the Pacific and Indian Oceans. Today, the Malay Peninsula is thought to still serve as a barrier to gene flow between populations occurring on its coasts. The pattern of genetic differentiation of R. apiculata supports the hypothesis of the land barrier effect of the Malay Peninsula, but such patterns were not found in R. mucronata and R. stylosa. Our findings suggest that R. apiculata, R. mucronata, and R. stylosa have different demographic histories despite being closely related and having sympatric distributions today. Furthermore, all three species appear to have high levels of inbreeding due to limited pollen and propagule dispersal, and that both these factors contributed to population differentiation. © 2014 Springer Science+Business Media Dordrecht. Source


Graudal L.,Copenhagen University | Graudal L.,International Center for Research in Agroforestry | Aravanopoulos F.,Aristotle University of Thessaloniki | Bennadji Z.,Instituto Nacional Of Investigacion Agropecuaria | And 6 more authors.
Forest Ecology and Management | Year: 2014

There is a general trend of biodiversity loss at global, regional, national and local levels. To monitor this trend, international policy processes have created a wealth of indicators over the last two decades. However, genetic diversity indicators are regrettably absent from comprehensive bio-monitoring schemes. Here, we provide a review and an assessment of the different attempts made to provide such indicators for tree genetic diversity from the global level down to the level of the management unit. So far, no generally accepted indicators have been provided as international standards, nor tested for their possible use in practice. We suggest that indicators for monitoring genetic diversity and dynamics should be based on ecological and demographic surrogates of adaptive diversity as well as genetic markers capable of identifying genetic erosion and gene flow. A comparison of past and present genecological distributions (patterns of genetic variation of key adaptive traits in the ecological space) of selected species is a realistic way of assessing the trend of intra-specific variation, and thus provides a state indicator of tree genetic diversity also able to reflect possible pressures threatening genetic diversity. Revealing benefits of genetic diversity related to ecosystem services is complex, but current trends in plantation performance offer the possibility of an indicator of benefit. Response indicators are generally much easier to define, because recognition and even quantification of, e.g., research, education, breeding, conservation, and regulation actions and programs are relatively straightforward. Only state indicators can reveal genetic patterns and processes, which are fundamental for maintaining genetic diversity. Indirect indicators of pressure, benefit, or response should therefore not be used independently of state indicators. A coherent set of indicators covering diversity-productivity-knowledge-management based on the genecological approach is proposed for application on appropriate groups of tree species in the wild and in cultivation worldwide. These indicators realistically reflect the state, trends and potentials of the world's tree genetic resources to support sustainable growth. The state of the genetic diversity will be based on trends in population distributions and diversity patterns for selected species. The productivity of the genetic resource of trees in current use will reflect the possible potential of mobilizing the resource further. Trends in knowledge will underpin the potential capacity for development of the resource and current management of the genetic resource itself will reveal how well we are actually doing and where improvements are required. © 2014 The Authors. Source


Pandey M.,Forest and Plant Conservation Research Office | Pandey M.,Texas Tech University | Changtragoon S.,Forest and Plant Conservation Research Office
American Journal of Botany | Year: 2012

Premise of the study: Microsatellite markers were isolated and characterized in a medicinal plant, Phyllanthus emblica, to study population genetics for designing an effective in situ and ex situ conservation of genetic resources of the species. Methods and Results: Six microsatellite markers were developed using an enrichment and magnetic separation protocol. They were characterized in two natural populations of P. emblica. Out of the six microsatellites, five showed polymorphism, with the number of alleles ranging from four to seven. Observed and expected heterozygosities ranged from 0.360 to 0.760 and 0.499 to 0.806, respectively. Conclusions: The five polymorphic microsatellite markers will be useful for studying the genetic structure, reproductive biology, and for identification of clones and provenances of this important medicinal plant. © 2012 Botanical Society of America. Source


Sthapit B.,Bioversity International | Vasudeva R.,University of Agricultural Sciences, Dharwad | Idris S.,Malaysian Agricultural Research and Development Institute MARDI | Changtragoon S.,Forest and Plant Conservation Research Office | And 4 more authors.
Acta Horticulturae | Year: 2015

South and Southeast Asia is the center of origin for many tropical fruit crops. This region is a prime habitat for in situ conservation of genetic diversity of longlived, largely out crossing wild/domesticated Tropical Fruit Tree (TFT) species. Wild TFT species in 36 project sites throughout India Indonesia, Malaysia and Thailand were examined with an objective of documenting species richness and understanding their local uses and potential value in plant breeding/ecosystem services. Multiple methods such as participatory rural appraisal, baseline survey, focus group discussion on traditional knowledge documentation, fruit diversity fairs, community fruit catalogues and key informant surveys of custodian farmers were carried out focusing on wild species of Mangifera, Garcinia, Nephelium and Citrus. For the genus Mangifera, highest number of wild species ('s') was recorded among the communities of Indonesia (11) and Malaysia (11), while it was 6 in Thailand and only one in India. Communities of Thailand also showed highest's' value for Garcinia (14), while it was 8 for Malaysian, 5 in Indian and 3 for Indonesian communities. For the genus Nephelium, 7 species were used in Malaysia, 5 in Indonesia and 5 in Thailand. However, communities of India showed higher species richness of Citrus (8) and it was 2 for communities of Thailand. This study concludes that South and South East Asian countries are stunningly rich in wild fruit tree species diversity. However their principal economic value as genetic resources and the benefits derived from their associated cultural value is seldom demonstrated by public-sector research initiatives. It is also concluded that there are potentials for marketing of wild species of Mangifera viz. M pajang, M caesia, M odorata, M casturi; of Citrus viz. C. indica, C. macroptera, C. assamensis, C. ichangensis, C. megaloxycarpa (Sour Pummelo); of Garcinia viz. G. cowa, G. atroviridis, G indica, G. xanthochymus, G. gummi-gutta and of Nephalium viz. N. ramboutan-ake. Source

Discover hidden collaborations