Rubber Research Institute of Thailand

of Thailand, Thailand

Rubber Research Institute of Thailand

of Thailand, Thailand
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Chanroj V.,Thammasat University | Rattanawong R.,Rubber Research Institute of Thailand | Phumichai T.,Rubber Research Institute of Thailand | Tangphatsornruang S.,National Center for Genetic Engineering and Biotechnology | Ukoskit K.,Thammasat University
Genomics | Year: 2017

Latex yield and growth are the key complex traits in commercial rubber production. The present study is the first to report genome-wide association mapping of latex yield and girth, for 170 Amazonian accessions grown in a suboptimal area characterized by limited rainfall and a lengthy dry season. Targeted sequence enrichment to capture gene transcripts generated 14,155 high quality filtered single nucleotide polymorphisms (SNPs) of which 94.3% resided in coding regions. The rapid decay of linkage disequilibrium over physical and genetic distance found in the accessions was comparable to those previously reported for several outcrossing species. A mixed linear model detected three significant SNPs in three candidate genes involved in plant adaptation to drought stress, individually explaining 12.7-15.7% of the phenotypic variance. The SNPs identified in the study will help to extend understanding, and to support genetic improvement of rubber trees grown in drought-affected regions. © 2017.

Moolsin S.,Rangsit University | Saksayamkul N.,Rangsit University | Wichien A.N.,Rubber Research Institute of Thailand
Journal of Elastomers and Plastics | Year: 2017

The effects of graft copolymers applied as compatibilizers for natural rubber/nitrile rubber (NR/NBR) blends at 50/50 (w/w) on cure characteristics, mechanical properties, thermal properties, oil resistance, and morphology were investigated. The graft copolymers of methyl methacrylate (MMA) onto NR initiated by benzoyl peroxide (NR-g-PMMA) and by potassium persulfate (NR-g-PMMA) under emulsion polymerization were synthesized and used to compatibilize the blends. The structures of the copolymers were characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. NR was blended with NBR via a two-roll mill at 70°C under the compatibilizer loading ranging from 0 to 10 parts per hundred of rubber (phr). The results showed that the tensile property and tear strength of the blends increased with the increasing amount of NR-g-PMMA as a compatibilizer. Thermal aging determined in terms of tensile properties exhibited the smaller difference between before and after aging in an oven with the increasing compatibilizer loading. The morphology of the compatibilized NR/NBR vulcanizates was investigated by scanning electron microscopy of the tensile fracture surfaces, which exhibited the improvement of interfacial adhesion between the two rubber phases. The thermal properties of compatibilized NR/NBR vulcanizates were reported in terms of a glass transition temperature under differential scanning calorimetry and dynamic mechanical analysis. The incorporation of an appropriate amount of the compatibilizer into the blends apparently improved the oil resistance of NR. Among them, the blend filled with 7.5 phr of NR-g-PMMA showed the lowest volume change in IRM 903 oil. © 2016 SAGE Publications.

Azhar A.,Kasetsart University | Sathornkich J.,Kasetsart University | Rattanawong R.,Kasetsart University | Kasemsap P.,Rubber Research Institute of Thailand
Advanced Materials Research | Year: 2014

This experiment aimed to evaluate the leaf chlorophyll fluorescence and gas exchange response to drought conditions of young rubber plants with different scions. Buds from four genotypes of a progeny derived from crossed clones of RRIM600 × RRII105 from Nongkhai Rubber Research Center, T187, T186, T149 and T172, were grafted to RRIM 600 rootstocks. Eight-month old plants with two flushes were used in this study. Two levels of water treatment were used, drought condition (W1) and well-watered as control (W0). Leaf chlorophyll fluorescence, stomatal conductance (gs) and net photosynthesis rate (Pn) were investigated in three phases: before drought, during drought and after re-watering. Leaf gas exchange parameters were measured using Li-6400 (LiCor Inc.). Leaf chlorophyll fluorescence was measured using FluorPen FP 100 (Photon Systems Instruments). Before drought, genotype T186 had the greatest net photosynthesis rates followed by T172, T187 and T149; there was no difference in maximum quantum yield of photosystem II (Fv/Fm) and performance index on absorption basis (PIABS). Drought conditions caused reduction in stomatal conductance, net photosynthesis rates, and leaf chlorophyll fluorescence in all genotypes. In re-watering conditions, genotype T186 and T172 experienced quick recovery while the others showed partial recovery but the values of all parameters did not reach previous levels before treatment. © (2014) Trans Tech Publications, Switzerland.

Phumichai C.,Kasetsart University | Phumichai T.,Rubber Research Institute of Thailand | Kongsiri N.,Kasetsart University | Wongkaew A.,Kasetsart University | And 2 more authors.
Biologia Plantarum | Year: 2011

Jatropha curcas L. (physic nut) is native to Central America and now naturalized widely in many tropical and subtropical areas. Microsatellite markers were isolated and characterized. Eleven out of 55 markers showed polymorphisms, and the allelic variation was investigated using 26 accessions of J. curcas collected from several provinces in Thailand. Each marker showed 2 to 5 alleles and the average polymorphic information content (PIC) was 0.49. Thirty four markers (62 %) were also successfully amplified in J. integerrima, J. gossypifolia and J. podagrica. © 2011 Springer Science+Business Media B.V.

Phumichai C.,Kasetsart University | Phumichai T.,Rubber Research Institute of Thailand | Wongkaew A.,Kasetsart University | Wongkaew A.,Tokyo University of Agriculture and Technology
Plant Molecular Biology Reporter | Year: 2015

Understanding the genetic diversity and population structure of Hevea is of great importance for managing its conservation and for utilization of rubber genetic resources. In this study, we investigated the genetic diversity and population structure of eight populations of Hevea rubber genotypes from Malaysia (MY), India (IN), Sri Lanka (LK), Indonesia (ID), France (FR), Thailand (TH), Brazil (BR), and China (CN), in addition to individual primary clones, using 10 nuclear and 11 polymorphic novel chloroplast microsatellite markers (nSSRs and cpSSRs, respectively). The BR population exhibited the greatest genetic diversity (He) for both nSSR (0.841) and haploid genetic diversity (cpSSR; 0.207) markers. Bayesian analysis was applied to infer genetic structure based on nSSR data using STRUCTURE software, and a neighbor-joining tree was used to construct an unrooted phylogram based on Nei’s genetic distance that clustered these Hevea genotypes into three groups. Six polymorphic cpSSR markers produced 13 alleles and eight chlorotypes. Seven chlorotypes, A, B, C, D, E, F, and H were detected among Brazilian populations from Acre (AC), Rondônia (RO), and Mato Grosso (MT) locations. The G and H chlorotypes were found in Asiatic genotypes or Wickham clones and only one genotype, 15 AC-F-7 38-62 from AC location. These results provide valuable data for in situ or ex situ conservation and utilization of germplasm collections for breeding programs. © 2015, Springer Science+Business Media New York.

Satakhun D.,Kasetsart University | Gay F.,Kasetsart University | Gay F.,CIRAD - Agricultural Research for Development | Chairungsee N.,Office of Agricultural Research and Development Region 1 | And 7 more authors.
Ecological Research | Year: 2013

Natural rubber is a valuable source of income in many tropical countries and rubber trees are increasingly planted in tropical areas, where they contribute to land-use changes that impact the global carbon cycle. However, little is known about the carbon balance of these plantations. We studied the soil carbon balance of a 15-year-old rubber plantation in Thailand and we specifically explored the seasonal dynamic of soil CO2 efflux (F S) in relation to seasonal changes in soil water content (W S) and soil temperature (T S), assessed the partitioning of F S between autotrophic (R A) and heterotrophic (R H) sources in a root trenching experiment and estimated the contribution of aboveground and belowground carbon inputs to the soil carbon budget. A multiplicative model combining both T S and W S explained 58 % of the seasonal variation of F S. Annual soil CO2 efflux averaged 1.88 kg C m-2 year-1 between May 2009 and April 2011 and R A and R H accounted for respectively 63 and 37 % of F S, after corrections of F S measured on trenched plots for root decomposition and for difference in soil water content. The 4-year average annual aboveground litterfall was 0.53 kg C m-2 year-1 while a conservative estimate of belowground carbon input into the soil was much lower (0.17 kg C m-2 year-1). Our results highlighted that belowground processes (root and rhizomicrobial respiration and the heterotrophic respiration related to belowground carbon input into the soil) have a larger contribution to soil CO2 efflux (72 %) than aboveground litter decomposition. © 2013 The Ecological Society of Japan.

Ghosh R.K.,Kasetsart University | Phumichai T.,Rubber Research Institute of Thailand | Sreewongchai T.,Kasetsart University | Nakasathien S.,Kasetsart University | Phumichai C.,Kasetsart University
Asian Journal of Plant Sciences | Year: 2013

Evaluation of jute genotypes for salt tolerance is highly important because of salt affected areas are constantly increasing worldwide especially in Bangladesh where salt tolerant jute variety is unavailable. A hydroponics experiment was conducted in the glasshouse to evaluate the salt tolerance of various jute (Corchorus spp.) genotypes. Sixty jute genotypes were evaluated in a factorial experiment under Hoagland's nutrient solution with three levels of salinity (0, 100 and 200 mM NaCl) in a randomized complete block design with three replications. Root length, shoot length, root dry matter, shoot dry matter, total dry matter and leaf Relative Water Content (RWC) decreased significantly with increasing salinity. However, the chlorophyll content of jute leaves was higher at 100 mMNaCl (42.89) than in control plants (37.76). The C. capsularis genotypes demonstrated higher levels of salt tolerance than did C. olitorius genotypes. The physiological traits shoot length (R2 = 0.95), RWC (R2 = 0.80) and chlorophyll content (R2 = 0.91) was strongly correlated with total dry matter production and was exhibited good potential for evaluation of salt tolerance in jute. The C. capsularis accessions 4965 and 4955 were the most salt tolerant in terms of their high index of salt tolerance (85.20 and 84.10% at 100 mM NaCl) and lowest reduction in shoot length, RWC and chlorophyll content under salt stress. These accessions could be useful for agriculture in saline areas, particularly at 100 mM NaCl (EC = 10 dSirT1) salinity. © 2013 Asian Network for Scientific Information.

Pootakham W.,National Center for Genetic Engineering and Biotechnology | Chanprasert J.,National Center for Genetic Engineering and Biotechnology | Jomchai N.,National Center for Genetic Engineering and Biotechnology | Sangsrakru D.,National Center for Genetic Engineering and Biotechnology | And 3 more authors.
American Journal of Botany | Year: 2011

Premise of the study: We demonstrated the application of high-throughput 454 sequencing technology in the identification of single nucleotide polymorphism (SNP) markers in Hevea brasiliensis. Methods and Results: A total of 5883 putative SNP positions were discovered in silico, and 10 biallelic SNP markers were validated from 454-derived EST sequences. The polymorphism information content (PIC) and the observed heterozygosity (Ho) ranged from 0.0963 - 0.5135 and 0.1071 - 0.4643, respectively. Conclusions: These markers can be useful for the construction of genetic maps, the identification of quantitative trait loci linked to commercially desirable traits, and the study of genetic structure in H. brasiliensis. © 2011 Botanical Society of America.

Triwitayakorn K.,Mahidol University | Chatkulkawin P.,Mahidol University | Kanjanawattanawong S.,Mahidol University | Sraphet S.,Mahidol University | And 7 more authors.
DNA Research | Year: 2011

To obtain more information on the Hevea brasiliensis genome, we sequenced the transcriptome from the vegetative shoot apex yielding 2 311 497 reads. Clustering and assembly of the reads produced a total of 113 313 unique sequences, comprising 28 387 isotigs and 84 926 singletons. Also, 17 819 expressed sequence tag (EST)-simple sequence repeats (SSRs) were identified from the data set. To demonstrate the use of this EST resource for marker development, primers were designed for 430 of the EST-SSRs. Three hundred and twenty-three primer pairs were amplifiable in H. brasiliensis clones. Polymorphic information content values of selected 47 SSRs among 20 H. brasiliensis clones ranged from 0.13 to 0.71, with an average of 0.51. A dendrogram of genetic similarities between the 20 H. brasiliensis clones using these 47 EST-SSRs suggested two distinct groups that correlated well with clone pedigree. These novel EST-SSRs together with the published SSRs were used for the construction of an integrated parental linkage map of H. brasiliensis based on 81 lines of an F1 mapping population. The map consisted of 97 loci, consisting of 37 novel EST-SSRs and 60 published SSRs, distributed on 23 linkage groups and covered 842.9 cM with a mean interval of 11.9 cM and ∼4 loci per linkage group. Although the numbers of linkage groups exceed the haploid number (18), but with several common markers between homologous linkage groups with the previous map indicated that the F1 map in this study is appropriate for further study in marker-assisted selection. © 2011 The Author.

PubMed | Rubber Research Institute of Thailand and National Science and Technology Development Agency
Type: | Journal: Frontiers in plant science | Year: 2015

Construction of linkage maps is crucial for genetic studies and marker-assisted breeding programs. Recent advances in next generation sequencing technologies allow for the generation of high-density linkage maps, especially in non-model species lacking extensive genomic resources. Here, we constructed a high-density integrated genetic linkage map of rubber tree (Hevea brasiliensis), the sole commercial producer of high-quality natural rubber. We applied a genotyping-by-sequencing (GBS) technique to simultaneously discover and genotype single nucleotide polymorphism (SNP) markers in two rubber tree populations. A total of 21,353 single nucleotide substitutions were identified, 55% of which represented transition events. GBS-based genetic maps of populations P and C comprised 1704 and 1719 markers and encompassed 2041 cM and 1874 cM, respectively. The average marker densities of these two maps were one SNP in 1.23-1.25 cM. A total of 1114 shared SNP markers were used to merge the two component maps. An integrated linkage map consisted of 2321 markers and spanned the cumulative length of 2052 cM. The composite map showed a substantial improvement in marker density, with one SNP marker in every 0.89 cM. To our knowledge, this is the most saturated genetic map in rubber tree to date. This integrated map allowed us to anchor 28,965 contigs, covering 135 Mb or 12% of the published rubber tree genome. We demonstrated that GBS is a robust and cost-effective approach for generating a common set of genome-wide SNP data suitable for constructing integrated linkage maps from multiple populations in a highly heterozygous agricultural species.

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