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Pestalotiopsis leaf fall disease (PLFD) has been on the increase in recent years, resulting in diminished latex yield in many rubber producing countries. Thus far, some reports have pointed to the presence of fungal pathogen(s) other than Pestalotiopsis sp. in the diseased leaves. To decipher the diversity of fungal pathogens, a total of 110 early-stage and another 110 late-stage symptomatic leaves were sampled from 12 Hevea clones in seven different areas in Malaysia during wintering and wet seasons at different times of the year. A total of 487 fungal isolates were obtained; 241 were from the early-stage and 246 from the late-stage symptomatic leaves. These isolates were clustered into 11 morphotypes based on colony appearance and microscopic observation of the spore. The diversity analysis revealed significant differences in morphotype richness and evenness when comparing different rubber clones, seasonal effects, and locations by which the fungal isolates were sampled. Five isolates representative of the five predominant morphotypes associated with PLFD were analysed using the Internal Transcribed Spacer (ITS) markers and BLAST analysis. Their closest relative species were identified as Colletotrichum conoides, Neopestalotiopsis surinamensis, Lasiodiplodia theobromae, Phyllosticta fallopiae and Letendraea cordylinicola. This study enhanced our understanding of PLFD, particularly the diversity and distribution of fungal communities associated with the disease across different rubber clones, seasons, and locations in Malaysia. The identification of these fungal isolates associated with PLFD symptoms paves the way for further research into their pathogenicity and the development of targeted management strategies to mitigate the disease. [ABSTRACT FROM AUTHOR]

The rubber tree (Hevea brasiliensis) is vulnerable to infections by various fungal pathogens. White root disease infection is one of the most prevalent diseases of rubber in Malaysia. This disease is caused by the fungus Rigidoporus microporus. Delayed management of this disease can cause considerable reduction in total tree stand and ultimately decreased land productivity. The utilisation of elicitor proteins to heighten host plant resistance represents a sustainable approach to disease control by reducing the use of chemical fungicides. The cerato-platanin protein family is the most widely reported class of elicitor proteins. This study isolated a member of the cerato-platanin family from R. microporus and evaluated its expression during H. brasiliensis infection. Total RNA was extracted from the mycelial sample of R. microporus followed by cDNA synthesis, isolation and cloning of the cerato-platanin transcript referred to as rmcp. In silico characterisation of the obtained sequence was then conducted and the relative expression of the gene was evaluated using RT-qPCR. A transcript of 438 bp encoding 145 amino acids protein, denoted as RmCP, was isolated and cloned. RmCP is composed of a cerato-platanin domain and a predicted N-terminal signal peptide. Phylogenetic analysis grouped RmCP into a cluster together with cerato-platanin proteins originating from basidiomycetes. The expression of rmcp gene was consistent throughout the study period and was not significantly different from axenic culture. This suggests the gene to have a fundamental function in the life cycle of R. microporus. [ABSTRACT FROM AUTHOR]

Land surface temperature is predicted to increase by 0.2 °C per decade due to climate change, although with considerable regional variability, and heatwaves are predicted to increase markedly in the future. These changes will affect where crops can be grown in the future. Understanding the thermal limits of plant physiological functioning and how flexible such limits are is thus important. Here, we report on the measurements of a core foliar thermotolerance trait, T 50, defined as the temperature at which the maximum quantum yield (Fv / Fm) of photosystem II declines by 50%, across nine different Malaysian Hevea brasiliensis clones. We explore the relative importance of interclonal versus intraclonal variation in T 50 as well as its association with leaf and hydraulic traits. We find very low variation in T 50 within individual clones (mean intraclonal coefficient of variation (CoV) of 1.26%) and little variation across clones (interclonal CoV of 2.1%). The interclonal variation in T 50 was lower than for all other functional traits considered. The T 50 was negatively related to leaf mass per area and leaf dry matter content, but it was not related to hydraulic traits such as embolism resistance (P 50) or hydraulic safety margins (HSM 50). The range of T 50 observed (42.9–46.2 °C) is well above the current maximum air temperatures T max,obs (T 50 − T max,obs >5.8 °C), suggesting that H. brasiliensis is likely thermally safe in this south-east Asian region of Malaysia. [ABSTRACT FROM AUTHOR]

Pestalotiopsis leaf fall disease (PLFD) has emerged as a significant and detrimental foliar disease affecting Hevea brasiliensis in Malaysia since 2017. The disease poses a severe threat to rubber plantations, leading to economic losses and impacting the country's rubber industry. Understanding the factors contributing to lesion incidence and the potential presence of a fungal complex is crucial for effective disease management. This study aimed to address key objectives, including the identification of primary fungal pathogens responsible for lesion development and examination of the role of co-infections in lesion incidence. To achieve these objectives, five fungal isolates (Neopestalotiopsis surinamensis, Colletotrichum conoides, Lasiodiplodia theobromae, Phyllosticta fallopiae and Letendraea cordylinicola) previously identified through the Internal Transcribe Spacer (ITS) regions were subjected to in vitro artificial inoculation experiments on detached rubber leaves. Various combinations of these fungal isolates were tested to evaluate their interactions as possible causal pathogens of PLFD. Three variables were assessed, viz. type of water source (sterile distilled water and rainwater), presence of leaf wounds, and inoculation techniques (conidial suspensions and mycelial agar plugs). Lesion incidence was evaluated based on sporulating occurrences on the detached leaves, recorded seven days after inoculation. Statistical analysis, including non-parametric Pearson's chi-square tests revealed that the fungal isolates Lasiodiplodia theobromae, Colletotrichum conoides and Neopestalotiopsis surinamensis were the primary contributors to lesion incidence, accounting for 83%, 69%, and 57% of cases, respectively. The study also revealed that lesion incidence was not significantly influenced by inoculation techniques or type of water source but was greater in wounded leaves compared to unwounded leaves. Co-inoculation experiments demonstrated increased lesion incidence, highlighting the role of co-infections in disease severity. Importantly, this study elucidated a potential fungal complex associated with PLFD and provided insights into its epidemiology. The findings contribute to deeper understanding of the disease, offering valuable guidance for effective disease management strategies in H. brasiliensis cultivation in Malaysia. [ABSTRACT FROM AUTHOR]

The brown bast (BB) syndrome causes a 15-20% loss of annual rubber (Hevea brasiliensis) production in Malaysia, and no sustainable remedy has been developed yet. Initial investigation showed a macronutrients deficiency in the bark of affected plants compared to non-affected plants. Therefore, this study was undertaken to know the effect of spraying the deficient macronutrients in curing BB syndrome and increasing latex productivity. The treatments were selected by adjusting deficient nutrients, especially in N, K, and S, compared to healthy plants. The treatments consisted of 13 combinations of nutrient concentrations and a control (no application on healthy rubber trees). One liter of individual treatment per tree was applied on the trunk of BB-affected trees once a week for one month. Data on latex production was collected one week after the last application and continued for up to three months. The results showed that the treatment T9 (0.5% N, 0.8 mg/L K, and 0.2% S), in addition to other prescribed nutrients, made a 100% cure of BB syndrome after three weeks of application, and the nutrient contents of the bark of the affected plants appeared to be similar to the healthy plants. Applying these additional nutrients enhanced the latex production at the rate of 51.85 g/tapping/tree after two months of treatment application under the agro-ecosystem of FELCRA, Simpang Renggam, Johor, Malaysia. It is a new finding to 100% cure BB syndrome and to increase the latex productivity in sustaining the rubber industry in Malaysia. [ABSTRACT FROM AUTHOR]

Rigidoporus microporus, which causes white root rot disease (WRD) in Hevea brasiliensis, is a looming threat to rubber plantation in Malaysia. The current study was conducted to determine and evaluate the efficiency of fungal antagonists (Ascomycota) against R. microporus in rubber trees under laboratory and nursery conditions. A total of 35 fungal isolates established from the rubber tree rhizosphere soil were assessed for their antagonism against R. microporus by the dual culture technique. Trichoderma isolates can inhibit the radial growth of R. microporus by 75% or more in the dual culture test. Strains of T. asperellum, T. koningiopsis, T. spirale, and T. reesei were selected to assess the metabolites involved in their antifungal activity. Results indicated that T. asperellum exhibited an inhibitory effect against R. microporus in both volatile and non-volatile metabolite tests. All Trichoderma isolates were then tested for their ability in producing hydrolytic enzymes such as chitinase, cellulase and glucanase, indole acetic acid (IAA), siderophores production, and phosphate solubilization. From the positive results of the biochemical assays, T. asperellum and T. spirale were selected as the biocontrol candidates to be further tested in vivo against R. microporus. The nursery assessments revealed that rubber tree clone RRIM600 pretreated with only T. asperellum or with the combination of T. asperellum and T. spirale was able to reduce the disease severity index (DSI) and exert higher suppression of R. microporus compared to other pretreated samples, with the average DSI below 30%. Collectively, the present study demonstrates that T. asperellum represents a potential biocontrol agent that should be further explored to control R. microporus infection on rubber trees. [ABSTRACT FROM AUTHOR]

The bending performance of wood is important for its application in furniture, and it is one of the criteria used to assess the suitability of a particular wood species for furniture. In this context, the steam-bending and surface roughness characteristics of four forest plantation wood species were evaluated. One batch of wood specimens were subjected to both surface roughness experiments using the stylus and toluene spread methods, while another batch of the wood specimens were subjected to steaming, clamped, and bent using a circular shape mold. The instantaneous spring-back was measured after 10 days, while the springback over time was measured from days 15 to 65. The surface roughness experiments showed that the Hevea brasiliensis had the lowest surface roughness, followed by the Eucalyptus pellita, Acacia mangium, and finally Revotropix paulownia. In terms of the bending performance, it was found that only the H. brasiliensis achieved the threshold 95% satisfactory level based on visual ranking. Furthermore, the wood species also recorded the lowest spring-back, both instantaneous and over-time, to register the best bending performance. On the other hand, R. paulownia had the worst bending performance, primarily due to its low density. [ABSTRACT FROM AUTHOR]

Hevea brasiliensis wood becomes residue at plantations in Malaysia. In this study, these residues were reinforced into silicone rubber to produce a new soft biocomposite (Hevea brasiliensis-silicone biocomposite). The newly introduced soft biocomposite has potential for use in cushioning and sealing applications. The specimens were prepared with five different compositions (0 wt%, 4 wt%, 8 wt%, 12 wt%, and 16 wt% fiber content). Tensile tests were conducted according to ASTM D412 (2008) to assess the mechanical properties. Morphological characteristics were analyzed from the fractured surface of specimens. Stress-stretch data was used to quantify the non-linear tensile behavior, which was based on Neo-Hookean, Mooney-Rivlin, and Ogden hyperelastic constitutive equations. An increase in fiber content improved the modulus of silicone rubber. However, it reduced the flexibility and elastic properties of the silicone rubber biocomposite. The increasing material constant values supported these findings. The hyperelastic models accurately represented the behavior of the Hevea brasiliensis-silicone biocomposite. This study contributes knowledge towards a better understanding of the mechanical behavior of Hevea brasiliensis-silicone biocomposites. [ABSTRACT FROM AUTHOR]

This study covers characterization of nine Rubber Research Institute of Malaysia (RRIM) clones. Among these, RRIM 3001, 2023, 2025, 2020 and 2015 showed above average dry rubber content (DRC > 40%) while RRIM 928, 2024, 2017 and 2007 gave DRC < 40% (average and below). No clone was below average (DRC < 31%) which is not suitable for commercial use. Viscosity of RRIM 2023 and 2025 was unusually lower than the rest; however, this did not affect dipping or causing any adverse effect in the physical properties of their respective dipped films. Except for RRIM 928, the minimum mechanical stability time (MST) requirement (650 s) was achieved by 3rd week for all clones. All dipped films prepared from the ammoniated latex concentrates of RRIM clones recorded mechanical properties within the acceptable range of standard requirements for rubber glove applications, with tensile strengths higher than 18 MPa, force-at-break greater than 12 N, stress at 500% elongation much lesser than 5.5 MPa, tear strength ranged 13–28 N/mm, elongation-at-break values above 650%, regardless unaged and aged treatments or subjected to natural ageing. Overall, the extractable protein (EP) contents of dipped films prepared from ammoniated latex concentrates for all clones have recorded much lower than 100 µg/g. The innate proteins in all clones were majority smaller than 95 kDa. All RRIM clones had passed the cytotoxicity test (with grade 2 and below) when tested at two-fold dilution. All results suggested the tested RRIM clones are suitable for dipped film applications. [ABSTRACT FROM AUTHOR]

The pathogenic fungi, Rigidoporus microporus and Corynespora cassiicola are among the major agents of root and leaf disease of rubber tree (Hevea brasiliensis). In this study, endophytic fungi were isolated from seeds of H. brasiliensis obtained from different regions of Malaysia to determine the diversity of endophytes inhabiting the seeds and to select a potential biocontrol agent against selected Hevea pathogens. Through morphological observation and molecular identification, six genera were identified namely Aspergillus, Colletotrichum, Diaporthe, Lasiodiplodia, Mucor and Pseudofusicoccum. Isolate PN3 which showed 99.82% identity to Aspergillus terreus was selected as a candidate to evaluate its biocontrol potential against R. microporus and C. cassiicola as it displayed promising inhibitory potential in preliminary experiments. A. terreus showed inhibition of 81.24%, 70.35% and 64.19% against R. microporus and two races of C. cassiicola namely CLN 16 and CSB 16 respectively in dual culture assay. In dipped stick inhibition assay, A. terreus showed 100% inhibition to the growth of R. microporus. A. terreus also reduced infection of leaves cultured with C. cassiicola CLN 16 and CSB 16 by 93.33% and 86.67% respectively. This study has identified some of the fungal species inhabiting the seeds of H. brasiliensis which may have potential as biocontrol agents. [ABSTRACT FROM AUTHOR]

Rubber clones' evaluation involves assessment of latex yield and performance stability across multiple locations. Clones with high yield and stability have the potential for wide planting across country, while unstable clones with high yield can be exploited in certain localities. Forty-five rubber clones were evaluated in five locations across Malaysia in the period between 2000 and 2011. There was a significant genotype by environment interaction effect on rubber yield, accounting 26.67% of total variation. Assessment of locations suitability for clone trial led to discovery of two mega-environments, which we predicted to form due to the level of agronomic inputs. Using the data from nine clones, PB 260 was shown to give the best performance compared to other clones in a low input environment. Two methods of stability analyses were used viz. linear regression and mean and coefficient of variation. The former method gave more confidence in the classification of stable clones due to its more systematic and stringent approach. Six clones were classified as stable, i.e., PB 374, PB 371, RRIM 2004, PB 260, RRIM 2001, and RRIM 2002, while three clones render more evaluation to confirm their stability, namely, RRIM 2007, RRIM 3001 and RRIM 2024. Four clones that were shown unstable but high yielding have the potential for planting in targeted region and these are RRIM 2005, PB 373, RRIM 2023 and PB 369. [ABSTRACT FROM AUTHOR]

Genetic improvement of the rubber tree (Hevea brasiliensis) through conventional breeding approaches depends mainly on the availability of diverse germplasm and the amount of genetic variability present in the population. The present study was undertaken to evaluate the extent of genetic variability in the 1995 Rubber Research Institute of Malaysia (RRIM) Hevea germplasm core collection to determine the correlation and the direct and indirect effects of morphological and bark structural characters on latex yield. The analysis of variance showed highly significant differences among the genotypes for all the nine characters studied. The phenotypic coefficient of variations was higher than the genotypic coefficient of variations for all characters studied, suggesting that the apparent variation is not only genetic but also influenced by the growing environment in the expression of the traits. High heritability and high genetic advance were noted for latex yield, indicating the possibility of improvement for this character through phenotypic selection. Latex yield showed significant and positive correlations with plant girth, total number of latex vessel rings, total bark thickness, and total leaf area at both phenotypic and genotypic level. Path coefficient analysis revealed the highest direct effect of plant girth on latex yield, followed by total number of latex vessel rings and total bark thickness indicating the importance of these characters for yield improvement and their potential as reliable indicators for indirect selection in the established core collection. [ABSTRACT FROM AUTHOR]

White root rot (WRR) disease which is caused by Rigidoporus microporus is a major agricultural disease. The disease affects tropical fruits, forest trees, ornamental trees as well as rubber (Hevea brasiliensis) trees. Although WRR causes significant economic losses to planters, there is no effective method to control this disease. The understanding on the population genetics of R. microporus isolates could mitigate WRR disease in plant management. Therefore, the objective of this work was to elucidate molecular phylogeny of R. microporus isolated from rubber trees. Twenty seven R. microporus isolates were characterised using internal transcribed spacer (ITS), Beta-tubulin (β-tubulin) and translation elongation factor-a (tef1-a) sequences data. Phylogenetic tree analyses of R. microporus isolates were divided into two major groups; the Asian and African groups. However, there was no distinct geographical structuring in the Asian group, suggesting gene flow happened among the populations. Somatic Incompatibility (SI) test and Inter Simple Sequence Repeat (ISSR) marker revealed that the R. microporus in the rubber plantations partially clustered based on geographical regions. The genetic diversity of R. microporus by ISSR revealed four major groups. The findings of the present study provide a baseline data for breeders and plant pathologists to enable them strategise effective and sustainable WRR disease management. [ABSTRACT FROM AUTHOR]

This article describes the fungi isolated from the blighted leaf of rubber (Hevea brasiliensis) tree in Malaysia. Previously, Neofusicoccum ribis (Family Botryosphaeriaceae) was reported as the causal agent of rubber leaf blight in Malaysia. To date, there are limited studies on this particular disease in Malaysia and worldwide. The current study was carried out on rubber leaves displaying leaf blight symptoms caused by N. ribis from different locations to discover the fungi that reside in the blighted leaves. Rubber leaf samples with blight symptoms were collected from two different locations in Malaysia. The fungal isolates were isolated following the agar plate method and subjected to cultural and morphological characterization. Based on the cultural and morphological characterization, eight fungal isolates were further subjected to molecular identification. Five fungal isolates namely SBI, SB2, SB3, SB6 and SPKT1 were identified as N. ribis, one fungus (SB4) as Diaporthe drenthii, and another two fungi namely SB5 and SPKT2 were identified as Lasiodiplodia pseudotheobromae. Based on the morphological and molecular identification, all the N. ribis isolates demonstrated similar characteristics of the rubber leaf blight pathogen as documented in a previous study. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate drying properties of some Malaysia fast-growing species timbers exposed to drying under different temperatures, and evaluated the effects of these drying temperatures on preservative retention and penetration of the dried timbers. Four Malaysian fast-growing species, namely acacia (Acacia mangium), rubberwood (Hevea brasiliensis), sentang (Azadirachta excelsa), and kelempayan (Neolamarckia cadamba) obtained from a local plantation in Kelantan, Malaysia were used in this study. Drying specimens with dimension of 30 × 150 × 500 mm were dried under air-drying condition, a constant temperature of 60, 80, 100, and 120 °C until the moisture content of the specimens reaches an equilibrium moisture content at each drying condition. The drying properties of the specimens were then examined. After drying, stick specimens with a dimension of 20 mm (radial) × 20 mm (tangential) × 110 mm (longitudinal) obtained from the heartwood of the drying specimen were immersed in cupper azole (CuAz) wood preservative solution for 10 minutes under normal atmospheric pressure for rubberwood and kelempayan, and 30 minutes for acacia and sentang. Retention and penetration of the specimens were evaluated. The results confirmed that drying temperature had a significant effect on drying time. Drying under air-drying condition demanding considerable time, particularly drying acacia and sentang under air-drying condition required longer drying time than the other timber species. Drying temperature also had significant effects on preservative retention of all timber species, except kelempayan. The results demonstrated that preservative retention of all timber species tends to increase as drying temperature increased. In addition, high-temperature drying gives a positive effect on preservative penetration. Drying acacia under temperature of 100 °C could maintain a higher percentage of preservative coverage area until a sufficient depth from the penetration surface. This finding suggests that high-temperature drying is more desirable for better preservative retention and penetration of the specimens used in this study. [ABSTRACT FROM AUTHOR]

White root disease caused by Rigidoporus microporus is the most devastating disease in majority of the rubber growing countries, including Malaysia. This study aimed to screen and decipher the mechanisms involved in the biocontrol agents responsible for the inhibition of R. microporus. Among 16 fungal isolates, Trichoderma spp. showed promising results with the highest percent of inhibition shown by Trichoderma asperellum (80.54%). Scanning electron microscopy study revealed coiling of hyphae by Trichoderma species against R. microporus. T. asperellum has demonstrated a maximum inhibition in both volatile and non-volatile metabolite tests with its 75% culture filtrate on PDA plate was observed to cause abnormal morphological character in R. microporus. All Trichoderma species were shown to produce hydrolytic enzymes (chitinase, cellulase and β-1,3-glucanase) and they were active siderophore producers. Present study demonstrated the possible mechanisms involved and responsible for successful inhibition of R. microporus under in vitro condition especially by T. asperellum. [ABSTRACT FROM AUTHOR]

Physio-chemical properties of locally available waste cooking oil (WCO), jatropha oil (JO) - Jatropha curcas , rubber seed oil (RSO) - Hevea brasiliensis , kapok seed oil (KSO) - Ceiba pentandra and castor oil (CO) - Ricinus communis were characterized to assess and evaluate their potential use as renewable diesel production feedstock in Malaysia. Physio-chemical properties such as density, kinematic viscosity, moisture content, flash point, calorific value, iodine value, acid value and fatty acid composition were determined under standard analytical methods established by American Oil Chemists’ Society (AOCS) and American Society for Testing and Materials (ASTM). Among the non-edible oil evaluated, the promising physio-chemical properties of RSO and WCO were found to be most applicable to serve as the raw feedstock due to its low iodine content, high free fatty acid content and high flash point. Furthermore, RSO feedstock can reach up to the capacity of 60 million ton per annum with a total 1.2 million hectares of existing rubber tree plantation in Malaysia, which is approximately 500-fold more than that of the annual waste cooking oil available in Malaysia (0.12 million ton per year). Thus, it can be concluded that RSO has the most promising potential in serving as the raw material for renewable diesel production in Malaysia. [ABSTRACT FROM AUTHOR]

Rubberwood (Hevea brasiliensis) has emerged as the most important source of wood raw material in Malaysia. Being a plantation crop, it is regarded as a green and environmental-friendly material that has found applications in almost all sectors of the wood industry. Despite its importance as a socio-economic sector, the future of the rubberwood industry in Malaysia is under scrutiny. The steadily declining rubber cultivation area in the country is raising alarms about the future supply of rubberwood. Although the government provides a replanting subsidy for smallholders, who make up the large proportion of the growers, there is an urgent need to enhance the profitability of rubber growing activities. Efforts to enhance the full recovery of wood biomass available and also expanding the use of rubberwood in high value applications must be pursued rigorously, to arrest the declining interests in rubber cultivation. Policy makers must ensure that rubber cultivation remains economical and the net value of rubberwood is further enhanced through application in non-traditional sectors. [ABSTRACT FROM AUTHOR]

The potential of heat and chemically treated rubber wood shavings (RWS) to remove Cu(II) and Ni(II) was evaluated at bench-scale by varying parameters such as initial Cu(II) and Ni(II) concentrations, contact time and adsorbent dosage. Maximum Cu(II) and Ni(II) uptake was achieved using NaOH-treated RWS after 5 h of contact time, pH 5.0 (Cu), 5.5 (Ni) and 6.0 (mixed-metal solution), initial Cu(II) and Ni(II) of 100 mg L and RWS dosage of 0.3% ( w/ v). Point of zero charge (pH) value of 4.35 suggests the appropriateness of pH range used. Higher Cu(II) and Ni(II) adsorption following NaOH treatment was due to smaller average pore diameter (34.63 Å), higher mesopore content and higher surface negativity charge. EDAX analysis confirmed the presence of Cu and Ni on the surface of the RWS. The importance of carboxyl and hydroxyl functional groups during Cu(II) and Ni(II) removal is supported by the FTIR analysis and good correlation ( R of 0.96-0.99) with the pseudo-second-order adsorption kinetic model. The results indicate the potential of using RWS as an alternative adsorbent to remove Cu(II) and Ni(II) from industrial wastewaters. [ABSTRACT FROM AUTHOR]

Abstract: The industrial usage of plant biomass, paper pulp manufacture, is increasing every day. In Malaysia, Rubber wood is the dominant raw material and the Soda-anthraquinone and total chlorine free bleaching processes lead the procedure of rubber wood paper pulp production. This paper aims to identify the structural modification in the pulp depending on the applied procedure. Fourier transform infrared (FTIR) spectrometry and HPLC have been applied to analyze rubberwood chip, soda-AQ and TCF pulp. The relationship between spectral characteristics and sample composition has been established, as well as the variation in the structural behavior after pulping and bleaching has been observed. FTIR spectra clearly show that after TCF the structure of the wood components is partially modified or removed. Along with FTIR data, the HPLC results confirmed the absence of chemically hazardous p-Hydroxybenzoic acid in the pulp samples, which finally results in the contamination of the river water streams. [Copyright &y& Elsevier]

Latex production from Hevea brasiliensis rubber tree is the second most important commodity in Malaysia, but this industry is threatened by the white root rot disease (WRD) caused by Rigidoporus microporus that leads to considerable latex yield loss and tree death. This study aimed to characterize and compare the virulence of five R. microporus isolates obtained from infected rubber trees located at different states in Malaysia. These isolates were subjected to morphological and molecular characterization for species confirmation and pathogenicity test for the determination of virulence level. BLAST search showed that the ITS sequences of all the pathogen isolates were 99% identical to R. microporus isolate SEG (accession number: MG199553) from Malaysia. The pathogenicity test of R. microporus isolates conducted in a nursery with 24 seedlings per isolate showed that isolate RL21 from Sarawak has developed the most severe above- and below-ground symptoms of WRD on the rubber clone RRIM600 as host. Six months after being infected with R. microporus, RL21 was evaluated with the highest average of disease severity index of 80.52% for above- and below-ground symptoms, followed by RL22 (68.65%), RL20 (66.04%), RL26 (54.38%), and RL25 (43.13%). The in vitro growth condition tests showed that isolate RL21 of R. microporus has optimum growth at 25–30 °C, with the preference of weakly acidic to neutral environments (pH 6–7). This study revealed that different virulence levels are possessed among different R. microporus isolates even though they were isolated from the same host species under the same climate region. Taken together, field evaluation through visual observation and laboratory assays have led to screening of the most virulent isolate. Determination of the most virulent isolate in the present study is vital and shall be taken into consideration for the selection of suitable pathogen isolate in the development of more effective control measures in combating tenacious R. microporus. [ABSTRACT FROM AUTHOR]

Fusicoccum sp. is reported as a pathogen of fully expanded leaves of Hevea brasiliensis in Malaysia. A short description is given. The fungus was isolated and shown to be pathogenic by inoculation of attached leaves and leaf discs under controlled conditions. [ABSTRACT FROM AUTHOR]

Increased volatility in global rubber prices has led to declining Malaysian rubber production and smallholder income. Identifying rubber clones that can produce a consistently high yield in various environments is one of the potential measures to alleviate the impact of price fluctuations and improve smallholder livelihoods. In this study, we assessed rubber yields and yield stability of 37 rubber tree clones at two major production regions in Malaysia: Kota Tinggi (Southern region) and Sungai Buloh (Central region). In addition, we assessed relationships between climate data with rubber yields. Rubber yield and stability differed widely by clone, but showed relatively consistent trends across regions. Clones RRIM 2007, PB 260, and RRIM 2012 were high yielding in both regions and had high stability. Conversely, clone RRII 308 had the lowest mean yield across both regions and low stability. Mean annual yields showed a negative relationship with rising minimum temperatures, declining by ~3 g per tapping per tree (g t−1 t−1) per 1 °C rise in minimum temperature. Our findings highlight clones capable of achieving stable high yields. This information may be useful for breeders and agronomists in identifying germplasm and traits for further development. Further, this information can be used to assist clone recommendations to smallholders in these regions to mitigate the dual impacts of climate change and market volatility. [ABSTRACT FROM AUTHOR]

In this study, RNA sequencing of several Hevea brasiliensis clones grown in Malaysia with different annual rubber production yields and disease resistance was performed on the Illumina platform. A total of 29,862,548 reads were generated, resulting in 101,269 assembled transcripts that were used as the reference transcripts. A similarity search against the non-redundant (nr) protein databases presented 83,771 (83%) positive BLASTx hits. The transcriptome was annotated using gene ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the Pfam database. A search for putative molecular markers was performed to identify single-nucleotide polymorphisms (SNPs). Overall, 3,210,629 SNPs were detected and a total of 1314 SNPs associated with the genes involved in MVA and MEP pathways were identified. A total of 176 SNP primer pairs were designed from sequences that were related to the MVA and MEP pathways. The transcriptome of RRIM 3001 and RRIM 712 were subjected to pairwise comparison and the results revealed that there were 1262 significantly differentially expressed genes unique to RRIM 3001, 1499 significantly differentially expressed genes unique to RRIM 712 and several genes related to the MVA and MEP pathways such as AACT, HMGS, PMK, MVD, DXS and HDS were included. The results will facilitate the characterization of H. brasiliensis transcriptomes and the development of a new set of molecular markers in the form of SNPs from transcriptome assembly for the genotype identification of various rubber varieties with superior traits in Malaysia. [ABSTRACT FROM AUTHOR]