Journal Articles by Dr. Rakib Rashid
Sarhad Journal of Agriculture, Nov 1, 2024
Trichoderma species are well-known biological control agents (BCAs) that have significant antagon... more Trichoderma species are well-known biological control agents (BCAs) that have significant antagonistic activity against various fungal phytopathogens. On the other hand, Ganoderma boninense has been identified as the phytopathogen causing basal stem rot (BSR), a devastating disease in oil palm crop (Elaeis guineensis). In this study, the in vitro and in planta inhibition of G. boninense using Trichoderma isolates were evaluated. A total of 20 Trichoderma isolates were collected. Among the isolates, T4RH and T8R were selected for further in planta experiments as they showed significant inhibitory activity against G. boninense via in vitro dual-culture and dual-plate assays. Isolates T4RH and T8R were identified as Trichoderma virens and Trichoderma asperellum by the internal transcribed spacer gene sequences. The in-planta experiment was conducted by inoculation of 3-month-old oil palm seedlings with rubber wood block inoculum. Single and mixture conidial suspensions 1×106 of T4RH and T8R were applied to the Ganoderma-inoculated plants. It was found that T4RH, T8R, and mixed Trichoderma treatments have significantly lower disease incidence, disease severity index, area under disease progress curve, and percentage of necrotic primary roots as compared to the positive control. The disease reduction was up to 57.70% and 43.86% when plants were treated with T4RH and T8R, respectively. Additionally, the Trichoderma treatment recorded significantly higher chlorophyll content, plant height, bole diameter, and number of fronds as compared to the positive control. The findings from this study suggested that T. virens T4RH and T. asperellum T8R have the potential to be used as promising BCAs against G. boninense.
Frontiers in Forests and Global Change, Jul 3, 2024
The assessment of environmental sustainability is of utmost importance for the forests and planta... more The assessment of environmental sustainability is of utmost importance for the forests and plantations in Borneo, given the critical need for environmental protection through the identification and mitigation of potential risks. This study was conducted to assess the environmental sustainability of tropical forest and plantations landscape, a case study in northern Sabah, Malaysian Borneo. Applications of the latest high-resolution multi-sensor remote sensing and geospatial MCDA are cost-effective and useful for large-scale environmental sustainability assessment. The land use land cover (LULC) of the study area was mapped with synergistic use of Sentinel-1 Synthetic Aperture Radar (SAR) and Sentinel-2 optical and high-resolution PlanetScope satellite imageries, resulting in overall accuracy of 87.24%. Five sustainability indicator layers: slope erosion protection, river buffer, landscape connectivity and quality, high conservation value (HCV), and water turbidity were developed from the LULC map, ancillary datasets of SRTM, and forest operation basemap with reference to standards from the Environment Protection Department (EPD), Roundtable on Sustainable Palm Oil (RSPO), and Forest Management Plan (FMP) for the analysis using multi-criteria decision analysis (MCDA) model. The results revealed that overall, the study areas are in the high sustainability category at 61%, medium at 31%, and low at only 8%. We analyzed the environmental sustainability of five land use boundaries, and the results showed that Industrial Tree Plantations (ITP) and Village Reserve are mostly in the high category. Meanwhile, oil palm plantations, rubber plantations, and forest reserve (FR) are the majority in the medium category. Both oil palm and rubber plantations are a majority in the medium class due to monocropping land use type having low landscape connectivity and quality individual sustainability indicator layer. The study presented the concept of use of multi-sensor remote sensing for LULC mapping with geospatial MCDA for environmental sustainability assessment useful to stakeholders for improving the management plan also contributing toward the progress of achieving UNSDGs and addressing REDD+.
IOP Conference Series: Earth and Environmental Science, 2024
The digestibility and rumen fermentation characteristics in goats fed with biologically pretreate... more The digestibility and rumen fermentation characteristics in goats fed with biologically pretreated oil palm empty fruit bunch (OPEFB) with Ganoderma lucidum as total mixed ration (TMR) were evaluated in this study. OPEFB biologically pretreated with G. lucidum for 12 weeks of solid-state fermentation (SSF) period were formulated as TMR in an animal feeding trial giving treatments to T1: Basal diet (Control); T2: Basal diet with 25% replacement of grass with untreated OPEFB; and T3: Basal diet with 25% replacement of grass with treated OPEFB. This delignification on the treated OPEFB indicated break down of lignin content and becomes more digestible for ruminant consumption. The feeding of T1, T2 and T3 shown significant difference (p<0.05) in acid detergent lignin digestibility (ADLD) and total bacterial count. T2 had higher lignin content, lower ADLD and lower bacterial population compared to T1 and T3. It is postulated that the high lignin content and lower ADLD in T2 negatively affected bacterial growth, while T1 and T3 were comparable. Consequently, OPEFB treated with G. lucidum can be used as a replacement for grass as roughage source in TMR, without causing negative effects on the animal’s digestion.
Scientific Reports, 2024
Greenhouse gases can cause acid rain, which in turn degrades soil chemical properties. This resea... more Greenhouse gases can cause acid rain, which in turn degrades soil chemical properties. This research was conducted to determine the effects of simulated acid rain (SAR) on the chemical properties of Nyalau series (Typic paleudults). A 45-day laboratory leaching and incubation study (control conditions) was conducted following standard procedures include preparing simulated acid rain with specific pH levels, followed by experimental design/plan and systematically analyzing both soil and leachate for chemical changes over the 45-day period. Six treatments five of which were SAR (pH 3.5, 4.0, 4.5, 5.0, and 5.5) and one control referred to as natural rainwater (pH 6.0) were evaluated. From the study, the SAR had significant effects on the chemical properties of the soil and its leachate. The pH of 3.5 of SAR treatments decreased soil pH, K + , and fertility index. In contrast, the contents of Mg 2+ , Na + , SO 4 2− , NO 3 − , and acidity were higher at the lower SAR pH. Furthermore, K + and Mg 2+ in the leachate significantly increased with increasing acidity of the SAR. The changes in Ca 2+ and NH 4 + between the soil and its leachate were positively correlated (r = 0.84 and 0.86), whereas the changes in NO 3 − negatively correlated (r = − 0.82). The novelty of these results lies in the discovery of significant alterations in soil chemistry due to simulated acid rain (SAR), particularly impacting soil fertility and nutrient availability, with notable positive and negative correlations among specific ions where prolonged exposure to acid rain could negatively affect the moderately tolerant to acidic and nutrientpoor soils. Acid rain can negatively affect soil fertility and the general soils ecosystem functions. Long-term field studies are required to consolidate the findings of this present study in order to reveal the sustained impact of SAR on tropical forest ecosystems, particularly concerning soil health, plant tolerance, and potential shifts in biodiversity and ecological balance. Acid deposition poses several threats to ecosystems by affecting plant health, diversity and structure, including processes and functions in the ecosystem 1,2. Acid deposition is defined as accumulation of undesired chemical compounds in the atmosphere at toxic concentrations 3. Acid deposits are materials (solids, liquids and gases) occurring in excess quantities from the average amount and present at the lowest layer of the atmosphere 4. Acid deposition in the atmosphere can be attributed to diverse chemical compounds originating from fossil fuel combustion, agriculture, mining, and manufacturing activities. Acid deposition is a global threat that has been shown to result in various environmental and human health hazards such as depleting essential nutrients and increasing toxic metals, which can lead to reduced plant growth and biodiversity 5-7. Acid deposits refer to rain, snow, fog, particulates, and gases, whereas acid rain only refers to rainwater at pH below 5.6 8,9. Acid rain mainly consists of sulfur dioxide (SO 2) and nitrogen oxides (NOx) forming acidic compounds, whereas other greenhouse gases like Cl − and CO 2 , linked to climate change and global warming. These gases undergo complex chemical reactions in the atmosphere after which they fall to the earth's surface as wet or dry deposition 10. According to Zhang et al. 11 , acid rain with a pH of 5.6 is deemed normal as atmospheric CO 2 at a pressure of 101 kPa and temperature of 20 °C lowers rainwater pH from 7 to 5.
Scientific Reports, 2023
Basal stem rot due to a fungal pathogen, Ganoderma boninense, is one of the most devastating dise... more Basal stem rot due to a fungal pathogen, Ganoderma boninense, is one of the most devastating diseases in oil palm throughout the major palm oil producer countries. This study investigated the potential of polypore fungi as biological control agents against pathogenic G. boninense in oil palm. In vitro antagonistic screening of selected non-pathogenic polypore fungi was performed. Based on in planta fungi inoculation on oil palm seedlings, eight of the 21 fungi isolates tested (GL01, GL01, RDC06, RDC24, SRP11, SRP12, SRP17, and SRP18) were non-pathogenic. In vitro antagonistic assays against G. boninense revealed that the percentage inhibition of radial growth (PIRG) in dual culture assay for SRP11 (69.7%), SRP17 (67.3%), and SRP18 (72.7%) was relatively high. Percentage inhibition of diameter growth (PIDG) in volatile organic compounds (VOCs) in dual plate assay of SRP11, SRP17, and SRP18 isolates were 43.2%, 51.6%, and 52.1%, respectively. Molecular identification using the internal transcribed spacer gene sequences of SRP11, SRP17, and SRP18 isolates revealed that they were Fomes sp., Trametes elegans, and Trametes lactinea, respectively.
LWT - Food Science and Technology, May 1, 2023
This study aimed to compare the nutritional composition and metabolites profiles of the Pleurotus... more This study aimed to compare the nutritional composition and metabolites profiles of the Pleurotus ostreatus oyster mushroom grown on oil palm empty fruit bunch (EFB) and rubber wood sawdust (RWS) substrates. The mushrooms were prepared for proximate analysis, beta-glucan content, and metabolites profiling using ultra high performance liquid chromatography-quadrupole time of flights mass spectrometer (UHPLC-QToF). Proximate analysis showed significantly higher crude protein, and beta-glucan contents (p < 0.05) were recovered from the mushrooms grown on EFB substrate as compared to those grown on RWS. Metabolite profiling of hot water extracts showed that three lipids (PE (17:1/0:0), PE (16:1/0:0), and hydroxyoctadecadienoic), two amino acids (acetyl-leucine, and threonic acid), and one polysaccharide (4-O-beta-D-galactopyranosyl-beta-D-xylopyranose) were present at a relatively higher level (maximum fold change >10) in mushrooms grown on EFB. Our results suggest that the metabolites of the mushroom cultivated on EFB substrate were altered. The innovative use of palm oil waste as mushroom cultivation substrate exerts the concept of waste-to-wealth, promoting Sustainable Palm Oil Initiative (SPOI), and enhancing food security through the production of high-protein mushrooms.
Horticulturae, Nov 6, 2022
The oyster mushroom (Pleurotus species) is a popular and widely cultivated edible mushroom that c... more The oyster mushroom (Pleurotus species) is a popular and widely cultivated edible mushroom that can be found worldwide, including in Malaysia. However, its local production is unable to fulfil the market demand, partly due to the limited availability of rubber wood sawdust (RWS) as the conventional cultivation substrate. Furthermore, the palm oil industry in Malaysia generates large volumes of organic by-products that have caused environmental concerns. Therefore, the potential utilisation of oil palm waste-based substrates in order to develop a substitute RWS for Pleurotus ostreatus mushroom production is evaluated in this study, based on their agronomic performance and nutritional properties. Empty fruit bunches (EFBs), oil palm fronds (OPFs), and oil palm trunks (OPTs) were used to formulate the substrates. The control used was 100% RWS. Generally, 100% EFB showed a better agronomic performance, and mushroom growth was 1.9 times faster compared to the control, with a comparable mushroom yield. The crude protein and beta glucan content of mushrooms grown on oil palm by-product-formulated substrates were significantly higher than those grown using the control. Additionally, the number of fruiting bodies, crude protein, and beta glucan content of the mushrooms were positively correlated with potassium in the substrate. Therefore, 100% EFB could be used as a potential substitute for RWS for the cultivation and production of P. ostreatus.
Transactions on Science and Technology, 2021
Malaysia produces a large quantity of empty fruit bunch (EFB) and oil palm frond (OPF) every year... more Malaysia produces a large quantity of empty fruit bunch (EFB) and oil palm frond (OPF) every year, these wastes are not efficiently utilized, and causing disposal problems and pollute the environment. On the other hand, it has been reported that oyster mushrooms grown on oil palm by-products produced good yield. Thus, this study was carried out to investigate the effect of physical and chemical properties of the substrate on the mycelia growth rate of Pleurotus ostreatus on three treatments: namely, 100% EFB, 100% OPF, and the mixture of 50% EFB and 50% OPF. All treatments had five replicates and arranged in a completely randomized design (CRD). Chemical and physical properties; concentration of C, N, K, P, Cu, Ca, Mg, Fe, Zn, moisture content, ash content, volatile solids content, pH, electrical conductivity, wet bulk density, particle density, and porosity were measured. The number of days taken for mycelia to entirely colonized the substrate bag was recorded. It was found that pH, EC, and the concentration of C, N, P, Cu, Ca, Mg, and Zn were significantly affected by substrate formulations. It took 23-25 days for mycelia to entirely colonized the substrate in all treatments. However, the mycelia growth rate of P. ostreatus was not significantly affected by the physicochemical properties of substrate formulations.
PLOS ONE, Sep 30, 2021
The changes in lignocellulosic biomass composition and in vitro rumen digestibility of oil palm e... more The changes in lignocellulosic biomass composition and in vitro rumen digestibility of oil palm empty fruit bunch (OPEFB) after pre-treatment with the fungus Ganoderma lucidum were evaluated. The results demonstrated that the pre-treatment for 2-12 weeks has gradually degraded the OPEFB in a time-dependent manner; whereby lignin, cellulose, and hemicellulose were respectively degraded by 41.0, 20.5, and 26.7% at the end of the incubation period. The findings were corroborated using the physical examination of the OPEFB by scanning electron microscopy. Moreover, the OPEFB pre-treated for 12 weeks has shown the highest in vitro digestibility of dry (77.20%) and organic (69.78%) matter, where they were enhanced by 104.07 and 96.29%, respectively, as compared to the untreated control. The enhancement in the in vitro ruminal digestibility was negatively correlated with the lignin content in the OPEFB. Therefore, biologically delignified OPEFB with G. lucidum fungal culture pre-treatment have the potential to be utilized as one of the ingredients for the development of a novel ruminant forage.
BioResources, Sep 4, 2020
The growth and yield of Pleurotus florida mushroom were evaluated in media with corn husk and woo... more The growth and yield of Pleurotus florida mushroom were evaluated in media with corn husk and wood sawdust substrates. Five formulations of substrates, namely 0%, 25%, 50%, 75%, and 100% of wood sawdust substituted with corn husk, were tested with 0% corn husk or 100% wood sawdust serving as the control. The total number of fruiting bodies, the number of effective fruiting bodies, the total fresh weight and dry weight of the mushroom, and biological efficiency were significantly increased with as low as 25% corn husk in the substrate, and they showed a significant increasing trend as the composition of corn husk in the substrate increased. Superior yield was produced by P. florida cultivated in 100% corn husk, where the total number of fruiting bodies, the number of effective fruiting bodies, the total fresh weight, and the total dry weight of the mushroom were 4.8 times, 5.4 times, 4.6 times, and 5.4 times greater than the control, respectively. The biological efficiency of P. florida increased gradually from 8.8% in the control to 51.37% in the 100% corn husk substrate. Therefore, corn husk could be exploited as a substitute or alternative substrate to wood sawdust for more sustainable production of P. florida.
ASM Science Journal, 2020
Sustainability of the oil palm in Malaysia is threatened by Ganoderma species causing stem rot. T... more Sustainability of the oil palm in Malaysia is threatened by Ganoderma species causing stem rot. There were many studies conducted to understand the etiology and epidemiology of the disease in West Malaysia, however none of them reported the situation in Sabah, one of the leading producers. Moreover, the mode of Ganoderma spread in oil palm is least understood. Thus, the aims for this study were to investigate the infection mode of Ganoderma species in oil palm based on the in-vitro cultural characteristics and somatic compatibility. A total of 21 Ganoderma basidiocarps were isolated from stem rot infected palms in an estate in Sandakan, Sabah. These samples were obtained (i) within infected palms; (ii) among infected neighbouring palms; and (iii) five clusters of infected palms. In-vitro morphology of the Ganoderma isolates was characterized based on 21 characteristics via a dendrogram. Somatic compatibility was accessed to investigate the genetic heterogenicity. There was a narrow variability (93 to 100%) in terms of the cultural characteristics, and the variations exhibited among the isolates regardless of their origin. The isolates may exhibit similar phenotype, but not necessarily have similar genotype, and vice versa. Based on the somatic compatibility test, it was found that all pairings showed incompatible reactions except in self-pairing and between isolates C5P3-1 and C5P3-2 which were isolated from the same infected palm (genetically identical). These findings indicated that infection of Ganoderma in a single palm and neighbouring palms generally were caused by mult iple unidentical strains. This further concludes that spread of Ganoderma species in oil palm via root-to-root contact is uncommon. Thus, the basidiospores may play an important role in the disease epidemiology, and further research and management strategies of the disease should focus on this.
Journal of the Bangladesh Agricultural University, Sep 2019
Establishment of disease in oil palm seedlings through artificial inoculation of Ganoderma are wi... more Establishment of disease in oil palm seedlings through artificial inoculation of Ganoderma are widely used for studies of various aspects of plant pathology, including epidemiology, etiology, disease resistance, host-parasite interaction and disease control. The estimation of chlorophyll content in the infected seedlings possibly could provide a good indicator for degree of disease or infection, and changes during pathogenesis. Thus, the objective of this study was to evaluate the relationship between disease severity index (DSI) and chlorophyll content in Ganoderma infected oil palm seedlings. Three-month-old oil palm seedlings were infected with Ganoderma inoculum on rubber wood block (RWB), where 44 isolates of Ganoderma were tested. Disease severity index (DSI) and chlorophyll content using a single-photon avalanche diode (SPAD) meter were recorded at 4 weeks interval for a period of 24 weeks after inoculation (WAI). Pearson's correlation analysis and regression analysis were performed to evaluate the relationship between the variables. It was found that the relationship between DSI and SPAD chlorophyll value was inversely proportional (R = -0.92) in a linear trend (R2 = 0.85). Furthermore, the increasing trend of the DSI across the weeks were fitted in a quadratic model (R2 = 0.99). In contrast, the SPAD chlorophyll value declined in a linear trend (R2 = 0.98). The SPAD chlorophyll value could be considered as a better alternative over the DSI as the SPAD chlorophyll value was strongly related to DSI, as well as able to detect physiological changes in the infected oil palm seedlings at the early stages of pathogenesis.
International Journal of Agriculture, Forestry and Plantation, Jun 2019
Livestock production in Malaysia is still inadequate to meet the demand especially ruminant produ... more Livestock production in Malaysia is still inadequate to meet the demand especially ruminant products. Efforts were made to increase the availability of local feed by having a better utilization of agro-industrial by-products which can increase the production of ruminant products. The extraction of palm oil produced abundant of empty fruit bunch (EFB), which considered as waste and has raised environmental concerns. It is a lignocellulosic raw material which consist high cellulose, hemicellulose and lignin. Researchers has reported that white-rot fungi have the ability for delignification by extracellular enzymes Thus, this study evaluated the cell wall constituents (cellulose, hemicellulose and lignin), the morphological surface changes, and in-vitro dry matter digestibility (IVDMD) of oil palm EFB fibres treated with mycelia culture of Ganoderma lucidum. Shredded EFB fibres were obtained and prepared as sterilized substrate in polypropylene bags, inoculated with mycelial culture of G. lucidum and incubated for 4, 8 and 12 weeks of incubation period. Result showed that there was significant reduction on EFB fibres fibre composition after treated with G. lucidum until reach the lowest at 12 weeks of incubation where 27.77% to 22.08% for cellulose, 19.30% to 14.15% for hemicellulose, while 12.69% to 7.49% for lignin content. The SEM images showed that silica bodies were removed from the strand surface and left only exposed pores at the bottom after treatment with G. lucidum. The IVDMD of treated EFB fibres were increased as incubation period increased where the highest at week 12 of incubation with 81.88%. These results suggested that the G. lucidum was effective in delignification of EFB fibres after 12 weeks of incubation and have the potential to be utilized as ruminant feedstuff. Utilization of biomass generated from palm oil mill not only will solve our environmental problem but also convert low quality biomass into valuable local feed for ruminants.
Transactions on Science and Technology, 2019
Polypore is a group of fungi from the order polyporales that form fruiting bodies with pores or t... more Polypore is a group of fungi from the order polyporales that form fruiting bodies with pores or tubes on the underside. Although tropical rainforests are one of the global biodiversity hotspots, but the diversity of polypore fungi has been little examined especially in Sandakan, Sabah. In addition, polypore fungi probably could be exploited as bio-control agents against phytopathogens, and they should be identified. Thus, the objectives of this study were to (i) investigate the macro-and micro-morphological characteristics of polypore fungi; (ii) identify the polypore fungi based on their macro-and micro-morphologies. Fruiting bodies of polypore fungi were collected from Rainforest Discovery Centre (RDC) and Sandakan Rainforest Park (SRP), located in Sandakan, Sabah. In addition, few samples of polypore fungi were obtained from mushroom farms and oil palm estates. A total 35 polypore fungi were collected, their macro-morphologies were characterized based on 47 characteristics of the fruiting bodies, and then isolated using potato dextrose agar (PDA). Moreover, the in-vitro micro-morphologies of the fungi were characterized based on 37 characteristics of the pure cultures. Dendrograms were generated using unweight pair group of arithmetic averages (UPGMA). The macro-morphological characteristics exhibited high variation (20% to 90%) among the fungi. The fungi were categorized into 29 groups at 90% similarity of their macro-morphologies. While for micro-morphology, the fungi were categorized into 32 groups at 100% similarity. The isolates for micro-morphology showed less than 33% dissimilarity among the fungi. These results indicated that most polypore fungi collected are from family Polyporaceae and Ganodermataceae. Among these family, there are about 10 different genera were identified based on their macro-and micro-morphological characteristics. Either the family, genus, or species of 25 out of 35 polypore fungi (71%) were identified and others remain unidentified based on their macro-and micro-morphological characteristics. Further research should be conducted to study the potential uses of the polypore fungi, such as in bio-control against phytopathogens.
Malaysian Journal of Animal Science, 2019
Efforts were made to reduce the wide gap between requirement and availability of local feed by ha... more Efforts were made to reduce the wide gap between requirement and availability of local feed by having a better utilization strategy of unconventional feed resources. Malaysia is one of the world's largest palm oil producers. The process of extraction of palm oil produces empty fruit bunch (EFB), which is considered as waste product. Biological delignification using white rot fungi (WRF) was reported to enhance the feeding values of agricultural by-products used in ruminant rations by fungal degradation of lignin. Steam sterilization before fungi inoculation is known to affect substrate composition. Thus, this study was conducted to evaluate the effect of steam sterilization of oil palm EFB fibres on the nutritive composition of oil palm EFB fibres treated with mycelia culture of Ganoderma lucidum at different incubation periods as a potential ruminant feedstuff. Shredded oil palm EFB fibres were prepared as sterilized substrate in polypropylene bags and inoculated with mycelia culture of G. lucidum. The uninoculated sterilized substrate was compared with unsterilized substrate. All inoculated substrates were incubated starting from week 2, 4, 6, 8, 10 and 12 with 4 replications for each period. All samples were analysed for their nutritive compositions. Result showed that only crude protein and cellulose content were significantly changed after steam sterilization process where crude protein was reduced from 6.07% to 1.97% and cellulose increased from 22.35% to 27.52%. All nutritive composition analysed (dry matter, organic matter, crude protein, ash, cellulose, hemicellulose and lignin) for oil palm EFB fibres treated with G. lucidum showed significant changes across incubation period. Its lignocellulose components such as lignin, hemicellulose and cellulose were significantly reduced by 21%, 20% and 35%, respectively after 12 weeks of incubation. These results suggest that oil palm EFB fibres treated with mycelial culture of G. lucidum have potential to be utilized as ruminant feedstuff. Ganoderma lucidum was proven to have the ability in delignification of lignin in oil palm EFB fibres. Exploitation of this biological treatment could possibly maximize the use of locally available agro-industrial by-products to increase the production of local cost-effective feed for ruminants.
Journal of Academia UiTM Negeri Sembilan, 2017
Oil palm is one of the most important plantation crops in Malaysia. The sustainability of oil pal... more Oil palm is one of the most important plantation crops in Malaysia. The sustainability of oil palm is threatened by Ganoderma species. It is commonly known that Ganoderma boninense is the causal pathogen for basal stem rot (BSR) in oil palm. However, little is known about the threats by other species of Ganoderma or upper stem rot (USR), which is associated with a similar pathogen. A total of 46 isolates of Ganoderma were isolated from BSR and USR infected oil palms. The isolates were identified using a multiplex PCR, and its genetic heterogeneity was determined using a somatic compatibility test. It was found that BSR and USR coexisted in the plantations, and USR emerged as one of the major diseases. The diseases were associated with similar pathogens, namely G. zonatum (71.7%), followed by G. boninense (26.1%), and G. miniatocinctum (2.2%). Somatic compatibility test indicated that all the isolates were genetically heterogeneous. These results show that G. zonatum and the transmission of the diseases through basidiospores play a vital role in the epidemiology of the diseases. Thus, USR should not be overlooked, and more emphasis should be given to G. zonatum and its mode of transmission for more effective disease management.
Journal of Phytopathology, 2017
Nutrients are essential for normal physiological processes in plants, and they play important rol... more Nutrients are essential for normal physiological processes in plants, and they play important roles in defence mechanisms against pathogens. Oil palms cultivated on peat are more prone to nutrient deficiency, especially micronutrients, and this may affect their susceptibility to Ganoderma species, the major threat to the sustainability of oil palm throughout South-East Asia. This study was conducted to investigate the association of copper (Cu) and zinc (Zn) in mature oil palm to the spatial distribution of Ganoderma species in the plantations on peat. Foliar samples (frond 17) of oil palm from two plantations (Betong and Miri) on peat in Sarawak, Malaysia, were collected based on the spatial distribution pattern of Ganoderma, and total Cu and Zn were quantified spectrometrically. The experiment was conducted twice at a 1-year interval. The concentrations of Cu and Zn were significantly lower in oil palms from infected areas in contrast to those from uninfected areas. In addition, oil palms in infected areas in Miri suffered Cu and Zn deficiencies. Furthermore, Cu and Zn were significantly lower in the oil palms in Miri that had higher Ganoderma occurrence, as compared to those in Betong, which had significantly higher Cu and Zn but lower Ganoderma occurrence.
Journal of Oil Palm Research, 2015
Currently, the most known devastating oil palm disease throughout South-east Asia is basal ... more Currently, the most known devastating oil palm disease throughout South-east Asia is basal stem rot (BSR) caused by Ganoderma boninense. However, there is insufficient information on G. zonatum which also has been associated with the BSR, and upper stem rot (USR). Thus, this study reports pathological symptoms and degree of aggressiveness amongst G. zonatum and G. boninense of USR and BSR on oil palm seedlings. All the Ganoderma isolates tested showed positive signs of infection on the seedlings at 12 and up to 24 weeks after inoculation. However, the symptoms of infection on the seedlings were indistinguishable amongst the Ganoderma species tested. In fact, they showed significantly different degree of aggressiveness in terms of area under disease progress curve (AUDPC), epidemic rate, severity of foliar symptoms (SFS), disease severity index (DSI), stem bole necrosis and primary roots necrosis. The present findings suggested that G. zonatum of USR was the most aggressive, followed by G. zonatum and G. boninense of BSR, and G. boninense of USR was the least aggressive. Hence, a new mechanism of control strategies is urgently required to contain the disease from spreading especially for USR and also for G. zonatum in Malaysia.
Journal of Food Agriculture and Environment, 2014
Oil palm is an important oil producing crop. The sustainability of oil palms in Southeast Asia re... more Oil palm is an important oil producing crop. The sustainability of oil palms in Southeast Asia region, including Malaysia, is threatened by a basidiomycete fungus, Ganoderma species, which causes upper stem rot (USR) and basal stem rot (BSR). There was limited information on USR compared to BSR, and better understanding is needed to distinguish between USR and BSR. Information on site specific occurrence and distribution of the disease are important for better experiment planning and effective site specific management. Hence, two study plots, consisted of 15 and 16 hectares, were established in Betong (18-year-old palms) and Miri (11-year-old palms) plantation, respectively, which were located in Sarawak, Malaysia. Each palm was examined for presence of the stem rot disease based on appearance of external symptoms. The number and location of infected palms within each plot were recorded. Geographical Information System (GIS) and geostatistical tools were used to graphically present the disease distribution separately between USR and BSR, and combined USR and BSR distribution. It was found that both USR and BSR were associated with Ganoderma species and showed similar symptoms, except for the different elevation point of infection. Infected palms were mainly identified by appearance of Ganoderma basidiomata on the stem and dissection on the stem revealed that the infection was at a single point of the stem, and there was no connection between infection of USR and BSR. In general, relatively higher disease occurred in Miri compared to that in Betong. USR and BSR coexisted in both plantations with higher USR compared to BSR occurrence recorded in Miri, and vice versa in Betong. Geostatistical analysis revealed weak spatial dependence for all the data analysed, and the infections were relatively at closer distance (denser occurrence) in Miri compared to that in Betong. Weak spatial dependence indicated that both USR and BSR occurred randomly, which suggested that USR and BSR disease spread probably through basidiospore dispersal at greater distance, instead of root to root infection. This study provided clear information on the disease occurrence, spatial distribution, and mode of disease spread at both study sites which were useful in future studies to investigate factors associated with the diseases outbreak and site specific disease management.
International Journal of Agriculture and Biology, 2014
The objectives of this study were to investigate the diversity of Ganoderma species isolated from... more The objectives of this study were to investigate the diversity of Ganoderma species isolated from upper stem rot (USR) and basal stem rot (BSR) infected palms in term of their genetic and morphological characteristics. A total of 46 samples of Ganoderma species were collected randomly from two oil palm plantations, namely Betong and Miri in Sarawak, Malaysia. The samples were identified using multiplex polymerase chain reaction (multiplex PCR) to reveal three pathogenic Ganoderma species (G. zonatum, G. boninense and G. miniatocinctum). Ganoderma zonatum was the dominant species (71.7%), followed by G. boninense (26.1%) and G. miniatocinctum (2.2%). This suggests that G. zonatum may have played a more vital role in the epidemiology of the disease than previously believed. The multiplex PCR was a precise identification technique compared to morphological based identification. Ganoderma species in the oil palm plantation was genetically heterogeneous based on somatic compatibility test which is suggestive of disease spread via spore disp ersal that generates new genetically distinct individuals. There were also significant variations within and between Ganoderma species in terms of their cultural morphology and basidiospore characteristics. Cluster analysis of the cultural morphology and scattered plot of basidiospore features also indicated that there was no distinct relationship within and between species, disease types or geographical origins of Ganoderma species
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Journal Articles by Dr. Rakib Rashid