Displaying publications 21 - 33 of 33 in total

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  1. Fulltext Genomic insights into the evolution of Echinochloa species as weed and orphan crop
    Wu D, Shen E, Jiang B, Feng Y, Tang W, Lao S, et al.
    Nat Commun, 2022 02 03;13(1):689.
    PMID: 35115514 DOI: 10.1038/s41467-022-28359-9
    As one of the great survivors of the plant kingdom, barnyard grasses (Echinochloa spp.) are the most noxious and common weeds in paddy ecosystems. Meanwhile, at least two Echinochloa species have been domesticated and cultivated as millets. In order to better understand the genomic forces driving the evolution of Echinochloa species toward weed and crop characteristics, we assemble genomes of three Echinochloa species (allohexaploid E. crus-galli and E. colona, and allotetraploid E. oryzicola) and re-sequence 737 accessions of barnyard grasses and millets from 16 rice-producing countries. Phylogenomic and comparative genomic analyses reveal the complex and reticulate evolution in the speciation of Echinochloa polyploids and provide evidence of constrained disease-related gene copy numbers in Echinochloa. A population-level investigation uncovers deep population differentiation for local adaptation, multiple target-site herbicide resistance mutations of barnyard grasses, and limited domestication of barnyard millets. Our results provide genomic insights into the dual roles of Echinochloa species as weeds and crops as well as essential resources for studying plant polyploidization, adaptation, precision weed control and millet improvements.
    Matched MeSH terms: Plant Weeds/classification; Plant Weeds/genetics*
  2. Morphological Study of the Relationships between Weedy Rice Accessions (Oryza sativa Complex) and Commercial Rice Varieties in Pulau Pinang Rice Granary Area
    Hussain ZP, Man A, Othman AS
    Trop Life Sci Res, 2010 Dec;21(2):27-40.
    PMID: 24575197
    Weedy rice (WR) is found in many direct-seeded rice fields. WR possesses morphological characteristics that are similar to cultivated rice varieties in the early stage of growth, making them more difficult to control than other weeds. A comparative morphological study was conducted by collecting WR accessions from four sites within the Pulau Pinang rice growing areas. The objective of the study was to characterise WR accessions of the Pulau Pinang rice granary by comparing their morphological characteristics to those of commercially grown rice in the area. Their morphometric relations were established by comparing 17 morphological characteristics of the WR accessions and the commercial varieties. A total of 36 WR morphotypes were identified from these 4 sites based on 17 characteristics, which included grain shattering habit and germination rate. The Principal Component Analysis (PCA) showed that 45.88% of the variation observed among the WR accessions and commercial varieties were within the first 3 axes. PB6, PP2 and SGA5 WR accessions had a higher number of tillers and longer panicle lengths, culm heights and leaf lengths compared to the commercial rice. The grain sizes of the commercial varieties were slightly longer, and the chlorophyll contents at 60-70 days after sowing (DAS) were higher than those of the WR accessions. Results from this study are useful for predicting potential WR accession growth, which might improve WR management and agriculture practices that control WR in the future.
    Matched MeSH terms: Plant Weeds
  3. Fulltext Morphological study of the relationships between weedy rice accessions (Oryza sativa Complex) and commercial rice varieties in Pulau Pinang rice granary area
    Zainudin PMD Hussain, Azmi Man, Ahmad Sofiman Othman
    Trop Life Sci Res, 2010;21(2):-.
    MyJurnal
    Weedy rice (WR) is found in many direct-seeded rice fields. WR possesses morphological characteristics that are similar to cultivated rice varieties in the early stage of growth, making them more difficult to control than other weeds. A comparative morphological study was conducted by collecting WR accessions from four sites within the Pulau Pinang rice growing areas. The objective of the study was to characterise WR accessions of the Pulau Pinang rice granary by comparing their morphological characteristics to those of commercially grown rice in the area. Their morphometric relations were established by comparing 17 morphological characteristics of the WR accessions and the commercial varieties. A total of 36 WR morphotypes were identified from these 4 sites based on 17 characteristics, which included grain shattering habit and germination rate. The Principal Component Analysis (PCA) showed that 45.88% of the variation observed among the WR accessions and commercial varieties were within the first 3 axes. PB6, PP2 and SGA5 WR accessions had a higher number of tillers and longer panicle lengths, culm heights and leaf lengths compared to the commercial rice. The grain
    sizes of the commercial varieties were slightly longer, and the chlorophyll contents at 60–70 days after sowing (DAS) were higher than those of the WR accessions. Results from this study are useful for predicting potential WR accession growth, which might improve WR management and agriculture practices that control WR in the future.
    Matched MeSH terms: Plant Weeds
  4. Varietal response of chickpea (Cicer arietinum L.) towards the allelopathy of different weeds
    Rahamdad Khan, Ijaz Ahmad Khan
    Sains Malaysiana, 2015;44:25-30.
    In a laboratory trial three chickpea varieties viz, Karak-I, Karak-III and Shenghar were tested against the phytotoxicity of five weed species: Parthenium hysterophorus L., Phragmites australis (Cav.) Trin., Datura alba L., Cyperus rotundus L. and Convolvulus arvensis L.in January 2013. The weed extracts were prepared at the rate of 120 g/L (w/v) after shade dry. The results indicated highly significant inhibitory effect of all the tested weed species on the chickpea varieties. The results also showed that the chickpea variety Karak-III was more susceptible to the phytotoxcity of the tested weed extracts. Among the extract, C. arvensis proved much toxic in term of inhibition of germination by giving only 43.33% germination in comparison with control where 97.50% germination was recorded. On the other hand, the effect of P. australis extract was found a little stimulator by speeding the seed germination in all varieties and giving a low (2.21) mean germination time (MGT) value. From the current results it can be concluded that the infestation of C. arvensis can pollute the soil by accumulating toxic chemicals that leads to the germination failure and growth suppression in chickpea. Therefore, the prevention and removal of C. arvensis in the chickpea growing areas could be recommended. In addition, P. australis must be tested against chickpea weeds (chickpea varieties withstand against its phytotoxcity), so that it can be popularized as bioherbicide in chickpea if it gave promising results in controlling chickpea weeds.
    Matched MeSH terms: Plant Weeds
  5. Effects of biotic and abiotic environmental stimuli on the morphology and biomass allocation of mimosa pigra l.
    Nur-Zhafarina A., Asyraf M.
    Sains Malaysiana, 2017;46:1241-1248.
    The main focus of this study was to examine the morphology of Mimosa pigra, an invasive weed in response to artificial biotic and abiotic stressors. Seedlings of M. pigra were subjected to stressors such as seed sowing density, leaf defoliation and water regime. Comparatively, morphological performance related to different sowing practices differed significantly (p<0.05), as seedlings that grew from high density populations had lean and outstanding apical growth. A comparison between the four different levels of defoliation on the morphological changes revealed that the increase in leaf defoliation significantly decreased the plant morphological traits (i.e. height, stem diameter and flower bud productivity) and biomass allocation. Relatively low growth performance was found in plants subjected to 100% defoliation, with markedly lower flower bud productivity in comparison with 0%, 25% and 50% (no flower buds compared to 27, 13 and 6 flower buds, respectively). For water stress treatment, M. pigra showed no significant difference (p>0.05) in morphological performance under different levels of water regime. However, seedlings that received low water (LW) treatment showed better growth performance than seedlings that received high water (HW) treatment, which had the lowest morphological traits and biomass allocation.
    Matched MeSH terms: Plant Weeds
  6. The effect of salinity on chlorophyll, proline and mineral nutrients in common weeds of coastal rice fields in Malaysia
    Hakim MA, Juraimi AS, Hanafi MM, Ismail MR, Rafii MY, Aslani F, et al.
    J Environ Biol, 2014 Sep;35(5):855-64.
    PMID: 25204059
    Six weed species (Leptochola chinensis, Echinochloa crus-galli, Echinochloa colona, Jussiaea linifolia, Oryza sativa (weedy rice) and Cyperus iria) were tested for their salt tolerant traits in terms of chlorophyll, proline and mineral nutrients accumulation against different salinity levels (0, 4, 8, 16, 24, 32, and 40 dS m(-1)). Chlorophyll a, b and total chlorophyll content, proline and mineral nutrients accumulation were determined. Salt stress showed prominent effect on all the parameters investigated and there were significant variations between the all weed species. Chlorophyll content, K+, Ca(2+) and Mg(2+) ions in both shoots and roots significantly decreased; while proline and Na+ accumulation significantly increased with increasing salinity up to 40 dS m(-1). In terms of overall performance, Cyperus iria and E. crus-galliwere relatively more tolerant; E. colona and J. linifolia were tolerant; L. chinensis and O. sativa L were salt sensitive, respectively.
    Matched MeSH terms: Plant Weeds/metabolism*
  7. High Throughput Residue Analysis of Indaziflam and its Metabolites in Palm Oil Using Liquid Chromatography-Tandem Mass Spectrometry
    Halim N, Kuntom A, Shinde R, Banerjee K
    J AOAC Int, 2020 Sep 01;103(5):1237-1242.
    PMID: 33241391 DOI: 10.1093/jaoacint/qsaa041
    BACKGROUND: Indaziflam (IND) is a herbicide that is used in palm oil plantations for broad spectrum management of weeds. Until now, no validated method has been available for residue estimation of this herbicide in palm oil products.

    OBJECTIVE: In this study, we report a rapid method for the residue analysis of IND and its metabolites, viz., IND-carboxylic acid, diaminotriazine, and triazine indanone in a wide range of palm oil matrices using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    METHOD: The optimized sample preparation workflows included two options: (1) acetonitrile extraction (QuEChERS workflow), followed by freezing at -80°C and (2) acetonitrile extraction, followed by cleanup through a C18 solid phase extraction (SPE) cartridge. The optimized LC runtime was 7 min. All these analytes were estimated by LC-MS/MS multiple reaction monitoring.

    RESULTS: Both sample preparation methods provided similar method performance and acceptable results. The limit of quantification (LOQ) of IND, IND-carboxylic acid, and triazine indanone was 0.001 mg/kg. For diaminotriazine, the LOQ was 0.005 mg/kg. The method accuracy and precision complied with the SANTE/12682/2019 guidelines of analytical quality control.

    CONCLUSIONS: The potentiality of the method lies in a high throughput analysis of IND and its metabolites in a single chromatographic run with high selectivity and sensitivity. Considering its fit-for-purpose performance, the method can be implemented in regulatory testing of IND residues in a wide range of palm oil matrices that are consumed and traded worldwide.

    HIGHLIGHTS: This work has provided a validated method for simultaneous residue analysis of indaziflam and its metabolites in crude palm oil and its derived matrices with high sensitivity, selectivity, and throughput.

    Matched MeSH terms: Plant Weeds
  8. Fulltext PHYTOTOXIC ACTIVITY OF GERANIOL-TREATED LEMONGRASS LEAF MULCH AGAINST COMMON WEEDS IN NURSERIES
    NORLIYANA FATIN OMAR, CHUAH TSE SENG
    UMT Journal of Undergraduate Research, 2019;1(1):1-11.
    MyJurnal
    Hand weeding continues to be one of the most laborious aspects of nursery
    maintenance. Oxygenated monoterpene, an important group of secondary metabolite found in
    essential oils, has a potential herbicidal activity that could be exploited as natural herbicide
    whereas organic mulch could delay weed emergence. Thus, this study aimed to examine the
    phytotoxicity of geraniol, an oxygenated monoterpene compound, in combination with
    lemongrass leaf mulch against three common weeds, Eleusine indica (grass), Cyperus distans
    (sedge), and Tridax procumbens (broadleaf). Greenhouse experiments were carried out by
    treating 4.0 t/ha lemongrass leaf mulch with 7.5% (v/v) geraniol compound. The pretreated
    mulch acted synergistically and inhibited the emergence and shoot growth of T. procumbens
    completely. However, the pretreated mulch exhibited a moderate inhibitory effect on C. distans
    emergence and growth. Geraniol-treated lemongrass leaf mulch acted synergistically and
    inhibited the emergence of E. indica by 72%, but it acted antagonistically and caused a 45%
    reduction of shoot biomass. The present findings suggest that geraniol-treated lemongrass leaf
    mulch has potent herbicidal activity but its phytotoxic effect is species-dependent.
    Matched MeSH terms: Plant Weeds
  9. Differential response of Zea mays L. in relation to weed control and different macronutrient combinations
    Khan M, Kakar S, Marwat K, Khan I
    Sains Malaysiana, 2013;42:1395-1401.
    Time of weed control and fertilizer application usually decide the profitability of crop production. The effects of weed control and macronutrients on maize crop were investigated. The study was undertaken in March 2009, using a RCBD design with split plot arrangements. The experimental set up was established at the Agricultural University Peshawar and seedbeds were prepared with the proper moisture regime. Maize was planted with one plot left weed free for first six weeks while another infested with weed. The combinations of macronutrients used were nitrogen, phosphorus, potassium, nitrogen-phosphorus, nitrogen-potassium, phosphorus-potassium and nitrogen-phosphorus-potassium. Control (no fertilizer) was included for comparison. The observations revealed that when a comparison was made between the application of fertilizers and weed control, the latter proved more important because weed infested plots had no harvestable maize plants. The role of main nutrients in crop production is well known and cannot be left aside, however weed infestation does not provide us a fair choice of fertilizers application. The maximum maize grain yield was recorded under nitrogen-phosphorus combination and promising results were obtained. The weeds and maize benefited equally in terms of fresh and dry weed biomass with an application of fertilizer in particular N singly or together with P. In view of this, application of fertilizer should be changed from broadcast to band and/or placement. In general, a positive interaction was seen between N and P promoting the growth of maize and weeds. It can be said that herbicide application for weed control is important because of the fact that hand weeding is not economical, difficult, time consuming because of perennial weeds and hot weather conditions in the month of June.
    Matched MeSH terms: Plant Weeds
  10. The potential use of oil palm frond mulch treated with imazethapyr for weed control in Malaysian coconut plantation
    Masilaman D, Mazira Che Mat, Chuah TS
    Sains Malaysiana, 2017;46:1171-1182.
    ntroduction of new weed management strategy for coconut plantation in Malaysia is essential since the current weed control methods are less effective and highly herbicide dependent, thus leading to development of herbicide resistance in weeds as well as environmental and human health concerns. Thus, the present study aimed to evaluate the phytotoxic effects of oil palm frond mulch treated with imazethapyr at a reduced rate on weed emergence and growth. The results of glasshouse experiments have shown that imazethapyr at 12 g a.i. ha-1 in combination with oil palm residues of leaflet (OPL), rachis (OPR) or frond (OPF) at rates of 1.4-1.8 t ha-1 inhibited Eleusine indica emergence and growth by 90-100%, implying that imazethapyr is compatible with oil palm residue mulches. In the field experiment, hand weeding followed by OPF at 3.4 t ha-1 treated with imazethapyr at 24 g a.i. ha-1 have demonstrated excellent control of Mikania micrantha, Asystasia gangetica, Phyllanthus amarus, Panicum sp. and Echinochloa colona by reducing their total dry weight up to 95% at three months after treatment. The present results suggested that the integration of chemical, physical and mechanical methods can provide effective weed control in the coconut plantation for months.
    Matched MeSH terms: Plant Weeds
  11. Evaluation of the allelopathic potential of fifteen common Malaysian weeds
    Nurul Ain MB, Ismail BS, Nornasuha Y
    Sains Malaysiana, 2017;46:1413-1420.
    The use of allelopathy concept in weed management has received attentions to minimize extensively the reliance on herbicide applications on the agriculture industry in Malaysia. A laboratory study was conducted to evaluate the allelopathic potential of 15 Malaysian common weed species of different morphological characteristics (broadleaves, sedges and grasses). They were screened using the Sandwich method (from leaf litter leachate) and the Dish pack method (for testing the presence and content of volatile compounds in weeds). Among the 15 weed species tested, the leaf litter leachate of Centrosema pubescens was observed to be the most sensitive plant material inhibiting the growth of lettuce radicle (84%) and hypocotyl (55%) in the Sandwich bioassay compared to the control. This was followed by Asystasia gangentica (81%) and Cynodon dactylon (80%) inhibiting the lettuce radicle growth. In the Dish pack bioassay, Rhynchelytrum repens demonstrated maximum inhibition on the radicle and hypocotyl elongations by 44% and 29%, respectively, (over control) at 41 mm distance from the source well. Meanwhile, at the same distance, Cynodon dactylon was observed to have the least inhibitory effect on lettuce radicle growth by 12%. The results presented can be utilized as benchmark information for further research on the identification and isolation of allelochemicals for weed control strategies.
    Matched MeSH terms: Plant Weeds
  12. Optimisation of culture composition for glyphosate degradation byBurkholderia vietnamiensisstrain AQ5-12
    Manogaran M, Shukor MY, Yasid NA, Khalil KA, Ahmad SA
    3 Biotech, 2018 Feb;8(2):108.
    PMID: 29430369 DOI: 10.1007/s13205-018-1123-4
    The herbicide glyphosate is often used to control weeds in agricultural lands. However, despite its ability to effectively kill weeds at low cost, health problems are still reported due to its toxicity level. The removal of glyphosate from the environment is usually done by microbiological process since chemical process of degradation is ineffective due to the presence of highly stable bonds. Therefore, finding glyphosate-degrading microorganisms in the soil of interest is crucial to remediate this glyphosate.Burkholderia vietnamiensisstrain AQ5-12 was found to have glyphosate-degrading ability. Optimisation of biodegradation condition was carried out utilising one factor at a time (OFAT) and response surface methodology (RSM). Five parameters including carbon and nitrogen source, pH, temperature and glyphosate concentration were optimised. Based on OFAT result, glyphosate degradation was observed to be optimum at fructose concentration of 6, 0.5 g/L ammonia sulphate, pH 6.5, temperature of 32 °C and glyphosate concentration at 100 ppm. Meanwhile, RSM resulted in a better degradation with 92.32% of 100 ppm glyphosate compared to OFAT. The bacterium was seen to tolerate up to 500 ppm glyphosate while increasing concentration results in reduced degradation and bacterial growth rate.
    Matched MeSH terms: Plant Weeds
  13. Fulltext Ser-653-Asn substitution in the acetohydroxyacid synthase gene confers resistance in weedy rice to imidazolinone herbicides in Malaysia
    Ruzmi R, Ahmad-Hamdani MS, Mazlan N
    PLoS One, 2020;15(9):e0227397.
    PMID: 32925921 DOI: 10.1371/journal.pone.0227397
    The continuous and sole dependence on imidazolinone (IMI) herbicides for weedy rice control has led to the evolution of herbicide resistance in weedy rice populations across various countries growing IMI herbicide-resistant rice (IMI-rice), including Malaysia. A comprehensive study was conducted to elucidate occurrence, level, and mechanisms endowing resistance to IMI herbicides in putative resistant (R) weedy rice populations collected from three local Malaysian IMI-rice fields. Seed bioassay and whole-plant dose-response experiments were conducted using commercial IMI herbicides. Based on the resistance index (RI) quantification in both experiments, the cross-resistance pattern of R and susceptible (S) weedy rice populations and control rice varieties (IMI-rice variety MR220CL2 and non-IMI-rice variety MR219) to imazapic and imazapyr was determined. A molecular investigation was carried out by comparing the acetohydroxyacid synthase (AHAS) gene sequences of the R and S populations and the MR220CL2 and MR219 varieties. The AHAS gene sequences of R weedy rice were identical to those of MR220CL2, exhibiting a Ser-653-Asn substitution, which was absent in MR219 and S plants. In vitro assays were conducted using analytical grade IMI herbicides of imazapic (99.3%) and imazapyr (99.6%) at seven different concentrations. The results demonstrated that the AHAS enzyme extracted from the R populations and MR220CL2 was less sensitive to IMI herbicides than that from S and MR219, further supporting that IMI herbicide resistance was conferred by target-site mutation. In conclusion, IMI resistance in the selected populations of Malaysian weedy rice could be attributed to a Ser-653-Asn mutation that reduced the sensitivity of the target site to IMI herbicides. To our knowledge, this study is the first to show the resistance mechanism in weedy rice from Malaysian rice fields.
    Matched MeSH terms: Plant Weeds/drug effects*; Plant Weeds/genetics
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