Universiti Putra Malaysia
Download Latest Complete Journal - JTAS Vol. 39 (3) Aug. 2016
Foreword by the Chief Executive Editor
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Abstract (Viewed: 48)Current climate change is projected to have significant effects on temperature and precipitation profiles, increasing the incidence and severity of drought. Drought is the single largest abiotic stress factor leading to reduced crop yields. Given the large share of water use in the agriculture sector and very low efficiency in this sector, selection and development of the new strategies to improve and optimise irrigation water use with significant savings is essential. The usage of Superabsorbent polymers (SAPs) is one of the strategies in this regard. This paper briefly mentions to the previous studies about the effects of SAPs on soils and plants, suitable usage rate of SAPs for improvement of soils, raising of WUE and amount of irrigation water saving in this field. The results showed that SAPs could store water and nutrients and release them in drought stress conditions in light soils. Therefore, an acceptable biologic and grain yield with less irrigation water depth could be achieved.Superabsorbent polymer, Irrigation interval, Deficit irrigation
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Abstract (Viewed: 5)Water-wise rice cultivation is a growing concern in rice production. We justified the effects of different water levels on rice production of upland variety. A completely randomised design was arranged with four treatments (T1: flooding at 5 cm depth, T2: flooding at 1 – 3 cm depth, T3: saturated to 1 cm flooding, and T4: alternative wetting and drying, or AWD) with five replications. Yield, plants and soil parameters were evaluated. Upland rice variety showed improved yields and yield parameters under flooding at 5 cm depth treatment than alternative wetting and drying treatment. Flooding water significantly increased plant height, tiller numbers, panicle numbers, panicle height, grains per panicle and yield compared to AWD treatment. Chlorophyll (Chl) content increased gradually with increasing plant age but flooding at 5 cm treatment increased Chl content after the secondary tillering. Net photosynthesis rate (Pn) and relative water content (RWC) decreased in plants under alternative wetting and drying treatment than control treatment. Saturated to 1 cm flooding treatment saved 42% of water used in the treatment of flooding at 5 cm depth, which showed a similar water use efficiency (WUE) to alternative wetting and drying treatment. However, treatments of flooding at 1 – 3 cm depth and saturated to 1 cm flooding showed a similar effects on rice yield. Meanwhile, saturated or above soil water condition did not affect soil pH, soil electric conductivity (EC) and phytoavailability of nutrients in the soil. These results suggested that saturated to 1 cm flooding irrigation could increase rice yield of upland variety and save fresh water for other purposes at the same time.Water use efficiency, chlorophyll content, photosynthesis, relative water content, flooding effects, rice yield
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Abstract (Viewed: 9)Roasting is the most important step in the coffee processing. The impact of superheated steam roasting temperature (150, 200, 250°C) and time (10-50 min) on the color (L*, a*, b*, browning index), moisture and hardness attributes of Coffea canephora (Robusta coffee) beans were studied. Increases in roasting temperature and time caused a decrease in all the responses except for browning index, a* and b* values of roasted coffee beans. A decrease in the hardness of coffee bean during roasting has been correlated to the loss of moisture content. Coffee beans exhibit greater bean volume, pore volume and larger micropores during roasting process, which indirectly lead to the loss of moisture content. With regards to the prolonged superheated steam roasting, it significantly affects colour attributes and moisture content. As the roasting temperature increased up to 250ºC, colour attributes such as browning index, a* and b* values decreased significantly whereas moisture content increased slightly.Cultivars, grass-legume, highworth, relative yield, rongai
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Abstract (Viewed: 3)Suitable protocol for identification and classification of microalgae using scanning electron microscopy, coupled with energy dispersive X-ray spectroscopy (SEM-EDX), is important to obtain accurate information of their ultrastructure description. The objective of this study was to modify microalgae pre-treatments for reliable SEM-EDX analysis. Sixteen cultured tropical microalgae were subjected to two-step chemical fixation of glutaraldehyde and osmium tetroxide, sample washing in sodium cacodylate, ethanol and acetone dehydration, critical point-drying, mounting and gold sputter-coating prior to SEM visualisation and elemental characterisation. In this study, short period of chemical fixation and optimum separation forces, at 3213 x g for 3 min during every chemical solution change, were successfully established with high quality SEM images. Ultrastructure, particularly clear and useful images of cell wall ornamentation in Scenedesmus spp. and Desmodesmus sp.; areola patterns in Biddulphia sinensis and Thalassiosira sp. and morphological appearances such as interconnecting structures in Coelastrum sp. and Crucigenia sp., were obtained. Twelve elements of Y, Nb, Fe, Ca, Cl, K, Cu, F, Ir, P, Mg and Si were detected within the 16 investigated microalgae species. This study illustrated that microalgae identification and classification, as well as their elemental characterisation, could be simultaneously and effectively analysed by SEM-EDX using a modified pre-treatment protocol.Microalgae, morphology, ultrastructure, elemental profiles, modified SEM-EDX pre-treatment protocol
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Abstract (Viewed: 4)A field study was conducted for two consecutive rice-growing seasons from August, 2013 to May, 2014 to understand the population dynamics of exotic apple snails, Pomacea spp. (Ampullariidae), as affected by ambient weather and aquatic weeds. A one-acre rice field was divided into four blocks and eight samples per block were taken using a 0.5x0.5m quadrat. Collected snails were recorded as numbers of egg clutches, juveniles, adult females and males. Average rainfall, relative humidity, temperature and water pH, along with number of aquatic weeds and seedlings, were also recorded. Results confirmed the presence of only Pomacea maculata. The numbers of egg clutches, juveniles and adults were relatively high during the off-season as compared to the main-season. Meanwhile, relative humidity had a significant effect on the number of egg clutches, and rainfall affected the densities of juveniles and adults. Among the weeds, Limnocharis flava (Alismataceae) had significant effect on the densities of different snail stages. Different stages showed uniform dispersion pattern during both seasons due presumably to continuous availability of water and abundant food. Thus, results obtained could be helpful in understanding the population dynamics of P. maculata and devising appropriate management strategy.Apple snail, rice, weeds, population fluctuation, dispersion, weather, Pomacea
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Abstract (Viewed: 3)Stingless bees are dispersed throughout Malaysia and form an important group of pollinators in agriculture and natural ecosystems. A study was conducted at Lojing Highland in Kelantan, Malaysia on the preference of stingless bees towards pre-mix bait [sugar and salt (1:2) (sugar: water:v:v)] with 2.5g NaCl added per 500 ml of solution] and urine bait for two consecutive days. A total of 285 stingless bees of 15 species were sampled for this purpose. Overall, stingless bees showed no preference for either bait, but a closer examination showed species-level preferences. Five species preferred urine bait over pre-mix bait, and another eight preferred pre-mix bait over urine bait. No significant differences were found on stingless bees preferences towards pre-mix bait and urine baits (p>0.05). Five stingless bee species (Lisotrigona scintillans, Pariotrigona pendleburyi, Lepidotrigona ventralis, Tetrigona apicalis, and Tetragonula collina) were found to be frequently attracted to the urine bait compared with pre-mix bait. Meanwhile, eight stingless bee species attracted to pre-mix bait compared with urine bait. This study shows that stingless bees' preference for pre-mix or urine baits depends on species.Stingless bee, pre-mix, urine, bait preference
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Abstract (Viewed: 3)This study was conducted to determine the laying performance, egg quality and meat texture of aged layer hens fed with soy lecithin. A total of 100 layer hens (Novogen Brown), aged 76-weeks old, were randomly assigned to five treatment groups and treated as follows: basal diet with 0% (control), 2%, 4%, 6% and 8% soy lecithin, respectively. After four weeks of treatment, lecithin showed no improvement in body weight gain, egg mass, egg production, feed intake, feed conversion efficiency, egg quality and meat texture. Meanwhile, egg weight increased in birds fed with 2% lecithin (P=0.02) and this might be attributed to the high linoleic acid content in soy lecithin. The results implied that feeding hens with 2% lecithin increased egg weight but it had no beneficial effects on other laying performance parameters. Thus, it is of interest to investigate potential benefits of lecithin on different dietary fat sources.Adulteration, crude palm oil, fatty acid methyl esters, GC-FID, HPLC-ELSD, principal component analysis, triacylglycerol
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Abstract (Viewed: 2)Bacterial wilt is a major ginger disease in Sabah after rhizome rot. The disease has affected the production of ginger in Sabah since 2005. In this study, the ginger plants with foliar symptoms (yellowing and wilting), collected from six ginger-growing areas in the Tambunan and Ranau districts, were observed to have signs of bacterial pathogen (i.e., rhizome rot and bacterial ooze). A total of 19 bacterial strains were isolated, and all of the isolates were characterised as rod-shaped and Gram-negative by Gram-staining and potassium hydroxide test and microscopic examination. MALDI-TOF analysis identified six species from the isolates: Enterobacter cloacae complex (57.9%), Ralstonia pickettii (10.5%), Agrobacterium tumefaciens (10.5%), Bacillus pumilus (10.5%), Stenotrophomonas maltophilia (5.3%) and Serratia marcescens (5.3%). In pathogenicity test, E. cloacae, which constituted most of the isolates, induced mild rot symptoms (discoloration) on ginger rhizome slices, but no disease symptoms were produced in ginger plants. Further studies on the interaction of E. cloacae with other isolated species are required to confirm the causes of ginger wilt disease in Sabah, Malaysia.ginger, ginger wilt disease, Enterobacter cloacae complex
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Abstract (Viewed: 5)Variability and correlation for twelve grain characters (before cooking) and eight characters (after cooking) on distinct six lines viz. S1, S2, S5, 42(i), 42(ii) and 44(i) of Basmati rice were studied. Before cooking, the maximum hulling (%), milling outturn (%) and head rice recovery were recorded in S2 genotype. The highest kernel length and breadth of rice were also found in S2, whereas the highest kernel length and breadth ratio (L/B) of brown, rough and milled rice were observed in S2, S1 and S5 genotypes, respectively. After cooking, the highest kernel length and breadth were recorded in S2, while the highest length and breadth ratio was noted in 42(ii) genotype. The highest kernel elongation ratio and volume expansion were recorded in S5. The maximum alkaline spreading value and the minimum cooking time were found in S2. The L/B ratio of rough rice exhibited significant positive relationship with L/B of brown, milled and cooked rice.Variability, correlation, grain quality components, Basmati rice

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