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Fulltext Genotypic and Phenotypic Relationship among Yield Components in Rice under Tropical Conditions

Oladosu Y, Rafii MY, Magaji U, Abdullah N, Miah G, Chukwu SC, et al.

Biomed Res Int, 2018;2018:8936767.
PMID: 30105259 DOI: 10.1155/2018/8936767

The associations among yield-related traits and the pattern of influence on rice grain yield were investigated. This evaluation is important to determine the direct and indirect effects of various traits on yield to determine selection criteria for higher grain yield. Fifteen rice genotypes were evaluated under tropical condition at five locations in two planting seasons. The experiment was laid out in a randomized complete block design with three replications across the locations. Data were collected on vegetative and yield components traits. The pooled data based on the analysis of variance revealed that there were significant differences (p < 0.001) among the fifteen genotypes for all the characters studied except for panicle length and 100-grain weight. Highly significant and positive correlations at phenotypic level were observed in grain weight per hill (0.796), filled grains per panicle (0.702), panicles per hill (0.632), and tillers per hill (0.712) with yield per hectare, while moderate positive correlations were observed in flag leaf length to width ratio (0.348), days to flowering (0.412), and days to maturity (0.544). By contrast, unfilled grains per panicle (-0.225) and plant height (-0.342) had a negative significant association with yield per hectare. Filled grains per panicle (0.491) exhibited the maximum positive direct effect on yield followed by grain weight per hill (0.449), while unfilled grain per panicle (-0.144) had a negative direct effect. The maximum indirect effect on yield per hectare was recorded by the tillers per hill through the panicles per hill. Therefore, tillers per hill, filled grains per panicle, and grain weight per hill could be used as selection criteria for improving grain yield in rice.

Matched MeSH terms: Tropical Climate
Mercury Bioaccumulation in Tropical Mangrove Wetland Fishes: Evaluating Potential Risk to Coastal Wildlife

Le DQ, Satyanarayana B, Fui SY, Shirai K

Biol Trace Elem Res, 2018 Dec;186(2):538-545.
PMID: 29577182 DOI: 10.1007/s12011-018-1313-2

The present study, aimed at observing the total concentration of mercury (Hg) in edible finfish species with an implication to human health risk, was carried out from the Setiu mangrove wetlands on the east coast of Peninsular Malaysia. Out of 20 species observed, the highest Hg concentrations were found among carnivores-fish/invertebrate-feeders, followed by omnivores and carnivores-invertebrate-feeders, while the lowest concentrations in herbivores. The Hg concentrations varied widely with fish species and body size, from 0.12 to 2.10 mg/kg dry weight. A positive relationship between body weight and Hg concentration was observed in particular for Toxotes jaculatrix and Tetraodon nigroviridis. Besides the permissible range of Hg concentration up to 0.3 mg/kg (cf. United States Environmental Protection Agency (USEPA)) in majority of species, the carnivore feeders such as Acanthopagrus pacificus, Gerres filamentosus, and Caranx ignobilis have shown excess amounts (> 0.40 mg/kg flesh weight) that raising concerns over the consumption by local people. However, the weekly intake of mercury-estimated through the fish consumption in all three trophic levels-suggests that the present Hg concentrations are still within the range of Provisional Tolerable Weekly Intake (PTWI) reported by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Perhaps, a multi-species design for Hg monitoring at Setiu wetlands would be able to provide further insights into the level of toxicity transfer among other aquatic organisms and thereby a strong health risk assessment for the local communities.

Matched MeSH terms: Tropical Climate
Fulltext Biodiversity hanging by a thread: the importance of fungal litter-trapping systems in tropical rainforests

Snaddon JL, Turner EC, Fayle TM, Khen CV, Eggleton P, Foster WA

Biol Lett, 2012 Jun 23;8(3):397-400.
PMID: 22188674 DOI: 10.1098/rsbl.2011.1115

The exceptionally high species richness of arthropods in tropical rainforests hinges on the complexity of the forest itself: that is, on features such as the high plant diversity, the layered nature of the canopy and the abundance and the diversity of epiphytes and litter. We here report on one important, but almost completely neglected, piece of this complex jigsaw-the intricate network of rhizomorph-forming fungi that ramify through the vegetation of the lower canopy and intercept falling leaf litter. We show that this litter-trapping network is abundant and intercepts substantial amounts of litter (257.3 kg ha(-1)): this exceeds the amount of material recorded in any other rainforest litter-trapping system. Experimental removal of this fungal network resulted in a dramatic reduction in both the abundance (decreased by 70.2 ± 4.1%) and morphospecies richness (decreased by 57.4 ± 5.1%) of arthropods. Since the lower canopy levels can contain the highest densities of arthropods, the proportion of the rainforest fauna dependent on the fungal networks is likely to be substantial. Fungal litter-trapping systems are therefore a crucial component of habitat complexity, providing a vital resource that contributes significantly to rainforest biodiversity.

Matched MeSH terms: Tropical Climate
Kinetic and stoichiometric characterization for efficient enhanced biological phosphorus removal (EBPR) process at high temperatures

Liau KF, Shoji T, Ong YH, Chua AS, Yeoh HK, Ho PY

Bioprocess Biosyst Eng, 2015 Apr;38(4):729-37.
PMID: 25381606 DOI: 10.1007/s00449-014-1313-3

A recently reported stable and efficient EBPR system at high temperatures around 30 °C has led to characterization of kinetic and stoichiometric parameters of the Activated Sludge Model no. 2d (ASM2d). Firstly, suitable model parameters were selected by identifiability analysis. Next, the model was calibrated and validated. ASM2d was found to represent the processes well at 28 and 32 °C except in polyhyroxyalkanoate (PHA) accumulation of the latter. The values of the kinetic parameters for PHA storage (q PHA), polyphosphate storage (q PP) and growth (μ PAO) of polyphosphate-accumulating organisms (PAOs) at 28 and 32 °C were found to be much higher than those reported by previous studies. Besides, the value of the stoichiometric parameter for the requirement of polyphosphate for PHA storage (Y PO4) was found to decrease as temperature rose from 28 to 32 °C. Values of two other stoichiometric parameters, i.e. the growth yield of heterotrophic organisms (Y H) and PAOs (Y PAO), were high at both temperatures. These calibrated parameters imply that the extremely active PAOs of the study were able to store PHA, store polyphosphate and even utilize PHA for cell growth. Besides, the parameters do not follow the Arrhenius correlation due to the previously reported unique microbial clade at 28 and 32 °C, which actively performs EBPR at high temperatures.

Matched MeSH terms: Tropical Climate
Fulltext Melioidosis: Cases Notified to Kota Kinabalu District Health Office Year 2017

Rosfina Ghazali

Borneo Journal of Medical Sciences, 2018;12(101):29-0.
MyJurnal

Melioidosis is a tropical infectious disease cause by gram-negative bacterium, Burkholderia pseudomallei. It is predominantly in tropical climate especially Southeast Asia and Northern Australia. This disease is associated with significant mortality due to early onset of sepsis.

Matched MeSH terms: Tropical Climate
Resource use of insect seed predators during general flowering and seeding events in a Bornean dipterocarp rain forest

Nakagawa M, Itioka T, Momose K, Yumoto T, Komai F, Morimoto K, et al.

Bull. Entomol. Res., 2003 Oct;93(5):455-66.
PMID: 14658448

Insect seed predators of 24 dipterocarp species (including the genera ot Dipterocarpus, Dryobalanops and Shorea) and five species belonging to the Moraceae, Myrtaceae, Celastraceae and Sapotaceae were investigated. In a tropical lowland dipterocarp forest in Sarawak, Malaysia, these trees produces seeds irregularly by intensely during general flowering and seeding events in 1996 and/or 1998. Dipterocarp seeds were preyed on by 51 insect species (11 families), which were roughly classified into three taxonomic groups: smaller moths (Trotricidae, Pyralidae, Crambidae, Immidae, Sesiidae, and Cosmopterigidae), scolytids (Scolydae) and weevils (Curdulionidae, Apionidae, Anthribidae, and Attelabidae). Although the host-specificity of invertebrate seed predators has been assumed to be high in tropical forests, it was found that the diet ranges of some insect predators were relatively wide and overlapped one another. Most seed predators that were collected in both study years changes their diets between general flowering and seeding events. The results of cluster analyses based on the number of adult of each predator species that emerged from 100 seeds of each tree species, suggested that the dominant species was not consistent, alternating between the two years.

Matched MeSH terms: Tropical Climate
Persistence of fenvalerate in three Malaysian agricultural soils

Ismail BS, Maznah Z

Bull Environ Contam Toxicol, 2005 Oct;75(4):789-96.
PMID: 16400562
Matched MeSH terms: Tropical Climate
Adsorption, desorption, and mobility of metsulfuron methyl in Malaysian agricultural soils

Abdullah AR, Sinnakkannu S, Tahir NM

Bull Environ Contam Toxicol, 2001 Jun;66(6):762-9.
PMID: 11353379
Matched MeSH terms: Tropical Climate
Degradation of two acetanilide herbicides in a tropical soil

Sahid IB, Wei CC

Bull Environ Contam Toxicol, 1993 Jan;50(1):24-8.
PMID: 8418934
Matched MeSH terms: Tropical Climate*
Fulltext Field and laboratory observations in Sabah, East Malaysia on the proportion of Anopheles balabecensis balabacensis eggs hatching after holding in a humid atmosphere

Rajapaksa N

Bull World Health Organ, 1971;45(2):263-5.
PMID: 5316626
Matched MeSH terms: Tropical Climate
Fulltext Influenza seasonality and vaccination timing in tropical and subtropical areas of southern and south-eastern Asia

Saha S, Chadha M, Al Mamun A, Rahman M, Sturm-Ramirez K, Chittaganpitch M, et al.

Bull World Health Organ, 2014 May 01;92(5):318-30.
PMID: 24839321 DOI: 10.2471/BLT.13.124412

OBJECTIVE: To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and south-eastern Asia that lie north of the equator.
METHODS: Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries.
FINDINGS: Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao People's Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator.
CONCLUSION: Most southern and south-eastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors.

Matched MeSH terms: Tropical Climate
Disease, race, and empire

Anderson W

Bull Hist Med, 1996;70(1):62-7.
PMID: 8850070
Matched MeSH terms: Tropical Climate
Effects of simulated warming on bacterial diversity and abundance in tropical soils from East Malaysia using open top chambers

Chua CY, Wong CMVL

Can J Microbiol, 2021 Jan;67(1):64-74.
PMID: 33084348 DOI: 10.1139/cjm-2019-0461

The effects of global warming are increasingly evident, where global surface temperatures and atmospheric concentration of carbon dioxide have increased in past decades. Given the role of terrestrial bacteria in various ecological functions, it is important to understand how terrestrial bacteria would respond towards higher environmental temperatures. This study aims to determine soil bacterial diversity in the tropics and their response towards in situ warming using an open-top chamber (OTC). OTCs were set up in areas exposed to sunlight throughout the year in the tropical region in Malaysia. Soil samples were collected every 3 months to monitor changes in bacterial diversity using V3-V4 16S rDNA amplicon sequencing inside the OTCs (treatment plots) and outside the OTCs (control plots). After 12 months of simulated warming, an average increase of 0.81 to 1.15 °C was recorded in treatment plots. Significant changes in the relative abundance of bacterial phyla such as Bacteroidetes and Chloroflexi were reported. Increases in the relative abundance of Actinobacteria were also observed in treatment plots after 12 months. Substantial changes were observed at the genus level, where most bacterial genera decreased in relative abundance after 12 months. This study demonstrated that warming can alter soil bacteria in tropical soils from Kota Kinabalu.

Matched MeSH terms: Tropical Climate
Fulltext Soil nitrogen concentration mediates the relationship between leguminous trees and neighbor diversity in tropical forests

Xu H, Detto M, Fang S, Chazdon RL, Li Y, Hau BCH, et al.

Commun Biol, 2020 06 19;3(1):317.
PMID: 32561898 DOI: 10.1038/s42003-020-1041-y

Legumes provide an essential service to ecosystems by capturing nitrogen from the atmosphere and delivering it to the soil, where it may then be available to other plants. However, this facilitation by legumes has not been widely studied in global tropical forests. Demographic data from 11 large forest plots (16-60 ha) ranging from 5.25° S to 29.25° N latitude show that within forests, leguminous trees have a larger effect on neighbor diversity than non-legumes. Where soil nitrogen is high, most legume species have higher neighbor diversity than non-legumes. Where soil nitrogen is low, most legumes have lower neighbor diversity than non-legumes. No facilitation effect on neighbor basal area was observed in either high or low soil N conditions. The legume-soil nitrogen positive feedback that promotes tree diversity has both theoretical implications for understanding species coexistence in diverse forests, and practical implications for the utilization of legumes in forest restoration.

Matched MeSH terms: Tropical Climate
Fulltext Habitat degradation and indiscriminate hunting differentially impact faunal communities in the Southeast Asian tropical biodiversity hotspot

Tilker A, Abrams JF, Mohamed A, Nguyen A, Wong ST, Sollmann R, et al.

Commun Biol, 2019;2:396.
PMID: 31701025 DOI: 10.1038/s42003-019-0640-y

Habitat degradation and hunting have caused the widespread loss of larger vertebrate species (defaunation) from tropical biodiversity hotspots. However, these defaunation drivers impact vertebrate biodiversity in different ways and, therefore, require different conservation interventions. We conducted landscape-scale camera-trap surveys across six study sites in Southeast Asia to assess how moderate degradation and intensive, indiscriminate hunting differentially impact tropical terrestrial mammals and birds. We found that functional extinction rates were higher in hunted compared to degraded sites. Species found in both sites had lower occupancies in the hunted sites. Canopy closure was the main predictor of occurrence in the degraded sites, while village density primarily influenced occurrence in the hunted sites. Our findings suggest that intensive, indiscriminate hunting may be a more immediate threat than moderate habitat degradation for tropical faunal communities, and that conservation stakeholders should focus as much on overhunting as on habitat conservation to address the defaunation crisis.

Matched MeSH terms: Tropical Climate*
Prevalence of dental fluorosis in children in Singapore

Lo GL, Bagramian RA

Community Dent Oral Epidemiol, 1996 Feb;24(1):25-7.
PMID: 8833510

Prevalence and severity of dental fluorosis was assessed in 1739 Singaporean children aged 9, 12 and 16 yr in three different ethnic groups. All subjects had resided since birth in Singapore, which has a tropical climate. The water supply was fluoridated in 1957 at a level of 0.7 ppm. In this sample, mouth prevalence was 82.6%, tooth prevalence was 66.9%, the community fluorosis index was at 1.96; 9.2% of children had severe fluorosis and 26.2% had moderate fluorosis. There were no significant gender or racial differences. Prevalences were higher than those reported in most other studies. Due to differences in indices used and methodology, comparisons could not be made directly with other studies.

Matched MeSH terms: Tropical Climate
The value of rehabilitating logged rainforest for birds

Edwards DP, Ansell FA, Ahmad AH, Nilus R, Hamer KC

Conserv Biol, 2009 Dec;23(6):1628-33.
PMID: 19775274 DOI: 10.1111/j.1523-1739.2009.01330.x

The recent advent of carbon crediting has led to a rapid rise in biosequestration projects that seek to remove carbon from the atmosphere through afforestation and forest rehabilitation. Such projects also present an important potential opportunity to reverse biodiversity losses resulting from deforestation and forest degradation, but the biodiversity benefits of different forms of biosequestration have not been considered adequately. We captured birds in mist nets to examine the effects of rehabilitation of logged forest on birds in Sabah, Borneo, and to test the hypothesis that rehabilitation restores avian assemblages within regenerating forest to a condition closer to that seen in unlogged forest. Species richness and diversity were similar in unlogged and rehabilitated forest, but significantly lower in naturally regenerating forest. Rehabilitation resulted in a relatively rapid recovery of populations of insectivores within logged forest, especially those species that forage by sallying, but had a marked adverse effect on frugivores and possibly reduced the overall abundance of birds within regenerating forest. In view of these results, we advocate increased management for heterogeneity within rehabilitated forests, but we strongly urge an increased role for forest rehabilitation in the design and implementation of a biodiversity-friendly carbon-offsetting market.

Matched MeSH terms: Tropical Climate
Predicting how defaunation-induced changes in seed predation and dispersal will affect tropical tree populations

Williams PJ, Brodie JF

Conserv Biol, 2023 Apr;37(2):e14014.
PMID: 36178021 DOI: 10.1111/cobi.14014

The loss of large animals due to overhunting and habitat loss potentially affects tropical tree populations and carbon cycling. Trees reliant on large-bodied seed dispersers are thought to be particularly negatively affected by defaunation. But besides seed dispersal, defaunation can also increase or decrease seed predation. It remains unclear how these different defaunation effects on early life stages ultimately affect tree population dynamics. We reviewed the literature on how tropical animal loss affects different plant life stages, and we conducted a meta-analysis of how defaunation affects seed predation. We used this information to parameterize models that altered matrix projection models from a suite of tree species to simulate defaunation-caused changes in seed dispersal and predation. We assessed how applying these defaunation effects affected population growth rates. On average, population-level effects of defaunation were negligible, suggesting that defaunation may not cause the massive reductions in forest carbon storage that have been predicted. In contrast to previous hypotheses, we did not detect an effect of seed size on changes in seed predation rates. The change in seed predation did not differ significantly between exclosure experiments and observational studies, although the results of observational studies were far more variable. Although defaunation surely affects certain tree taxa, species that benefit or are harmed by it and net changes in forest carbon storage cannot currently be predicted based on available data. Further research on how factors such as seed predation vary across tree species and defaunation scenarios is necessary for understanding cascading changes in species composition and diversity.

Matched MeSH terms: Tropical Climate
The siamang in Malaya. A field study of a primate in tropical rain forest

Chivers DJ

Contrib Primatol, 1974;4:1-335.
PMID: 4474071
Matched MeSH terms: Tropical Climate
Distinctive exotic flavor and aroma compounds of some exotic tropical fruits and berries: a review

Lasekan O, Abbas KA

Crit Rev Food Sci Nutr, 2012;52(8):726-35.
PMID: 22591343 DOI: 10.1080/10408398.2010.507910

The characteristic flavor of exotic tropical fruits is one of their most attractive attributes to consumers. In this article, the enormous diversity of exotic fruit flavors is reviewed. Classifying some of the exotic fruits into two classes on the basis of whether esters or terpenes predominate in the aroma was also attempted. Indeed, as far as exotic tropical fruits are concerned, the majority of fruits have terpenes predominating in their aroma profile. Some of the fruits in this group are the Amazonian fruits such as pitanga, umbu-caja, camu-camu, garcinia, and bacuri. The ester group is made up of rambutan, durians, star fruit, snake fruit, acerola, tamarind, sapodilla, genipap, soursop, cashew, melon, jackfruit, and cupuacu respectively. Also, the role of sulphur-volatiles in some of the exotic fruits is detailed.

Matched MeSH terms: Tropical Climate*

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