Comparative study of endophytic and endophytic diazotrophic bacterial communities across rice landraces grown in the highlands of northern Thailand

Communities of bacterial endophytes within the rice landraces cultivated in the highlands of northern Thailand were studied using fingerprinting data of 16S rRNA and nifH genes profiling by polymerase chain reaction–denaturing gradient gel electrophoresis. The bacterial communities’ richness, diversity index, evenness, and stability were varied depending on the plant tissues, stages of growth, and rice cultivars. These indices for the endophytic diazotrophic bacteria within the landrace rice Bue Wah Bo were significantly the lowest. The endophytic bacteria revealed greater diversity by cluster analysis with seven clusters compared to the endophytic diazotrophic bacteria (three clusters). Principal component analysis suggested that the endophytic bacteria showed that the community structures across the rice landraces had a higher stability than those of the endophytic diazotrophic bacteria. Uncultured bacteria were found dominantly in both bacterial communities, while higher generic varieties were observed in the endophytic diazotrophic bacterial community. These differences in bacterial communities might be influenced either by genetic variation in the rice landraces or the rice cultivation system, where the nitrogen input affects the endophytic diazotrophic bacterial community

Effects of arbuscular mycorrhizal fungi on resistance to Phytophthora parasitica of citrus seedlings and on growth of Thai honey tangerine scions on citrus rootstocks

Thai honey tangerine (Sainamphueng tangerine) is generally grown by grafting on rootstocks of another variety of tangerine or citrus species which may differ in their reaction to beneficial and pathogenic soil organisms. The objectives of this study were to evaluate responses to arbuscular mycorrhizal (AM) fungi and Phytophthora parasitica of different citrus genotypes and the effect of AM fungi on the growth of scions of Thai honey tangerine grafted on different citrus rootstocks including Cleopatra tangerine, lime, pomelo, Swingle citrumelo and Troyer citrange. Significant differences were found among citrus species in the percentage of root colonization by the AM fungi and in the severity of root rot disease when inoculated with P. parasitica alone. Thai honey tangerine was most susceptible and Cleopatra tangerine was most resistant to P. parasitica. Inoculation with AM fungi could reduce disease severity of all the citrus plants from P. parasitica. AM fungi enhanced the growth of seedling to the greatest extent in lime. Variation in the response to AM fungi was found among the scions of Thai honey tangerine on different citrus rootstocks. The scion of Thai honey tangerine grew best on the lime rootstock inoculated with AM fungi.Key words: Phytophthora parasitica, citrus, rootstock, arbuscular mycorrhizal (AM) fungi, root rot

Easy and rapid detection of iron in rice grain

In this study, we show how a preliminary determination of grain Fe in rice may be made with reaction to Perls’ Prussian blue, a stain for Fe (III). Differential localization of Fe in grain parts was indicated by the intensity of reaction of tissue Fe to the dye. The blue colour reaction was most intense in the embryo, weak in the aleurone layer of the pericarp and invisible in the endosperm. The staining intensity also varied with the region of the embryo, generally being strongest in the scutellum, intermediate in the coleorhiza and weakest in the coleoptile. Variation in the reaction to Perls’ Prussian blue was observed among eleven rice genotypes with varying grain Fe contents. The intensity of the blue colour reaction in the embryo of different rice genotypes was indicative of their grain Fe contents for both brown and white (polished) rice. Those with high grain Fe, >14 mg Fe kg-1, were clearly distinguishable from those with <10 mg Fe kg-1 with Perls’ Prussian blue. We suggest that this simple staining procedure may be used to quickly screen for high Fe contents in large germplasms containing hundreds of rice entries, using reactions in genotypes with known grain contents as standards

Variation of milling and grain physical quality of dry season Pathum Thani 1 in Thailand

Pathum Thani 1 (PTT1) is a photoperiod-insensitive, aromatic Thai rice variety that is grown year-round. The rice from some locations is often priced lower than others due to sub-standard grain quality. This study sought to determine the limiting grain quality characteristic(s) in dry season PTT1 and their distribution across Thailand’s irrigated rice regions. To do so, we evaluated the milling and physical quality of milled rice grain of dry season PTT1 from 24 provinces in 5 regions in Thailand. Sixty-seven paddy rice samples were collected and evaluated for head rice yield, chalkiness, whiteness, and translucency. Head rice yield varied by region, with the highest (48.1%) found in samples from the Central region, compared to 34.5-39.7% elsewhere. Head rice chalkiness was the physical quality that varied more widely among the provinces within each region than among regions, with chalkiness at a level that would adversely affect price in more than one-half of the samples. Contrary to the general perception that chalky grain is less resistant in milling, head rice yield actually increased with total chalkiness, expressed as % chalky grain by weight. The total chalkiness correlated negatively with translucency, while the head rice chalkiness correlated positively with whiteness. Grain chalkiness was identified as the grain quality attribute of PTT1 rice that varied with location; this directly affected the price of milled rice grain, as well as indirectly through its relationship with head rice yield and visual appearance of the milled rice grai

Responses of milling quality to nitrogen and water management in modern long grain rice varieties

This study determined how nitrogen (N) fertilizer and water management affect grain yield and milling quality of 9 modern rice varieties with long, slender grain in two field experiments. The effect of N on rice grown in wetland culture was evaluated at 0, 60 and 120 kg N ha-1. In a second experiment the rice in aerobic and wetland culture were compared. The rice in both experiments were grown to maturity and evaluated for yield, head rice yield and chalkiness. Grain yield increased with increasing N application, head rice yield increased with increasing N in 8 varieties, while chalkiness was more than halved in 7 varieties. Grain N also increased with increasing N fertilizer, but high head rice yield in several varieties was associated with relatively low grain N. Under aerobic cultivation, all 9 varieties yielded less than in wetland culture, the head rice yield was lower and chalkiness was higher except in 2 varieties. In both experiments, grain yield was associated positively with head rice yield and negatively with chalkiness. Head rice yield and chalkiness were negatively associated in the water experiment but not in the N experiment. This study has shown that modern high yielding rice varieties generally respond positively to nitrogen fertilizer in better milling quality as well as in yield. Grain chalkiness of the varieties was more stable against variation in the environment than head rice yield

Early life urban exposure as a risk factor for developing obesity and impaired fasting glucose in later adulthood: results from two cohorts in Thailand.

BACKGROUND: Obesity and obesity related conditions, driven by processes such as urbanization and globalization, are contributing to pronounced cardiovascular morbidity and mortality in developing countries. There is limited evidence on the influence of living in an urban environment in early life on obesity and obesity related conditions later in life in developing countries such as Thailand. METHODS: We used data from two cohort studies conducted in Thailand, the Thai Cohort Study (TCS) and the Chiang Mai University (CMU) Health Worker Study, to investigate the association between early life urban (vs rural) exposure and the later development of obesity. We additionally explored the association between early life urban exposure and impaired fasting glucose in adulthood using data from the CMU Health Worker Study. RESULTS: Among 48,490 adults from the TCS, 9.1 % developed obesity within 4 years of follow-up. Among 1,804 initially non-obese adults from CMU Health worker study, 13.6 % developed obesity within 5 years of follow-up. Early life urban exposure was associated with increased risk of developing obesity in adulthood in both cohorts. Adjusting for age and sex, those who spent their early lives in urban areas were 1.21 times more likely to develop obesity in the TCS (OR 1.21, 95 % CI 1.12 to 1.31) and 1.65 times more likely in the CMU Health Worker study (OR 1.65, 95 % CI 1.23 to 2.20). These associations remained significant despite adjustment for later life urban exposure and current household income. No evidence for an association was found for impaired fasting glucose. CONCLUSIONS: Early life urban exposure was associated with increased risk of developing obesity in adulthood. These findings support public health intervention programs to prevent obesity starting from early ages

Effects of arbuscular mycorrhizal fungi on a fallow enriching tree (Macaranga denticulata)

Macaranga denticulata is a fallow enriching species that is important in upland agriculture in parts of northern Thailand. The root zone of this tree supports a high biodiversity of arbuscular mycorrhizal (AM) fungi and it has been postulated that these are important for Macaranga to rapidly establish in disturbed fields. To evaluate this, seedlings were inoculated with spores of AM fungi (Glomus spp., G. fasciculatum, Acaulospora spp. and mixed species of AM fungi) collected from the field, and then grown without P fertilizer. Growth of the host was compared with plants grown concurrently at six rates of phosphorus application (0 to 150 mg P/kg soil). The experiments were conducted in pots containing 5 kg sterilized soil. Arbuscular mycorrhizal inoculation increased height and plant dry weight. Dry weights of M. denticulata inoculated with Acaulospora spp. or mixed species of AM fungi were equivalent to uninoculated plants given 150 mg P/kg soil, whereas plants inoculated with Glomus spp and G. fasciculatum were similar to those with 25 mg P/kg soil. Nutrient contents of plant inoculated with Acaulospora spp. and mixed species of AM fungi were higher than plants inoculated with Glomus spp and G. fasciculatum. Root colonization of plants inoculated with Acaulospora spp. and mixed species of AM fungi was not significantly different, and was higher than other inoculated treatments. These experiments have shown that M. denticulata is dependent on AM fungi for rapid growth in a low P soil. Acaulospora morrowiae appeared to be the dominant species sporulating in root zones of plants inoculated with either Acaulospora spp. or mixed species of AM fungi. Further work is required to identify the most effective AM species for M denticulata since the abundance of AM spores in the root zone may not be directly related to the effectiveness of root colonization in nutrient uptake of the tree

Iron and zinc variation along the grain length of different Thai rice varieties

ABSTRACT: This study examined the distribution of iron (Fe) and zinc (Zn) along the grain length of seven rice varieties. The experiment was conducted in a completely randomized design with two factors (variety and grain fraction) and three independent replications. Samples of brown and white rice of six common Thai rice varieties and a high Fe and Zn variety, IR68144, were transversely cut into three fractions per grain (basal, middle, and distal) with approximately the same length in each fraction. The concentration of Fe and Zn was determined by the dry ashing method and quantified using atomic absorption spectrometry. The middle grain fraction of brown rice was found to have the lowest Fe and Zn with greater concentration of Fe and Zn in the basal (embryo end) than the other fractions. The rice varieties differed in the amount of Fe and Zn allocated to different fractions of the endosperm (white rice). The potential for loss of Fe and Zn during milling due to their uneven distribution along the grain length will become more significant when higher nutrient concentrations are involved, such as those achieved by biofortification efforts. Micronutrient distribution needs to be taken into consideration to ensure that rice consumers benefit from Fe and Zn biofortification

Scalable solution for delivery of diabetes self-management education in Thailand (DSME-T): a cluster randomised trial study protocol.

INTRODUCTION: Type 2 diabetes mellitus is among the foremost health challenges facing policy makers in Thailand as its prevalence has more than tripled over the last two decades, accounting for considerable death, disability and healthcare expenditure. Diabetes self-management education (DSME) programmes show promise in improving diabetes outcomes, but this is not routinely used in Thailand. This study aims to test a culturally tailored DSME model in Thailand, using a three-arm cluster randomised controlled trial comparing a nurse-led model, a peer-assisted model and standard care. We will test which model is effective and cost effective to improve cardiovascular risk and control of blood glucose among people with diabetes. METHODS AND ANALYSIS: 21 primary care units in northern Thailand will be randomised to one of three interventions, enrolling a total of 693 patients. The primary care units will be randomised (1:1:1) to participate in a culturally-tailored DSME intervention for 12 months. The three-arm trial design will compare effectiveness of nurse-led, peer-assisted (Thai village health volunteers) and standard care. The primary trial outcomes are changes in haemoglobin A1c and cardiovascular risk score. A process evaluation and cost effectiveness evaluation will be conducted to produce policy relevant guidance for the Thai Ministry of Public Health. The planned trial period will start in January 2020 and finish October 2021. ETHICS AND DISSEMINATION: Ethical approval has been obtained from Thailand and the UK. We will share our study data with other researchers, advertising via our publications and web presence. In particular, we are committed to sharing our findings and data with academic audiences in Thailand and other low-income and middle-income countries. TRIAL REGISTRATION NUMBER: NCT03938233

Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland

Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red clover (Trifolium pratense L.) and lucerne (Medicago sativa L.) were leaf-labelled with 15N enriched urea during one growing season. N transfer to grasses (Lolium perenne L. and xfestulolium), white clover, red clover, lucerne, birdsfoot trefoil (Lotus corniculatus L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), salad burnet (Sanguisorba minor L.)and caraway (Carum carvi L.) was assessed. Neighbouring plants contained greater amounts of N derived from white clover (4.8 gm-2) compared with red clover (2.2 gm-2) and lucerne (1.1 gm-2). Grasses having fibrous roots received greater amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes to neighbouring plants differed among nitrogen donors and nitrogen receivers and may depend on root characteristics and regrowth strategies of plant species in the multi-species grassland