Effect of different water regimes on nematode reproduction, root galling, plant growth and yield of a lowland and upland Asian rice cultivar grown in two soil types infested by the rice root-knot nematode Meloidogyne graminicola

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Evaluation of the host response of lowland and upland rice varieties from Myanmar to the rice root-knot nematode Meloidogyne graminicola

The rice root-knot nematode Meloidogyne graminicola is considered one of the most potentially important nematode pathogens of rice, especially in South and Southeast Asia, in a range of rice production systems. Identification of M. graminicola-resistant or -tolerant rice varieties will enable breeding programmes to develop rice varieties which are able to limit yield losses caused by this nematode species. The host response to M. graminicola infection of 15 lowland rice varieties and 9 upland rice varieties, which are being grown in the summer-irrigated lowland and rainfed upland rice ecosystems in Myanmar, was evaluated in two experiments under screenhouse conditions. The lowland rice experiment was carried out under intermittently flooded conditions in a clay loam soil (i.e. simulating the summer-irrigated lowland rice ecosystem) and the upland rice experiment was carried out at field capacity in a sandy loam soil (i.e. simulating the monsoon rainfed upland rice ecosystem). None of the15 lowland and 9 upland rice varieties were resistant to M. graminicola infection although differences in susceptibility and sensitivity were observed. Six (or 40%) out of the 15 lowland varieties examined were classified as less susceptible (LS) to M. graminicola infection, five (or 33.3%) as moderately susceptible (MS) while four (or 26.7%) as highly susceptible (HS). One (or 11.1%) out of the nine upland varieties examined was classified as LS to M. graminicola infection, three (or 33.3%) as MS while five (or 55.6%) as HS. Five (or 33.3%) out of the 15 lowland varieties examined were classified as either less sensitive or tolerant to M. graminicola infection. One (or 11.1%) out of the nine upland varieties examined was classified as tolerant to M. graminicola infection. This study offers interesting information for the farmer regarding which rice variety should be grown in M. graminicola-infested fields under either lowland or upland conditions. © 2013 © 2013 Taylor & Francis.status: publishe

Population dynamics of Meloidogyne incognita on black pepper plants in two agro-ecological regions in Vietnam

The objective of our study was to examine the effect of local environmental conditions, especially air temperature and rainfall, in two agro-ecological regions in Vietnam on the population dynamics of Meloidogyne incognita on black pepper plants and on percentage root galling. The two study sites were situated in Cam Lo, Quang Tri province (North Central Coast) and Buon Ma Thuot, Dac Lac province (Central Highlands). At the study sites, 13 plant-parasitic nematode taxa belonging to 12 genera were identified. Ten of these taxa were present in both study sites. Helicotylenchus certus, Hemicriconemoides cocophilus and Pratylenchus coffeae were only found in Buon Ma Thuot. Based on nematode population densities, M. incognita was the most abundant taxon present. Rainfall and air temperature differed significantly between the two study sites. The most important climatic difference was rainfall: in Buon Ma Thuot, the rainy season lasted 2 months longer and the monthly rainfall during the rainy season was much higher compared to Cam Lo. Although this difference resulted in some differences in the population dynamics of M. incognita in the soil and roots of the black pepper variety Vinh Linh, the highest root population densities were observed in both study sites during the first half of the dry season. In Cam Lo, the highest percentage root galling was observed during the first half of the dry season. In Buon Ma Thuot, the highest percentage root galling was observed towards the end of the rainy season. Estimating the population densities if M. incognita to decide on the application of a management strategy should be done during the first half of the dry season. © 2012 Copyright Taylor and Francis Group, LLC.status: publishe

The impact of gender and the social determinants of health on the clinical course of people living with HIV in Myanmar: an observational study

Background: There is a growing recognition of the impact of gender and the social determinants of health on the clinical course of people living with HIV (PLHIV). However, the relative contribution of these factors to clinical outcomes of PLHIV is incompletely defined in many countries. This study was performed to gain a greater understanding of the non-clinical determinants of prognosis of PLHIV in Myanmar. Methods: Selected demographic, behavioural and socioeconomic characteristics of outpatients at two specialist HIV hospitals and one general hospital in Yangon, Myanmar were correlated with their subsequent clinical course; a poor outcome was defined as death, hospitalisation, loss to follow-up or a detectable viral load at 6 months of follow-up. Results: 221 consecutive individuals with advanced HIV commencing anti-retroviral therapy (ART) were enrolled in the study; their median CD4 T-cell count was 92 (44–158) cells/mm3, 138 (62.4%) were male. Socioeconomic disadvantage was common: the median (interquartile range (IQR) monthly per-capita income in the cohort was US$48 (31–77); 153 (69.9%) had not completed high school. However, in a multivariate analysis that considered demographic, behavioural, clinical factors and social determinants of health, male gender was the only predictor of a poor outcome: odds ratio (95% confidence interval): 2.33 (1.26–4.32, p = 0.007). All eight of the deaths and hospitalisations in the cohort occurred in males (p = 0.03). Conclusions: Men starting ART in Myanmar have a poorer prognosis than women. Expanded implementation of gender-specific management strategies is likely to be necessary to improve outcomes

Effect of planting and irrigation practices on nematode reproduction, root galling, plant growth and yield of two Asian lowland rice varieties infected by the rice root-knot nematode Meloidogyne graminicola

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Host status of rotation crops in Asian rice-based cropping systems to the rice root-knot nematode Meloidogyne graminicola

© 2016, Sociedade Brasileira de Fitopatologia. Rotation with nonhost crops is an important practice used for root-knot nematode (RKN) management. Screenhouse experiments were conducted to evaluate the response infection of 27 cultivars belonging to 14 crops (blackgram, cabbage, cauliflower, chickpea, cowpea, garlic, ginger, greengram, groundnut, maize, potato, sesame, soybean, sunflower), which are grown in rotation with rice in lowland and upland rice-based ecosystems, to the RKN Meloidogyne graminicola. Root galling indices observed on all crop rotation cultivars were significantly lower compared with the rice cv. Thihtatyin, used as positive control. Differences in host response to M. graminicola infection were observed between cultivars. All 27 cultivars were poor or non-hosts of M. graminicola, except cv. Yezin 4 of chickpea considered as good host. No significant differences in plant growth were observed between non-inoculated and inoculated plants of all plant/species cultivars, with the exception of a reduction in root length in the chickpea cv. Yezin 4 (good host) and the garlic cv. Shan (poor host). Rotation crops identified as poor or non-hosts of M. graminicola could be useful in the management of RKN in rice-based cropping systems.status: publishe