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Irrigation projects with reservoirs have contributed to the stabilization of traditional rainfed rice and to the introduction of double-rice in monsoon Asia. This type of irrigation also has the capability of shifting the traditional rice-cropping season. This paper discusses the influences of the shifted cropping season on water resources and the effective use of the reservoir in the Ngamoeyeik Irrigation Project Area in Lower Myanmar. Synthesized streamflow data were applied to simulate water storage in the reservoir. The main results are as follows: (1) shifting the cropping season to avoid inundation problems can increase water availability, (2) the amount of evaporation loss in the reservoir water budget can be as high as 16%, which decreases water efficiency in the reservoir operation during the dry season, (3) a shifted cropping season is preferable under the special hydrological conditions found in Lower Myanmar.  相似文献   
3.
Abstract

The effect of different rice-based crop rotation sequences on the population densities of Meloidogyne graminicola and on the yield of rice was evaluated in a microplot experiment under lowland rice field conditions. Ten treatments of cropping sequences were grown in four successive growing seasons: continuous growing of the susceptible rice cultivar Thihtatyin (rice-rice-rice-rice), four treatments of 1- season crop rotation sequences (rice-rice-chickpea-rice, rice-rice-black gram-rice, rice-rice-soybean-rice, rice-rice-cowpea-rice), and five treatments of 2-season crop rotation sequences (groundnut-rice-chickpea-rice, green gram-rice-black gram-rice, cowpea-rice-soybean-rice, sesame-rice-cowpea-rice, sunflower-rice-sesame-rice). Population densities of M. graminicola recovered from the rice plants and the nematode multiplication factors (Mf) in the soil in the continuous rice cropping sequence (rice-rice-rice-rice) was the highest among the ten cropping sequences. Lowest nematode Mf in the soil was observed in the 2-season crop rotation sequence sunflower-rice-sesame-rice and the highest was observed in the 1-season crop rotation sequence rice-rice-cowpea-rice among the nine crop rotation sequences. Highest rice yield was obtained in the 2-season crop rotation sequences green gram-rice-black gram-rice, sesame-rice-cowpea-rice and sunflower-rice-sesame-rice, which were about 2 times higher compared with the 1-season crop rotation sequences and about 3 times higher compared with the continuous rice cropping sequence.  相似文献   
4.
Evolving resistance to artemisinin-based compounds threatens to derail attempts to control malaria. Resistance has been confirmed in western Cambodia and has recently emerged in western Thailand, but is absent from neighboring Laos. Artemisinin resistance results in reduced parasite clearance rates (CRs) after treatment. We used a two-phase strategy to identify genome region(s) underlying this ongoing selective event. Geographical differentiation and haplotype structure at 6969 polymorphic single-nucleotide polymorphisms (SNPs) in 91 parasites from Cambodia, Thailand, and Laos identified 33 genome regions under strong selection. We screened SNPs and microsatellites within these regions in 715 parasites from Thailand, identifying a selective sweep on chromosome 13 that shows strong association (P = 10(-6) to 10(-12)) with slow CRs, illustrating the efficacy of targeted association for identifying the genetic basis of adaptive traits.  相似文献   
5.
The mithun (Bos frontalis), synonymous with mithan and gayal, is considered to be a domesticated form of gaur (B. gaurus). However, there has been a controversy concerning its origin. In an effort to address this issue, the mitochondrial cytochrome b (cytb) genes of 20 mithun from Myanmar and 13 from Bhutan were sequenced to trace its maternal origin. Seven cytb haplotypes were found in the 33 mithun, and the phylogenetic tree for these haplotypes clearly showed three embranchments involving five gaur types, a B. indicus type, and a B. taurus type. Sixteen Myanmar and 12 Bhutan mithun had gaur haplotypes, while a B. indicus haplotype was found in three Myanmar and one Bhutan mithun. The B. taurus haplotype was detected in a single Myanmar animal. These results demonstrated that the principal maternal origin of mithun was gaur and suggested that it was directly domesticated from gaur. However, some introgression of domestic cattle existed in current mithun populations. The presence of cattle mtDNA raised the question of how many cattle nuclear genes might have been integrated into the gene pool of mithun.  相似文献   
6.
Methylated N-methylol melamine (NMM) is known for its ability to enhance physico-mechanical properties, anti-fungal ability, and hydrophobicity and was therefore used to impregnate two less used and non-durable wood species from Myanmar, Bombax ceiba and Bombax insigne. Solution uptake, weight percent gain and nitrogen content were increased by increasing melamine concentrations with B. ceiba always achieving higher values compared with B. insigne. According to the leaching results, a higher degree of condensation after curing as well as a better crosslinking of NMM could be obtained at higher temperatures. However, both curing temperatures used (90 and 120 °C) resulted in almost the same amount of nitrogen fixed in the cell wall. UV microspectrophotometry confirmed the penetration of the NMM into different morphological regions of wood tissues, which was again supported by the analysis of point measurement spectra of treated and untreated specimens.  相似文献   
7.
Since the early 1980s, Myanmar Forest Department has been recruiting shifting cultivators, establishing plantation villages and applying the taungya method in establishing teak plantations. From the beginning, there has been an argument about whether the program is creating ‘forest protective groups’ or ‘forest destructive groups’. A key determinant to that question from the research viewpoint is the socio-economic situation; knowing the present situation of the plantation villagers can help to understand their forest management practices. Interview surveys were carried out in three villages in Bago Yoma, the main region of the special teak plantation program, to examine the current economic benefits to plantation villagers. Questions were designed mainly to explore the incentives for people participation and the socio-economic situations of the plantation villagers. Principal component analysis was used to group landholder types. It was found that local people are willing to participate in the initial establishment of plantations. However, all the incentives relating to plantation projects are temporary, with no long-term consideration for taungya farmers, which jeopardizes the plan to create forest protective groups. It is concluded that the time has come for the Myanmar Forest Department to change its main aim of earning foreign exchange from establishment of teak plantations through the taungya method to redressing deforestation through people participation based on rural socio-economic development.
Tin Min MaungEmail:
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8.
Paddy and Water Environment - In Myanmar’s Ayeyarwady Delta, mangrove forests were widely converted to paddy fields, then abandoned. However, the mangrove ecosystems often fail to recover. To...  相似文献   
9.
Cassava is a major staple, bio‐energy and industrial crop in many parts of the developing world. In Southeast Asia, cassava is grown on >4 million ha by nearly 8 million (small‐scale) farming households, under (climatic, biophysical) conditions that often prove unsuitable for many other crops. While SE Asian cassava has been virtually free of phytosanitary constraints for most of its history, a complex of invasive arthropod pests and plant diseases has recently come to affect local crops. We describe results from a region‐wide monitoring effort in the 2014 dry season, covering 429 fields across five countries. We present geographic distribution and field‐level incidence of the most prominent pest and disease invaders, introduce readily‐available management options and research needs. Monitoring work reveals that several exotic mealybug and (red) mite species have effectively colonised SE Asia's main cassava‐growing areas, occurring in respectively 70% and 54% of fields, at average field‐level incidence of 27 ± 2% and 16 ± 2%. Cassava witches broom (CWB), a systemic phytoplasma disease, was reported from 64% of plots, at incidence levels of 32 ± 2%. Although all main pests and diseases are non‐natives, we hypothesise that accelerating intensification of cropping systems, increased climate change and variability, and deficient crop husbandry are aggravating both organism activity and crop susceptibility. Future efforts need to consolidate local capacity to tackle current (and future) pest invaders, boost detection capacity, devise locally‐appropriate integrated pest management (IPM) tactics, and transfer key concepts and technologies to SE Asia's cassava growers. Urgent action is needed to mobilise regional as well as international scientific support, to effectively tackle this phytosanitary emergency and thus safeguard the sustainability and profitability of one of Asia's key agricultural commodities. © 2016 Society of Chemical Industry  相似文献   
10.
A 10-page questionnaire on biosecurity practices was mailed to 187 growers on the Delmarva Peninsula in October 2000. The growers were selected by three broiler integrators on the basis of flock performance and were classified as cases (bottom 10% performers) and controls (top 10% performers). After two mailings, 71 growers (38%) responded to the survey, of which 47 (66.2%) represented good performers and 24 (33.8%) represented poor performers. Univariate and multivariate statistical analyses revealed that increased frequency of sanitizing water lines was statistically significantly associated with good flock performance (P = 0.0449). The presence of wild birds inside poultry houses during grow-out showed a slightly statistically significant association with poor flock performance (P = 0.0633).  相似文献   
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