To determine optimum timing of foliar spraying of thiourea after application of Paclobutrazol (PBZ) or Chlorate kali (KClO3) by collar drenching, an experiment was carried out in Cau Ke district, Tra Vinh province; fourteen-year-old trees were used in this experiment. The experiment was carried out in Random Complete Block Design with seven treatments: (1) Control treatment was without spraying thiourea or applying either PBZ or KClO3; (2), (3), and (4) spraying thiourea 0.4% after application of PBZ (2 g a.i./m canopy diameter) at 1, 2 and 3 months; (5), (6), và (7) spraying thiourea 0.4% after application of KClO3 (40 g a.i./m canopy diameter) at 1, 2 and 3 months. The results showed that: timing of thiourea spraying had effect on flowering ratio, yield, and quality of fruit. Spraying of thiourea at 2 months after application of PBZ or KClO3 resulted in flowering ratio and yield/tree higher than those of 1 and 3 months.

The development of biogas digester in the Mekong Delta (MD) was slow in the past years, due to the lack of pig manure (PM) - the main feeding source for the digester - as a result of pig epidemic, and the unstable market price of pig. Therefore, this study focuses on seeking for some kinds of materials which can be feed to biogas digester as additional material beside the pig manure in order to solve the problem. Two kinds of popular local materials in the Mekong Delta used in our case study are water hyacinth (WH) and rice straw (RS) used for mushroom cultivation. The lab-scale anaerobic digesters were used for co-digestion PM+WH and PM+RS with difference mixing ratios during 35-days. The outcomes showed that farmers in the MD can apply these two materials as additional feeding material for biogas digester in case of pig manure shortage, or even pig manure is not available.

White spot syndrome virus (WSSV) is one of serious viruses in black tiger shrimp (Penaeus monodon). The aim of this study was making recombinant DNA content of VP28 gene of WSSV for using as antigen to develop antibody. DNA fragment of VP28 was amplified from WSSV, which infected to shrimp and showed specific band 516bp. PCR product was digested by restriction enzyme BamHI and PstI, and cloned to plasmid pUC18 by T4 DNA ligase. Recombinant DNA VP28-pU18 was transformed to Escherchia coli XL1Blue, the E. coli after transformation was examined and showed consisting DNA VP28 of WSSV

Basing on analysis of 2,104 individual earthworms in 235 quantitative holes at 34 sampling points, a total of 27 species of earthworms have been found in An Giang, belong to 7 genus of 5 families, genus Pheretima is the most dominant (19 species). Among them, there are 2 new species (Ph. mangophila Nguyen, 2011; Ph. thaii Nguyen, 2011). There are 1 species, Drawida barwelli, was firstly found in Vietnam, and  6 species were firstly found in An Giang (Lampito mauritii, Ph. bahli, Ph. californica, Ph. peguana, Glyphidrilus papillatus, Dichogaster bolaui). There are 11 taxon was not indentified the scientific name(most of them are new species). The averaged density in the fauna earthworms of An Giang is 64 inviduals/m2, and averaged biomass is 36.15 g/m2. Pheretima posthuma is the most dominant species. Characteristics of distribution of earthworms in this area follow the general rule of earthworms distribuiton in Vietnam: that is rich in number of species in mountainous area but lower in plain area which is higher in density and biomass; Number of species, density and biomas in rainy season is higher than in dry season (except plain area); The index of species diversity decreases gradually basing on the impact level of human on that habitat and density and biomass are contrast.

The study was carried out in the key provinces of the fruit trees in the Mekong Delta in order to analyze the current training activities of farmers. Qualitative research methods were used through the KIP, PRA survey with 183 samples surveying by questionnaire as quantitative method. The results showed that farmers are organized to attract farmers to participate in the largest. Knowledge of fruit tree farmers accumulated from neighbors and family farmers, agricultural extension programs showing on TV, and attending training courses. Opportunities for farmers to interact and communicate with extension agent is very limited. Training method was remained too theoretical, not combined with practice, visiting or crop-pattern applied. The method combines lecture materials and advertising are very popular. The biggest drawback is not meet demand for specialized training and the number of farmers involved. There should be coordination of the farmers, agricultural extension club and the local political organizations for training activities, transfer and application of science, technology, training for local human resources.

The objective of this study was to evaluate the effect of bio-organic and inorganic fertilizers on the improvement of soil microbial activity in coconut-cacao intercrop at Chau Thanh- Ben Tre. Fives treatments were arranged to compared the effect of bio-organic compost in combination with low dose of inorganic fertilizer and inorganic fertilizer on the microbial density, microbial cellulose degradation and enzyme catalase.  At the early stage, 30 days after amendment, inorganic fertilization showed the highest density of total micro-organism but lower microbial cellulose degradation and catalase enzyme activity (P

High accumulation of dissolved nitrogen (N) and phosphorus (P) in the ponds which were used for intensive catfish (Pangasianodon hypophthalmus) cultivation may lead to risk of environmental pollution when pond water is drained into the surrounding canals or rivers. This study aimed to investigate the accumulation of different dissolved forms of N and P in the water and the bottom sediment. To this end, this study sampled the water and sediments from different catfish ponds located in different areas in the Mekong delta where catfish is popularly cultured in earth ponds. The results showed that both dissolvable inorganic and organic forms of N and P in the ponds were extremely high as compared to the upper limits of N and P elements accepted for drinking water. The concentrations of dissolved inorganic N ranged from 0.5 to 11.6 ppm and those of P ranged from 0.05 to 7.7 ppm. As compared to organic forms, inorganic N and P were predominant and reached a peak at 3 - 4 months after stocking catfish. The ratios between N and P were in approximately 10 through the cycle of catfish cultivation. This result indicates a risk of algal bloom in the ponds or when the water is drained into the surrounding environment. In pond sediments, the contents of organic matter, N and P were higher than those in alluvial soil in most cases. However, the accumulation of these elements was highly varied, depending on how often the sediment is pumped out of the ponds.

Thirty seven orchid species belonging to two subfamilies Cypripedioideae and Orchidioideae were analyzed and classified based on morphologic and argonomic traits. After being collected, encoded, statistically treated by NTSYSpc 2.1 program, the morphologic and argonomic traits were analysed based on UPGMA method. The research results revealed that Dendrobium pulchellum, Dendrobium Gatton Sunray and Dendrobium moschatum have a very close relationship, the similarity are at 96,5% and 95%. In addition, Dendrobium anosmum 'Alba' and Dendrobium parishii 'Alba' have a very close relationship, the similarity are at 98%. Similarly, Dendrobium anosmum (Hawaii) and Dendrobium parishii are similarly at 95%. Brassavola nodosa, Brassavola digbyana, and Brassavola ?Jimminey Cricket? have close relationship. Besides, nine species belonging to the five different genera Renanthera, Rhynchostylis, Acampe, Aerides and Ascocentrum but they have a close relationship and they can be bred together to create new hybrids with expected characteristics. This phenotypic study proves for classification of the relationships between species of orchids through appearance assessment by data system. This data of relationships will provide us a lot of valuable information to select parents as material sources for breeding hybrids with desirable traits.

A cross-sectional study on composition of Culex mosquito species and prevalence of Japanese encephalitis in pigs was concurrently carried out in Ninhkieu urban district and Codo suburban district of Cantho city, Vinhloi and Donghai suburban districts of Baclieu province. The results showed that Culex was the most abundant mosquito genus comprising 57.59% of total collected mosquitoes. The highest number of Culex mosquitoes was Culex tritaeniorhynchus comprising 52.88%, followed by Culex vishnui with 24.84%. The positive prevalence of Japanese encephalitis in pigs was correlated with average density of Culex mosquitoes (R2= 0,9996), Culex tritaeniorhynchus         (R2= 0,9998) and Cx. vishnui (R2=0,6629) mosquitoes but not correlated with other Culex species mosquitoes.

The objective of this study was to evaluate the effect of rice straw treated, incorporated  into top soil and the effect of compost made from muddy waste of fish ponds on improvement of rice yield. Experiments was carried out at Chau Thanh A district, Hau Giang province. Treatments were arranged in randomized complete block design: 1) Control treatment with recommended inorganic fertilizer (80-30-30); 2) Application of rice straw mixed with Trichoderma sp. and recommended  inorganic fertilizer; 3) Amendment of one ton compost from muddy waste of fish ponds (CFP) and 75% recommended inorganic fertilizer; 4) Rice straw was burnt and incorporated into topsoil and recommended inorganic fertilizer; 5) Amendment of one ton CFP. Rice straw treated with Trichoderma  sp. and rice straw burnt in combination with recommended inorganic fertilizer resulted on increasing of soil organic matter, labile organic nitrogen and available nitrogen in soil. The density of fungi and actinomyces functioning in cellulose degradation in soil tended to increase compared to control treatment. Incorporation of rice straw burnt showed the most positive effect to rice yield. Rice straw treated with Trichoderma sp. also led to increase rice yield but less extend. This result indicated that  rice straw burnt incorporated or rice straw mixing with Trichoderma sp. were the promising technique to improve soil N supplying capacity and rice yield .

The study was conducted to evaluate the possibility of reducing irrigation and effecting to the crop yield in cultivating peanut by supplying GAM Sorb P, a type of super absorbent polymer. In this experiment, peanut variety HL25 was planned on the weathered soil in Tri Ton district, An Giang province from January to April, 2011. The results showed that there were the differences in soil moisture but the similar yield was achieved accordingly to every treatment. Thus, the using of GAM Sorb P in this experiment reduced approximately two third total water irrigated in peanut cultivation, by irrigated cycle of once time/18 days (7 times/crop of 3 months) compared to once time/6 days of control (17 times/crop of 3 months).

This research study on genetic analysis and evaluation of 12 orchid accessions belong to 9 wild species and 2 hybird species come from Thailan of Dendrobium using 10 random RAPD primers for breeding, exploitation and propagation of orchid species in Vietnam. Results showed that all the orchid species gave high polymorphism in all 10 primers (nearly 100% of polymorphic bands). The DNA band sizes obtained in the range of 0.15?2kb. The highest frequency of theDNA band size was 500-600bp position. In particular, the primer OPF04 amplified the most numbers of DNA band (29 bands). The medium numbers of DNA band were obtained with primers: OPF01, OPF02, OPF05, OPF08, OPR07, OPA08 and OPA12 (20-24 bands). The OPR012 primer amplified the least numbers of DNA bands (14 bands). The band sizes obtained were scored by the binary coding for genetic cluster analysis using NTSYS2.1 software with UPGMA method. Results of genetic clustering of 12 Dendrobium orchid accessions showed genetic differences ranged from 0 to 42%. At around 59% similarity, 12 orchids accessions can be divided into three groups: A, B, C. Group A had 7 accessions of seven species, group B was 1 accession of a species and group C included four accessions of 3 species. In the group C, the orchid species had a relationship closer than groups A and B with about 80% homologous. Seven orchid species in group A correlated approximately 61.6% similarity.

The rice varieties from 2008 to 2010 collection were tested for resistance to brown plant hopper (bph), evaluated the yield and the adaptation of promising rice varieties, and tested for the presence of bph genes by molecular techniques. The results showed that there were 77 varieties owning only bph4 gene, 44 varieties containing only Bph18 gene, and 31 varieties possessing both bph4 and Bph18 genes. Regarding the evaluation of the yield and the adaption of the varieties in Long An, Can Tho and An Giang, MTL512, MTL649, MTL657 and OM10043 had the high yield and highly adapted to all trial site conditions. Particularly, the MTL649 and OM10043 varieties did not only had the high  yield in the experiments, but also possessed both bph4 and bph18 genes. These varieties would be the important genetic resources for producing as well as breeding in theMekongDelta.      

Quinalphos is an organophosphate pesticide, which has widely used in rice production in the MekongDelta. The pesticide is often applied a few times in a rice crop that can give effects on the fishes stocked in the integrated rice?fish system, including silver barb (Barbodes gonionotus). In this study, silver barb was exposed to 4  quinalphos concentrations including 0,0; 0,0856; 0,1712 and 0,428 mg/L to determine changes in ChE activites and five concentrations including 0,0; 0,0856; 0,1875; 0,58 and 0,856 mg/L of quinalphos to determine the growth performance in tank conditions. The results showed that the LC50-96 hrs of quinalphos for silver barb was 0,856 mg/L. The brain, muscle and gill ChE activities levels and growth performance of the tested fishes were  significantly inhibited at all tested concentrations of quinalphos if compared to control treatment (p

Four tracer experiments were conducted with the using kitchen salt (Sodium Chloride, NaCl) as tracer for determining the peak travel flow speed of domestic wastewater  transported through a root zone in a constructed subsurface flow wetland. The flow was homogeneous through the cross-section of the constructed wetland system built at Can ThoUniversity. The theoretical hydraulic retention time of water in the reed bed is 18 days based on the calculation as the ratio between the pore volume of the wetland, the porosity of porous media and the flow rate through its system. The average peak travel flow speed, determining as the length of reed bed divided by the nominal hydraulic retention time, is estimated to be 0.67 m/day. The results also proved that tracer with kitchen salt as a cheap and suitable tracer to determine the peak velocities in a constructed subsurface flow wetland. This could be considered as a creative on constructed wetland research in the developing countries asVietnam.

In order to obtain high quality palm wine (in Tri Ton district, An Giang province) as well as using post-harvest raw materials to increase income for local people, the research was conducted on the basis of survey (i) the influence of harvesting time (morning, afternoon), (ii) the conditions of palm juice treament before harvesting (treament by sodium metabisulfite, ?Sến? wood and the control sample) and (iii) selecting of yeast for making high quality palm wine, There are 18 yeast trains were obtained from palm juice at different treatment conditions. The treatment conditions did not affect the ability of yeast isolation. However, the ability of the presence of yeast in palm juice could be affected by harvesting time. Selected yeast train, which was isolated from palm juice harvested in afternoon without treatment, showed the best yeast strain for making palm wine with high alcohol content (13-14% v/v).

Pesticide has been commonly used in rice farming for controlling pests. Residue of pesticide can affect on the aquatic animal health such as fish and crustaceans. The use of enzyme activity in fish, especially common species in rice field for instance common carp, silver barb,.. as bio-indicators for pesticide pollution monitoring is a new research direction. This study was conducted with two experiments. The first experiment was the determination of LC50-96 hrs. of quinalphos for fingerling sized common carp (Cyprinus carpio). The second experiment was determination of the cholinesterase (ChE) and glutathione-S-transferase (GST) activities of common carp (Cyprinus carpio) exposed to quinalphos at different concentrations. The treatments were 0; 0.076; 0.152 và 0.380 mg/l, 6 replicates for each concentration, 15 fish per 60 L-aquarium, and for 28 days. The LC50-96 hrs.of quinalphos for common carp was 0.76 mg/L. The brain, muscle and gill ChE activities levels of the fishes were significantly inhibited after 28 days at three tested concentrations if compared to control. The ChE inhibition tend to increase with increased concentrations Meanwhile, quinalphos had no significant effect (p>0.05) on brain, muscle and gill GST activities. The study indicated that ChE activity of common carp can be used to assess level of organophosphate pollution in rice fields.

This study aims to determine kind of drugs and chemicals were used and chemical composition of sludge from intensive striped catfish culture pond. The status of drug and chemical use was determined by interviewing of 30 fish culture households with prepared questionnaire. Chemical compositions of sludge were determined by analyzing sludge samples collected from three ponds at middle and end of crop. The results showed that there were 28 kinds of disinfection chemical and 14 kinds of restorative and 14 kinds of drug were used during culture period. Most of used drugs and chemicals are soluble organic compound so they little affect chemical compositions of sludge of fish pond. Ratio of organic matter, total nitrogen and total phosphorus in fish pond sludge were rather high. Concentration of macro-elements and micro-elements in sludge were normal and concentration of heavy metals in sludge were very low. Therefore, sludge of intensive striped catfish pond may be used for producing organic fertilizer.

This research aims to analyse impacts of growing rice on economic return of shrimp culture in the integrated rice ? shrimp system in coastal region of the Mekong Delta, particularly in Thuan Hoa commune, An Minh district, Kien Giang province. The research is done through direct intensive interview with structured questionnaire involving 120 random selected households in the commune, who practiced rice ? shrimp system at different levels of integration. Results indicated that there is a positive economic impact of rice growing to shrimp production and the whole system as compared with absence of rice component in the system. Policies encourage as well as measures to assist farmers to grow rice in the system such as growing short duration, salinity tolerant rice variety and technical training for local people are necessary to implement, which would contribute to agricultural sustainable development in the coastal region.

Phosphorus (P) supplying capacity in soils was affected by P adsorption. This study aimed at investigation of P adsorption capacity in 24 soil samples which had high and low soil available P at Thot Not- Can Tho, Cho Moi-An Giang, Binh Tan- Vinh Long and Chau Thanh-Tra Vinh. Phosphorus adsorption was evaluated based on (i) % P adsorption versus P applied, (ii) maximum P adsorption based on Langmuir equation, and (iii) P adsorption capacity based on slope of the tangential line and the adsorption curve between amount of P adsorbed and equilibrium P concentration. Results showed that P adsorption percentage was high (> 95% of the amount of P added) in soils which have low and medium available P and was lower in soils which have high available P (15-95% of the amount of P added). Maximum P adsorption in clay and silty clay soils was 400-714mgP/kg, in clay loam soils was 227-555mgP/kg; in loamy sand soils was 200-357mgP/kg. In soils high in available P, phosphorus adsorption was low, especially in sandy soils; therefore decreasing amount of P fertilizer applied is recommended to increase efficiency of P fertilizer and decrease environmental impact.

The objective of this study is to quantify the impact of BioGro fertilizer and alternate wetting and drying irrigation method (AWD) on rice yield, methane and nitrous oxide emission in rice crop. Trials were conducted with two consecutive rice crops. In experiment 1, a 2 x 2 factorial experiment with a split-split plot was designed. The main-plot were treated with water management method: (1) ?alternate wetting and drying irrigation? method (2) continuous flooding method (farmer?s practice). The subplot, BioGro application includes 3 levels: (1) without BioGro + a full amount of chemical N application (90 kg N/ha), (2) BioGro and 50% of the normal amount of chemical N application (45 kg N/ha), (3) without BioGro and 50% of the normal amount of chemical N application (45 kg N/ha). The experiment 2 was designed as experiment 1 but  without level (3) without BioGro and 50% of the normal amount of chemical N of experiment 1 to measure methane and nitrous oxide gas. Results showed that BioGro fertilizer and water-saving method applied to irrigated rice system had a high efficiency. For summer-autumn crop, applying BioGro fertilizer, grain yield was 5tons/ha, it is equivalent to applying 100% N-chemica fertilizer. The AWD method reduced 400m3 (about 22%) of irrigation water inputs and increased grain yield (170kg/ha) compared to continuous flooding method. For autumn-winter crop, both methods of BioGro applying contributed to reduce methane and nitrous oxide emissions than conventional method. Water saving irrigation helped to decrease methane gas but increased nitrous oxide emission

Catfish (Pangasianodon hypophthalmus) is a  popular freshwater fish species which is culturing and exporting a lot  in the MekongDelta. Low concentration of dissolved oxygen in the pond could affect directly or indirectly on the fish. The objective of this study was to evaluate effects of dissolved oxygen levels on the growth of the striped catfish. The study included two experiments on the effect of dissolved oxygen level on the growth and digestibility of striped catfish. The experiments was conducted in tanks (1 m3) with three different levels of oxygen saturation: 30%, 60% and 100% (2,38; 4,77 and 7,95 mgO2/l at 270C, respectively). The results showed that the growth rate, digestibility coefficients of feed, protein and energy of 100% oxygen saturation treatment were significantly higher than the two other treatments (30% and 60% of oxygen saturation) (p0.05) between the treatments of 30%, 60% and 100% saturation of dissolved oxygen levels. However, the plasma glucose concentration of 30% and 60% oxygen saturation treatments were significant higher than the treatment with 100% of oxygen saturation level (sampling at the 30th and 60th date). This means that the fish was stressed at the low dissolved oxygen level. The results of study showed that the fish performed the better growth at the high oxygen level (100% of oxygen saturation level) without any stress.

The objectives of the study are to assess the social ecomomy of people who live in project area of Gas - Electricity - Nitrogen Factory, research and propose efficiently farming models for re-settlement area of Khanh An commune, U Minh District, Ca Mau province. The results of the study showed that: After planning, the social ecomomy of inhabitant was not stable, the number of people without jobs increased, and the rest was un-stable jobs. The support work of resettlement ? refarming for people faces difficulty because of a complete infrastructure was not constructed. The cultivated land has affected by acid soil, so the renovation production of the people was weak. Result showed that in the resettlement, there were four farming models as: (1) mono rice; (2) rice ? livestock; (3) rice ? livestock ? upland crops; (4) rice - fish ? livestock ? upland crops. There were two models which were selected and proposed such as: rice - livestock ? upland crops and rice - fish - livestock ? upland crops.

This study was carried out to investigate flowering in nature condition in the Mekong delta and effect of treatment duration of 15oC and 18oC on flowering of the two ?Corn Plant? cultivars, solid and speckled. The investigation was conducted on 30 bearing flower ?Corn plant? of the two cultivars grown in six households at Ninh Kieu district Can Tho city, on February 2009. The experiment to determine the effect of low temperature, duration, and cultivar on flowering of ?Corn plant? was arranged in three factors factorial complete randomized design, with three replications, each of which equal to one tree. The first factor included the treatment periods, 7, 14, and 21 days. The second and third one are levels of applied temperature (15oC and 18oC), and cultivars (solid and speckled). The two control treatments are non-treated trees of the two cultivars. Results reflect that ?Corn plant? flowered naturally in the low temperature condition (18.6oC). Flowering trees were at the age of 2-5 years, 0.52-2.8 m height, with the total number of leaves/tree of 23-124 leaves. Flowering rate of 15oC treatment (82.5%) was significantly higher than that of the 18oC (26.3%). Duration treatments did not affect flowering rate, but 7 days treated plant had the number of panicle/inflorescence higher than that of the 14 or 21 days. The speckled cultivar did not flower under the treatment of 18oC within 14 or 21 days. ?Corn plant? is able to be induced flowering by putting in the condition of 15oC within 7 days.

An investigation on Gumboro disease status in scavenging chickens was carried out by clinical observations, necropsy findings and agar gel precipitin (AGP) test from 47 outbreaks in Hau Giang province in 2010. The results showed that there were 18 Gumboro disease outbreaks from 22 suspected outbreaks. The mortality of Gumboro disease chickens was (22.30%) higher than that of chickens involved with other diseases (18.62%). The highest infection flock rate was reported in chickens from 15 to 30 days of age (62.5%), followed by 31 to 45 day old chickens (53.85%) and chickens older than 45 days of age (23.08%). Gumboro disease outbreaks mostly happened in unvaccinated chicken flocks (75.0%), followed by flocks with one vaccination (62.5%) and flocks with 2 vaccinations (28.57%). There was no significant difference between the infection flock rate of chicken breeds.

Genetic diversity of thirty six mango cultivars collected from some regions of Vietnam, mostly in Dong Thap area, were analyzed using combination of Amplified fragments length polymorphism (AFLP) technique and sequencing the ITS (Internal Transcript Space) region. The results showed that there were 149 peaks of AFLP observed, and 49 peaks presented in all samples with the highest frequency. The genetical similarity was high with r = 0,853. There were 2934 phylogenetic trees in ITS analysis. The final tree had the CI = 0.4594, and it means the DNA sequences had a considerable difference. Based on results of both AFLP and ITS analysis, two cultivars including Da and Gao mango cultivars were the same spieces. The Bom and Kensington Pride mango cultivars might origined from the same species. The Thuy Trieu mango cultivar and the cultivars planted in Nha Trang area with the similar phenotype derived from the same species with Thanh Ca mango cultivar grown in the South of Vietnam. The Bac-Tam-Bang variety which is Cambodian?s favourite was a type of Hon xanh No.19 cultivar. The Cat Chu mango cultivars had a variety of genotype and phenotype. Thanh ca mango variety could be the original species of Tuong, Thom and Cat Chu mango cultivars. Some of Thai mangoes had different genotype as well as phenotype with Vietnamese mangoes, but the Manduongcao cultivar probably had a certain gene that is similar to Tuong cultivar. The Yen Chau mango cultivar in the Northern West of Vietnam had the same origin with the Kensington Pride and Bom cultivars which derived from Malaysia and Oceania, respectively.

For the purpose of improving the peel color and prolonging the preservation of ?Mật? orange, some Ethephon treatments (single and combined chemical) were used. The chemical treatments were sprayed on fruits at 1 week (Ethephon) and 1 month before harvest (calcium chloride and gibberellic acid). The research results showed that spraying Ethephon at 1 week before harvest could improve the peel color stably with the ?E and b values always in the highest level; the pH level and Brix ratio was also stable. Ethephon combined with CaCl2 and GA3 could reduce the fruit loss weight and vitamin C during harvest time; the fruits could be prolonged to 5 weeks with the stable value in sensory evaluation in postharvest.

This study was conducted to determine the period of time and methods for effectively weaning artificial food in rearing giant snakehead (Channa micropeltes). Nine treatments with 3 replications were set up with different time using artificial food (20, 30, 40 days post- hatch) and different duration of the changeover period from live to artificial food (10%/day, 10%/2 days, 10%/3 days). Gaint snakehead larvae were stocked into 27 composite tanks (100L per tank), with density of 200 individuals per tank. The experiment lasted for 10 weeks. The results showed that gaint snakehead larvae weaned 20 days post- hatch (DPH) had significantly lower survival than fish weaned 30 or 40 DPH (p

This research was aimed to use sustainability of land resources. Based on survey of current land use, patternts were studied, including: (i) evaluating the current status in agricultural sector in the Phong Dien district comparing to land use planning the projected period (2005-2010), (ii) building scenarios and proposing the solutions for each alternative land use efficiency. Using statistical methods, data analysis and socioeconomic assessment environment has been gotten the results as follows: the current land use patterns for agriculture activities in Phong Dien district in 2010 significantly changed in comparision to 2005. Assessments of physical condition showed  4 suitable zones were identified with 4 land use types (LUT), including: 3 crops rice, double rice and upland crops, upland crop and fruit tree. With the households classification based on the integrated criteria of economic, social and environment setting, two scenarios proposed by the adaptation to different solutions.

The objective of the study was partly to describe the status of fermented leaf mustard processing in the trade village of Tan Luoc (Binh Tan district, Vinh Long province). The problem in technical process and food safety that applied in this trade village was evaluated. Based on production process and procedure for cleaning which applied in 27 processing facilities, the three collected samples were used to determine the physico-chemical properties and microbiological quality in the washing water, brine, raw materials and products. The survey results showed that traditional fermentation process was developed largely as an art, rather than through scientific principles. Production technique was not standardized. The mass of fermentation sample can change from 5 kg to 50 kg. With the addition of 3.5% to 4% NaCl, fermentation process occurred in suitable condition of lactic acid bacteria. Fermentation time ranged during 8 - 12 days. Although procedure and equipment used by this process was relatively simple, microbiological and biochemical aspects were not fully understood. Microbiological parameters of all collected samples (water, raw materials and fermented leaf mustard) were exceeded the prescribed limits.

This study was conducted to evaluate the combination effects of salinity and exposed time on the growth and survival rates of clam Meretrix lyrata. Two-factor experiment was conducted with 9 treatments and 3 replications was run per each treatment in different salinities (10, 20, 30?) in combination with different exposed time (2, 4, 6h). Clams were classified into 2 groups (14 mm and 24mm) and were cultured in 200-liter composite tank. Clams were fed daily with algae diets consist of Chlorella sp. and Chaetoceros sp. with the ratio 1:1 at the density of 500000 cells/ml. After 60 days of experiments, results showed that in small size clams, salinity of 10? and exposed time of 2h leading in highest survival rates 87,8%. For large size, highest survival rate was observed at salinity of 10? and exposed time of 4h (97,8%). Salinity of 30?  and exposed time of 6h  resulted in  decreased survival rate of clams at the end of experiment (11,1% and 12,2%, respectively). Our findings contribute initial information for site selection and management for clam culture in practices.

This study was conducted to determine effect of paclobutrazol (PBZ) doses applied under with or without mulching conditions on off-season flowering of Ha Chau baccaurea. An experiment was carried out on 12-year-old ?Ha Chau? baccaurea in Phong Dien district, Can Tho city, from August 2010 to July 2011. The employed experimental design was factorial randomized complete block design with four replications each of which equals to one tree. The first factor was PBZ doses (0, 0.5, 1.0, and 1.5 g a.i./m canopy diameter), and the second one was with or without mulching using thin plastic sheet after PBZ application. The results showed that PBZ doses correlated negatively to leaf GA3-like compounds, and positively with leaf C/N ratio. Mulching contributed to early flowering, increasing of flowering ratio and fruit yield. Treatment of PBZ 0.5-1.0 g a.i./m canopy diameter combined with mulching induced earlier flowering for 8-15 days; increased flowering rate, average fruit weight, fruit weight per bunch which led to double yield in comparison to that of control treatment.