Vol. 14 No. 3 (2016)

Development of rice genotypes tolerant to complete submergence in the Mekong Delta was carried out for three continuous years by CLUES Project fund. Eighty five high-yielding cultivars and eighty four progenies from backcrossing population (BC3F3) of OM1490/IR64 Sub1were used to study the yield components and submergence tolerance. Phenotyping was implemented at three stages: seedling, tillering and heading. Different segregation ratio and phenotypical variation indicated the complex genetic background. All genotypes have been evaluated under both submergence and non-submergence treatments. Correlation coefficient between the survival rate (%) and tiller number /10 hills was positively significant of 0.8880**. Marker-assisted backcrossing (MAB) was exploited on chromosomes 9 to address ten molecular markers (SSRs). Of them, only three polymorphic SSRs really linked to the target QTLs. Marker-assisted selection helped identify elite lines, which would be breeding materials via three molecular markers on the target region viz. RM3269, RM5304 and RM1367 on chromosome 9. Three selected offspring lines from BC3F3population of OM1490/IR64 Sub1as 26, 38 and 50 exhibited good adaptation to submergence.

The growth and quality of 10 mugwort accessionswere evaluated in a replicated experiment (RCBD with 3 replications). Harvest wasdone when plants reach a height of 30-35 cm for all accessions. Highest individual plant yield and hectare yield per year were obtained from accessionG6with shorter cut interval and more cuts per year.The accession G6 had higher content of total essential oil (0.37%), which is well suited for useas fresh vegetable or medicinal materials. AccessionsG5, G13 and G14 with high content of total essential oils (0.5%), high total flavonoid content ( >7000 mg/100 g) are suitable for essential oil and flavonoid extraction. Accession G2 with low total essential oil (0.21%) and slightly bitter is good for using as fresh vegetableas supplementalfood.

The study was carried out to determine the optimal level of potassium for growth and grain yield of three mungbean varieties (ĐX22, ĐX208, ĐX16) in coastal sandy soils ofNghe An province. The experiment was conducted in 2013 and 2014 Summer - Autumn seasons ina split - plot with and 3 replicationswherein mungbean varieties being the main plot factor and levels of potassium (0, 30, 60 and 90 kg K2O/ha) combined with 30 kg N/ha - 60 kg P2O5/ha) the subplot factor. The results showed that 60 kg K2O/ha combined with 30 kg N/ha and 60 kg P2O5/ha increased grain yield of mungbean varieties by 29,1-42,4% in comparison withoutpotasium application. This rate of potassium can be recommended for mungbean cultivation in coastal sandy soilsinNghe An.

Local shallot (Allium cepaL. ), Aggregatum group) variety grown inKinh Mon, Hai Duong was treated with colchicine in order to produce polyploid materials for high-quality shallot breeding in Viet Nam. The research was carried out at Faculty of Agronomy, Vietnam National University of Agriculture. The shallot bulbs were immersedincolchicine solution with different concentrations (0,2%; 0,4%; 0,6%; 0,8%; 1,0%; 1,2%; 1,4%; 1.6%; 1,8%; 2,0%)for oneto tendays. The results revealed that colchicine treatment at concentration 1,0% for 6 days was most suitable for inducing tetraploid shallot plants with survival rate of 80%. Thepercentage of tetraploids was20% in total treated bulbs. Treatment at higher concentration and longer duration increased the percentage of dead plants up to 100%. Thirty six tetraploid plants of shallot were produced.

The objective of this study was to evaluate efficiency of nitrogen application by leaf color chart (LCC) on growth, yield and N uptake of sugarcane on alluvial soils applied with sugarcane filter cake (SFC) in the Mekong Delta. The experiment was conducted in a randomized complete block with four replications. The treatments were (i) nitrogen application timing by LCC, (ii) nitrogen application timing by recommendation,(iii) nitrogen application timing by LCC on alluvial soils applied with SFC and (iv) nitrogen application timing by recommendation on alluvial soils applied with SFC. Results showed that the nitrogen application by LCC increased plant height, yield, N uptake compared to nitrogen application by recommendation on alluvial soils with and without SFC. Besides, nitrogen application by LCC was equally efficient as nitrogen application by recommendation combined withSFC in terms of plant height, plant density, yield, N uptake in Cu Lao Dung and Long My. The nitrogen application timing by LCC was extended on alluvial soils appliedwith SFC compared to LCCalone. Sugarcane yield increasedby12 -15 tons ha-1in Cu Lao Dung and 11-13 tons ha-1in Long My through nitrogen application by LCC on soils with and without SFC.

The sedge stem borer Bactra venosanaZeller isconsidered as one of themajor pestsonsedge. The studywas carried out to examine the biological characteristics of B. venosanaunder semi-natural conditions (green house)int Nga Son, Thanh Hoa. Themean developmental time was from 55.82 ± 0.90 days, 44.57 ± 0.87 days and 33.07 ± 0.82 days at 21.83 ± 0.74oC, 25.89 ± 0.89oC and 29.83 ± 0.71oC, respectively.The number of eggs laid by a female was 69.13 eggs at 25.4oC and 91.93%RH. The egg hatching percentage was high 84,1-90,1%. Male adult longevity was significantly shorter than thefemales.

This study was carried out to evaluate and select superior purple waxy corn lines derived from self-pollination (S3to S6generation) with high grain yield, marketable fresh cob yield, anthocyanin content, good eating quality and desirable agronomical characteristics. These lines were extracted from exotic and domestic germplasm. Phenotypic data collected included growth and developmental characteristic, yield and yield components, marketablefresh cob yield, total anthocyanin content, eating quality, pericarp thickness, sugar content,tenderness and taste.. Eighteen purple waxy corn lines out of 45 lines were selected based on selection index computed from ideotype plant analysis with 12 traits. These lines had high anthocyanin content (22.4 to 260.10 µg/L), acceptable grain yield (2.0 to 3.5 t/ha) and marketable fresh cob yield (3.8 to 6.4 t/ha), good eating quality and suitable agronomical characteristics. These lines were recommended for further purple waxy corn inbred line and hybrid development.

The objective of this study was to evaluate the growth and yield characteristics of quinoa genotypes grown under salinity stresses at different stages of development. The experiment was conducted in Vietnam National University of Agriculture. Two quinoa genotypes and four NaCl salt concentrations (0, 50, 150 and 300 mM) were laid out in factorial experiment in RCBD with three replications. Salinity stress was induced by irrigation with nutrient solution containing NaCl with corresponding concentrations to quinoa plants grown in sands for two weeks during flowering initiation (35 days after sowing). The results showed that salinity reduced plant height, number of leaves on main stem, number of branches on plant, root length, root dry weight, shoot dry weight, SPAD Chlorophyll Meter Reading (SCMR), panicle length, seed amount, the number of branches per panicle and 1000-seed weight. Quinoa genotypes with high potential for the number of leaves on main stem, the number of branches on plant, root length, root dry weight, SCMR and shoot dry weight under non-stress conditions performed well under salinity conditions.

The study was performed to analyse the technical and financialaspects of Suminoe oyster (Crassostrea rivularis) cultured in cage in Bac Lieu Province during August to December2014. The results showed that Suminoe oysters werecultured throughout the year, mostly in January and February lunar calendar, and its culture density was 239 ±29.93 individual/m2; the average size of breeder was 103 ±3.45 gram/ individual. After 8-10 months of culture, the average production was 71.62 ±7.20kg/m2, and the survival rate was90 ±1.16%. The average total cost and income was 384 million and 466 million Viet Nam dong per crop, respectively, with high benefit-cost ratio (1.21). The culture system had many advantages, including good natural conditions, simple farming techniques, easy to manage, and lowdiseaseincidence. The main disadvantages include fulldependenceonthe natural resources, lack of funds for expandingthe culture scales, solely domesticconsumption. The study providesbasic information for development of the Suminoe oyster culture industry in Bac Lieu Province in future.

Xylanase is widely used as feed additive to reduce viscosity and to improve digestibility. Thermostability and activity at low pH of feed grade xylanase are important characteristicsthatallow itto withstand pelleting process at high temperature and to remain active in acidic environment of animal stomach. This study was aimed at producing recombinant xylanase for application in feed industry. The GenBank sequence FJ212324 of 636 nucleotides encoding endo-1,4-β-xylanase Xyl11B from Bisporasp. MEY-1 was optimized for codon usage in Pichia pastoris and synthesized by GenScript. The synthetic sequence was inserted to pPICZαA and transformed into P. pastoris X33 for heterologous extracellular enzyme production.Recombinant P. pastoris X33 strain showed xylanase activity of 96 IU.ml-1after 10 days of cultivation using flask culture in mineral medium with methanol as sole carbon source. The purified enzyme had a molecular weight of 30 kDa. Endo-1,4-β-xylanase was most active at 65C and pH 3.0. It was thermostable and retained 90% of activity after 20 min of incubation at 70C. Recombinant enzyme retained more than 90% activity at a wide range of pH from 1 to 8.5. The enzyme was resistant to the proteolytic activity of pepsin. The enzyme activity was inhibited by the presence of SDS. Metal ions, such as Mn2 + , Cu2 + negatively affected the enzyme activity.Endo-1,4-β-xylanase obtained met the important requirements for feed grade enzyme. With high level of extracellular enzyme production. The recombinant P. pastoris strain could be a potential candidate for industrial application.

A study was carried out at 3 households of An Duong district, Hai Phong city to evalue reproductive capacity of Ri and crossbred chicken (Ri-Sasso-Luong Phuong) (RSL). Results showed that the rate of survival of Ri and RSL chicken were highand they were well adapted tolocal conditions. Body weight of crossbred chicken was higher than Ri chicken at 01 day, 8 and 19 weeks of age.Reproductive maturity age of crossbred chicken (145 days) was later than Ri chicken (131 days).Reproductive peak of crossbred chickenwas at 30 weeks of ageas compared with 26 weeks forRi chicken.Theegg quality parameters of Ri and crossbredchickensmet specified standards andhatchabilityand chick quality were similar.

Doan Hung district, Phu Tho province had 5 land use types for agricultural production with 21 land use patterns, distributed in soils of different fertility and texture. The pH value varied from low (3.39) to slightly low (5.42), organic matter from medium (2.37%) to poor (1.03%), total phosphorous from poor to very poor (from 0.06% to 0.14%). The results showed that there were 3 major soil groups: Fluvisols with 1,704.95ha, accounting for 13.56%; Alluvium with 2,912.28ha, accounting for 23,16%, mainly cultivated rice and rice-cash crops; and Ferrasols occupied the largest area (7,955.22ha, or 63.28%). Soil quality database was standardized following the National Land database, including soil map, current utilization map and soil characteristic data. Soil quality database can be integrated with cadastral database and other database to form Land information system of the district. Study results canhelp the district in comprehensive management ofboth soil quality and quantity.

The study area included3 communes (Thach Quy, Thach Mon and Thach Ha) in the suburbs of Ha Tinh city: The total area is 760.62 ha. Sixclassification criteria were identifiedincluding soil type, terrain, top soil depth, texture, soil fertility and irrigation regime. Consequently, sixcorresponding thematic maps were constructed using GIS functions in ArcGIS software. Those maps were overlaid in order to construct a land unit map. The results showedthat there were 31 land mapping units(LMU), among which LMU number 16 had the smallest area (9.64 ha)whileLMU number 31 had the largest area (113.6 ha). Both of them are Thionic Pluvisols in FAO classification. By assessing the land quality of the LMUs, 456.05 ha were identified assuitable for paddy rice, 490.49 ha suitable for paddy rice and vegetable cultivation,alternately and 526.62 ha suitable for vegetable cultivation.

In this study, we have developeda colorimetric sensor for rapid and selective detection of mercury ions (Hg2 + ) in water by using the gold nanoparticle solution (AuNPs) and thymine-single stranded DNA (T-ssDNA). AuNPs is used as a sensing element based on their unique surface plasmon resonance propertiesand the T-ssDNA isself-assembled on gold nanoparticles to produce the AuNPs-T-ssDNA complex. Single-stranded DNA (T-ssDNA) could enhance the AuNPs against NaNO3-induced aggregation. However, the presence of mercury ions in the complex of AuNPs-T-ssDNA will reduce the stability of AuNPs due to the formation of Hg2 + mediated T-Hg2 + -T base pairs accompanied with the AuNPs color change from red to purple or even to dark blue. As a result, Hg2 + can be detected qualitatively or quantitatively by the naked eye or by UV-vis spectral measurement. The lowest detectable concentration of mercury ions by naked eye and by the UV-vis spectral measurement was 0.06µMand1nM, respectively.

One of the methods for increasing crop yield is to nurture plants in greenhouse.Important factorsdirectly affecting the growth stages of plants are temperature,air humidity, soil humidity and light intensity. Therefore, collecting data on these factors is of great concern to help growers observe closely and adjust accordingly. The manufacture of a data collection system will help growers approach new technologies. The system was designedand manufactured in order to collect and store the parameters such as temperature (20-60oC, step 0,1); humidity (40-100%, step 0,1); light intensity (10-14000 lux, step 0,1) with accuracy of 5% of measured value. The research provides preliminary solution to the collection andmanagement of the data for greenhousecrop production in Viet Nam.

Cascade control systems are widely used in practice with one or more loops inside the primary loop and thecontrollers are in cascade. In this structure, the control signal calculated by the outer loop is the setpoint of the inner loop. This paper presents an algorithm that directly uses the experimental data to simultaneously tune parameters of the controllers in cascade control systems. The algorithm does not require a mathematical model of the plan but only one-shot experimental data collected from the closed loop system.

Selection of relevant genes that have effects in some diseases is a challenging task in gene expression studies. Most gene selection studies focused on assessing the association between individual gene and the disease. In fact, diseases are thought to involve a complex etiology including complicated interactions between many genes and the disease. Random Forest (RF) method has recently been successfully used for identifying genetic factors that have effects in some complex diseases. In spite of performing well in some data sets with moderate size, RF still suffers from working for selecting informative genes and building accurate prediction models. In this paper, we investigatedsome methods in learning advanced random forests that allow one to select a sub-set of informative genes (most relevant to disease). The method can therefore reduce the dimensionality and can perform well in prediction high-dimensional data sets. The performance of these methods has been analyzed for finding the robust one for each interest objective (the accuracy of the prediction model or the smallest possible set of relevant genes) based on experiments results on 8 available public data sets of gene expression from the repository of biomedical data sets (Kent Ridge) and bioinformatics data sets(Bioinformatics).

In the curent study, the biological age of tomato cv 'Savior' grown in spring summer season was determined using modeling approach. The model was calibrated based on two input variables: mass and fruit color changes during fruit development and ripening. The model was successfully validated using a single point estimation method. The data in this study canbe combined with the quality attributes at diferent physiological stages to calibrate the model for predicting the optimal harvest timeof tomato cv Savior in further research.

The paper addresses the problem of predicting soil organic matter content in an agricultural field using information collected by a low-cost network of mobile, wireless and noisy sensors that can take discrete measurements in the environment. In this context, it is proposed that the spatial phenomenon of organic matter in soil to be monitored is modeled using Gaussian processes. The proposed model then enables the wireless sensor network to estimate the soil organic matter at all unobserved locations of interest. The estimated values at predicted locations are highly comparable to those at corresponding points on a realistic image that is aerially taken by a very expensive and complex remote sensing system.

The main objective of this study was to investigate the effect of different temperatures of hot air drying on the quality attributes of orange fleshed sweet potato including colour parameters and colour sensory quality. The drying experiments were carried out at five air temperature of 40, 50, 60, 70 and 80oC. The colour parameters, L(whiteness/darkness), a(redness/greenness) and b(yellowness/blueness) for colour change of the materials were quantified by the Hunter Lab system. These values were also used for calculation of total change (E), hue angle, chroma and browning index. A consumer preference test was conducted with 80 consumers to assess the colour quality of five dried orange fleshed sweet potato samples. Relationship between colour sensory scores of consumer’s taste and quantification of three Hunter parameters using least square regression indicated that all colour values significantly affect colour quality ranking of dried orange fleshed sweet potato. The zero-order model appeared best suited to explain the colour change kinetics during hot drying orange fleshed sweet potato slices at 70oC.