Vol. 11 No. 1 (2013)

In this study, we used DNA markers (5 RAPD markersand 5 SSR markers) to screen genetic diversity in 60 samples of taro(Colocasia esculenta)that collected. Total 67 alleleswere amplified by RAPD markers, in that has 47 polymorphic alleles. 20 alleleswere amplified by SSRmarkersand 9 alleles were polymorphic. From the electrophoresis PCR products of these two directives, 60 taro accessions were grouped into 12 clusters with similarity coefficients of 0.8 by NTSYSpc 2.1 software. The information found in this study may be used for taro conservation and breeding programs.

The pot experiment was carried out in the greenhouse to estimate the effect of different fertilizer levels on photosynthetic and physiological characters at active tillering, flowering and early ripen stage of barnyard grass (Echinocloa crus-galli (L.) Beauv) and the rice cultivar Khang dan 18 in both summer and autumn cropping seasons in 2012. Seeds of each species were sown in distinct pots containing 6 kg dry soil per pot. When rice and grass had 2 leaves, the plant was kept in single pot. There were three nitrogen levels, no nitrogen (N0), 0.1grN (N1), 0.12 grN (N2) with the same base of percentage N: P2O5 : K2O: 1: 0.5: 0.5 per one kg dry soil. The result showed that photosynthetic rate and dry matter accumulation rate of barnyard grass were higher than those of rice at all growth stages in both seasons, although stomatal conductance, transpiration rate and SPAD of rice were higher than those of barnyard grass. As increasing fertilizer, the photosynthetic rate, dry matter accumulation rate and nitrogen content in leaves were also increased in both rice and barnyard grass.

A study was carried out from December 2011 to August 2012 to evaluate reproductive performance of nucleus herd of stress negative Piétrain (Piétrain) and Duroc pigs raised at the experimental farm of Hanoi University of Agriculture. A total of 35 gilts, including 21 Piétrain (11 with halothane genotype CC and 10 with CT) and 14 Duroc CC gilts were monitored for their reproductive performance. Piétrain boars (3 CC and 5 CT) were mated to Piétrain and Duroc gilts to produce Piétrain purebred and crossbred Piétrain x Duroc pigs. Results showed that genotype of the boar and the sow affected body weight and litter weight at birth and at weaning (P<0.05). Total number of pigs born, number born alive, number alive to weaning, individual bodyweight at birth, individual bodyweight at weaning, litter weight at birth, litter weight at weaning, survival rate at birth, survival rate to weaning were 9.91, 9.26, 8.11 piglets, 1.4, 6.4, 12.97, 51.96kg, 94.32 and 88.55%, respectively. Body weight and litter weight at birth and at weaning of piglets from Piétrain CC boars were higher than those of piglets from Piétrain CT boars (P<0.05). Reproductive performance was highest for Duroc CC sows, followed by Piétrain CC and lowest for Piétrain CT sows (P<0.05). Reproductive performance of the nucleus herd could be improved by using Piétrain CC boars mated to Piétrain CC sows and Duroc CC sows.

Dietary study onintensive rearing female otter clam(Lutraria philippinarum)stocked at a density of 30 pieces/m2 in 1m3 composite tank using Schizochytrium and fresh algae complex (Chlorella, Isochrysis, Chaetoceros) showed significantly higher percentage of mature and spawning in female otter clam fed on Schizochytrium (92,86 ± 1,50%) than that fed on fresh algae (74,06 ± 2,50%; P<0,05); however, there was no considerable difference in absolute fecundity, fertilization rate and rate of transformation to Trochophore larvae between the two treatments.Other experiment on survival rate of larvae otter clam fed on mix of Schizochytrium and Spirulina while the other fed on fresh algae complex (Isochrysis galbana, Chroomonas salina) from 4 to 21 days in 2m3 composite tank demonstrated no significant distinction in survival rate between the two experiments with survival of 21,6 ± 5,6% and 20,4 ± 3,5% respectively (P>0,05).

The present study conducted on three different breeds of Tau Vang (n=237), Noi (n=34) and commercial Cobb 500 chickens (n=23) aimed at evaluating single nucleotide polymorphims in IGFBP2 (Insulin-like growth factor binding protein 2) using PCR-RFLP method. Three poplymorphisms at positions g.639G>A (exon 2), g.1023C>T (intron 2) and g.738G>A (exon 3) were detected based on restriction enzymes Bsh1236I, Eco72I and Alw21I, respectively. Genotypic and allelic frequencies at these polymorphisms, which were also identified in previous studies, have effects on economic traits in various chicken populations and follow Hardy-Weinberg equilibrium. These can be considered as important evidences for developing further studies for IGFBP2 polymorphic association with growth, meat yield and meat quality traits in Tau Vang chicken.

The experiments were carried out to evaluate the effects of temperature and salinity on embryonic development of the Tiger grouper (Epinephelus futcoguttatus)and to determine the optimal temperature and salinity for incubation of Tiger grouper eggs. The fertilized egg of Tiger grouper was incubated in a series of 1L-glass beakers at a density of 100 eggs/L and divided two separated trials. The first experiment was conducted at five temperature levels of 23ºC, 26ºC, 29ºC, 32ºC, 35ºC, each treatment was run in triplicate. The second experiment was implemented at different salinity of 23‰, 26‰, 29‰, 32‰, 35‰. The study results clearly show that the highest hatching rate (89.6 ± 3.2%) and the lowest deformity rate (6.3 ± 0.4%) were obtained in the treatment which were incubated at 29oC compared to the others (P<0.05). The second experiment demonstrated that the salinity of 32 -35‰ are suitable for incubation of tiger grouper egg as the highest hatching rate of 83.4 -85.6% and the lowest deformity rate of 1.79 -1.85% were obtained (P<0.05). In conclusion, among the treatments, the temperature of 29ºC and salinity of 32 and 35‰ are the best conditions for Tiger grouper eggs incubation.

Possibility of using rice bran as raw material for common carp feed was evaluated throughthe digestibility value and its incorporation level in diet. The apparent digestibility coefficients (ADC) of rice bran was measured by indirect method using chromic oxide Cr2O3 as inert marker, feces were collected by sedimentation. The chemical composition of rice bran was 8.41% protein and 13.51% lipid. The digestibility of dry matter, protein and lipid of rice bran were high, reachingvalues​​of97.86%, 87.45% and80.21%, respectively. Digestibilityof mineralsinrice branfor commoncarpvery high, reaching87.16%. Comparedwiththeprevious studiesonthedigestibilityoftherawmaterialsforcarp, rice branhasa relatively highdigestibilitywhich can beexplainedbythe different digestibility measure method. Evaluationthe effects ofdifferentricebranincorporation level ongrowth performance was carried out on common carp of size50g/fishwith3diets which weresupplemented35%, 40% and45% of rice bran. The growth performanceoffish fed 35% rice bran diet was significantly better than that of fish fed 40% and 45% rice bran diets. There was no significant difference between growth performace of fish used40% and45% rice bran diets. Rice bran can be incorporated in common carp diet at the suitable level of 35%. Thedaily growth weight gain was 2.23 g/fish/day and feed conversion ratio was 1.87 for common carp fed diet contenning 35% rice bran.

Sorption isotherm curve of freeze dried (FD) product was investigated at 20oC, 30oC, and 40oC. Experimental data obtained were verified by eight mathematical models including BET, Bradley, GAB, Halsey, Henderson, Kühn, Mizrahi, and Oswin. Eight models agreed well with experimental data (R2= 0.9374-1,0000) when water activity (Aw) varied from 0.12 to 0.43. However, when Aw is extended ranging from 0.12 to 0.93, only four models named as GAB, Kühn, Halsey and Oswin still show a good agreement with the experimental data. These models can be used in predicting water absorption of FD salmon product at 20oC, 30oC, and 40oC withacorrelation coefficient (R2) ranged from 0.9776-0.9917, 0.9867-0.9991, 0.9821-0.9920 and 0.9464-0.9995, respectively. Errors between experimental and calculated data from the four models were 5.1%, 4.9%, 8.7% and 9.4%, respectively. Water monolayer value is determined at approximately 5%.

The study focused on analyzingthesituationofland recoveryfortheconstructionofindustrialzones; influenceofagriculturalland recoverytoeconomic growthandeconomicrestructuring, laborrestructuring, the employment and income ofthehouseholdswhich are recovered land , thechallengesofland recoveryinthe development process. Research results show thatfrom2000 -2010, VanLamdistrictagriculturalland recoveryof14,260playshouseholds; totalarearecoveryis928.52ha, ofwhichagricultural landis736.50ha. Positiveeconomic structuralshiftin the direction ofincreasingtheproportionofindustryandconstruction(from 31.00% in 2000to74.99% in2010) andreducedtheproportionofagriculture(57.50% in2000toreduceto12.65% in2010). The average incomeper man rosefrom3.82millionin2000to27.2millionin 2010. Creatingmore new jobs, attractingaround25,000employeesto work intheindustrialzones, etc.However, thelossofagriculturallandhas madepartoffarmersunemployed, raisinganumberothersocialactivities, directlyaffectson their lives. Specifically, households with agricultural land recovery rate (> 70%) have high rates of job change (94.17%), thus their income, spiritual and cultural life also increase in comparison with the past. On the actual results of the investigation, there are still some households with income unchanged, a number of households whose income is less than before, focusing mainly on households with land recovery rate is low (<30 %), the mentality of the people is afraid to change careers, which is the main reason, so they try to hang on the remaining agricultural land.

Foreigndirect investment (FDI) plays a crucial role in the process of development for Vietnam. Over the two decades of Renovation, a large number of FDI capital flowed into the country, especially after joining the WTO in 2007, an amount reaching up to approximatelyUSD 229,913.7 million. Agravity model constructed using the Hausman – Taylor(1981) estimatorwasapplied to 1995 to 2011panel data that included18 of Vietnam’s major country partnersandprovided by Vietnam’s authorities and international organizations. Thepurposewasto reexamine the possible effect of trade liberalization under the WTO regime and various FTAs on FDI flows. The estimates wereconsistent in line with the prediction that the WTO exerted great impact onFDI flows to Vietnam. By contrast, there is no evidence that demonstrates convincingly that the various FTAs in which Vietnamhas signed/joined recently, increased FDI capital into the country. The paper also proposes recommendations for attracting FDI and using FDI capital more effectively.

This paper reviews the previous studies related value chain in Vietnam as well as in the world; discusing on views of value chain and value chain analysis for aqua-culture sector including concepts, conponents, actors of the value chain. This paper discusses also on models and methods have been used to analyze performance and efficiency of the value chain. The value chain analysis in aqua-culture refers to four stages: mapping, analyzing performance, management and improving value chain. In particular, the content analyzing performance and efficiency of the value chain need to evaluate four areas: performanceand efficiency, flexibility, responsiveness and product quality.