Vol. 17 No. 3 (2019)

The pot experiments were carried out to evaluate growth and salt tolerance at early vegetative stageof five taro cultivars, viz. Tim Tua Chua, Trang Pu Nhung, Tim Moc Chau, Trang Thuan Chau and KS4,under four different salinity levels. Four-leaf plants were treated with four NaCllevelsof 0%,0.15%, 0.3%, and 0.45%for eight weeks. The results indicated that taro cultivars reponded differently to salinitylevel.Tim Moc Chau was the most salt tolerant cultivar, followed by Trang Pu Nhung, Trang Thuan Chau, and Tim Tua Chua, whereas KS4 was the most salt susceptible cultivar. The growth of cv. Tim Moc Chau was enhanced at0.15% NaCl and thiswas maintained atNaCl of 0.45% in 8 weeks. Shoot dry weight wasnot correlatedwith root dry weight but positively correlated with petiole length, leaf blade width and length, and plant canopy diameter.

A pot experiment was set up ingreenhouse conditions at the Faculty of Agronomy, Vietnam National University of Agriculture in the Spring-Summer and Summer seasonof 2018to determine the effects of waterlogging at 3 days after germination, 2-3 leaf, 5-6 leaf and flowering stages on the physiological traitsand individual yield of mungbean cv. ĐXVN5. Each growth stage of mungbean was treated as a separate experiment consisting of 2 treatments:non-waterlogging as control and waterlogging.Waterlogging treatments were maintained at 3 cm-water for one week. The results showed that the waterlogging significantlyreduced plant height, number of leaves, leaf relative water content, root length and root dry matter, chlorophyll content index (SPAD index), dry matter and individual yield of mungbean in bothseasons. Plants at 5-6 leaf stage showed better growth and recovery under waterlogging conditions. The flowering stage was adversely affected by waterlogging stress.

The objectives of the research were todetermine: (i) N, P,and K contentsof rice plantsand (ii) uptake requirements for N, P,and K to produce rice grain in dry and wet seasonsin Mekong Delta acid sulfate soils. Field demonstration plots of 1.000m2were conducted on acid sulfate soils located atfive locations in the Mekong Delta, during the wet season (WS) 2015 and the dry season (DS) of 2015-2016. The locations were Phung Hiep- Hau Giang, Hon Dat- Kien Giang, Hong Dan-Bac Lieu, Long My-Hau Giang, and Thap Muoi-Dong Thap. For each location, three farm plots with the same soil type were selected. Results showed thatthe average contentsof N, P, K in the grains were 1.08% N, 0.44% P2O5, 0.33% K2O, respectively. The figures f in rice straw were 0,62% N, 0,27% P2O5, 1,67% K2O, respectively.To produce one ton of grain, the rice plant took-up 17 kg N - 7 kg P2O5and 20 kg K2O. The average rice yield in the wet season was 5.0 tha-1andin dry season was 7.0 t ha-1.In the case without return ofrice straw into the soil, the amount of N, P, K removed by rice grain was 54 kgN - 22 kg P2O5- 16,5 kg K2O, in WS and75,6 kg N - 30,8 kg P2O5- 23,1 kg K2O in DS.

This study was conductedto determine the presence of the canine zoonotic hookworm species, Ancylostoma ceylanicum, in humans in Vietnam and to analyze the single nucleotide polymorphism in thegenesegment encoding A. ceylanicumcathepsin D aspartic protease, one of the hydrolytic enzymes with an important role in thelife cycle of hookworm. The existence of Ancylostoma ceylanicumin dogs and humans in Vietnam was confirmedby KOD-PCR. Comparative analysis of tthesequences encoding A. ceylanicumcathepsin D aspartic proteaserevealed, some mutations in exon 7, 8,and 9. Three SNPs non-synonymous mutations (one from exon 7 and two from exon 9)caused the changes in amino acid sequences of aspatyl protease.Our results can be considered forfuther studies on the development of effective vaccine against hookworm diseaseusing recombinant cathepsin D aspartic protease as an antigen.

This study aimed to identify species andassessgenetic diversity of four pompano populations collected in Nha Trang, Vung Tau, Hai Phong and Quang Ninh. The molecular makers based on COI sequencing and microsatellite markers were applied. The results revealed that the sequences of the COI gene isolated form Vietnamese pompano were highly similar (99-100%) to the COI sequences of pompano Trachinotus ovatus(Genbank accession number: KF356397.1, HQ127346.1 and 10 KJ642220.1). Genetic diversity inferred from microsatellite markers indicated high allele polymorphism (average of 8-15.33 alleles) and high polymorphism information content (average of PIC values: 0.685-0.839). The coefficient of inbreeding Fis>0 was recorded in Hai Phong and Vung Tau populations, while Nha Trang and Quang Ninh fish populations contained low inbreeding coefficient with Fis <0. The genetic relationship reflected by Fst coefficient indicated the moderated level of genetic difference amongstfour populations, in which the Vung Tau population is more closely related to the populations of Hai Phong, Quang Ninh and Nha Trang. The analysis revealed an unclearpopulation structure according tothe Analysis of Molecular Variance (AMOVA)results. This study mightsupport for managing the stockof selective breeding program of the pompano.

This study aimed to assess the effectiveness of forest protection contract program in Thuong Tien special-use forest (SUF) in Hoa Binh province and Xuan Nha in Son La province. The program was designed and implemented to establish a pilot model for forest protection and management in special-use forests from different financial sourcesby allocating the forest inside SUF for local people to protect.Results from in-depth interviews with 52 officials at different levels, 200 local peoplefrom8 villages (including 4 villages implementing forest protection contracts and 4 villages without contract) and 36 group discussions indicated that the program achieved high efficiency with a relative small support.The program successfully developed a forest protection contract model in SUFin Vietnam to ensure transparency of paymentandto develop a comprehensive forest protection plan with specific assessment criteria. Consequently, the local government andspecial-use forest management boards successfully promoted forest protection through local communities.

In recent years, the area under sugarcane in Ngoc Lac district hasbeen decreasing dramatically (6,428.4 ha and 2,285,30 ha in 2010and 2017, respectively). One of the reasonsis that local farmers shifted tocultivating market-orientedcropswithoutconcerning the long-termland use efficiency. The aim of this research was to determine the efficiency of land use for sugarcane as a basis for the managers and farmers to use land appropriately. Surveying and interviewingfarmers were conducted to evaluate the economic, social and environmental efficiency for 4 land use types of sugarcane crop in the study area. The results showed that the land use for sugarcane intercroppedwith groundnut crop had the highest value, the specialized land for sugarcane, sugarcane intercropping with mungbean, and sugarcane intercroppedwith soybean crops broughtaboutmoderate efficiency of land use. In addition, the research also showedthatland use type for sugarcane intercropping with groundnut crop not only hadhighimcome, but also helped improvethe soil fertility.It was thereforerecommendedthat land use types for Ngoc Lac districtfrom high to moderate efficiency were as follows: sugarcane intercroppedwith groundnut, the specialized sugarcane cropping, sugarcane intercroppedwith mungbean, andsugarcane intercroppedwith soybean.

Bacterial leaf streak caused by Xanthomonas oryzaepv. oryzicola (Xoc)is a commondisease occurring in most rice growingareas in Vietnam, especially in Autumn season. This study aimed to isolate and analyze the genetic diversity of Xocin North Vietnam. Infected leaves were collected in 5 provinces: Lao Cai, Thai Nguyen, Hanoi, Thai Binh and Nam Dinh in the Autumn seasonof 2014. Twenty-three isolates were isolated usingWakimono medium and confirmed by both multiplex PCR and artificial inoculation. The genetic diversity was characterized by rep-PCR and IS-PCR techniqueswith 3 markers ERIC2F, BOXA1RF and J3F. A phylogenetic tree was constructed and23 isolates were classified into 4 clusters with polymorphic information content value of 0.72. Theresultsprovided a better understanding onthe diversity of Xocin North Vietnamand served as basis for breeding and disease control.

Ổi (Psidium guajavaL.) là một loại cây nhiệt đới, được sử dụng làm thực phẩm và thuốc để chữa một số bệnh. Nghiên cứu này nhằm đánh giá sự biến đổi về chỉ số sinh lý, hàm lượng phenolic và khả năng kháng oxy hóa trong quá trình chín của hai giống ổi, Đồng Du và Đại Loan. Quả ổi được thu hoạch ở bốn giai đoạn khác nhau, giá sinh lý, chuyển màu, chín và chín quá. Hàm lượng phenolic và hoạt tính kháng oxy hóa được xác định bằng phương pháp Folin-Ciocalteu và DPPH. Kết quả cho thấy trong quá trình chín, đường kính và trọng lượng của giống ổi Đông Du tăng đáng kể, trong khi các biến số này của giống Đại Loan không thay đổi đáng kể. Về chỉ số màu sắc, các giá trị L, a và b tăng lên, trong khi giá trị hue giảm ở cả hai giống trong quá trình chín của quả. Hàm lượng acid ascorbic tăng trong quá trình chín và không có sự khác biệt giữa hai giống. Hàm lượng phenolic và hoạt tính kháng oxy hóa giảm trong quá trình chín và hai chỉ số này cao hơn ở giống Đông Du so với giống Đại Loan. Hàm lượng phenolic và khả năng chống oxy hóa có mối tương quan chặt (P <0,001), cho thấy các hợp chất phenolic là chất kháng oxy hóa chính trong ổi. Giai đoạn chín là thời điểm thích hợp để thu hoạch trái cây để tiêu thụ để. Thời gian thu hoạch phù hợp là rất quan trọng để sản xuất các sản phẩm ổi chất lượng cao như nước ép ổi và mứt.

The objective is to assess the situation and propose solutions to provide public services for the development of pork value chain in Hanoi, Surveys were conducted with 150 providers and300 receivers of public services for pork value chain development in Hanoi. The study conducted surveys through questionnaires and in-depth interviews with agents and unit representatives. It was found that the public services for pork value chain development were provided by state management offices, state service providers and private sector. However, there were overlaps among public services; state service providers play both roles of players and referee and highly concentrated in prior-checking in public service provision. Service fees were low but the costs for accessing the services were high. All the services were provided in a mode of direct meeting at the offices, no service was provided on-line. Virtually, customers were not highly satisfied with the public services theygot. In oder to improve public service provision, there is a need to change viewpoints on sector state management, moving from prior-checking to post-productcontrolling, from instructing toenabling a strong participation of public and privatesectors, applyingaprice-basedmechanism in thepublic service provision, flexible application of bothtraditional and online service provision modes, upgrading knowledge, skills and attitude of service,andstrong dissemination of public services to customers involved in theporkvalue chain.