Vol. 17 No. 1 (2019)

This study was carried out to evaluate agronomical characteristicsand combining ability of the new three-line hybrid rice parental lines in NamDinh province.The results showed thattheparental lines hadshort growth duration(73-84 days for the female lines and 103-114 days for the male lines). Two female lines,S201AandS202A,and four male lines,R1, R2, R3, and R4 haddesirable agronomical characteristicssuitable forthree-line hybrid rice development. The female line S202A and male line R4showed good resistance to bacterial leaf blight disease. The new three-line hybrid combinations hadshort growth durationof which eight combinations showed yieldcomparable to the check variety. Especially, the hybrid S202A/R4 hadyied higher than the check varietyand good resistance to bacterial leaf blight disease. The parental lines with high general combining ability for yield wereS201A and S202A. Tthe male lines R1 and R2 showed good combining ability for 1000 grain weight and actual yield. The hybrids withhigh specific combining abilityfor yieldwere S203A/R2 and S204A/R4.

Waterlogging is a major environmental stress limiting maize yield in the monsoonal areas of Asia, as well as in other parts of the world. The objective of this study was to evaluate thephenotypic variation in root development under hypoxia condition at the seedling stageofdiverse maize inbred lines in 0.1% agar-hydroponic culture. The root length (RLD), root surface area (RSAD) and root volume (RVD) under hypoxia wereinvestigated by means of WinRHIZO analysis before and after the treatment. Based on the evaluation results of 30 lines under hypoxia, root development of15 selected lines was also evaluated in soil culture. Significant phenotypic variation in hypoxia tolerance in roots was observed among studiedmaize lines. Root developmentin hydroponic and soil culture wassignificantly correlated. The results suggested that nine potential lines (VNT2, VNT3, VNT7, VNT9, VNT12, VNT13, VNT14, VNT24 và VNT25)hada high ability to develop roots under hypoxia. These resultsprovide insights into the mechanisms of waterlogging adaptation and the hypoxia tolerant materials can be usedto improve the waterlogging tolerance of modernmaizecultivars at the seedling stage.

Glinus oppositifolius (L.), an indigenous medicinal plant, has long beenused as a liver detoxification in Vietnam. Generally, seeds could be used for propagation. However, the drawbacks of this method include small seeds, low germination rateand slow seedling growth. In vitropropagation is apotential approach to increase the quantityand quality of planting meterials. In this study, a protocol for in vitromultiplication of Glinus oppositifolius was established by optimizing initial culture, shoot propagation and rootinductionin vitroand plantlet acclimatization.For explant isolation from stems,sterilization by Johnson (1%) for10 minutes yieldedthe highest survival rate(76.67%).BA concentration of 0.5 mg/L was most suitablefor shoot formation and growth. The medium added with0.5 mg/LBA and 0.5 mg/L-NAA/IAA showed the highestmultiplication rate, leaf number and plant height after four weeks of culture. Supplementing with0.5 mg/L-NAA for rooting stage resulted in100% rootinduction.The substrate containing100% coconut coiryieldedbest quality of plantletsat 40 days after planting.

This objective of this study was to determine the occurrence of the gastrointestinal parasites in cattle. Ninety-four fecal samples of beef cattle, dairy cattle and calves raised in Phu Dong were collected by stratified random sampling from August 2017 to August 2018. Fecal samples were examined by simple sedimentation and sugar floatation techniques. 93/94 animals infected with at least one parasite. Nematode was found in 84/94 samples, and all beef cattle (n = 50) were infected. By observation of egg morphology, Strongyloides papilosus, Nematodirusspp., Cappilariaspp., Trichurisspp., Mecistocirrusspp. and Strongyle- type roundworm eggs were identified. In addition, other round worms belonging to Strongyle group including Haemonchusspp., Trichostrongylusspp., Ostertagiaspp., and Bunostomum spp. were also identified by morphology of nematode larvae. Coccidia were found in 54/94 animals, especially all calves (n = 24) were infected. Nine Eimeriaspecies were determined, among them Eimeria zuernii, E. bovis, E. auburnensis, and E. ellipsoidaliswere predominant, especially in calves. No fluke, tapeworm, and other protozoa were found in this study. In conclusion, Nematode and Coccidia were usually prevalent in gastrointestines of cattle in Phu Dong. Thus, effective prevention and treatment methods are needed for improving cattle husbandry.

The objective of this study was to examine the pathogenesis of highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) in crossbred-wild pigs through experimentally infected model. Twenty eight healthy crossbred-wild pigs, 42-49 day-old, originated from CSFV-PRRSV-negative farms were allocated in two experimental groups.The findings in clinical signs and pathology showed that the acute phase of infection took place from 5 to 14 days post infection. The major manifestations were fever, anorexia, respiratory failure, eye discharge and swelling, shivering and death. Severe interstitial pneumonia happened in all infected animals and interstitial pneumonia accompanied with hemorrhage recorded in died pigs. The laboratory indicators (viremia in the blood/tissues, IHC score, IgG antibodies, IL-1) were in homology with clinical pathology in acute phase of the disease. There were variations ofthe antigen distribution in various tissues over time-points post infection. This virus was first detected intheepithelial cells of bronchioles, stomach, kidney, bile duct and hepatic cells. The study results demonstrated that HP-PRRSV might cause severe pathology, wide antigenic distribution in visceral organs and could be fatal in crossbred-wild pigs through experimental infection.

In traditional tofu (soybean curd) production, fermented tofu whey (acidic whey) - the watery part of soymilk remaining after the formation of tofu curd which is then naturally fermented -isutilized as protein coagulant. The aim ofthis studywas to investigate the changes of severalmajor chemical and microbiological components of the tofu whey during natural fermentation as well as the effect of fermentation time of tofu whey on the quality of tofu. The sugar and soluble protein content decreaseddue tomicroorganisms’ consumption as substrates. The increase of acid concentration was attributed tothe development of lactic acid bacteria. The whey after different fermentation times used as coagulants gavetofu with variablequality. Tofucoagulated with the whey after 24 h fermentation hadhigh protein and lipid content (14.8% and 5.2%, respectively)andgood water holding capacity(5 g water / g protein), and attainedhighest sensory evaluation scores (17.7). In addition,the whey after 24 h of fermentation used to coagulate tofu brought the highest yield(159%).

Solanum hainanense,a valuablemedicinal herbis used for detoxifying and protecting the liver. This plant accumulates different alkaloids and glycol-alkaloids that could inactivate Hepatitis B virus, acting as antioxidant and preventing cirrhosis effectively. Callus culture is a potential method to producesafe and high quality medical materials. Light spectrum and elicitors (yeast extract and salicylic acid) hadsignificantly positive effect on the increase of biomass and antioxidant activity of Solanum hainanensecallus culture on gel medium. LED lighting with a 30/70% of Blue/Red spectrum increased the dry biomass of callusesby 2.46 times compared with lighting by T8 fluorescence lamps. When adding 100 M salicylic acid or 3g/L yeast extract to the culture medium, the dry biomass of the calluseswas 2.43 or 3.04 times higher than the control, respectively. In addition, elicitors increased the antioxidant activity of the callus extract from 1.26 to 1.49 times of that of the control callus extract and increased from 2.31 to 2.73 times compared tothe two-year-old natural herbalextracts. These results could serve as the basisfor the development of in vitroculture systemfor improving the biomass and antioxidant activity of Solanum hainanense callusesand for expanding the research to other medicinal plants.