Tuber Resistance and Slow-Rotting Characteristics of Potato Clones Associated with the Solanaceae Coordinated Agricultural Project to the US-24 Clonal Lineage of <Emphasis Type="Italic">Phytophthora infestans</Emphasis>

Late blight, caused by Phytophthora infestans, is a devastating disease on potato worldwide and new lineages of the pathogen continue to develop in the U.S. Breeding for resistance is important for economic and environmental purposes. The Solanaceae Coordinated Agricultural Project (SolCAP) focuses on linking allelic variation in genes to valuable traits in elite cultivated potato germplasm. This research assessed the SolCAP diversity panel (206 clones in Washington and 213 clones in Wisconsin) for tuber resistance to the US-24 clonal lineage of P. infestans after potatoes were harvested from fields in Washington and Wisconsin in 2011. This is the first time this germplasm has been evaluated for tuber resistance to P. infestans using a non-intrusive zoospore inoculation technique. Clones with a percent incidence of 30% or less were considered resistant and only eight clones (Palisade Russet, AWN86514–2, MSL268-D, MSM171-A, MSM182–1, MSN230-1RY, Patagonia and Yukon Gem) were characterized as resistant at both locations. These clones have previously demonstrated high to moderate partial foliar resistance to isolates of P.infestans and therefore represent germplasm with both foliar and tuber resistance. Nine clones (AWN86514–2, F66041, MN 18747, MSM 182–1, MSN230-1RY, Modoc, Ama-Rosa, Patagonia and Purple Majesty), were characterized as slow-rotting at both locations with a mean percent internal rot of 75% or less after 33 days of storage. Two clones, MN 18747 and Modoc, are considered to have the highest risk of being a carrier for P. infestans of all the clones evaluated in the SolCAP collection. Not a single clone demonstrated complete tuber resistance to the US-24 strain at both locations.     

Effect of neuroactive compounds on larval metamorphosis of New Zealand geoduck (Panopea zelandica)

We present here the first laboratory study on the effects of pharmacologically active compounds on the larval metamorphosis of the New Zealand geoduck, Panopea zelandica (Quoy and Gaimard, 1835). Two batches of competent hatchery‐reared larvae were exposed to acetylcholine chloride, epinephrine hydrochloride and excess potassium ions in the form of KCl and K₂SO₄. None of the tested chemicals increased the proportion of metamorphosed geoducks, and in some cases, the chemical caused significant mortality, despite having been used extensively with other species, such as mussels and oysters. This might indicate that geoduck larval physiology and development differs from other bivalves. Geoducks may have evolved distinct chemoreceptor patterns that facilitate metamorphosis under environmentally favourable conditions for subtidal soft sediment habitats suitable for burrowing. Thus, further research is needed to identify alternative cues (e.g. conspecific adults, sediment characteristics and surface biofilm) and understand their role in settlement and metamorphosis. This information will aid the design of reseeding methods and contribute to the development of reliable hatchery production of geoduck spat.     

广东黄秋葵黄脉曲叶病样中检测到烟粉虱传双生病毒

黄秋葵是近几年来从日本和我国台湾引进的一种蔬菜作物。近期,广东的黄秋葵上发生了黄脉曲叶病。病株的典型症状表现为叶脉黄化,在叶片正面形成网络状,在叶背面叶脉肿大突起明显,病株幼叶小且向下卷曲,甚至整片幼叶黄化。植株早期被感染表现矮化。在发生黄脉曲叶病的黄秋葵田间,其病株率高达60%以上。用烟粉虱传双生病毒简并引物对随机采集的病样进行PCR检测,从这些病样中均能扩增出1条预期大小为570 bp的特异片段;基因克隆及测序分析结果表明,与该特异片段同源的均属双生病毒科菜豆金色花叶病毒属病毒DNA,其中与木尔坦棉花曲叶病毒（Cotton leaf curl Multan virus, CLCuMV）分离物G6相似性最高,为99%。这些研究结果表明,广东黄秋葵黄脉曲叶病中存在烟粉虱传双生病毒,该病害可能也是由CLCuMV侵染引起的。     

Soil fertility affected by land use history,relief position,and parent material under a tropical climate in NW-Vietnam

In Vietnam as much as half of the total land area is already degraded by soil erosion and nutrient depletion. In particular, degradation due to deforestation is increasingly affecting mountainous areas in north-western Vietnam. The necessity to safeguard the farmers' livelihoods requires sustainable resource management, which firstly requires a qualitative and quantitative evaluation of resources. The objectives of the present study were to (1) identify the dominant soil types and their vulnerability using elicitation of local soil knowledge, (2) characterise the physical and chemical properties of the soils and (3) link them to the relief position and land use in order to (4) initiate sustainable soil use based on recommendations deduced from objectives (1) to (3). These objectives were achieved also by the elicitation of local knowledge. The final aim of the study was to initiate sustainable soil use based on recommendations for sustainable land use scenarios. The Chieng Khoi commune in Son La province of northern Vietnam was chosen as representative for other erosion-prone Southeast Asian sloping areas. In a participatory approach, combining local and scientific knowledge, sixteen sites were selected, representative for distinct relief positions, parent material (sand stone and silt stone), land use history, and erosion hazard. Chemical (e.g. content of organic matter, nitrogen, cation exchange capacity, base saturation, and plant available phosphorous) and physical properties (e.g. air capacity, plant available water) were used to estimate soil fertility. The predominant reference soil groups in the study area are Alisols and Luvisols, with a high diversity in respect to soil fertility. These soils are locally named ‘red soil’ and ‘black soil’, respectively. Although the main physical processes are erosion and selective sedimentation, farmers tend to underestimate their impact and causes, whereas soil quality was well-evaluated. Soils with high fertility were found on less eroded upper parts of hills and at sites, where agricultural use started only recently. Once degraded by cultivation practices, soils derived from sandstone did not recover even after more than 50 years of fallow. As a result of unsustainable land use, soils on middle and lower slopes are often affected by severe soil erosion, whereas foot slope soils suffer from accumulation of eroded infertile subsoil material as well as stagnic conditions. This study showed that unsustainable land use at upslope landscape positions has a severe impact on downslope areas. The elicitation of local knowledge facilitated the identification of such hot spots, allowing the implementation of spatially targeted conservation measures.     

Survival of faecal indicator bacteria in treated pig manure stored in clay-covered heaps in Vietnam

Small-scale pig farmers in Vietnam typically store manure in heaps covered by a layer of clay. However, the hygienic quality of manure applied to agricultural soil is uncertain as storage time is determined by the need for soil fertilizer. This study aimed to assess how the storage of pig manure added straw, lime stone or urea in heaps covered by clay affected the survival of faecal bacteria. E. coli was reduced from 4 log(10)CFU/g to below the detection limit within 2 weeks with 2% (w/w) urea (CO(NH(2))(2)) whereas other amendments were associated with limited E. coli reductions. Enterococcus spp. were not reduced in any heaps indicating possible re-growth and that enterococci should be used as hygiene indicators with caution. Follow-up research should document the practical conditions under which the farmer practice of storing manure with a clay cover can be utilized to obtain a bactericidal effect of ammonia and a safe product with high fertilizer value.     

An evaluation of fish health‐management practices and occupational health hazards associated with Pangasius catfish (Pangasianodon hypophthalmus) aquaculture in the Mekong Delta,Vietnam

This study aimed to evaluate the current status on the use of probiotics, disinfectants and antimicrobials in hatcheries, nurseries and grow‐out farms producing Pangasius catfish (Pangasianodon hypophthalmus) in the Mekong Delta, Vietnam. Semi‐structured interviews were conducted with 83 aquaculture enterprises (15 hatcheries, 32 nurseries and 36 grow‐out farms). Farmers reported use of a total of 24 different antimicrobials, e.g. for treatment of bacillary necrosis and motile aeromonad septicaemia, and a variety of disinfectants, probiotics and nutritional supplements. In contrast to small‐scale farmers, all large‐scale grow‐out farmers studied were certified and therefore had higher levels of formal education and specialized aquaculture training to diagnose and treat diseases. All farmers prepared their own medicated feed with a high risk of treatment failure, negative environmental impact from released antimicrobials and resistance development. Small‐scale farmers were at particular occupational health risks when handling antimicrobials and other chemicals, e.g. mixing medicated feed with bare hands. There is an urgent need to improve knowledge and use innovative approaches, e.g. private‐public partnerships, to assure a prudent use of chemicals, to improve capacity and access to disease diagnosis, particularly for small‐scale grow‐out farmers and nurseries. Efforts to control use of antimicrobials in aquaculture should be coordinated with the livestock and human health sectors taking an One‐Health approach.     

Molecular characterization of bovine foamy virus and its association with bovine leukemia virus infection in Vietnamese cattle

The detection of bovine foamy virus (BFV) in Vietnamese cattle was performed using conventional PCR targeting pol and gag genes. Out of 243 tested samples, ten (4.1%) and eight (3.3%) samples were positive for BFV gag and pol DNA, respectively. The prevalence of bovine leukemia virus (BLV) estimated by detection of proviral DNA using nested PCR targeting env gene was 26.7% (65/243). The results of nucleotide sequence alignment and the phylogenetic analysis suggested that Vietnamese BFV strains showed high homology to isolates belonging to either European or non-European clades. There was no significant correlation between BLV and BFV. This study provides information regarding BFV infection and confirms the existence of two BFV clades among Vietnamese cattle for the first time.