Herbage production,nutritive value and animal productivity within hardwood silvopasture,open and mixed pasture systems in Appalachia,United States          下载免费PDF全文

J. P. S. Neel  D. P. Belesky 《Grass and Forage Science》2017,72(1):137-153

Demand for livestock food products is projected to increase dramatically through to 2050. Increased livestock production capacity on marginal lands will be critical to meeting this demand. A 5‐year research effort was undertaken to evaluate lamb and sward productivity within open and hardwood silvopasture (SP) systems in Appalachia, USA. Grazing began in mid to late April each year, with the grazing season averaging 141 d. Grazing system treatments during 2002 and 2003 grazing seasons were as follows: 100% open pasture (OP), 67% OP and 33% SP, and 67% OP and 33% SP with delayed SP grazing initiation (OSD). In 2004, a 100% SP (SP) system was added. Animals were rotationally stocked through either 6 (2002–2004) or 7 (2005–2006) paddocks. Open pasture produced greater (P < 0·001) grazing season herbage yield, while all systems generated similar animal performance. Based on summer solstice, herbage production in spring was greater (P < 0·001) than summer, except in 2003. Total non‐structural carbohydrate (TNC) content was greater (P < 0·05) in spring than in summer, except in 2004. Animal performance was superior in spring versus summer (P < 0·001). Animal plasma urea nitrogen (PUN) was lower (P < 0·05) for OP in 2003. When PUN was correlated with nutritive value indicators, the ratio of TNC to crude protein (CP) had the strongest correlation. The strong correlation indicates the need for synchronized ruminal energy and CP availability. Development of silvopasture from existing woodlots has potential to improve whole farm productivity on marginal lands.  相似文献   

Milk vetch dwarf virus infection in the Solanaceae and Caricaceae families in Southeast Asia     

Aamir Lal  Eui-Joon Kil  Vo T. B. Thuy  Chairina Fadhila  Phuong T. Ho  Hee-Seong Byun  Hang T. Dao  Ji-Kwang Kim  Sukchan Lee 《Plant pathology》2020,69(6):1026-1033

Milk vetch dwarf virus (MDV) is an important member of the genus Nanovirus and is transmitted by the aphid Aphis craccivora. MDV has multiple single-stranded DNA genome components, each approximately 1 kb, and two or three alpha-satellite molecules. It mainly infects plants of the legume family Fabaceae. Recently, papaya (Carica papaya) collected in Yesan, South Korea, displaying symptoms of leaf yellowing and dwarfism, was identified as a new host for MDV. To examine the geographical distribution of MDV, papaya samples with symptoms were harvested in South Korea, Vietnam, and Taiwan in August 2018, along with tomato and pepper samples grown in adjacent fields in Vietnam. The results revealed the presence of MDV not only in papaya but also in pepper and tomato. This MDV infection in members of the Solanaceae family was confirmed by Southern blot hybridization performed using a PCR product of segment S as a probe. Based on sequence analysis of three MDV components (M, S, and C3), we verified the presence of three different isolates of MDV in these three countries and homology between sequences of isolates from papaya and from members of the Solanaceae from Vietnam. Taken together, our results clearly demonstrate MDV infection in Vietnam and Taiwan for the first time and confirm that MDV can infect economically important pepper and tomato.  相似文献   

Atypical thymoma in a horse: Diagnostic approach and application of an alternative histological classification system     

T. Pudert  A. Weyrich  F. Geburek  C. Herden  M. Röcken 《Equine Veterinary Education》2021,33(11):e386-e392

Thymoma is a rare condition in horses. This case of a 24-year-old Warmblood gelding that was presented with oedema and signs of vascular congestion of the left forelimb caused by a thoracic mass is described. The diagnostic work-up included blood chemistry, cytology of pleural effusion, ultrasonography, radiography and the visualisation and collection of a tissue sample by thoracoscopy. Finally, post-mortem findings and histopathology revealed thymic epithelial neoplasia with histomorphologic features previously unreported in horses. The unique mixture of spindle-shaped and epithelioid tumour cells in combination with clear features of malignancy suggested the application of the Moran and Suster histological classification system for thymomas in humans (Moran and Suster, 2008, Curr. Treat. Options Oncol., 9, 288), which has not been reported in an equine case before and fits well to the present case.  相似文献   

Leaf carbohydrates assimilation and metabolism affect seed yield of rapeseed with different waterlogging tolerance under the interactive effects of nitrogen and waterlogging     

Jie Kuai  Xiaoyong Li  Zhen Li  Yan Xie  Bo Wang  Guangsheng Zhou 《Journal of Agronomy and Crop Science》2020,206(6):823-836

Waterlogging is a main factor causing rapeseed (Brassica napus L.) yield loss, and reasonable nitrogen (N) applications can compensate for this loss. To investigate the effects of N rates on seed yield of waterlogged rapeseed, the waterlogging-tolerant rapeseed variety ZS 9 and sensitive variety GH01 were waterlogged for 0 and 10 days with five leaves at the seedling stage under four N rates (0, 90, 180 and 270 kg/ha). Waterlogging significantly decreased seed yield, while N application can alleviate the yield loss. The yield decrease rate of waterlogged GH01 was greater than that of ZS 9 under the same N rate. During the seedling and bolting stage, the leaf photosynthetic rate (Pn) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity increased, while activities of adenosine diphosphate glucose pyrophosphorylase (AGPase), sucrose synthase (SuSy) and sucrose phosphate synthase (SPS) decreased with more N under the same watering conditions. Compared to the plants without waterlogging, the leaf Pn and Rubisco activity, starch and sucrose contents of waterlogged rapeseed decreased at the two stages; activities of AGPase, SuSy and SPS of waterlogged rapeseed decreased at the seedling while increased at the bolting stage for both the two varieties. At the flowering stage, the Pn, the activities of Rubisco, AGPase, SuSy, SPS and contents of sucrose, starch increased with more N application for both ZS 9 and GH01. Compared to the plants without waterlogging, the Pn and Rubisco activity for waterlogged plants of the two varieties increased; the waterlogged plants of tolerant variety had higher activities of AGPase, SuSy and SPS, while those of sensitive variety was significantly lower. However, the decreased starch and sucrose content were found in both tolerant and sensitive varieties. The activities of AGPase, SuSy and SPS at flowering were highly positively correlated with yield under the interactive effects of N and waterlogging. These results suggested that the flowering stage is the most important stage that N had the positive regulation on waterlogged rapeseed growth. The carbohydrates translocation from leaves to seeds of the tolerant variety were enhanced after waterlogging, while that of the sensitive variety was still inhibited. This was the main reason for the difference in yield between the two waterlogged varieties.  相似文献   

Synchytrium endobioticum – risk from biogas plants?     

Y. Schleusner  P. Müller  M. Bandte  M. Heiermann  C. Büttner 《EPPO Bulletin》2019,49(1):92-103

Synchytrium endobioticum is one of the most important pathogens of potato and is known for its persistent propagation structures. Under favourable conditions, infection of highly susceptible potato cultivars leads to clearly visible cauliflower‐like tissue warts, the typical symptom of potato wart disease. However, unfavourable infection conditions or low infection pressure may result in symptoms being overlooked. Thus, the introduction of pathogen structures into stages of the processing industry cannot be ruled out. As the amounts of processed potato products continue to rise, phytosanitary risks from processing discarded potatoes and potato waste in biogas plants have to be considered. Hence, the resilience of resting spores against mesophilic anaerobic digestion was analysed in stirred tank reactors. Laboratory‐scale results show that S. endobioticum not only withstands mesophilic anaerobic digestion but also subsequent storage of the digestate for at least 4 weeks. Large numbers of viable resting spores were detectable by microscopic assessment in all samples. Viability was proved and verified additionally by bioassay. Consequently, potatoes, potato waste and processing water from potato processing industries used in biogas plants pose a phytosanitary risk if the accruing digestates are returned as fertilizer to arable land.  相似文献   

Do cover crops change the lability of phosphorus in a clayey subtropical soil under different phosphate fertilizers?          下载免费PDF全文

A. P. B. Teles  M. Rodrigues  W. F. Bejarano Herrera  A. Soltangheisi  L. R. Sartor  P. J. A. Withers  P. S. Pavinato 《Soil Use and Management》2017,33(1):34-44

Plants have developed different mechanisms to absorb and solubilize phosphorus (P) in the soil, especially in environments with low P availability. This study evaluated the effects of different winter cover crops on soil P availability in a clayey subtropical (Hapludox) soil receiving soluble P fertilizer and a rock phosphate applied to the summer crop, under no‐tillage. The experiment was carried out over 3 yrs (2009–2011) with five different cover crop species: common vetch, fodder radish, ryegrass, black oat, white clover and fallow as control. The soil was sampled after the third year of cover crop cultivation and analysed for inorganic and organic P forms according to the well‐established Hedley fractionation procedure. Phosphate fertilizers promoted accumulation of both labile and nonlabile P pools in soil in the near surface layer, especially under rock phosphate. Fertilizer applications were not able to change P fractions in deeper layers, emphasizing that the Brazilian clayey soils are a sink of P from fertilizer and its mobility is almost nil. Although the cover crops recycled a great amount of P in tissue, in a short‐term evaluation (3 yrs) they only changed the content of moderately labile P in soil, indicating that long‐term studies are needed for more conclusive results.  相似文献   

Pigeonpea improvement: An amalgam of breeding and genomic research     

Sameer Kumar Chanda Venkata  Ganga Rao Nadigatla Veera Prabha Rama  Rachit K. Saxena  Kulbhushan Saxena  Hari D. Upadhyaya  Moses Siambi  Said N. Silim  Kothapally Narasimha Reddy  Anupama J. Hingane  Mamta Sharma  Shivali Sharma  Stephen Dominic Lyimo  Rose Ubwe  Meshack Makenge  Kananji Gad  Paul Kiprotich Kimurto  Manuel Amane  Kennedy Kanenga  Yuventino Obong  Emanuel Monyo  Chris Ojiewo  Nagesh Kumar Mallela Venkata  Jaganmohan Polineni Rao  Prashanthi Lakkireddy  Sudhakar Chourat  Indraprakash Singh  Sobhan Sajja  Shruthi Hirikara Beliappa  Rajeev K. Varshney 《Plant Breeding》2019,138(4):445-454

In the past five decades, constant research has been directed towards yield improvement in pigeonpea resulting in the deployment of several commercially acceptable cultivars in India. Though, the genesis of hybrid technology, the biggest breakthrough, enigma of stagnant productivity still remains unsolved. To sort this productivity disparity, genomic research along with conventional breeding was successfully initiated at ICRISAT. It endowed ample genomic resource providing insight in the pigeonpea genome combating production constraints in a precise and speedy manner. The availability of the draft genome sequence with a large‐scale marker resource, oriented the research towards trait mapping for flowering time, determinacy, fertility restoration, yield attributing traits and photo‐insensitivity. Defined core and mini‐core collection, still eased the pigeonpea breeding being accessible for existing genetic diversity and developing stress resistance. Modern genomic tools like next‐generation sequencing, genome‐wide selection helping in the appraisal of selection efficiency is leading towards next‐generation breeding, an awaited milestone in pigeonpea genetic enhancement. This paper emphasizes the ongoing genetic improvement in pigeonpea with an amalgam of conventional breeding as well as genomic research.  相似文献   

The effect of feeding a novel multistrain yeast fraction on European seabass (Dicentrachus labrax) intestinal health and growth performance     

Mark D. Rawling  Nicola Pontefract  Ana Rodiles  Ilektra Anagnostara  Eric Leclercq  Marion Schiavone  Mathieu Castex  Daniel L. Merrifield 《Journal of the World Aquaculture Society》2019,50(6):1108-1122

Fish were fed a single‐strain yeast fraction (SsYF; 2 g/kg) or a multistrain yeast fraction (MsYF; 0.8 g/kg) for 10 weeks. The results demonstrated significant (p ≤ 0.03) elevations in weight gain, specific growth rate, protein efficiency ratio, and feed conversion ratio in fish fed the yeast fraction‐supplemented diets. In the distal intestine, a significant elevation in microvilli density was observed after 5 and 10 weeks of dietary supplementation with MsYF and SsYF, respectively, compared to control fed fish (p < 0.001). A significant elevation (p = 0.02) in the perimeter ratio was observed in fish fed diets supplemented with the yeast fractions. After 10 weeks of feeding on the experimental diets, Rt‐qPCR demonstrated a significant downregulation (p < 0.05) in the stress response genes, heat‐shock protein 70 (hsp70) and proliferating cell nuclear antigen (pcna), in fish fed diets supplemented with the yeast fractions. Significant (p < 0.05) elevations in interleukin 1‐beta (il1β) and interleukin‐10 (il10) gene expression were observed in fish fed diets supplemented with the MsYF compared to the other dietary groups. These findings suggest that feeding an MsYF specifically at a lower incorporation rate < 1 g/kg, compared to a commercial SsYF at 2 g/kg, is effective in improving the intestinal health status and growth performance of European seabass.  相似文献   

Changes in wettability of wood surface using electron beam irradiation     

H. Huber  R. Haas  A. Petutschnigg  G. Grüll 《Wood material science & engineering》2020,15(4):237-240

ABSTRACT

This study deals with the influence of electron beam irradiation (EBI) on the wettability of Norway spruce surface samples. To evaluate this possible effect in detail, the changes in chemistry and wood structure were analysed using the methods of IR spectroscopy and Scanning Electron Microscopy (SEM). The surface wettability was determined by the contact angle measurement method. The results of infrared spectra show decreased relative numbers of available hydrophilic groups (e.g. hydroxyl and carbonyl groups) in the wood surfaces due to the electron beam irradiation. This behaviour is consistent with the values from the surface wettability measurements. Structural differences of the wood surfaces after electron beam irradiation were not detectable. Based on these findings pre-treatment of wood surfaces for industrial usages can be a potential field of application of this technology.  相似文献   

11个葡萄品种在乐山地区的花芽分化规律     

张顺英  周勇  刘忠  钟倩  周世彬 《落叶果树》2020,52(3):18-21

研究了11个葡萄品种3年生树在四川乐山地区避雨栽培条件下的花芽分化表现。结果表明,结果母枝的花芽分化率,魏可、维多利亚、黑芭拉多、金手指、金优2号和巨玫瑰6个品种的都高于50%,较易形成花芽;户太8号、巨峰、夏黑的在43%~48%;美人指和红指较难形成花芽。结果母枝不同节位的花芽分化率,多数品种在第3节位≥50%;结果枝上花穗着生节位在第3.8~4.9节,其中双花率以巨玫瑰、巨峰和户太8号较高,分别为83.45%、73.61%和73.06%。以结果母枝的花芽分化率≥50%节位作为冬剪的最低节位,则金优2号、户太8号、巨玫瑰、金手指、维多利亚5个品种在第3~4节,黑芭拉多和巨峰2个品种在第2~3节,魏可在1~2节。夏黑表现花芽分化率较低,为43.33%,可能与夏黑不耐弱光有关,设施栽培时应加强透光性。  相似文献