Dicamba resistance: enlarging and preserving biotechnology-based weed management strategies   总被引：1，自引：0，他引：1  

Behrens MR  Mutlu N  Chakraborty S  Dumitru R  Jiang WZ  Lavallee BJ  Herman PL  Clemente TE  Weeks DP 《Science (New York, N.Y.)》2007,316(5828):1185-1188

The advent of biotechnology-derived, herbicide-resistant crops has revolutionized farming practices in many countries. Facile, highly effective, environmentally sound, and profitable weed control methods have been rapidly adopted by crop producers who value the benefits associated with biotechnology-derived weed management traits. But a rapid rise in the populations of several troublesome weeds that are tolerant or resistant to herbicides currently used in conjunction with herbicide-resistant crops may signify that the useful lifetime of these economically important weed management traits will be cut short. We describe the development of soybean and other broadleaf plant species resistant to dicamba, a widely used, inexpensive, and environmentally safe herbicide. The dicamba resistance technology will augment current herbicide resistance technologies and extend their effective lifetime. Attributes of both nuclear- and chloroplast-encoded dicamba resistance genes that affect the potency and expected durability of the herbicide resistance trait are examined.  相似文献   

Predictive soil mapping with limited sample data          下载免费PDF全文

A. X. Zhu  J. Liu  F. Du  S. J. Zhang  C. Z. Qin  J. Burt  T. Behrens  T. Scholten 《European Journal of Soil Science》2015,66(3):535-547

Existing predictive soil mapping (PSM) methods often require soil sample data to be sufficient to represent soil–environment relationships throughout the study area. However, in many parts of the world with only a limited quantity of soil sample data to represent the study area, this is still an issue for PSM application. This paper presents a method, named ‘individual predictive soil mapping’ (iPSM), which can make use of limited soil sample data for PSM. With the assumption that similar environmental conditions have similar soils, iPSM uses the soil–environment relationship at each individual soil sample location to predict soil properties at unvisited locations and estimate prediction uncertainty. Specifically, the environmental similarities of an unvisited location to a set of soil sample locations are used in a weighted average method to integrate the soil–environment relationships at sample locations for prediction and uncertainty estimation. As a case study, iPSM was applied to map soil organic matter (SOM) content (%) in the topsoil layer using two sets of soil samples. Compared with multiple linear regression (MLR), iPSM produced a more accurate SOM map (root mean squared error ( RMSE) 1.43, mean absolute error ( MAE) 1.16) than MLR (RMSE 8.54, MAE 7.34) the ability of the sample set to represent the study area is limited and achieved a comparable accuracy (RMSE 1.10, MAE 0.69) with MLR (RMSE 1.01, MAE 0.73) when the sample set could represent the study area better. In addition, the prediction uncertainty estimated by iPSM was positively related to prediction residuals in both scenarios. This study demonstrates that iPSM is an effective alternative when existing soil samples are limited in their ability to represent the study area and the prediction uncertainty in iPSM can be used as an indicator of its prediction accuracy.  相似文献   

Pitfall or priority drift? Participatory tree domestication programs: The case of agroforestry in the Peruvian Amazon     

Thorsten Wiersberg  Frank Ewert 《Journal of Sustainable Forestry》2013,32(7):486-499

ABSTRACT

The Agroforestry Tree Domestication Program was globally launched in the 1990s by the World Agroforestry Center to increase farmers’ living standards and slow deforestation. After 20 yr of operation, we screen the impacts on farmers’ livelihoods and prospects in one of the implementation sites: the Ucayali region of the Peruvian Amazon. We contrast the viewpoints of two sets of stakeholders: (a) “outsiders”—scientists, technicians, and development workers; and (2) “insiders”—local farmers organized and not organized. Group and semistructured interviews were used for data collection, and system analyses were conducted for their integration and interpretation. Results diverge by subset. “Outsiders” praised the program lastingness but questioned its dependence on external parties for management; they considered land property and product marketing keys to persist and succeed. In contrast, “insiders” considered the program financially not viable as well as third-party and locally dependent. As an alternative they had initiated activities, both forestry related and otherwise, to profit from their acquired technical and managerial skills. Based on these findings, broadening stakeholders’ diversity and set conveniently roles and decision power during the rationale and implementation phases of similar initiatives could prevent such divergences.  相似文献   

Incorporating limited field operability and legacy soil samples in a hypercube sampling design for digital soil mapping   总被引：2，自引：0，他引：2       下载免费PDF全文

Felix Stumpf  Karsten Schmidt  Thorsten Behrens  Sarah Schönbrodt‐Stitt  Giovanni Buzzo  Christian Dumperth  Alexandre Wadoux  Wei Xiang  Thomas Scholten 《植物养料与土壤学杂志》2016,179(4):499-509

Most calibration sampling designs for Digital Soil Mapping (DSM) demarcate spatially distinct sample sites. In practical applications major challenges are often limited field accessibility and the question on how to integrate legacy soil samples to cope with usually scarce resources for field sampling and laboratory analysis. The study focuses on the development and application of an efficiency improved DSM sampling design that (1) applies an optimized sample set size, (2) compensates for limited field accessibility, and (3) enables the integration of legacy soil samples. The proposed sampling design represents a modification of conditioned Latin Hypercube Sampling (cLHS), which originally returns distinct sample sites to optimally cover a soil related covariate space and to preserve the correlation of the covariates in the sample set. The sample set size was determined by comparing multiple sample set sizes of original cLHS sets according to their representation of the covariate space. Limited field accessibility and the integration of legacy samples were incorporated by providing alternative sample sites to replace the original cLHS sites. We applied the modified cLHS design (cLHS_adapt) in a small catchment (4.2 km²) in Central China to model topsoil sand fractions using Random Forest regression (RF). For evaluating the proposed approach, we compared cLHS_adapt with the original cLHS design (cLHS_orig). With an optimized sample set size n = 30, the results show a similar representation of the cLHS covariate space between cLHS_adapt and cLHS_orig, while the correlation between the covariates is preserved (r = 0.40 vs. r = 0.39). Furthermore, we doubled the sample set size of cLHS_adapt by adding available legacy samples (cLHS_adapt+) and compared the prediction accuracies. Based on an external validation set cLHS_val (n = 20), the coefficient of determination (R²) of the cLHS_adapt predictions range between 0.59 and 0.71 for topsoil sand fractions. The R²‐values of the RF predictions based on cLHS_adapt+, using additional legacy samples, are marginally increased on average by 5%.  相似文献   

Influence of soil aeration on rooting and growth of the Beuys-trees in Kassel,Germany     

Katharina Weltecke  Thorsten Gaertig 《Urban Forestry & Urban Greening》2012,11(3):329-338

Soil aeration is an important factor in tree growth. Oxygen must be taken from the atmosphere for root respiration, and carbon dioxide must be discharged to the atmosphere. Because the pore space of the soil could be considered the “dead end” of the free atmosphere, topsoil gas diffusivity is particularly important for soil aeration. Due to diverse land uses, several soil cover types alternate on a small scale at urban sites, competing with the natural function of soil as the living space for roots.During Documenta 7 in 1982, the artist Joseph Beuys initiated the spectacular landscape art project “7000 Oaks”. Seven thousand trees of approximately the same age were planted over the whole city of Kassel, Germany, offering best possible conditions for investigating the influence of specific site factors on root and tree development. At 8 different sites featuring 36 Beuys-oaks and 15 Beuys-planes, topsoil gas diffusivity, soil CO₂ concentration and soil respiration of different soil cover types were measured and correlated with fine root density and tree growth.Topsoil gas diffusivity and soil respiration depend on soil cover type. The lowest gas diffusivities and respiration rates were found at sealed sites, and the highest values were measured at vegetated sites such as lawn or flower beds. Soil gas diffusivity primarily controls soil respiration. Soil CO₂ concentration is not strictly linked to the coverage type and does not show a strictly directed dependence on top soil gas diffusivity and soil respiration. Tree root density and height as well as diameter at breast height (1.3 m) of the oaks were decisively shaped by the gas diffusivity of the soil cover, whereas the investigated planes were not affected by soil aeration deficiencies. The vitality of urban trees can be controlled by the design of the tree site and the choice of the species.  相似文献   

Radioresistance of Salmonella species and Listeria monocytogenes on minimally processed arugula (Eruca sativa Mill.): effect of irradiation on flavonoid content and acceptability of irradiated produce     

Nunes TP  Martins CG  Behrens JH  Souza KL  Genovese MI  Destro MT  Landgraf M 《Journal of agricultural and food chemistry》2008,56(4):1264-1268

This work studied the radiation resistance of Listeria monocytogenes and Salmonella species and the effect of irradiation on leaf flavonoid content and sensory acceptability of minimally processed arugula. Immersion in ozone-treated water reduced the analyzed microorganisms by 1 log. L. monocytogenes and Salmonella were not isolated from samples. Samples of this vegetable were inoculated with a cocktail of Salmonella spp. and L. monocytogenes and exposed to gamma irradiation. D10 values for Salmonella ranged from 0.16 to 0.19 kGy and for L. monocytogenes from 0.37 to 0.48 kGy. Kaempferol glycoside levels were 4 and ca. 3 times higher in samples exposed to 1 and 2 kGy, respectively, than in control samples. An increase in quercetin glycoside was also observed mainly in samples exposed to 1 kGy. In sensory evaluation, arugula had good acceptability, even after exposure to 2 and 4 kGy. These results indicate that irradiation has potential as a practical processing step to improve the safety of arugula.  相似文献   

Toward fish and seafood traceability: anchovy species determination in fish products by molecular markers and support through a public domain database     

Jérôme M  Martinsohn JT  Ortega D  Carreau P  Verrez-Bagnis V  Mouchel O 《Journal of agricultural and food chemistry》2008,56(10):3460-3469

Traceability in the fish food sector plays an increasingly important role for consumer protection and confidence building. This is reflected by the introduction of legislation and rules covering traceability on national and international levels. Although traceability through labeling is well established and supported by respective regulations, monitoring and enforcement of these rules are still hampered by the lack of efficient diagnostic tools. We describe protocols using a direct sequencing method based on 212-274-bp diagnostic sequences derived from species-specific mitochondria DNA cytochrome b, 16S rRNA, and cytochrome oxidase subunit I sequences which can efficiently be applied to unambiguously determine even closely related fish species in processed food products labeled "anchovy". Traceability of anchovy-labeled products is supported by the public online database AnchovyID ( http://anchovyid.jrc.ec.europa.eu), which provided data obtained during our study and tools for analytical purposes.  相似文献   

The Failure of Purified T-2 Mycotoxin to Produce Hemorrhaging in Dairy Cattle   总被引：3，自引：0，他引：3       下载免费PDF全文

G. A. Weaver  H. J. Kurtz  C. J. Mirocha  F. Y. Bates  J. C. Behrens  T. S. Robison    S. P. Swanson 《The Canadian veterinary journal. La revue veterinaire canadienne》1980,21(7):210-213

A Holstein cow was intubated with 182 mg of 97% pure T-2 toxin (0.44 mg/kg of body weight) for 15 days. A dairy ration containing 50 mg/kg (50 ppm) of T-2 toxin was refused. A calf, born four days after onset of maternal treatment, was intubated with 26.2 mg of purified T-2 toxin (0.6 mg/kg of body weight) for seven consecutive days and then on alternate days for a total of 16 days. The calf was severely affected clinically by the T-2 toxin. The T-2 toxin failed to cause bovine hemorrhagic syndrome in either animal. Unspecific gastrointestinal lesions were noted in the cow but none were detected in the calf. In the calf, severe depression, hindquarter ataxia, knuckling of the rear feet, listlessness and anorexia were caused by the T-2 toxin.  相似文献   

Comparative serological studies of blood and milk in the diagnosis of enzootic bovine leukosis     

D Manz  D Wiegand  F Behrens  R Ziegelmaier 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1981,28(4):280-291

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Hygiene in pig raising     

H Behrens 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1966,13(2):149-155

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