Infection and damage potential of Meloidogyne javanica on Sesbania sesban in different soil types

Nematology ◽  
2000 ◽  
Vol 2 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Johan Desaeger ◽  
Meka Rao
Keyword(s):  
Soil Texture ◽  
Meloidogyne Javanica ◽  
Nematode Infection ◽  
Sesbania Sesban ◽  
Seedling Mortality ◽  
Damage Potential ◽  
Inoculum Level ◽  
Wide Range ◽  
Gall Index ◽  
Extractable Cations

AbstractAn experiment in western Kenya tested the effects of six inoculum levels (0, 80, 400, 800, 2000 and 4000 eggs per 100 cm3 soil) of Meloidogyne javanica on nematode infection and growth of two Sesbania sesban provenences (Kakamega and Kisii) in six soils with sand contents of 26 to 82%. At 1 month after sowing, nematode infection, gall index and seedling mortality increased with inoculum level and sand/clay ratio. Gall index decreased and seedling growth improved with extractable cations, particularly calcium. At 3 months, nematode infection and damage were affected neither by soil texture nor by extractable cations. However, nodulation and plant growth decreased with increasing inoculum levels in all soils. Soils with higher cations and inherent fertility were less prone to nematode infestation and sustained better Sesbania growth irrespective of soil texture. It appears that as Sesbania grows it develops tolerance to M. javanica, suggesting that nematode infection is important at seedling stage primarily in determining stand establishment and early growth. Kisii provenance was more tolerant to the nematode and more productive than Kakamega. There is a need for screening a wide range of Sesbania germplasm for nematode resistance to select appropriate provenances and exploring low cost methods to minimise nematode damage to Sesbania at establishment stage. In einem Versuch in Westkenia wurde die Wirkung von sechs Inokulumstufen (0, 80, 400, 800, 2000 und 4000 Eier je 100 ml Boden) von Meloidogyne javanica auf die Nematodeninfektion und auf das Wachstum von zwei Herkünften von Sesbania sesban (Kakamega und Kisii) in sechs verschiedenen Böden mit Sandanteilen zwischen 26 und 82% untersucht. Einen Monat nach der Aussaat stiegen die Nematodeninfektion, der Vergallungsindex und die Keimlingssterblichkeit mit der Inokulumsgrösse und dem Sand/Lehm-Verhältnis an. Der Vergallungsindex nahm ab, und das Keimlingswachstum verbesserte sich mit dem Gehalt an extrahierbaren Kationen, insbesondere Kalzium. Nach 3 Monaten wurden Nematodeninfektion und Schaden weder durch die Bodentextur noch durch die extrahierbaren Kationen beeinflusst. Die Gallbildung und das Pflanzenwachstum nahmen jedoch in allen Böden mit steigenden Inokulumsstufen ab. Böden mit einem böheren Gehalt an Kationen und natürlicher Fruchtbarkeit neigten weniger zu Nematodeninfektionen und unterstützten das Wachstum von Sesbania unabhängig von der Bodentextur. Anscheinend entwickelt Sesbania mit zunehmendem Wachstum eine Toleranz gegenüber M. javanica. Das weist daraufhin, dass eine Nematodeninfektion im Keimlingsstadium in erster Linie wichtig ist für die Entwicklung des Standplatzes und für das frühe Wachstum. Die Herkunft Kisii war toleranter gegenüber den Nematoden und auch produktiver als Kakamega. Es muss eine breite Palette von Sesbania-Genplasmen auf Nematodenresistenz geprüft werden, um geeignete Herkünfte zu selektieren und preiswerte Methoden zur Minimierung des Nematodenschadens an Sesbania im frühen Entwicklungsstadium auszuprobieren.

A generally applicable pedotransfer function that estimates field capacity and permanent wilting point from soil texture and bulk density

2008 ◽  
Vol 88 (5) ◽  
pp. 761-774 ◽  
Author(s):  
J. A. P. Pollacco
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Bulk Density ◽  
Soil Texture ◽  
The United States ◽  
Pedotransfer Functions ◽  
Pedotransfer Function ◽  
Data Set ◽  
Wide Range ◽  
Fitting Parameters

Hydrological models require the determination of fitting parameters that are tedious and time consuming to acquire. A rapid alternative method of estimating the fitting parameters is to use pedotransfer functions. This paper proposes a reliable method to estimate soil moisture at -33 and -1500 kPa from soil texture and bulk density. This method reduces the saturated moisture content by multiplying it with two non-linear functions depending on sand and clay contents. The novel pedotransfer function has no restrictions on the range of the texture predictors and gives reasonable predictions for soils with bulk density that varies from 0.25 to 2.16 g cm-3. These pedotransfer functions require only five parameters for each pressure head. It is generally accepted that the introduction of organic matter as a predictor improves the outcomes; however it was found by using a porosity based pedotransfer model, using organic matter as a predictor only modestly improves the accuracy. The model was developed employing 18 559 samples from the IGBP-DIS soil data set for pedotransfer function development (Data and Information System of the International Geosphere Biosphere Programme) database that embodies all major soils across the United States of America. The function is reliable and performs well for a wide range of soils occurring in very dry to very wet climates. Climatical grouping of the IGBP-DIS soils was proposed (aquic, tropical, cryic, aridic), but the results show that only tropical soils require specific grouping. Among many other different non-climatical soil groups tested, only humic and vitric soils were found to require specific grouping. The reliability of the pedotransfer function was further demonstrated with an independent database from Northern Italy having heterogeneous soils, and was found to be comparable or better than the accuracy of other pedotransfer functions found in the literature. Key words: Pedotransfer functions, soil moisture, soil texture, bulk density, organic matter, grouping

scholarly journals Applying Nitrogen Site-Specifically Using Soil Electrical Conductivity Maps and Precision Agriculture Technology

2001 ◽  
Vol 1 ◽  
pp. 767-776 ◽  
Author(s):  
E.D. Lund ◽  
M.C. Wolcott ◽  
G.P. Hanson
Keyword(s):  
Electrical Conductivity ◽  
Case Studies ◽  
Crop Yield ◽  
Soil Texture ◽  
Precision Agriculture ◽  
Management Practices ◽  
N Availability ◽  
Soil Electrical Conductivity ◽  
Variable Yield ◽  
Wide Range

Soil texture varies significantly within many agricultural fields. The physical properties of soil, such as soil texture, have a direct effect on water holding capacity, cation exchange capacity, crop yield, production capability, and nitrogen (N) loss variations within a field. In short, mobile nutrients are used, lost, and stored differently as soil textures vary. A uniform application of N to varying soils results in a wide range of N availability to the crop. N applied in excess of crop usage results in a waste of the grower’s input expense, a potential negative effect on the environment, and in some crops a reduction of crop quality, yield, and harvestability. Inadequate N levels represent a lost opportunity for crop yield and profit. The global positioning system (GPS)-referenced mapping of bulk soil electrical conductivity (EC) has been shown to serve as an effective proxy for soil texture and other soil properties. Soils with a high clay content conduct more electricity than coarser textured soils, which results in higher EC values. This paper will describe the EC mapping process and provide case studies of site-specific N applications based on EC maps. Results of these case studies suggest that N can be managed site-specifically using a variety of management practices, including soil sampling, variable yield goals, and cropping history.

scholarly journals Soil, snow, weather, and sub-surface storage data from a mountain catchment in the rain–snow transition zone

2013 ◽  
Vol 6 (2) ◽  
pp. 811-835 ◽  
Author(s):  
P. R. Kormos ◽  
D. Marks ◽  
C. J. Williams ◽  
H. P. Marshall ◽  
P. Aishlin ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Transition Zone ◽  
Soil Texture ◽  
Soil Depth ◽  
Meteorological Data ◽  
Dew Point ◽  
Soil Profiles ◽  
Data Set ◽  
Hydrologic Condition ◽  
Wide Range

Abstract. A comprehensive hydroclimatic data set is presented for the 2011 water year to improve understanding of hydrologic processes in the rain-snow transition zone. This type of dataset is extremely rare in scientific literature because of the quality and quantity of soil depth, soil texture, soil moisture, and soil temperature data. Standard meteorological and snow cover data for the entire 2011 water year are included, which include several rain-on-snow events. Surface soil textures and soil depths from 57 points are presented as well as soil texture profiles from 14 points. Meteorological data include continuous hourly shielded, unshielded, and wind corrected precipitation, wind speed, air temperature, relative humidity, dew point temperature, and incoming solar and thermal radiation data. Sub-surface data included are hourly soil moisture data from multiple depths from 7 soil profiles within the catchment, and soil temperatures from multiple depths from 2 soil profiles. Hydrologic response data include hourly stream discharge from the catchment outlet weir, continuous snow depths from one location, intermittent snow depths from 5 locations, and snow depth and density data from ten weekly snow surveys. Though it represents only a single water year, the presentation of both above and below ground hydrologic condition makes it one of the most detailed and complete hydro-climatic datasets from the climatically sensitive rain-snow transition zone for a wide range of modeling and descriptive studies. Data are available at doi:10.1594/PANGAEA.819837.

THE FOUNDATIONS OF CONTINUUM DAMAGE MECHANICS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Siamak Yazdani ◽  
Sevenn Borgersen ◽  
Asli Pelin Gurgun ◽  
Hossein Nazari
Keyword(s):  
Damage Mechanics ◽  
Nonlinear Behavior ◽  
Continuum Damage Mechanics ◽  
Uniaxial Stress ◽  
Internal Variable ◽  
Continuum Damage ◽  
Damage Potential ◽  
Variable Theory ◽  
Wide Range ◽  
The Many

Damage Mechanics has become a useful theory in describing the nonlinear behavior of solids driven by the nucleation and growth of cracks and microcracks. This approach, based on the first principles of mechanics and thermodynamics, has also been combined with classical theories of plasticity to address a wide range of loading applications. In spite of the many different damage mechanics models and representations that are proposed, the foundation of damage mechanics is not well understood or at least not thoroughly published giving rise to the many inaccurate definitions and formulations. The intent of this paper is to provide the background of the continuum damage mechanics outlining the fundamentals on which this field theory is set up. The internal variable theory of continuum thermodynamics is reviewed and is shown that with Legendre transformation technique, various potential functions can be developed for damage mechanics formulation in either stress or strain space. The concept of constrained or neighboring equilibrium state is also introduced and is explained. The paper will conclude with the derivation of the general damage potential and a suggestion is given for the isotropic damage formulation with the resulting uniaxial stress-strain relation.

Nutritional influences on the expression of genotypic resistance to gastrointestinal nematode infection in sheep

2003 ◽  
Vol 43 (12) ◽  
pp. 1445 ◽  
Author(s):  
S. W. Walkden-Brown ◽  
S. J. Eady
Keyword(s):  
Nutrient Availability ◽  
Host Resistance ◽  
Gastrointestinal Nematode ◽  
Nutritional Intervention ◽  
Nematode Infection ◽  
Genotypic Resistance ◽  
Full Spectrum ◽  
Nutritional Conditions ◽  
Wide Range ◽  
Faecal Egg Count

This paper reviews experiments investigating the responses of resistant and susceptible genotypes of sheep to gastrointestinal nematode infection under differential nutrition. Using faecal egg count as a measure of host resistance, differences between genotypes appeared to be greatest under conditions of low nutrient availability and under such conditions both resistant and susceptible genotypes generally responded to supplemental protein by reducing faecal egg count. However, when nutritional conditions were moderate to good, responses to additional protein tended to be observed only in susceptible genotypes. In general, host genetic resistance was associated with reliable reductions in faecal egg count of moderate to large magnitude, while nutritional intervention was less reliable at reducing faecal egg count, and induced reductions of smaller magnitude. The situation was very different when examining host resilience to infection, as determined by sheep productivity in the face of infection. Increased host resistance was rarely associated with improved growth or production during the period of infection. In contrast, nutritional supplementation reliably increased host productivity irrespective of infection status and prevailing nutritional conditions. A general model of the relationship between nutrient availability and host resistance and resilience in resistant and susceptible genotypes is postulated. Taken together, the studies reviewed in this paper suggest that selection for host resistance and strategic nutritional intervention have complementary roles in the integrated control of gastrointestinal nematode infection in sheep. The former will contribute primarily to the epidemiology of the disease by reliably reducing faecal egg output over a wide range of conditions, reducing host challenge and the number of treatment interventions required. The latter will reliably boost host resilience to infection, with lesser effects on resistance, and the economic rationale for use will require accounting for the full spectrum of production and disease responses.

The relationship between soybean cyst nematode seasonal population dynamics and soil texture

Nematology ◽  
2004 ◽  
Vol 6 (4) ◽  
pp. 511-525 ◽  
Author(s):  
Felicitas Avendaño ◽  
Francis J. Ierce ◽  
Haddish Melakeberhan
Keyword(s):  
Population Dynamics ◽  
Soil Texture ◽  
Soybean Cyst Nematode ◽  
Reproductive Potential ◽  
Cyst Nematode ◽  
Stable Relationship ◽  
Wide Range ◽  
The Relationship ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

Abstract The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, cyst population densities at planting and at harvest have been related to soil texture but the seasonal mechanisms by which these correlations are established are less well known. The purpose of this work was to analyse the relationship of SCN life stages and reproductive potential (number of eggs per cyst) with soil texture. Cyst population density was positively correlated with sand and negatively correlated with clay and silt percentage in the soil within the ranges of 45-80% sand, 8-23% clay, and 8-43% silt in one field, but not in the other at five sampling times. The relationship between soil texture and juvenile stages in roots was weak. The stable relationship between SCN spatial and seasonal population dynamics and soil properties provides further support for potential delineation of management zones in SCN infested fields with a wide range of soil textures.

scholarly journals Comparative predictions of discharge from an artificial catchment (Chicken Creek) using sparse data

2009 ◽  
Vol 13 (11) ◽  
pp. 2069-2094 ◽  
Author(s):  
H. M. Holländer ◽  
T. Blume ◽  
H. Bormann ◽  
W. Buytaert ◽  
G.B. Chirico ◽  
...  
Keyword(s):  
Soil Texture ◽  
Hydrological Cycle ◽  
Actual Evapotranspiration ◽  
Soil Parameters ◽  
Discharge Data ◽  
Sparse Vegetation ◽  
North East ◽  
Wide Range ◽  
A Minor ◽  
Coarse Soil

Abstract. Ten conceptually different models in predicting discharge from the artificial Chicken Creek catchment in North-East Germany were used for this study. Soil texture and topography data were given to the modellers, but discharge data was withheld. We compare the predictions with the measurements from the 6 ha catchment and discuss the conceptualization and parameterization of the models. The predictions vary in a wide range, e.g. with the predicted actual evapotranspiration ranging from 88 to 579 mm/y and the discharge from 19 to 346 mm/y. The predicted components of the hydrological cycle deviated systematically from the observations, which were not known to the modellers. Discharge was mainly predicted as subsurface discharge with little direct runoff. In reality, surface runoff was a major flow component despite the fairly coarse soil texture. The actual evapotranspiration (AET) and the ratio between actual and potential ET was systematically overestimated by nine of the ten models. None of the model simulations came even close to the observed water balance for the entire 3-year study period. The comparison indicates that the personal judgement of the modellers was a major source of the differences between the model results. The most important parameters to be presumed were the soil parameters and the initial soil-water content while plant parameterization had, in this particular case of sparse vegetation, only a minor influence on the results.

Analysis of genes expressed in second stage juveniles of the potato cyst nematodes Globodera rostochiensis and G. pallida using the expressed sequence tag approach

Nematology ◽  
2000 ◽  
Vol 2 (5) ◽  
pp. 567-574 ◽  
Author(s):  
Herman Popeijus ◽  
Vivian Blok ◽  
Linda Cardle ◽  
Erin Bakker ◽  
Mark Phillips ◽  
...  
Keyword(s):  
Expressed Sequence Tag ◽  
Meloidogyne Javanica ◽  
Globodera Rostochiensis ◽  
Chorismate Mutase ◽  
Secreted Proteins ◽  
Parasitic Nematodes ◽  
Small Scale ◽  
Pomme De Terre ◽  
Wide Range ◽  
Expressed Sequence

Abstract Expressed sequence tag (EST) projects offer a rapid route to the discovery of novel genes. Genes expressed in a wide range of parasitic nematodes of medical or veterinary importance have been investigated using EST analysis but these techniques have not yet been applied to plant parasitic nematodes. We describe a small scale EST project using cDNA libraries made from the two species of potato cyst nematode, Globodera rostochiensis and G. pallida, and assess the utility of this approach to identify mRNAs encoding abundantly expressed secreted proteins and other proteins present in the nematode at the onset of parasitism. Approximately 1000 sequences were obtained from G. rostochiensis and 100 from G. pallida. A variety of genes was characterised and approximately 11% of the cDNAs sequenced were apparently PCN specific. Secreted proteins identified included a novel PCN homologue of chorismate mutase, a cDNA recently cloned from the gland cells of Meloidogyne javanica. The results obtained justify a much larger scale application of this technology to these parasites. Utilisation de L'Expressed Sequence Tag pour l'analyse de gènes s'exprimant chez les juvéniles de deuxième stade des nématodes à kyste de la pomme de terre Globodera rostochiensis et G. pallida - l'Expressed Sequence Tag (EST) ouvre une voie rapide vers la découverte de nouveaux gènes. Des gènes s'exprimant chez un large éventail de nématodes parasites d'importance médicale ou vétérinaire ont été étudiés par analyse EST alors que cette technique n'a pas encore été appliquée aux nématodes phytoparasites. Nous décrivons ici un projet EST à petite échelle utilisant les banques d'ADNc constituées à partir de deux espèces de nématodes à kyste de la pomme de terre (PCN), Globodera rostochiensis et G. pallida et nous évaluons l'utilité de cette approche pour identifier les ARNs codant les protéines abondamment sécrétées - et les autres protéines - présentes chez les nématodes lors de l'attaque parasitaire. Mille séquences environ ont été obtenues chez G. rostochiensis et 100 chez G. pallida. Des gènes variés ont été caractérisés et environ 11% des ADNc séquencés sont apparemment spécifiques des PCN. Parmi les protéines sécrétées identifiées figurent un nouvel homologue PCN de la chorismate mutase ainsi qu'un ADNc récemment cloné à partir de cellules glandulaires de Meloidogyne javanica. Les résultats ainsi obtenus justifient une utilisation à plus grande échelle de l'EST pour l'étude de ces parasites.

scholarly journals The predicted Meloidogyne javanica effectome is governed by the 9-hydroxide oxylipin of linolenic acid

2019 ◽  
Author(s):  
Nathalia Fitoussi ◽  
Eli Borrego ◽  
Michael V Kolomiets ◽  
Qing Xue ◽  
Patricia Bucki ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
Meloidogyne Javanica ◽  
Immune Defense ◽  
Nematode Infection ◽  
Differentially Expressed ◽  
Root Knot Nematode ◽  
Feeding Site ◽  
Defense Signaling ◽  
Stressful Environment ◽  
Tomato Roots

Abstract Background: The sedentary root-knot nematode Meloidogyne spp. secretes effectors in a spatial and temporal manner to interfere with and mimic multiple physiological and morphological mechanisms, supporting construction and maintenance of nematodes' feeding sites. For successful parasitism, many effectors act as immunomodulators, aimed to manipulate and suppress immune defense signaling triggered upon nematode invasion. Results: Comprehensive oxylipin profiling of tomato roots, performed using LC–MS/MS, indicated a sharp fluctuation in oxylipin profile following Root Knot Nematode infection. To identify genes that might respond to the lipidomic defense pathway mediated through oxylipins, RNA-Seq was performed by exposing Meloidogyne javanica second-stage juveniles to tomato protoplasts and the oxylipin 9-HOT, early induced in tomato roots upon nematode infection. A total of 4810 differentially expressed genes were identified. To target putative effectors, we explored differentially expressed genes carrying a predicted secretion signal peptide. Among these, several were homologous with known effectors in other nematode species; other unknown, potentially secreted proteins may have a role as root-knot nematode effectors that are induced by plant lipid signals. These include effectors functioning in the manipulation of plant defense signaling and root lipidomics, cell-wall weakening, detoxifying the stressful environment at the plant-nematode interface, allowing feeding site construction and development. Conclusions: Being an integral part of the plant's defense response, oxylipins may play an important signaling role in the regulation of nematode effectors. Herein we uncover activation of specific oxylipins signaling pathways upon nematode infection, which in turn result in reprogramming the nematode effector repertoires responsible for promotion of feeding site construction and nematode parasitism.

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