Growth comparison of Asian Nile and red tilapia strains in controlled and uncontrolled farm conditions     

Maria Rowena R. Romana-Eguia  Minoru Ikeda  Zubaida U. Basiao  Nobuhiko Taniguchi 《Aquaculture International》2010,18(6):1205-1221

Growth of several genetically improved Nile tilapia (GIFT or Genetically Improved Farmed Tilapia, FaST or Freshwater Aquaculture Center Selected Tilapia, SEAFDEC-selected) and domesticated red tilapia (BFS or Binangonan Freshwater Station, NIFI-red or National Inland Fisheries Institute red, HL or Hacienda Luisita) stocks were compared in controlled (tank) and uncontrolled farm conditions (lake-based cages) with unselected NIFI or Chitralada Nile tilapia as control. Specific growth rate differed significantly (P = 0.009) in tank-reared Nile tilapia stocks where GIFT grew best at 1.358%/day followed by FaST (1.307%/day), control stock NIFI (1.257%/day) and SEAFDEC-selected (1.202%/day). Genetic effect explained 84.4% of the variance in growth of Nile tilapia in tanks. Although Nile tilapia growth in cages followed the same trend where GIFT grew best at 1.570%/day, no significant stock differences (P = 0.479) were noted. Meanwhile, red tilapia reared in either tanks or cages showed no significant stock differences in terms of growth. However, survival of the red tilapia stocks in cages differed significantly with HL having the highest percentage survival at 93.3%. The different growth responses of the Nile tilapia stocks especially under controlled (tank) farm conditions were largely due to genetic factors (stock differences).Under uncontrolled farm conditions, environmental factors were generally observed to have also affected the survival and to some extent, the growth of Asian Nile and red tilapia stocks.  相似文献   

Vergleichende bodenphysikalische untersuchungen zwischen Lysimetern und Ihren Herkunftsflächen am beispiel von drei typischen böden mitteldeutschlands unter landwirtschaftlicher nutzung i. Mitteilung ermittlung bodenphysikalischer kenngrössen     

U. Keese  C. Nitsche  S. Knappe  U. Waldschmidt 《Archives of Agronomy and Soil Science》2013,59(3):209-231

Zur Quantifizierung möglicher Veränderungen zwischen langjährig genutzten Lysimetern und ihren Herkunftsflächen wurden ausgewählte bodenphysikalische Parameter ermittelt und eine erste Interpretation der angetroffenen Unterschiede zwischen Lysimeter und Herkunftsfläche vorgenommen.

Zur Ermittlung bodenhydraulischer Kenngrößen können unterschiedliche Verfahren eingesetzt werden. So wurden Saugspannungs‐Sättigungs‐Funktionen (pF‐Kurven) mittels AMHYP‐Anlage und mit der Verfahrenskombination: Sandbett‐Kaolinbett‐Drucktopfapparatur erstellt. Die dabei festgestellten deutlichen Abweichungen geben Anlaß zur Überprüfung der bisher verwendeten Verfahren, der damit ermittelten Meßwerte und deren Interpretation.  相似文献   

Infectivity,inoculum density and germination of Spongospora subterranea resting spores: a solution-culture test system1     

U. MERZ 《EPPO Bulletin》1989,19(3):585-592

Spongospora subterranea, causal agent of powdery scab of potatoes and vector of potato mop-top furovirus, survives in the soil as balls of resting spores (cystosori). So far, the factors affecting longevity, germination and infectivity of cystosori have not been investigated. A rapid and versatile bioassay with tomatoes as bait plants has been developed to quantify the infectivity of cystosorus inoculum or infested soil. The intensity of root infection, as a measure of infectivity, was determined by evaluating the quantity of zoosporangia present in epidermal cells and root hairs of the whole, stained root system. A correlation was obtained between the intensity of root infection and the cystosorus inoculum density in nutrient solution. Sterile soil suppressed the inoculum potential of pure cystosori. Infectivity of untreated soil decreased with increasing time of storage. Root infection was not influenced by the pH level of the nutrient solution.  相似文献   

Sensitivity of Rhizoctonia species to different fungicides   总被引：1，自引：0，他引：1  

H. R. KATARIA  U. HUGELSHOFER  U. GISI 《Plant pathology》1991,40(2):203-211

Of 14 fungicides with different modes of action, cyproconazole and tolclofos-methyl were generally inhibitory both in vitro and in vivo against all tested isolates of five Rhizoctonia species belonging to the teleomorphs Thanatephorus cucumeris, Waitea circinata or Ceratobasidium cereale. Triadimenol and carboxin provided considerable variation in activity against different species and isolates, whereas prochloraz was ineffective against all isolates. Imazalil and fenarimol showed moderate control, whereas flusilazole, propiconazole, fenpropimorph and benomyl showed strong activity against R. zeae and R. oryzae, but were much less effective against R. sasakii, R. cerealis and R. solani. Benodanil and iprodione controlled all isolates of R. cerealis and R. solani, but were not very effective against R. zeae and R. oryzae. Pencycuron showed strong activity against R. sasakii and most R. solani isolates, moderate activity against R. zeae, and was ineffective against R. oryzae and R. cerealis.  相似文献   

Trifluralin effects on the development of cotton in arid zone soils     

D. DORNAI  Z. GERSTL  Y. CHEN  U. MINGELGRIN 《Weed Research》1991,31(6):375-384

The effect of trifluralin on the growth and development of cotton plants in low-organic-matter soils from the northern Negev of Israel was studied. Trifluralin exhibited linear sorp tion isotherms on these soils, Trifluralin and dinitramine losses from soils under varying moisture regimes and application practices were determined in open systems. The data were fitted to both first-order and biexponential kinetic equations. In about 50% of cases the biexponential kinetic model provided a better fit to the data, but no relationship could be found between the model parameters and environmental or soil properties. Losses were generally greater at field capacity than at 50% field capacity, and at 27°C than at 15°C, and in soils with a lower organic matter content. The trifluralin application rate was negatively correlated with vegetative growth parameters of cotton, but the correlation became weaker with increasing soil organic carbon content. Trifluralin delayed boll production in coarse textured soils, the longest delay occurring at higher application rates. It is concluded that in light soils that contain very little organic matter, trifluralin rates must be maintained at the minimum level required for adequate weed control to prevent damage to crops.  相似文献   

2.2 A differentiated test method for examination of the sensitivity of cereal powdery mildews (Erysiphe graminis) to DMI fungicides     

U. SCHULZ 《EPPO Bulletin》1991,21(2):296-298

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2.3 A method for routine testing of the sensitivity of cereal powdery mildew (Erysiphe graminis) to DMI fungicides     

U. SCHULZ 《EPPO Bulletin》1991,21(2):298-301

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2.6 A method for examining the sensitivity of Rhynchosporium secalis to DMI fungicides     

U. SCHULZ 《EPPO Bulletin》1991,21(2):308-309

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Comparison of immunofluorescence staining and indirect isolation for the detection of Corynebacterium flaccumfaciens in bean seeds1     

A. CALZOLARI  M. TOMESANI  U. MAZZUCCHI 《EPPO Bulletin》1987,17(2):157-163

Corynebacterium flaccumfaciens, causing bacterial wilt in bean, is a quarantine organism for Europe. This paper compares two methods for detecting C. flaccumfaciens in seed lots on the market. Experimentally contaminated bean seeds were homogenized and a standard extraction and concentration procedure was used. The final pellets were used for immunofluorescence staining and indirect isolation (through bean seedlings). The immunofluorescence staining sensitivity threshold was 1.23 × 10⁷, corresponding to 1.82 × 10⁴ fluorescent cells per ml of final concentrate. The risk of false negative reactions to immunofluorescence staining caused by serologically unrelated C. flaccumfaciens strains was also examined. The indirect isolation sensitivity threshold was 1.23 × 10⁶ producing 43% symptomatic plants and 53% positive reisolation. There was no serious interference between C. flaccumfaciens and Pseudomonas syringae pv. phaseolicola in mixed inoculations and both pathogens were successfully reisolated. The comparative results are discussed in relation to the applicability of the methods to commercial lots of bean seeds.  相似文献   

The joint action of fungicides in mixtures: comparison of two methods for synergy calculation   总被引：3，自引：0，他引：3  

Y. LEVY  M. BENDERLY  Y. COHEN  U. GISI  D. BASSAND 《EPPO Bulletin》1986,16(4):651-657

Two methods for evaluating the joint action of fungicides in mixtures were analysed. In order to obtain a relatively rapid answer on the type of interaction between fungicides in a mixture (additivity, synergism or antagonism), one can apply the Abbott formula to data on fungus survival. Tests with this method will not be accurate at high effective dose values. A more accurate determination of the joint action of fungicides can be made by the Wadley method, applied to data on effective doses. This involves more experimental work than the Abbott method. Optimization of mixing ratios of fungicides required a set of experimental data on effective doses with several mixing ratios.  相似文献