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  • Articles  (186)
  • fish  (109)
  • Triticum aestivum
  • Springer  (186)
  • 1995-1999  (186)
  • 1998  (102)
  • 1997  (84)
  • 1
    Electronic Resource
    Electronic Resource
    Interspecific variation in sustained swimming ability of late pelagic stage reef fish from two families (Pomacentridae and Chaetodontidae) (1998)
    Springer
    Coral reefs 17 (1998), S. 111-119 
    Details
    ISSN: 1432-0975
    Keywords: Key words Dispersal ; coral reefs ; fish ; swimming ; Larvae ; Juveniles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  Characteristics of the pelagic stages of reef fishes have generally been investigated at the family level, which may mask important differences among species. Here the variation in sustained swimming ability of the late pelagic stages is examined among species, within two families (Pomacentridae and Chaetodontidae). The pomacentrids displayed a 7.5-fold difference in sustained swimming ability across 24 species, while the chaetodontids displayed a 2-fold difference across 10 species. The variation within the Pomacentridae was not related to pelagic larval duration, post-settlement habitat or taxonomy. There was, however, a significant correlation between sustained swimming ability and total length (TL) of individuals (r=0.435, P〈0.0001). Differences in the mean distance swum by pomacentrid species, however, was most strongly related to differences in mean wet weight (r=0.814, P〈0.0001). When the mean distance swum by species was scaled with respect to mean TL there was still a strong correlation with mean wet weight (r=0.644, P〈0.005). Among chaetodontid individuals TL and sustained swimming ability were not correlated (r=−0.004, P=0.978). Furthermore, sustained swimming ability was not significantly related to the trans-oceanic distribution of species in either family. The variation in sustained swimming ability, however, may contribute to explanations of the observed levels of gene flow within populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003380050104
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  • 2
    Electronic Resource
    Electronic Resource
    Estuarine reconnection of an impounded mangrove salt marsh in the Indian River Lagoon, Florida: short-term changes in fish fauna (1998)
    Springer
    Mangroves and salt marshes 2 (1998), S. 29-36 
    Details
    ISSN: 1572-977X
    Keywords: culverts ; culvert trap ; mosquito impoundment ; seine ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fish population dynamics in a 24.3 ha mangrove-dominated mosquito impoundment in east-central Florida were examined by seining and culvert traps before and after installation of culverts that established estuarine connection for the first time in 39 years. In a 27-day period following the culvert opening, fish species increased from 9 to 21, while total number of fish in the impoundment decreased. Movement of fishes through culverts in both directions commenced immediately following culvert opening. Recruitment of transient species into the impoundment appeared to key on a single wind-driven high tide event. Such short-term events may be important cues for fish movement into and out of impounded salt marshes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009969708038
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  • 3
    Electronic Resource
    Electronic Resource
    Early signs of disruption of wheat anther development associated with the induction of male sterility by meiotic-stage water deficit (1997)
    Springer
    Sexual plant reproduction 10 (1997), S. 40-48 
    Details
    ISSN: 1432-2145
    Keywords: Key words Male sterility ; Starch ; Triticum aestivum ; Water stress ; Anther ; Pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Water deficit during meiosis in microspore mother cells of wheat (Triticum aestivum L.) induces male sterility, which reduces grain yield. In plants stressed during meiosis and then re-watered, division of microspore mother cells seems to proceed normally, but subsequent pollen development is arrested. Stress-affected anthers generally lack starch. We employed light microscopy in conjunction with histochemistry to compare the developmental anatomy of water-stress-affected and normal anthers. The earliest effects of stress, detectable between meiosis and young microspore stages, were the degeneration of meiocytes, loss of orientation of the reproductive cells, and abnormal vacuolization of tapetal cells. Other effects observed during subsequent developmental stages were deposition of starch in the connective tissue where it is normally not present, hypertrophy of the middle layer or endothecial cells, and deposition of sporopollenin-like substances in the anther loculus. The resulting pollen grains lacked both starch and intine. These results suggest that abnormal degeneration of the tapetum in water-stressed anthers coupled with a loss of orientation of the reproductive cells could be part of early events leading to abortion of microspores.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004970050066
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  • 4
    Electronic Resource
    Electronic Resource
    In vitro development of wheat (Triticum aestivum L.) from zygote to plant via ovule culture (1997)
    Springer
    Plant cell reports 16 (1997), S. 663-667 
    Details
    ISSN: 1432-203X
    Keywords: Key words Embryogenesis ; Ovule culture ; Triticum aestivum ; Zygote
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ovules of the wheat breeding line Veery #5 were excised and transferred to culture within 24 h after pollination. When ovules were cultured on Phytagel-solidified medium, and the pericarp removed exclusively at the micropylar tip and the abaxial side, zygotes from up to 79.2% of the ovules underwent embryogenesis with the same developmental pattern as found in planta. Embryos from more than 50% of the cultured ovules germinated when transferred to regeneration medium. More than 100 plantlets were randomly chosen for transfer to soil, all of which developed to phenotypically normal and fertile plants. With this system, the entire process of zygotic embryogenesis can be studied using living material. Furthermore, the method could be used as an embryo rescue technique for plant breeding purposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050298
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of light on the accumulation of abscisic acid and expression of an early cysteine-labeled metallothionein gene in microspores of Triticum aestivum during induced embryogenic development (1997)
    Springer
    Plant cell reports 16 (1997), S. 458-463 
    Details
    ISSN: 1432-203X
    Keywords: Key words Abscisic acid ; Anther culture ; Light ; Metallothionein ; Pollen embryogenesis ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cloned cDNA to the wheat (Triticum aestivum) early cysteine-labeled metallothionein has many characteristics of a molecular marker for pollen embryogenesis in this plant. This transcript was not detected in uninucleate microspores at the time of culture or in pollen at any stage during normal ontogeny; its mRNA did begin to increase in embryogenic microspores within 6 h of culture, peaked at around 24 h, declined, then leveled off through the 21-day-old embryoid stage. Additionally, the accumulation of the embryoid-abundant EcMt gene transcript showed a direct and positive correlation with an increase of ABA in embryogenic microspores and developing pollen embryoids. Irradiating cultures with high intensity white light or with far-red, or blue light, suppressed EcMt transcript accumulation and the ability of microspores to form embryoids; however, light did not affect ABA concentrations during the early stages of culture. These results suggest that although a promoter of pollen embryogenesis in bread wheat, ABA alone cannot maintain the sporophytic differentiation of microspores subjected to inhibitory regimes of light in vitro. Whether or not light acts directly or indirectly in suppressing EcMt gene expression and pollen embryogenesis remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01092766
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  • 6
    Electronic Resource
    Electronic Resource
    Are Tropical Herbivores More Resistant Than Temperate Herbivores to Seaweed Chemical Defenses? Diterpenoid Metobolites from Dictyota acutiloba as Feeding Deterrents for Tropical Versus Temperate Fishes and Urchins (1997)
    Springer
    Journal of chemical ecology 23 (1997), S. 289-302 
    Details
    ISSN: 1573-1561
    Keywords: Acutilol diterpenes ; biogeography ; chemical defenses ; Dictyota ; diffuse coevolution ; fish ; plant–herbivore interactions ; sea urchin ; secondary metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Because herbivory is more intense in the tropics, tropical seaweeds may be better defended against herbivory than are temperate seaweeds. A “diffuse” coevolutionary corollary to this hypothesis is that tropical herbivores should be more resistant to seaweed defenses than temperate herbivores because tropical herbivores more commonly encounter heavily defended seaweeds. We begin to test the latter prediction using three newly discovered diterpenoid secondary metabolites from the tropical brown alga Dictyota acutiloba. We tested the feeding deterrent properties of these compounds against common herbivorous fishes and sea urchins from warm-temperate North Carolina versus tropical Guam using standardized laboratory feeding assays. The temperate herbivores were deterred by lower concentrations of secondary metabolites than the tropical herbivores. In no case was a tropical herbivore more deterred by a compound than a temperate herbivore, suggesting that temperate herbivores may be more strongly affected by seaweed chemical defenses. Feeding by the temperate pinfish Lagodon rhomboides was significantly reduced by two of the three diterpenes at a concentration that was only 13–18% of the natural concentration found in the alga. Feeding by four species of tropical fishes (two parrotfishes and two surgeonfishes) was unaffected by metabolite concentrations that deterred the temperate fish. At 100% of natural concentrations, only one of the three compounds deterred the two parrotfishes, and none of the three compounds deterred the surgeonfishes. Contrasts between the temperate sea urchin Arbacia punctulata and the tropical sea urchin Diadema savignyi showed a similar pattern; low concentrations of acutilol A acetate strongly deterred the temperate, but not the tropical, urchin. Tropical herbivores appear more resistant than temperate herbivores to seaweed chemical defenses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/B:JOEC.0000006360.36833.13
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  • 7
    Electronic Resource
    Electronic Resource
    WHOLE-CATCHMENT LIMING AT TJØNNSTROND, NORWAY: AN 11-YEAR RECORD (1997)
    Springer
    Water, air & soil pollution 94 (1997), S. 163-180 
    Details
    ISSN: 1573-2932
    Keywords: acid deposition ; liming ; catchment ; lake ; water chemistry ; fish ; soil ; model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract In June 1983 a whole-catchment liming experiment was conducted at Tjønnstrond, southernmost Norway, to test the utility of terrestrial liming as a technique to restore fish populations in remote lakes with short water-retention times. Tjønnstrond consists of 2 small ponds of 3.0 and 1.5 ha in area which drain a 25-ha catchment. The area is located at about 650–700 meters above sea-level in sparse and unproductive forests of spruce, pine and birch with abundant peatlands. A dose of 3 ton/ha of powdered limestone were spread by helicopter to the terrestrial area. No limestone was added to the ponds themselves. The ponds were subsequently stocked with brown and brook trout. Liming caused large and immediate changes in surface water chemistry; pH increased from 4.5 to 7.0, Ca increased from 40 to 200 μeq/L, ANC increased from –30 to +70 μeq/L, and reactive-Al decreased from about 10 to 3 μmol/L. During the subsequent 11 years the chemical composition of runoff has decreased gradually back towards the acidic pre-treatment situation. The major trends in concentrations of runoff Ca, ANC, pH, Al and NO3 in runoff are all well simulated by the acidification model MAGIC. Neither the measured data nor the MAGIC simulations indicate significant changes in any other major ion as a result of liming. The soils at Tjønnstrond in 1992 contained significantly higher amounts of exchangeable Ca relative to those at the untreated reference catchment Storgama. In 1992 about 75% of the added Ca remains in the soil as exchangeable Ca, 15% has been lost in runoff, and 10% is unaccounted for. The whole-catchment liming experiment at Tjønnstrond clearly demonstrates that this liming technique produces a long-term stable and favourable water quality for fish. Brown trout in both ponds in 1994 have good condition factors, which indicate that the fish are not stressed by marginal water quality due to re-acidification. The water quality is still adequate after 11 years and 〉20 water renewals. Concentrations of H+ and inorganic Al have gradually increased and approach levels toxic to trout, but the toxicity of these are offset by the continued elevated Ca concentrations. Reduced sulphate deposition during the last 4 years (1990–94) has also helped to slow and even reverse the rate of reacidification. The experiment at Tjønnstrond demonstrates that for this type of upland, remote terrain typical of large areas of southern Norway, terrestrial liming offers a suitable mitigation technique for treating acidified surface waters with short retention times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026442821924
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  • 8
    Electronic Resource
    Electronic Resource
    Structural and functional impairment of the hypothalamo- pituitary-interrenal axis in fish exposed to bleached kraft mill effluent in the St Maurice River, Quebec (1997)
    Springer
    Ecotoxicology 6 (1997), S. 1-12 
    Details
    ISSN: 1573-3017
    Keywords: cortisol ; BKME ; fish ; interrenal ; pituitary ; morphol ogy ; acute stress ; endocrine dysfunction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The effects of bleached kraft mill effluent (BKME) on blood cortisol levels and the morphology of the pituitary-interrenal axis were investigated in two species of teleost fish, the northern pike, Esox lucius, and the yellow perch, Perca flavescens, sampled upstream and downstream from a pulp and paper mill on the St Maurice River, Quebec. Fish were acutely stressed by a standardized capture and sampling protocol at both sites, and their ability to elevate blood cortisol levels in response to the capture stress was compared. Blood cortisol levels in fish from the upstream site (〉100 ng/ml plasma) were higher than the levels in fish from the BKME site, and the pituitary corticotropes and the interrenal steroidogenic cells of the upstream fish were larger and had larger nuclei compared with cells from the downstream fish. The low blood cortisol levels in fish exposed to BKME were correlated to cellular atrophy within the hypothalamo-pituitary-interrenal (HPI) axis. The reduced ability to elevate blood cortisol in response to an acute stress may be an endocrine dysfunction occuring in fish chronically exposed to chemical stressors in their environment
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018699405158
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  • 9
    Electronic Resource
    Electronic Resource
    Allozymes Reflect the Population-Level Effect of Mercury: Simulations of the Mosquitofish (Gambusia holbrooki Girard) GPI-2 Response (1998)
    Springer
    Ecotoxicology 7 (1998), S. 141-150 
    Details
    ISSN: 1573-3017
    Keywords: fish ; mercury ; natural selection ; allozyme ; population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Measurements of the differential tolerance between enzyme genotypes and shifts in allozyme frequencies in populations from contaminated habitats have prompted the use of allozymes as markers of population-level toxicant effects. However, such studies often do not consider other factors that influence allele frequencies, including natural clines, migration, the intensity and specificity of selection and toxicant-induced genetic bottlenecks. In addition, selection components other than survival are not included. Consequently, the associated conclusions remain speculative. To assess this approach rigorously, a simulation study was conducted with the mosquitofish (Gambusia holbrooki) GPI-2 locus. Laboratory studies have shown the GPI-238/38 homozygote at this locus to be less tolerant than other genotypes during acute exposure to mercury. The GPI-2100/100 genotype has also been shown to have a reproductive disadvantage at lower mercury concentrations. Simple and then more complex models were used to quantify the relative effects of viability selection, random genetic drift and migration on the GPI-238 allele frequency. Simulations were also performed to assess the contribution of sexual and fecundity selection. A simple population model suggested that viability selection plays a greater role than does mortality-driven, genetic drift in the decrease of the sensitive allele under the conditions of this study. A more complex, stochastic model indicated that no significant mortality-driven drift was taking place in this system. In both models, migration mitigated the effect of selection. Sexual and fecundity selection had little effect on the allele frequencies in these simulations. We conclude that, provided the system under study is clearly understood, shifts in allele frequency can indicate the population-level effects of pollutants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1014352226686
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  • 10
    Electronic Resource
    Electronic Resource
    Flow Cytometric Analysis of Erythrocyte and Leukocyte DNA in Fish from Chernobyl-Contaminated ponds in the Ukraine (1998)
    Springer
    Ecotoxicology 7 (1998), S. 211-219 
    Details
    ISSN: 1573-3017
    Keywords: genotoxicity ; Chernobyl ; fish ; flow cytometry ; coefficient of variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Flow cytometric (FCM) analysis was used to assess the potential impact of chronic radionuclide exposure in fish populations inhabiting contaminated sites in the vicinity of the Chernobyl nuclear accident. Four species of fish, channel catfish (Ictalurus punctatus), crucian carp (Carassius carassius), carp (Cyprinus carpio) and tench (Tinca tinca), were collected within a 10 km radius of the Chernobyl Nuclear Power Plant and compared with 'control' populations from two uncontaminated locations far removed from the plant. Assays of whole blood, as well as separate erythrocyte and leukocyte components, revealed aneuploid-like patterns in the DNA histograms of some fish, as well as widened G0/G1 peaks. None of the fish collected from the uncontaminated sites demonstrated these kinds of changes in their DNA histograms. Increases in the coefficient of variation (CV) of the G0/G1 peak, indicating abnormal DNA distributions, were observed in several of the fish from Chernobyl relative to the control populations. Cell cycle perturbation in fish from the contaminated sites was also detected, with a higher percentage of cells in G2/M phase relative to the controls. Leukocytes proved more sensitive than erythrocytes, as they displayed a larger number of abnormal DNA histograms. Variations in the cellular DNA content similar to those reported here have been shown for other vertebrate species exposed to radiation and other genotoxic agents in laboratory and field settings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008986727743
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  • 11
    Electronic Resource
    Electronic Resource
    Influence of Taxonomy, Ecology, and Seasonality in River Stage on Fish Contamination Risks in Floodplain Swamps of the Lower Mississippi River (1998)
    Springer
    Ecotoxicology 7 (1998), S. 325-334 
    Details
    ISSN: 1573-3017
    Keywords: contamination risks ; fish ; Mississippi River ; ecological factors ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We compared contamination levels in fish from contaminated and uncontaminated floodplain swamps of the lower Mississippi River to assess differences in contamination risks between swamps, across different taxonomic and ecological groupings of fishes within and between swamps, and with seasonality in river stage. Fish tissue levels of inorganic contaminants were substantially lower than environmental levels in both swamps, suggesting either that fish were not uptaking these contaminants, or they were effectively eliminating the contaminants from their bodies. Tissue levels of organic contaminants were high relative to environmental levels, suggesting that these contaminants were bioaccumulating. Organic contaminants were significantly higher in fish from the contaminated swamp (Devil's Swamp) than in fish from a reference swamp up river (Tunica Swamp). Because the organic contaminants were largely confined to sediments, we expected bottom-oriented fishes to have higher concentrations than pelagic fishes. Assuming that uptake was primarily through the food chain, we expected top predators to exhibit higher concentrations than low-level consumers. We also expected year- round swamp residents to exhibit higher accumulations than more transitory users of backswamp habitat. However, organic contaminant levels did not differ in the directions expected for any of these groupings. We did observe differences in organic contaminant levels within and between swamps for different taxonomic groupings of fishes (species and genera). Some taxa occupying low to middle positions in the food web (e.g., gizzard shad, Lepomis spp.) exhibited higher concentrations than taxa near the top of the food web. Within Devil's Swamp, organic contaminant levels were significantly higher at low river stage, when fish were confined to the swamp, than at high river stage, when fish were free to move between the river and the swamp. We caught more species and more fish per unit effort in Devil's Swamp than in Tunica Swamp, contrary to expectations if contaminants in the former were negatively impacting population and community structure. Species richness differences between swamps were a consequence of catch differences, with higher catch corresponding to inclusion of more rare species. The lower catch in Tunica Swamp may have resulted from physical modifications of its waterways to support agriculture and hunting. The results of this study underscore the importance in factoring information on the taxonomy and ecology of organisms, and seasonal changes in environmental conditions, into assessments of contamination risks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008811713427
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  • 12
    Electronic Resource
    Electronic Resource
    Effects of light on the accumulation of abscisic acid and expression of an early cysteine-labeled metallothionein gene in microspores ofTriticum aestivum during induced embryogenic development (1997)
    Springer
    Plant cell reports 16 (1997), S. 458-463 
    Details
    ISSN: 1432-203X
    Keywords: Abscisic acid ; Anther culture ; Light ; Metallothionein ; Pollen embryogenesis ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cloned cDNA to the wheat (Triticum aestivum) early cysteine-labeled metallothionein has many characteristics of a molecular marker for pollen embryogenesis in this plant. This transcript was not detected in uninucleate microspores at the time of culture or in pollen at any stage during normal ontogeny; its mRNA did begin to increase in embryogenic microspores within 6 h of culture, peaked at around 24 h, declined, then leveled off through the 21-day-old embryoid stage. Additionally, the accumulation of the embryoid-abundant EcMt gene transcript showed a direct and positive correlation with an increase of ABA in embryogenic microspores and developing pollen embryoids. Irradiating cultures with high intensity white light or with far-red, or blue light, suppressed EcMt transcript accumulation and the ability of microspores to form embryoids; however, light did not affect ABA concentrations during the early stages of culture. These results suggest that although a promoter of pollen embryogenesis in bread wheat, ABA alone cannot maintain the sporophytic differentiation of microspores subjected to inhibitory regimes of light in vitro. Whether or not light acts directly or indirectly in suppressing EcMt gene expression and pollen embryogenesis remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01092766
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  • 13
    Electronic Resource
    Electronic Resource
    Analysis and optimisation of DNA delivery into wheat scutellum and Tritordeum inflorescence explants by tissue electroporation (1998)
    Springer
    Plant cell reports 18 (1998), S. 64-70 
    Details
    ISSN: 1432-203X
    Keywords: Key words Bread wheat ; Triticum aestivum ; Tritordeum ; Tissue electroporation ; Transient gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat scutella and tritordeum inflorescences were transformed by tissue electroporation with plasmid DNA containing a β-glucuronidase (GUS) gene (gus A) under the control of the rice actin1 promoter. Factors affecting electroporation efficiency were analysed. Important factors were electroporation voltage and pulse length, the volume of electroporation buffer, the osmoticum of electroporation buffer and medium, the osmoticum of pre-electroporation culture medium, and pre-electroporation incubation time and temperature. Maximum transient gene expression was obtained with a single pulse of 550 V/cm from a 960-μF capacitor, using 200 μl of electroporation buffer, after 2–3 h culture on media with 357 mOsm for wheat scutella or 1 day on media with 222 mOsm for tritordeum inflorescences, and 0.5–1 h pre-electroporation incubation with DNA at 24 °C. Under these conditions, up to 90% of the explants showed GUS expression, and up to 149 expression signals were recorded per replicate. Electroporated explants showed high rates of survival and retained the ability to regenerate plants via somatic embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050533
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  • 14
    Electronic Resource
    Electronic Resource
    The application of wheat microsatellites to identify disomic Triticum aestivum-Aegilops markgrafii addition lines (1998)
    Springer
    Theoretical and applied genetics 96 (1998), S. 138-146 
    Details
    ISSN: 1432-2242
    Keywords: Key words Aegilops markgrafii ; Triticum aestivum ; Addition lines ; Chromosome markers ; Homoeology ; Wheat ; Wheat microsatellites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We describe the use of wheat microsatellites for the discrimination of Aegilops markgrafii chromosomes. Twenty out of eighty eight wheat microsatellites (WMS) tested were able to distinguish Triticum aestivum-Ae. markgrafii addition lines. Six, three, three, one and six of 18 WMS can be used as markers for single Ae. markgrafii chromosomes B, C, D, F and G, respectively. Addition line A is not available but additional bands, appearing only in Ae. markgrafii and the T. aestivum-Ae. markgrafii amphiploid and not in any of the available addition lines, indicate that three WMS detect markers for Ae. markgrafii chromosomes A. Addition line E could not be detected by any of the WMS markers applied, although the 20 WMS represented all the homologous groups of wheat. All three WMS located on the short arm of group-2 chromosomes were located on Ae. markgrafii chromosome B; three of four WMS, located on the long arm of wheat group-2 chromosomes, were specific to Ae. markgrafii chromosome G and three of four WMS, specific to group-5 chromosomes, were markers for Ae. markgrafii chromosome C, indicating the homoeology of these wheat chromosome arms with the respective Ae. markgrafii chromosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001220050720
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  • 15
    Electronic Resource
    Electronic Resource
    Genetic diversity in Australian wheat varieties and breeding material based on RFLP data (1998)
    Springer
    Theoretical and applied genetics 96 (1998), S. 435-446 
    Details
    ISSN: 1432-2242
    Keywords: Key words RFLP analysis ; Triticum aestivum ; Genetic diversity ; Genetic similarity estimates ; Cluster analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Restriction fragment length polymorphisms (RFLPs) have been used to characterise the genetic diversity of wheat (Triticum aestivum) germplasm. One hundred and twenty-four accessions comprising all major Australian wheat varieties and lines important for breeding purposes were assayed for RFLPs with clones of known genetic location and selected to give uniform genome coverage. The objectives of this study were to determine RFLP-based genetic similarity between accessions and to derive associations between agronomically significant traits and RFLP phenotypes. Ninety-eight probes screened against genomic DNA digested with five restriction endonucleases detected a total of 1968 polymorphic fragments. Genetic similarity (GS) calculated from the RFLP data ranged from 0.004 to 0.409 between accessions, with a mean of 0.18. Cluster analysis based on GS estimates produced four groupings that were generally consistent with available pedigree information. Comparisons of the RFLP phenotypes of accessions containing disease resistance genes present on introgressed alien segments enabled the identification of specific alleles characteristic of these regions. Associations were derived for a range of stem-rust, leaf-rust and yellow-rust resistance genes. These results suggest that RFLP analysis can be used for the characterisation and grouping of elite breeding material of wheat and RFLP profiling can identify chromosome segments associated with agronomic traits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001220050760
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  • 16
    Electronic Resource
    Electronic Resource
    Protein evolution in dynamically managed populations of wheat: adaptive responses to macro-environmental conditions (1997)
    Springer
    Theoretical and applied genetics 95 (1997), S. 932-941 
    Details
    ISSN: 1432-2242
    Keywords: Key words Genetic resources ; Dynamic conservation ; Two-dimensional electrophoresis ; Artificial population ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Dynamic management of genetic resources aims to conserve genetic variability between different populations evolving in contrasting environments. It is thus of importance to determine whether differences appearing between populations are stochastic or if they come about from adaptation. Two-dimensional electrophoresis (2DE) was used to study genetic differentiation of 11 wheat populations evolving since 1984 in a multi-site network covering the major cultivation area of wheat in France. Gels were scanned and protein-spot intensities were measured through image analysis. As it was not possible to assay each individual, populations were characterized using pooled extracts from several plants. In the first step, two parents among the 16 parental lines involved in the initial wheat composite-cross population were exhaustively studied to identify a set of polymorphic spots against which the entire set of evolved populations could be compared. This analysis confirmed the efficiency of gel image-processing to determine the composition of pooled extracts. Of the 48 spots used to investigate population differentiation, 15 showed significant differences at the P〈0.05 level. Populations that evolved independently at the same location showed similar differentiation, even when their cultivation methods were different. These results suggest that natural selection acted strongly on the evolution of the populations, and that responses to selection were determined primarily by macro-environmental conditions.
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    URL: http://dx.doi.org/10.1007/s001220050644
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    Chromosomal location of genes for resistance to powdery mildew in common wheat (Triticum aestivum L. em. Thell.) 4. Gene Pm 24 in Chinese landrace Chiyacao (1997)
    Springer
    Theoretical and applied genetics 95 (1997), S. 950-953 
    Details
    ISSN: 1432-2242
    Keywords: Key words Wheat landrace ; Triticum aestivum ; Powdery mildew resistance ; Monosomic analysis ; Gene location
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Chinese wheat landrace Chiyacao exhibited a response pattern different from that of the cultivars/lines possessing documented Pm genes after inoculation with 106 isolates of Erysiphe graminis f. sp. tritici. To characterize this resistance and to determine the chromosomal location of the gene or genes present, we crossed the landrace to susceptible cultivar ‘Chinese Spring’ and also to a set of 21 ‘Chinese Spring’ monosomic lines. Monosomic F1 plants were allowed to self-pollinate and to produce F2 seeds. Seedlings of F2 plants and their parents were inoculated with isolates nos. 5 and 12 of Erysiphe graminis f. sp. tritici. The results revealed that one major dominant gene is located on chromosome 6D of Chinese common wheat landrace Chiyacao. The new gene is designated Pm 24.
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    URL: http://dx.doi.org/10.1007/s001220050646
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    DNA content of wheat monosomics at interphase estimated by flow cytometry (1997)
    Springer
    Theoretical and applied genetics 95 (1997), S. 1300-1304 
    Details
    ISSN: 1432-2242
    Keywords: Key words Flow cytometry ; Triticum aestivum ; DNA analysis ; Monosomics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Two complete, independently maintained sets of 21 monosomic wheat lines derived from cv. ‘Chinese Spring’ were analyzed for their DNA content at the G1 stage with flow cytometry. The DNA content of individual chromosomes was estimated by subtracting the value of a monosomic line from that of euploid wheat. Our data show that the estimated 2C DNA of individual wheat chromosomes in 21 monosomics at the G1 stage ranges from about 0.58 pg in chromosome 1D to approximately 1.12 pg in chromosome 3A. The A genome (2C=6.15 pg) seems to contain more DNA than the B (2C=6.09 pg) and D (2C=5.05 pg) genomes. Analysis of variance showed significant differences (α=0.01) in DNA content both among homoeologous groups and among genomes. Our estimates of interphase DNA content of wheat chromosomes from monosomic lines were poorly correlated to the chromosome sizes at metaphase (r=0.622, P≤0.01). This poor correlation might be due to differential coiling among chromosomes during cell division, possible bias of fluorochrome binding to heterochromatin, or heterogeneity among monosomic lines. Finally, flow cytometry may aid but cannot replace cytological checks in aneuploid maintenance.
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    URL: http://dx.doi.org/10.1007/s001220050696
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    Genetic diversity in Eastern U.S. soft winter wheat (Triticum aestivum L. em. Thell.) based on RFLPs and coefficients of parentage (1997)
    Springer
    Theoretical and applied genetics 94 (1997), S. 472-479 
    Details
    ISSN: 1432-2242
    Keywords: Key words Genetic diversity ; RFLP ; Coefficient of parentage ; Triticum aestivum ; Gene pool
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Genetic diversity in a set of 11 red and 11 white wheat lines from the Eastern U.S. soft wheat germplasm pool was measured using restriction fragment length polymorphism (RFLP) assay and coefficients of parentage (COP) analysis. On average, 78% of all bands revealed by three enzymes with 48 RFLP clones were monomorphic. Average pairwise genetic similarity (GS) was 0.97 when data from all enzymes were pooled. Probe Polymorphic Information Content (PIC) indexes ranged from 0 to 0.73 with a mean of 0.2. Fewer than 55% of the probes revealed any polymorphism. The frequency of polymorphism in the Eastern U.S. soft white winter (SWW) wheat gene pool was much lower than that observed in the Eastern U.S. soft red winter (SRW) wheat gene pool. SWW lines formed a single group on a dendrogram based on cluster analysis of RFLP-derived GS estimates, while SRW lines did not form a single group. COP values for all pairs of the Eastern U.S. soft wheat lines ranged from 0.02 to 0.9 with a mean of 0.21. SWW wheat lines traced to 53 ancestral lines and had an average COP of 0.51. The SRW wheat gene pool had more complex parentages (mean COP=0.15 and a total of 65 ancestral lines). COPs were correlated with RFLP-based GS for all line pairs (r=0.73, P〈0.01). However, correlations between the two similarity measures were substantially lower when the SRW and SWW wheat gene pools were considered individually (r values of 0.23 and 0.28, respectively). The actual GS among unrelated lines in the U.S. Eastern soft wheat gene pool appears to be higher than that observed for unrelated landraces from Southwest Asia (0.96 vs. 0.905), suggesting that the ancestral landrace parents of this gene pool were themselves drawn from a base population where inbreeding, i.e., F, was greater than zero.
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    URL: http://dx.doi.org/10.1007/s001220050439
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    RAPDs as molecular markers for the detection of Aegilops markgrafii chromatin in addition and euploid introgression lines of hexaploid wheat (1997)
    Springer
    Theoretical and applied genetics 94 (1997), S. 934-940 
    Details
    ISSN: 1432-2242
    Keywords: Key words Aegilops markgrafii ; Triticum aestivum ; RAPD ; Addition lines ; Leaf rust ; Powdery mildew
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Aegilops markgrafii contains resistance genes to powdery mildew, leaf rust and stripe rust, and also has high crude protein and lysine contents, which can be useful for wheat improvement. These important traits are localized on different chromosomes. Disomic Triticum aestivum-Ae. markgrafii addition lines and euploid introgression lines showing leaf-rust and powdery mildew resistance were screened with RAPDs to detect chromosome-specific markers which can accelerate the breeding process. RAPD markers for all six available disomic addition lines were obtained. The additional chromosomes B, C, D, E, F and G were identified by three, three, three, two, one and seven primers, respectively. All three chromosome-B-specific RAPD markers demonstrated the presence of alien chromatin in the leaf-rust-resistant 42-chromosome introgression lines as well as in the segregating progeny. The three chromosome-C-identifying primers also demonstrated the presence of that chromosome in powdery mildew-resistant euploid introgression lines. The substitution lines (5A)5C and (5D)5C with different genetic backgrounds for both parents, in comparison to the lines mentioned above, showed the chromosome C-specific band with only two of the three primers. The chromosome F-specific primer and a primer evident on all the Ae. markgrafii chromosomes analysed did not generate the expected fragments on the chromosome Fdel addition line, indicating that the markers are located on the deleted part of chromosome F.
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    URL: http://dx.doi.org/10.1007/s001220050498
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    Relationships between the chromosomes of Aegilops umbellulata and wheat (1998)
    Springer
    Theoretical and applied genetics 96 (1998), S. 69-75 
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    ISSN: 1432-2242
    Keywords: Key words Aegilops umbellulata ; Co-linearity ; Comparative mapping ; Translocations ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A comparative genetic map of Aegilops umbellulata with wheat was constructed using RFLP probes that detect homoeoloci previously mapped in hexaploid bread wheat. All seven Ae. umbellulata chromosomes display one or more rearrangements relative to wheat. These structural changes are consistent with the sub-terminal morphology of chromosomes 2 U, 3 U, 6 U and 7 U. Comparison of the chromosomal locations assigned by mapping and those obtained by hybridization to wheat/Ae. umbellulata single chromosome addition lines verified the composition of the added Ae. umbellulata chromosomes and indicated that no further cytological rearrangements had taken place during the production of the alien-wheat aneuploid lines. Relationships between Ae. umbellulata and wheat chromosomes were confirmed, based on homoeology of the centromeric regions, for 1 U, 2 U, 3 U, 5 U and 7 U. However, homoeology of the centromeric regions of 4 U with wheat group-6 chromosomes and of 6 U with wheat group-4 chromosomes was also confirmed, suggesting that a re-naming of these chromosomes may be pertinent. The consequences of the rearrangements of the Ae. umbellulata genome relative to wheat for gene introgression are discussed.
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    Molecular cytogenetic characterization of Thinopyrum intermedium-derived wheat germplasm specifying resistance to wheat streak mosaic virus (1998)
    Springer
    Theoretical and applied genetics 96 (1998), S. 1-7 
    Details
    ISSN: 1432-2242
    Keywords: Key words Fluorescence in situ hybridization ; Translocation ; WSMV resistance ; Thinopyrum intermedium ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract   Thinopyrum intermedium is a promising source of resistance to wheat streak mosaic virus (WSMV), a devastating disease of wheat. Three wheat germplasm lines possessing resistance to WSMV, derived from Triticum aestivum×Th. intermedium crosses, are analyzed by C-banding and genomic in situ hybridization (GISH) to determine the amount and location of alien chromatin in the transfer lines. Line CI15092 was confirmed as a disomic substitution line in which wheat chromosome 4A was replaced by Th. intermedium chromosome 4Ai?2. The other two lines, CI17766 and A29-13-3, carry an identical Robertsonian translocation chromosome in which the complete short arm of chromosome 4Ai?2 was transferred to the long arm of wheat chromosome 4A. Fluorescence in situ hybridization (FISH) using ABD genomic DNA from wheat as a probe and S genomic DNA from Pseudoroegneria stipifolia as the blocker, and vice versa, revealed that the entire short arm of the translocation was derived from the short arm of chromosome 4Ai?2 and the breakpoint was located at the centromere. Chromosomal arm ratios (L/S) of 2.12 in CI17766 and 2.15 in A29-13-3 showed that the translocated chromosome is submetacentric. This translocated chromosome is designated as T4AL ⋅ 4Ai?2S as suggested by Friebe et al. (1991).
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    Characterization of spelt (Triticum spelta L.) forms by gel-electrophoretic analyses of seed storage proteins. III. Comparative analyses of spelt and Central European winter wheat (Triticum aestivum L.) cultivars by SDS-PAGE and acid-PAGE (1998)
    Springer
    Theoretical and applied genetics 97 (1998), S. 1340-1346 
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    ISSN: 1432-2242
    Keywords: Key words Triticum spelta ; Triticum aestivum ; SDS-PAGE ; Acid-PAGE ; Seed storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Seed storage proteins of a few selected spelt forms and crosses have already been electrophoretically analysed by SDS-PAGE and acid-PAGE and compared with a few winter wheat cultivars. In the analyses presented here further important Central European spelt varieties were included, as well as modern winter wheat cultivars which were chosen as standards. In this study gliadin and glutenin band patterns of modern Central European winter wheat cultivars were analysed, in particular for a comparison with spelt varieties. An improved differentiation within and between the two species was obtained.
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    Comparative analyses of RFLP diversity in landraces of Triticum aestivum and collections of T. tauschii from China and Southwest Asia (1998)
    Springer
    Theoretical and applied genetics 96 (1998), S. 312-318 
    Details
    ISSN: 1432-2242
    Keywords: Key words Genetic diversity ; Triticum tauschii ; Triticum aestivum ; RFLP ; Landrace wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Chinese accessions of Triticum tauschii and T. aestivum L. from the Sichuan white (SW), Yunnan hulled (YH), Tibetan weedrace (TW), and Xinjiang rice (XR) wheat groups were subjected to RFLP analysis. T. tauschii and landraces of T. aestivum from countries in Southwest Asia were also evaluated. For T. tauschii, a west to east gradient was apparent where the Chinese accessions exhibited less diversity than those from Southwest Asia. Compared to the Southwest Asian gene pool, the Chinese T. tauschii was highly homogeneous giving a low frequency of polymorphic bands (16%) and banding patterns (1.33 per probe) with 75 RFLP probe-HindIII combinations. Accessions of T. tauschii from Afghanistan and Pakistan were genetically more similar to the Chinese T. tauschii than those from Iran. Of 368 bands found for 39 Chinese hexaploid wheat accessions with 63 RFLP probe-HindIII combinations, 28.3% were polymorphic with an average of 2.6 banding patterns per probe and 5.0 bands per genotype. The individual Chinese landrace wheat groups revealed less variation than those from Afghanistan, Iran, and Turkey. When classified into country based groups, however, the diversity level over all Chinese landraces was greater than that of some Southwest Asian landraces, especially those from Afghanistan and Iran . The XR wheat group was genetically distinct from the other three Chinese landrace groups and was more related to the Southwest Asian landraces. The TW group was genetically similar to, but more diverse than, the SW and YH groups. The Chinese landraces had a higher degree of genetic relatedness to the Southwest Asian T. tauschii, particularly to accessions from Iran, rather than to the Chinese T. tauschii. ‘Chinese Spring’ was most related to ‘Chengdu-guang-tou’, a cultivar from the SW wheat group.
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    Hessian fly-resistance gene transferred from chromosome 4Mv of Aegilops ventricosa to Triticum aestivum (1997)
    Springer
    Theoretical and applied genetics 94 (1997), S. 858-864 
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    ISSN: 1432-2242
    Keywords: Key words Aegilops ventricosa ; Triticum aestivum ; Mayetiola destructor ; Hessian fly ; Resistance gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A new Hessian fly (Mayetiola destructor) resistance gene from Aegilops ventricosa and its transfer to hexaploid wheat is described. The 4D(4Mv) substitution line H-93-33 derived from the cross [(Triticum turgidum H-1-1×Aegilops ventricosa no. 11)×Triticum aestivum H-10-15] was highly resistant to the Spanish population tested. Resistance seemed to be inherited as a single dominant factor in the F2 generation resulting from a cross of H-93-33 with its susceptible parent (H-10-15). Resistance in Ae. venticosa no. 10 was located on chromosome 4Mv using Mv wheat/Ae. ventricosa addition lines. The resistance gene transferred from Ae. ventricosa no. 11 to H-93-33 (H27) is allelic with respect to that of Ae. ventricosa no. 10 and is non-allelic with respect to the genes H3 and H6 from Monon and Caldwell respectively. The assignment of H27 gene to chromosome 4Mv is further supported by its linkage to a gene encoding isozyme Acph-Mv1, previously located on chromosome 4Mv in the line H-93-33. A new marker from homoeologous chromosome group 4 (Amp-Mv2) present in H-93-33 and the 4Mv addition line is described.
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    The development of a nuclear male sterility system in wheat. Expression of the barnase gene under the control of tapetum specific promoters (1997)
    Springer
    Theoretical and applied genetics 95 (1997), S. 125-131 
    Details
    ISSN: 1432-2242
    Keywords: Key words Wheat ; Triticum aestivum ; Transformation ; Nuclear male sterility ; DNA-integration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Nuclear male sterility within Triticum aestivum is considered as the ideal basis for the development of a hybridization system for wheat. We engineered nuclear male sterility in wheat by introducing the barnase gene under the control of tapetum-specific promoters derived from corn and rice. A biolistic-mediated transformation method, based on the use of the poly(ADP-ribose)polymerase inhibitor niacinamide, was set up which enriched for low-copy integrations (1–3 copies). Most of these copies were not linked and segregated in the next generation.
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    A cereal cyst nematode (Heterodera avenae Woll.) resistance gene transferred from Aegilops triuncialis to hexaploid wheat (1998)
    Springer
    Theoretical and applied genetics 96 (1998), S. 1135-1140 
    Details
    ISSN: 1432-2242
    Keywords: Key words Aegilops triuncialis ; Triticum aestivum ; Heterodera avenae ; Cereal cyst nematode ; Resistance gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The cereal cyst nematode (Heterodera avenae) is an important root parasite of common wheat. A high level of resistance was transferred to wheat from Aegilops triuncialis (TR lines) using the cross [(T. turgidum×Ae. triuncialis)×T. aestivum]. Low fertility (3–5 viable kernels per plant) was observed during the process but the surviving hybrid plants were highly vigorous. To obtain stable resistant lines further crosses to T. aestivum were performed. The resistance in TR lines seems to be transferred from the C genome of Ae. triuncialis (genomes CCUU). Ae. triuncialis was highly resistant to the two Spanish populations of H. avenae tested, as well as to four French races and two Swedish populations. The histological analysis showed a hypersensitive reaction in the roots of a resistant TR line inoculated with the Ha71 pathotype of H. avenae, whereas well-formed syncytia were observed in the roots of the susceptible control. Resistance to the H. avenae Ha71 pathotype seemed to be inherited as determined by a single dominant factor in the crosses between resistant TR lines and susceptible cultivars.
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    URL: http://dx.doi.org/10.1007/s001220050849
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    Risk from genetically engineered and modified marine fish (1997)
    Springer
    Transgenic research 6 (1997), S. 59-67 
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    ISSN: 1573-9368
    Keywords: Sparus aurata ; transgenic ; ecologicalrisk ; release ; genetic modification ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In support of the emerging industries of warmwater marine fish mariculture, genetic engineering and classical genetic improvement programmes have been initiated for a variety of exclusively marine fish. These programmes have the potential to perturb allele and genotype frequencies, or introduce novel alleles and genes into conspecific wild populations. Despite concerns to the contrary, the following hypothesis remains to be falsified: ‘laboratory induced allele frequency/genotype changes and novel alleles or genes have a negligible probability of being selectively favoured in wild populations under natural selection, and accordingly, without sustained large scale releases, have little potential for ecological impact’
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    URL: http://dx.doi.org/10.1023/A:1018457100476
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    Molecular Characteristics of Transgenic Wheat and the Effect on Transgene Expression (1998)
    Springer
    Transgenic research 7 (1998), S. 463-471 
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    ISSN: 1573-9368
    Keywords: particle bombardment ; transgene expression ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A population of R0 transgenic wheat plants, generated by particle bombardment, was analyzed to define molecular, genetic and phenotypic properties resulting from transformation with a cointegrate vector, or cotransformation with two separate plasmids. By evaluating the progeny of 70 independently-derived transgenic plants, we also identified rare events such as chimerism and transgene elimination, which provide valuable information concerning the development of transgenic cereal plants following bombardment experiments. The frequency of chimerism in our transgenic wheat plants was very low. Furthermore, while transgene elimination did occur, this was also a very rare event. We determined the copy numbers of integrated transgenes and the levels of transgene expression. Comparisons to transgenic rice plants generated in the same manner demonstrated some similarities, but also important differences in transgene behavior. Whereas in rice there is no evidence for any direct relationship between transgene copy number and transgene expression or stability, multicopy populations in wheat demonstrated a bias towards higher levels of expression for the two genes and the maize ubiquitin promoter evaluated in the present study.
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    Fusarium nisikadoi, a new species from Japan (1997)
    Springer
    Mycoscience 38 (1997), S. 329-333 
    Details
    ISSN: 1618-2545
    Keywords: conidial morphology ; form-sectionLiseola ; Fusarium nisikadoi ; Phyllostachys nigra var.henonis ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species ofFusarium, F. nisikadoi, isolated fromPhyllostachys nigra var.henonis (bamboo) andTriticum aestivum (wheat) in Japan, is described, illustrated and discussed. This species is differentiated from other known species of the genus by the following characteristics: whitish colony color, long zigzag-like chains of 0–3(-5)-septate clavate conidia, intermixed with pyriform conidia, produced mostly from monophialides and rarely from polyphialides in the aerial mycelium, very long and slender sporodochial conidia, and no chlamydospores. The long chains of septate conidia are known only in this species of the genusFusarium. The conidiophores on the aerial mycelium sometimes proliferate sympodially. The species is tentatively placed in the form-sectionLiseola.
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    URL: http://dx.doi.org/10.1007/BF02464091
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    Predation by juvenile roach on the calanoid copepod Eudiaptomus gracilis and the cyclopoid copepod Cyclops vicinus: a laboratory investigation with mixed and single prey (1998)
    Springer
    Aquatic ecology 32 (1998), S. 335-340 
    Details
    ISSN: 1573-5125
    Keywords: calanoid copepod ; cyclopoid copepod ; fish ; predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We tested the outcome of predation by juvenile roach on the calanoid copepod Eudiaptomus gracilis and the similar sized cyclopoid copepod Cyclops vicinus in laboratory experiments with mixed and single-prey. When ovigerous females and adult non-ovigerous females of the calanoid copepod and the cyclopoid copepod were offered in equal numbers to the fish in the mixed-prey experiments, the cyclopoid copepods were significantly more heavily preyed upon than the calanoids. Between 14 and 16 females of the cyclopoid copepod and only between 2 and 4 calanoids had been consumed after the observation period of two hours. The single-prey experiments revealed that the conspicuousness of the calanoid vs the cyclopoid depended on sex and gravidity. Ovigerous females of the cyclopoid copepod were slightly earlier detected by the fish than ovigerous females of the calanoid, probably a result of the highly visible egg-sacs carried by the cyclopoid females. Females without eggs and males of the cyclopoid copepod were recognized later by the predator than females without eggs or males of the calanoid, probably a result of the different behaviours of the different copepod taxa. Cyclopoids frequently congregated near the aquarium bottom while calanoids were closer to the water surface where they were better visible. The calanoid copepod could better escape the fish's attacks than the cyclopoid copepod. Egg-bearing females of both the calanoid and the cyclopoid copepod could significantly better escape than non-ovigerous females or males. Probably ovigerous females react very early to water disturbances caused by the predator. Activity measurements showed that the cyclopoid copepod displayed 2 to 4 times more hops per time unit than the calanoid. Probably the high number of jerky movements displayed by the cyclopoid attracted attention of the predator and contributed to its greater vulnerability.
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    Negative Impact on the Aquatic Ecosystems of the State of Morelos, Mexico from Introduced Aquarium and Other Commercial Fish (1998)
    Springer
    Aquarium sciences and conservation 2 (1998), S. 67-78 
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    ISSN: 1573-1448
    Keywords: fish ; introductions ; management ; México ; native species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Of the 22 fish species presently inhabiting the waters of the state of Morelos, México, more than half (64%) have been introduced, mainly for fisheries and ornamental aquaculture purposes. Even though there are other significant problems such as pollution, eutrophication and drought, we found that fish introductions have caused the worst ecological impacts. These problems stem from a general lack of knowledge regarding the characteristics, importance and appropriate use and management of aquatic resources. Conservational actions are proposed.
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    Food-web manipulation in a small, eutrophic Lake Wirbel, Poland: the effect of replacement of key predators on epiphytic fauna (1997)
    Springer
    Hydrobiologia 342-343 (1997), S. 377-381 
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    ISSN: 1573-5117
    Keywords: key-predator replacement ; fish ; invertebrate carnivores ; epiphytic fauna ; Chironomidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of fish removal on the invertebrate fauna associatedwith Stratiotes aloides was studied in a shallow, eutrophiclake. The biomass of invertebrate predators was approximately 2.5times higher in the invertebrate-dominated year (1992) than in thefish-dominated year (1991), while the density of non-predatoryinvertebrates in 1991 was ca half that in theinvertebrate-dominated year. The decrease was due to a sharp fallin the density of epiphytic chironomids, with the density ofplant-mining chironomids being far less affected. Marked declinesin the density of non-predatory invertebrates in theinvertebrate-dominated year were most probably caused byinvertebrate predators. Once freed from suppression induced byfish, invertebrate predators were able to control the density ofepiphytic prey more effectively than fish.
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    Ecomorphological diet predictions: an assessment using inland silverside (Menidia beryllina) and longear sunfish (Lepomis megalotis) from Lake Texoma (1997)
    Springer
    Hydrobiologia 350 (1997), S. 87-98 
    Details
    ISSN: 1573-5117
    Keywords: ecomorphology ; trophic ecology ; physiology ; diet ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The functions of an organism‘s morphological structures indicatethe organism‘s potential resource use (fundamental niche). Whilethis information often is also used to predict differences inactual resource use (realized niche) among individuals or species,such predictions may not be accurate because the maximum abilitiesmay not be useful to the organism under specific conditions or inspecific environments. We investigated the importance of sixpreviously studied morphologically based performanceabilities/constraints in structuring the diet of Menidiaberyllina (inland silverside) and Lepomis megalotis (longearsunfish) in Lake Texoma, a reservoir in the Red River basin(Oklahoma-Texas, USA). Of the six morphological characteristicsmeasured (number of gill rakers, length of gill rakers, spacebetween gill rakers, eye lens diameter, mouth size, mouthprotrusibility), only one characteristic for M. beryllina(mouth size) and three for L. megalotis (space betweenrakers, mouth size, and raker length) correlated with the gutcontents as predicted by previous functional morphology studies.This indicates that caution should be exercised when makinguntested predictions about the ecology of an organism based on itsfunctional morphology.
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    URL: http://dx.doi.org/10.1023/A:1003075529973
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    Effects of zebra mussels on food webs: interactions with juvenile bluegill and water residence time (1997)
    Springer
    Hydrobiologia 354 (1997), S. 141-150 
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    ISSN: 1573-5117
    Keywords: Dreissena ; mesocosm ; seston ; fish ; food web ; manipulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We evaluated how water residence time mediated the impact of zebramussels Dreissena polymorpha and bluegill sunfish Lepomis macrochirus on experimental food webs established in1100-l outdoor mesocosms. Water residence time was manipulated asa surrogate for seston resupply – a critical variable affectinggrowth and survival of suspension-feeding invertebrates. We used a2×2×2 factorial experimental design witheight treatment combinations (3 replicates/treatment) including thepresence or absence of Dreissena (2000 per m2), juvenilebluegill (40 per mesocosm), and short (1100 l per d) or long (220 lper d) water residence time. Measures of seston concentration(chlorophyll a, turbidity and suspended solids) were greaterin the short- compared to long water-residence mesocosms, butintermediate in short water-residence mesocosms containing Dreissena. Abundance of rotifers (Keratella and Polyarthra) was reduced in Dreissena mesocosms and elevatedin short residence time mesocosms. Cladocera abundance, in general,was unaffected by the presence of Dreissena; densities werehigher in short-residence time mesocosms, and reduced in thepresence of Lepomis. The growth of juvenile Lepomiswere unaffected by Dreissena because of abundant benthicfood. The final total mass of Dreissena was significantlygreater in short- than long-residence mesocosms. Impacts of Dreissena on planktonic food webs may not only depend on thedensity of zebra mussels but also on the residence time of thesurrounding water and the resupply of seston.
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    Genetic variability in the European minnow, Phoxinus phoxinus (L.) (1997)
    Springer
    Hydrobiologia 364 (1997), S. 183-188 
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    ISSN: 1573-5117
    Keywords: fish ; genetic variability ; protein polymorphism ; heterosis ; heterozygosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An electrophoretic study of genetic variation at 11 loci was performedfor a population of European minnows, Phoxinus phoxinus (L.). Ten loci, EST-1 *, EST-2 * EST-3 *,GPD-1 *,GPD-2 *,GPI-1 *,GPI-2 *,MPI *,6PGD * and PGM * were polymorphic. IDH *wasmonomorphic. The mean number of heterozygotic loci over all 176 fish was 3.05 ± 0.104(SE). Observed mean heterozygosity was 0.28±0.058(SE) and expected mean heterozygosity was 0.27±0.054(SE). EST-2 *, EST-3 * andPGM * were not in Hardy-Weinberg equilibrium. Length,condition, parasite numbers or male breeding characters, i.e. red colorationand tubercles, were not influenced by single enzyme loci.
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    URL: http://dx.doi.org/10.1023/A:1003151121442
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    Influence of fish on the breeding of the red-necked grebe Podiceps grisegena (Boddaert, 1783) (1997)
    Springer
    Hydrobiologia 344 (1997), S. 57-63 
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    ISSN: 1573-5117
    Keywords: red-necked grebe ; breeding sites ; fish ; macroinvertebrates ; food competition ; physical and chemicalconditions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract I determined whether selection of breeding sites by thered-neckedgrebe Podiceps grisegena (Boddaert, 1783) was affectedbycompetition for food with fish. During 1987–89, ten ponds inScania, southern Sweden were investigated, five with(‘breedingsites’) and five without breeding red-necked grebe(‘non-breedingsites’). I quantified the biomass of fish and macrozoans(here:larger invertebrates and small vertebrates) and measured thephysical and chemical conditions of the ponds.Breeding sites had significantly lower relative fish abundancethannon-breeding sites. They were either devoid of fish or hadonly nine-spined sticklebackPungitius pungitius. The biomass (dry weight) ofmacrozoans,many of which represent a food resource for grebes, was 16timesgreater at breeding than at non-breeding sites. The physicalandchemical conditions of the ponds did not differsignificantly.These results are consistent with the hypothesis thatcompetitionfor macrozoans occurs between red-necked grebe and fish andthat adense population of many fish species caused red-necked grebestoavoid otherwise acceptable breeding sites.
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    Tolerance levels of redbreast tilapia, Tilapia rendalli (Boulenger, 1896) to natural suspended silt (1997)
    Springer
    Hydrobiologia 344 (1997), S. 11-18 
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    ISSN: 1573-5117
    Keywords: fish ; silt ; exposure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tilapia rendalli was exposed to various siltconcentrationsfor different exposure periods to determine LC50 andsublethalconcentration ranges. The extent of damaging effects, if any,ofsuspended silt on the exposed fish, were investigated by meansofscanning electron microscopy. The LC50 values rangedbetween21 to 24 g l™1 and 42–48 g l™1 for juveniles andadultsrespectively. The silt concentrations tolerated by the testfisheswere above those found in most natural waters. The resultstherefore support the hypothesis that suspended silt is lethaltofish at concentrations higher than those naturally observed insurface water. The observed mortalities can be attributed tothecombined physical effects of high silt concentrations andassociated reduction in dissolved oxygen levels. To preventfishmortalities and other impacts on biota, anthropogenicactivitiesthat affect the natural variation in suspended siltconcentrationsin surface water should be carefully monitored and, wherepossible,be restricted.
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    URL: http://dx.doi.org/10.1023/A:1002985707694
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    Polynuclear Aromatic Hydrocarbons (PAHs) in fish from the Red Sea Coast of Yemen (1997)
    Springer
    Hydrobiologia 352 (1997), S. 251-262 
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    ISSN: 1573-5117
    Keywords: Red Sea ; PAHs ; oil pollution ; HPLC ; GC/MS ; fish ; origin ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A detailed analytical study using combined normal phase high pressure liquid chromatography (HPLC), gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) of Polynuclear Aromatic Hydrocarbons (PAHs) in fish from the Red Sea was undertaken. This investigation involves a preliminary assessment of the sixteen parent compounds issued by the U.S. Environmental Protection Agency(EPA). The study revealed measurable levels of Σ PAHs (the sum of three to five or six ring parent compounds) (49.2 ng g−1 dry weight) and total PAHs (all PAH detected) (422.1 ng g−1 dry weight) in edible muscle of fishes collected from the Red Sea. These concentrations are within the range of values reported for other comparable regions of the world. Mean concentrations for individual parent PAH in fish muscles were; naphthalene 19.5, biphenyl 4.6, acenaphthylene 1.0, acenaphthene 1.2, fluorene 5.5, phenanthrene 14.0, anthracene 0.8, fluoranthene 1.5, pyrene 1.8, benz(a)anthracene 0.4, chrysene 1.9, benzo(b)fluoranthene 0.5, benzo(k)fluoranthene 0.5, benzo(e)pyrene 0.9, benzo(a)pyrene 0.5, perylene 0.2, and indeno(1,2,3-cd)pyrene 0.1 ng g−1 dry weight respectively. The Red Sea fish extracts exhibit the low molecular weight aromatics as well as the discernible alkyl-substituted species of naphthalene, fluorene, phenanthrene and dibenzothiophene. Thus, it was suggested that the most probable source of PAHs is oil contamination originating from spillages and/or heavy ship traffic. It was concluded that the presence of PAHs in the fish muscles is not responsible for the reported fish kill phenomenon. However, the high concentrations of carcinogenic chrysene encountered in these fishes should be considered seriously as it is hazardous to human health. Based on fish consumption by Yemeni‘s population it was calculated that the daily intake of total carcinogens were 0.15 µg/person/day.
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    Top-down control in freshwater lakes: the role of nutrient state, submerged macrophytes and water depth (1997)
    Springer
    Hydrobiologia 342-343 (1997), S. 151-164 
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    ISSN: 1573-5117
    Keywords: top-down control ; shallow lakes ; trophic structure ; trophic cascade ; macrophytes ; zooplankton ; fish ; biomanipulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Based on data from 233 Danish lakes, enclosure experiments, full-scaleexperiments and published empirical models we present evidence that top-downcontrol is more important in shallow lakes than in deep lakes, excepting lakeswith a high abundance of submerged macrophytes. The evidence in support is: (1)That at a given epilimnion total phosphorus concentration (TP) the biomass offish per m2 is independent of depth, which means that biomassper m3is markedly higher in shallow lakes. (2) That the biomass of benthic invertebratesis higher in shallow lakes, which means that the benthi-planktivorous fish areless dependent on zooplankton prey than in deep lakes. By their ability to shiftto zooplankton predation their density can remain high even in periods whenzooplankton is scarce and they can thereby maintain a potentially high predationpressure on zooplankton. (3) That the possibilities of cladocerans to escapepredation by vertical migration are less. (4) That the zooplankton:phytoplanktonmass ratio per m2 is lower and presumably then also thegrazing pressure onphytoplankton. (5) That nutrient constraints appear to be weaker, as evidenced bythe fact that at a given annual mean TP, summer TP is considerably higher inshallow lakes, especially in eutrophic lakes lacking submerged macrophytes. (6)That negative feedback on cladocerans by cyanobacteria is lower as cyanobacterialdominance is less frequent in shallow lakes and more easily broken (at least inNorthern temperate lakes), and (7) That top-down control by benthi-planktivorousfish is markedly reduced in lakes rich in submerged macrophytes because theplants serve as a refuge for pelagic cladocerans and encouragepredatory fish at the expense of prey fish. We conclude that manipulation of fishand submerged macrophytes may have substantial impact on lake ecosystems, inparticular in shallow eutrophic lakes. On the contrary, if the conditions formore permanent changes in plant abundance or fish community structure are lackingthe feed-back mechanisms that endeavour a return to the original turbid state willbe particularly strong in shallow lakes.
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    Lake Volkerak-Zoom: a lake shifting from the clear to the turbid state (1997)
    Springer
    Hydrobiologia 342-343 (1997), S. 367-376 
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    ISSN: 1573-5117
    Keywords: phytoplankton ; zooplankton ; eutrophication ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Volkerak-Zoom (area 6000 ha, mean depth 5 m) was createdin1987 by isolating a part of the Eastern Scheldt estuary. A fewyears after enclosure the new freshwater lake was cleardespite ahigh phosphorus loading. However from 1990 on the transparencydropped.This paper describes the transition from the clear to theturbidstate of lake Volkerak-Zoom. The processes responsible for theultimate lowering of the transparency in the period 1988–1994willbe discussed and also the measures necessary to meet thetargetsituation: clear water with a transparency of 2 m. From 1990ontransparency is decreasing due to an increasing algal biomass,probably caused by a reduced grazing of the zooplankton. It ispossible that deterioration of the food quality (by increasedcyanobacterial blooms) reduced the zooplankton grazing.However,there are indications that increased mortality, caused by fishpredation, played the most important role in the reduction ofthezooplankton grazing. In 1992 the recruitment of fish,especially ofroach (Rutilus rutilus), was high (c. 40 kg ha−1).Thiscaused a high predation pressure on the zooplankton and isshown bya decrease of the mean length and vertical migration of Daphnia in 1992. In the same year the largest zooplanktonspecies,Daphnia pulex, disappeared from the lake. Smallerzooplanktonspecies with a lower grazing capacity remained. Because of thedecreased grazing, the algal biomass increased and thetransparencydropped. We expect that inthe future the lake will become more turbid. As an additionalmeasure to P-reduction, removing of fish is suggested to meetthetarget situation: a lasting clear water state.
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    Developmentally regulated organ-, tissue-, and cell-specific expression of calmodulin genes in common wheat (1998)
    Springer
    Plant molecular biology 37 (1998), S. 109-120 
    Details
    ISSN: 1573-5028
    Keywords: calcium ; in situ hybridization ; multigene family ; polyploid ; signal transduction ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recently, we reported on the characterization of the calmodulin (CaM) gene family in wheat [44]. We classified wheat CaM genes into four subfamilies (SFs) designated SF-1 to SF-4, each representing a series of homoeoallelic loci on the homoeologous chromosomes of the three genomes of common wheat. Here we studied the expression of these wheat CaM genes in the course of wheat development. Northern blot analysis using SF-specific probes revealed differences in SF expression levels in different organs and stages of development. Subsequently, cell-specific expression of CaM SFs was investigated by in situ RNA hybridization. In developing seeds, all CaM SFs showed highest expression in the embryo and less in the aleurone and in the starchy endosperm. In primary roots, all four CaM SFs were expressed in the root cap, meristematic regions and in differentiating cells. During development of the roots, expression gradually decreased. The wheat glutenin gene, which was used as a control throughout our experiments, was found to be expressed in the starchy endosperm but not in the aleurone, embryos or vegetative tissues. In stems, at advanced stages of growth, differences in cell-specific expression of CaM SFs were found. For example, SF-2 was highly expressed in differentiating phloem fibers. Thus, CaM genes in common wheat exhibit a developmentally regulated organ-, tissue-, cell- and SF-specific expression patterns.
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    Changes in the abundance and diversity of coastal wetland fauna from the open water/macrophyte edge towards shore (1998)
    Springer
    Wetlands ecology and management 6 (1998), S. 59-68 
    Details
    ISSN: 1572-9834
    Keywords: marsh ; community structure ; physical and chemical ; fish ; zooplankton ; microcrustacea ; benthic ; Laurentian Great Lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Great Lakes coastal wetlands are widely recognized as areas of concentrated biodiversity and productivity, but the factors that influence diversity and productivity within these systems are largely unknown. Several recent studies have suggested that the abundance and diversity of flora and fauna in coastal wetlands may be related to distance from the open water/macrophyte edge. We examined this possibility for three faunal groups inhabiting a coastal wetland in Saginaw Bay, Lake Huron. We sampled crustacean zooplankton and benthic macro-invertebrates at five distances from open water in the summer 1994, and fish at three distances from open water in 1994 and 1995. We found significant spatial trends in the total abundance and diversity of zooplankton and fish, as well as the diversity of benthic macro-invertebrates. Zooplankton abundance and taxa richness were highest at intermediate distances from open water in a transition zone between the well-mixed bayward portion of the wetland, and the non-circulating nearshore area. Benthic macro-invertebrate taxa richness increased linearly with distance from open water. In contrast, fish abundance and species richness declined linearly and substantially (abundance by 78%, species richness by 40%) with distance from open water. Of the 40 taxa examined in this study, 21 had significant horizontal trends in abundance. This led to notable differences in community composition throughout the wetland. Our results suggest that distance from open water may be a primary determinant of the spatial distributions of numerous organismal groups inhabiting this coastal wetland. Several possible reasons for these distributions are discussed.
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    Swamp-riverine tropical fish population: a comparative study of two spatially isolated freshwater ecosystems in Peninsular Malaysia (1998)
    Springer
    Wetlands ecology and management 6 (1998), S. 261-268 
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    ISSN: 1572-9834
    Keywords: Malaysia ; swamps ; freshwater ; fish ; riverine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-four fish species were collected during a study from October 1996 of the swamp-riverine fish populations of two spatially isolated Malaysian freshwater swamp ecosystems. Twenty one species were collected from the Beriah Kanan River, which is located in northern Peninsular Malaysia, compared to only 10 species obtained from the Ulu Sedili River in the south. At both sites, the species Rasbora einthovenii and Hemirhamphodon pogognathu appeared to be the most dominant species, whereas Rasbora pauciperforata and Nemacheilus selangoricus were very rarely caught and Beriah Kanan and Ulu Sedili River, respectively. An analysis of the physico-chemical data showed that although pH, conductivity and ammonium levels were fairly similar at both sites, orthophosphate, hardness and total suspended solids were relatively higher for Ulu Sedili River.
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    The induction of the “turbo reductase” is inhibited by cycloheximide, cordycepin and ethylene inhibitors in Fe-deficient cucumber (Cucumis sativus L.) plants (1998)
    Springer
    Protoplasma 205 (1998), S. 156-162 
    Details
    ISSN: 1615-6102
    Keywords: Cucumis sativus ; Ethylene ; Ferric-reducing capacity ; Iron deficiency ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Dicotyledonous plants respond to Fe deficiency by enhancing the capacity of their roots to reduce Fe(III) to Fe(II). It has been suggested that there are two different ferric redox systems in the roots: the standard reductase, active with ferricyanide and not inducible by Fe deficiency, and the turbo reductase, active with both ferricyanide and ferric chelates and inducible by Fe deficiency. We have used different experimental approaches to test whether or not the Fe(III)-reducing capacity of cucumber (Cucumis sativus L. cv. Ashley) roots can be explained by considering the standard and the turbo reductase as the same enzyme. For this, we used both Fe-sufficient and Fe-deficient plants, which were treated with ethylene inhibitors (cobalt or silver thiosulfate; found to inhibit the turbo reductase in a previous work), a protein synthesis inhibitor (cycloheximide), or an mRNA polyadenylation inhibitor (cordycepin). At different times after application of these inhibitors, reduction of both ferricyanide and Fe(III)-EDTA were determined. In addition, we studied the effects of pH and temperature on the reduction of ferricyanide and Fe(III)-EDTA by both Fe-sufficient and Fe-deficient plants. Results suggest that there are, at least, two different ferric redox systems in the roots. Enhancement of Fe(III)-reducing capacity (turbo reductase) by Fe-deficient plants probably requires the de novo synthesis of a (or several) protein(s), which has a high turnover rate and whose expression is presumably regulated by ethylene.
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    Cytoplasmic effects on quality traits of bread wheat (Triticum aestivum L.) (1998)
    Springer
    Euphytica 100 (1998), S. 189-196 
    Details
    ISSN: 1573-5060
    Keywords: cytoplasmic effects ; inheritance ; quality ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The inheritances of thousand kernel weight (TKW), protein percentage, protein quality and grain hardness were studied through an 11 x 11 complete diallel set of bread wheat genotypes consisting of four alloplasmic lines of Selkirk, two alloplasmic lines of Siete Cerros 66, and five commercial cultivars. Genetic components accounted for 93%, 90%, 78%, and 92% of total variation for TKW, protein percentage, protein quality, and grain hardness, respectively. General combining ability (GCA) effects were dominant for TKW (48% GCA, 38% SCA [specific combining ability], and 7% reciprocal effects [RE]), protein percentage (70% GCA, 10% SCA, and 10% RE), and grain hardness (59% GCA, 29% SCA, and 4% RE). However, SCA effects dominated for protein quality (30% GCA, 43% SCA, and 5% RE). Broad- and narrow-sense heritabilities were estimated at 0.95 and 0.65 for TKW, 0.94 and 0.82 for protein percentage, 0.83 and 0.47 for protein quality, and 0.95 and 0.74 for grain hardness. Reciprocal effects were highly significant for all quality traits, but less effective than additive and non-additive gene effects. Aegilops cylindrica, Ae. ventricosa, and Triticum turgidum cytoplasms showed positive effects on TKW in some crosses. Ae. cylindrica, Ae. variabilis, and Ae. uniaristata cytoplasms seemed to have potential for improving protein percentage. T. aestivum cytoplasms were superior to alien cytoplasms for protein quality. Bolal 2973, Kiraç 66 and Bezostaja 1 cytoplasms increased protein quality in some crosses. Ae. cylindrica, Ae. variabilis, Ae. ventricosa and Ae. uniaristata cytoplasms had significant effects on grain hardness. The cytoplasmic variation in B type T. aestivum cytoplasm was found to be significant for all traits.
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    Bread wheat: F1 hybrid performance and parental diversity estimates using molecular markers (1998)
    Springer
    Euphytica 100 (1998), S. 273-279 
    Details
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; combining ability ; heterosis ; genetic distance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In wheat, the possibility of introducing F1 seed into practical agriculture has been greatly enhanced by the discovery of effective chemical hybridising agents (CHAs). Although some technical and economic problems concerning the use of CHAs for large-scale production of F1 seed remain to be solved, a first group of F1 hybrids has been submitted for registration in several European countries i.e., France, England and Italy. Combining ability for grain yield and several agronomic and quality traits was studied in an eight-parent diallel cross. Highly significant combining ability effects were observed for all the traits while specific combining ability effects were statistically significant for grain yield, plant height, heading time and Chopin alveograph parameter P. The level of genetic diversity between parents as estimated using molecular markers is considered a tool for predicting the hybrid performance and heterosis of crosses. To explore this possibility, RFLP and RAPD markers were used to predict the performance of hybrids obtained from diallel and top crosses. The performance of the hybrids was determined in replicated plot trials sown at normal seed density in several locations. Coefficient of parentage (rp), based on pedigree information for all the pairwise combinations of the parents ranged from 0.01 to 0.34. The parents were assayed for random amplified polymorphic DNA (RAPD) with 87 primers which generated 304 polymorphic bands. Genetic similarity between parents, estimated on the basis of common bands using the Jaccard's similarity coefficient (J), ranged from 0.25 to 0.57. Correlation between parental diversity and hybrid performance was generally weak. A positive trend is observed in the yield potential of the hybrids produced in Italy in the last 10 years. In fact among the first set of hybrids produced by random crossing of the available cultivars, none produced 10% more than the checks whereas the last generation of hybrids includes combinations yielding 15% more than the best standards. Our results clearly indicate the need to develop specific strategies in order to identify and/or to select parental lines with a high level of general combining ability (GCA) and specific combining ability (SCA). The information regarding the genetic diversity of the parental lines do not appear helpful for predicting F1 performance.
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    The detection of allelic variants at the recessive vrn loci of winter wheat (1998)
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    Euphytica 101 (1998), S. 9-16 
    Details
    ISSN: 1573-5060
    Keywords: heading time ; Triticum aestivum ; vernalisation response ; Vrn – genotypes ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Substitution lines with reciprocal substitutions of chromosomes containing recessive alleles of the homoeologous group 5 chromosomeVrn genes between varieties of winter wheat with high vernalisation requirement (‘Mironovskaya 808’) and low vernalisation requirements (‘Bezostaya 1’) have been created. On this basis the genetic determination of vernalisation requirement was established. Substitution lines Mironovskaya 808 (Bezostaya 1 5A), Mironovskaya 808 (Bezostaya 1 5B), Mironovskaya 808 (Bezostaya 1 5D) and reciprocal substitution lines Bezostaya 1 (Mironovskaya 808 5A), Bezostaya 1 (Mironovskaya 808 5B) and Bezostaya 1 (Mironovskaya 808 5D) were grown under different durations of vernalisation (3, 4, 5, 6, 7 and 8 weeks) and their response was evaluated. Photoperiodic sensitivity of the original parental genotypes was also determined. Reciprocal substitution lines of the same chromosome that carries the same vrn allele responded differently to vernalisation deficit. Differences have been shown between all group 5 reciprocal substitutions. Lines carrying chromosomes 5A and 5D of Mironovskaya 808 had a high vernalisation requirement whereas lines carrying chromosome 5B of Bezostaya 1 (vrn2B) had a low vernalisation requirement. The reciprocal lines had a reverse requirement. This explains the different vernalisation requirements of the original varieties: Mironovskaya 808 with a high vernalisation requirement carries two alleles (vrn1M and vrn3M) in its genotype that increase the vernalisation requirement, whereas Bezostaya 1 with a lower requirement for vernalisation contains only one such allele (vrn2B). By combination of the alleles in the lines with the substitution of chromosome 5B carrying vrn2 allele that in both original genotypes work inversely to the other alleles, transgressive genotypes have been formed: genotype vrn1M vrn2B vrn3M determines a higher vernalisation requirement than original variety Mironovskaya 808, and genotype vrn1B vrn2M vrn3B determines a lower vernalisation requirement than the original Bezostaya 1. An incomplete vernalisation requirement prolonged the time to heading, with exponential dependence on the vernalisation deficit, or prevented heading altogether. The original varieties further differed in photoperiodic sensitivity (Mironovskaya 808 sensitive, Bezostaya 1 less sensitive) that also influenced the background of substitution lines. The impact of the background on the heading time showed itself by about one week difference between Mironovskaya 808 and Bezostaya 1 grown under 8 weeks vernalisation and normal photoperiod. The difference between the lines with Mironovskaya 808 background and the lines with Bezostaya 1 background was approximately the same and was not significantly changed in different vernalisation variants of the lines. This difference may be caused by different photoperiodic sensitivity of the original varieties, but also by other genes, such as genes of earliness per se.
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    Studies on somaclonal variants for resistance to scab in bread wheat (Triticum aestivum L.) through in vitro selection for tolerance to deoxynivalenol (1998)
    Springer
    Euphytica 101 (1998), S. 213-219 
    Details
    ISSN: 1573-5060
    Keywords: bread wheat ; Triticum aestivum ; tolerance to deoxynivalenol ; somaclonal variant ; in vitro selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study was conducted to develop an efficient in vitro selection system for scab resistance by using in vitro screening for tolerance to deoxynivalenol (DON). Immature embryos of two wheat varieties, a scab-resistant variety Sumai 3 and a susceptible variety Mianyang 11, and their reciprocal F1 hybrids were cultured on MS medium supplemented with 2,4-D 2 mg/l and 0.6 × 10-4 M DON for callus induction. The responses of callus induction and plant regeneration to 0.6 × 10-4 M DON differed significantly between resistant and susceptible varieties, according to observed scab resistance levels at the plant level in the field. The percentage of callus formation of resistant variety Sumai 3 on induction medium containing DON was higher than that of susceptible variety Mianyang 11. Regeneration of DON-tolerant calli on DON-containing differentiation medium differed significantly between Sumai 3 and Mianyang 11. Averaged across the DON-tolerant calli of two varieties and their reciprocals, regeneration of DON-tolerant calli was decreased 3-fold on DON-containing medium. By an inoculation test with conidiospores of Fusarium graminearum Schw, we obtained several resistant lines from progenies of regenerated plants from DON-tolerant calli. These somaclonal lines had lower disease scoring (reaction index, infected spikelets and disease incidence), shorter plants and better yield components than Sumai 3, a famous Chinese resistant variety.
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    Agronomic performance of chromosomes 1B and T1BL.1RS near-isolines in the spring bread wheat Seri M82 (1998)
    Springer
    Euphytica 103 (1998), S. 195-202 
    Details
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; Secale cereale ; T1BL.1RS ; chromosome substitution and translocation ; yield components
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The T1BL.1RS wheat (Triticum aestivum L.) - rye (Secale cereale L.) translocations have been of particular interest and are widely used in bread wheat breeding programs. The objective of this study was to determine the effect of the T1BL.1RS chromosome on grain yield and its components using 20 near-isolines of spring bread wheat cultivar ‘Seri M82’ (10 homozygous for chromosome 1B substitution and 10 homozygous for T1BL.1RS). The test lines have been produced by substituting the 1B chromosome in Seri M82 (T1BL.1RS, T1BL.1RS) through backrossing. Two field experiments were evaluated under optimum (five irrigations) and reduced (one irrigation) moisture conditions for two consecutive production cycles at the Mexican National Agricultural Research Institute, Ciudad Obregon, Sonora, Mexico. The presence of T1BL.1RS had a significant effect on grain yield, harvest index, grains/m2, grains/spike, 1000-grain weight, test weight, flowering date and physiological maturity in both moisture conditions. The agronomic advantage of the 1B substitution lines on above-ground biomass yield at maturity, spikes/m2and grain-filling duration was expressed only under the optimum moisture condition. The presence of T1BL.1RS increased grain yield 1.6% and 11.3% for optimum and reduced moisture conditions, respectively. These results encourage further use of T1BL.1RS wheats in improving agronomic traits, especially for reduced irrigation or rainfed environments.
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    Inheritance of excised-leaf water loss and relative water content in bread wheat (Triticum aestivum) (1998)
    Springer
    Euphytica 104 (1998), S. 39-47 
    Details
    ISSN: 1573-5060
    Keywords: drought resistance ; diallel graph ; gene action ; excised-leaf water loss ; relative water content ; bread wheat ; osmotic adjustment ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Little information is available on the genetics of excised leaf water loss and relative water content in wheat. An experiment conducted on the F1 generation from a half-diallel set of crosses involving two drought tolerant, two moderately tolerant and two sensitive varieties was initiated to investigate the inheritance of excised-leaf water loss and relative water content. This experiment was conducted under glass-house and field conditions at tillering and anthesis stages of plant development. Additive gene action, in general, played a major role in determining the inheritance of these traits. General combining ability (GCA) was the main source of genetic variation among crosses, while specific combining ability (SCA) was negligible. Strong phenotypic correlations existed between per se performance and GCA effects in the majority of cases. Heterosis was unimportant. Genotype-environmental interactions and/or differential gene expression appeared to account for different results found between environments and growth stages, respectively. Selection for relative water content appeared to be more effective at anthesis, while for excised-leaf water loss at both stages of plant growth. In addition to drought resistance, wide differences for morphological characters and relative positions of parental arrays revealed the possibility of obtaining desirable segregants for drought stress conditions from the cross Kharchia 65 × WH 147.
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    Heterosis and combining ability for plant height and its components in hybrid wheat with Triticum timopheevi cytoplasm (1997)
    Springer
    Euphytica 95 (1997), S. 337-345 
    Details
    ISSN: 1573-5060
    Keywords: hybrid wheat ; Triticum aestivum ; plant height ; internode length ; heterosis ; combining ability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The heterosis and combining ability for plant height and its components of hybrid wheat were investigated in an incomplete diallel experiment including 5 CMS lines and 4 restorer lines. The results showed that heterosis (HS) and heterobeltiosis (HBS) occurred in plant height (PH) and length of the first internode (LFI), second internode (LSI), third internode (LTI), basal internode (LBI) and the spike (LS) of hybrids, but their values varied among crosses and characters; the HS and HBS of LBI were larger than those of other characters, the HS and HBS of LSI and LTI contributed a lot to those of PH. There were significant relationships between internode lengths and PH for specific combining ability (SCA) and general combining ability (GCA), and among lengths of the adjacent internodes for SCA and/or GCA effects. However, the relationships of LS with the lengths of internodes and PH were insignificant for GCA, SCA, HS and HBS. The SCA effects were more important than GCA effects for LFI, the reverse was true for LSI, LTI, LS and PH, and the SCA effects was nearly equal to the GCA effects for LBI. So, LFI was mainly influenced by non-additive effect of genes, while LSI, LTI, LS and PH were mainly controlled by additive gene effects, LBI was controlled equally by additive and non-additive effects of genes. The genes that control the length of specific internode not only affect PH, but also the length of the adjacent internode. The genetic system in charge of lengths of internodes and plant height is independent of that for length of spike. Thus, it is possible to develop new wheat cultivars or hybrid combinations having long spike but dwarf plant height.
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    URL: http://dx.doi.org/10.1023/A:1003092432309
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    Components of quantitative resistance to yellow rust in ten spring bread wheat cultivars and their relations with field assessments (1997)
    Springer
    Euphytica 96 (1997), S. 215-223 
    Details
    ISSN: 1573-5060
    Keywords: Puccinia striiformis ; Triticum aestivum ; association of components ; stripe rust ; durable resistance ; infection frequency ; latency period ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Latency period, infection frequency, lesion length, lesion growth, disease severity and percentage of infected leaf parts were assessed on 10-day-old seedling leaves and flag leaves of ten bread wheat (Triticum aestivum L.) cultivars after inoculation with urediospores of Puccinia striiformis Westend. f. sp. tritici. For all components significant genotypic differences were detected. Components of resistance tended to be associated. A long latency period was associated with a low infection frequency, small lesions, a low disease severity and a low percentage of infected leaf parts. The latency period, measured as time period until first pustule appearance (LP1), was highly correlated with the latency period measured as time period until 50% of the pustules appeared (LP50). Assessment of latency period of large numbers of cultivars could therefore be reliably done by measuring LP1 which is less time consuming than measuring LP50. Latency period, infection frequency and disease severity were highly correlated with disease development data from field experiments. These results suggest that selection in the greenhouse for one of these components should result in cultivars with high levels of quantitative resistance. Disease severity after uniform inoculation in the greenhouse can be used for monocyclic evaluations because it is the easiest to assess.
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    URL: http://dx.doi.org/10.1023/A:1002916110347
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    Effects of barley chromosome on heading characters in wheat-barley chromosome addition lines (1997)
    Springer
    Euphytica 96 (1997), S. 281-287 
    Details
    ISSN: 1573-5060
    Keywords: heading character ; Hordeum vulgare ; Triticum aestivum ; wheat-barley chromosome addition line
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Heading time in cereals is a composite character determined by vernalization requirement, photoperiodic sensitivity and narrow-sense earliness. To study the effects of added barley chromosomes on the heading characters in wheat, two sets of wheat-barley chromosome addition lines, i.e., ‘Betzes’ barley chromosomes 2H to 7H added to ’Chinese Spring‘ wheat (CS-Be2H to CS-Be7H) and ‘New Golden’ barley chromosomes 5H and 6H added to ‘Shinchunaga’ wheat (Shi-NG5H, Shi-NG6H), were examined for their heading characters. All barley chromosomes except Be6H affected vernalization requirement and/or narrow-sense earliness in CS or Shi. Be5H chromosome also slightly increased the photoperiodic sensitivity of CS. Shi-NG5H addition line showed significantly decreased vernalization requirement in comparison with Shi, whereas CS-Be5H did not show any difference from CS. The F1 hybrid of the cross, Shi-NG5H × CS-Be5H, exhibited the same level of vernalization insensitivity as the Shi-NG5H addition line, and plants with and without a vernalization requirement segregated in a 1 : 3 ratio in the F2 generation. These observations, together with previous reports, suggest that the decreased vernalization requirement in the Shi-NG5H addition line was caused by the presence of a major dominant gene for spring habit, Sh2, located on the NG5H barley chromosome. Furthermore, this study revealed that the Sh2 gene in barley has a similar but weaker effect than the wheat vernalization insensitive gene, Vrn1, on the vernalization response in wheat.
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    URL: http://dx.doi.org/10.1023/A:1003025501591
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    Response of wheat genotypes to sowing date and boron fertilization aimed at controlling sterility in a rice-wheat rotation in Nepal (1997)
    Springer
    Plant and soil 188 (1997), S. 249-256 
    Details
    ISSN: 1573-5036
    Keywords: boron ; rice-wheat rotation ; sterility ; time of sowing ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Spikelet sterility in wheat (Triticum aestivum L.) is emerging as a production threat in different parts of Nepal. This study was aimed at determining the effects of sowing date and boron application in controlling spikelet sterility in four different genotypes of spring wheat in a rice-wheat system in the western hills of Nepal. Four genotypes of known different responses to boron were planted on 21 November, 6 December and 21 December, 1994 with or without boron application at 1 kg B ha-1 (i.e. 9 kg borax ha-1) on a soil that was known to be deficient in boron. The effect of sowing date was significant for the phenology, yield components, percentage sterility and grain yield. Sterility was significantly increased in the crop planted on 21 December, which had also the lowest 1000 seed weight and grain yield; there was an almost 50% grain yield reduction compared to the crop planted on 21 November. Terminal moisture stress (i.e. lack of moisture during the later part of the development) was observed in the late sown crop which also amplified the extent of sterility associated with boron deficiency. Genotypes differed in response to sowing dates and boron treatment for all of the phenological events measured, yield components, grain yield and percentage sterility. SW-41 and BL-1022 had significantly higher sterility at all sowing dates. BL-1249 showed a consistently lower% sterility over all sowing dates and boron treatments. The addition of boron significantly increased the number of grains set per spike thereby decreasing the total sterility in boron responsive genotypes SW-41 and BL-1022 while those not susceptible did not respond. The boron concentration in the flag leaf at anthesis was increased in treatments with added B in the soil but genotypes did not differ in boron concentration for any soil treatment.
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    URL: http://dx.doi.org/10.1023/A:1004202725382
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    Phytochelatins as biomarkers for heavy metal stress in maize (Zea mays L.) and wheat (Triticum aestivum L.): combined effects of copper and cadmium (1998)
    Springer
    Plant and soil 203 (1998), S. 119-126 
    Details
    ISSN: 1573-5036
    Keywords: biomarker ; cadmium ; copper ; heavy metal ; PC ; PC-SH ; phytochelatin ; stress ; toxicity ; Triticum aestivum ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Heavy metal contaminated soils often show increased levels of more than one metal, e.g. copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb) or nickel (Ni). In case such soils are used for crop production, prediction of yield reduction or quality decline due to heavy metals in the soil is inadequate when based only on chemical soil analysis. The use of biomarkers such as phytochelatins (PC), non-protein thiols specifically induced in plants upon exposure to heavy metals, may be an additional tool or diagnostic criterion in heavy metal research and in practice. In the present work, Cu and Cd uptake and induction of PC synthesis are studied with hydroponically grown maize and wheat plants exposed to mixtures of the two metals. We observed a close positive relationship between the concentrations of Cd and PC in the plant shoot material. A decreased shoot concentration of Cd after addition of Cu, due to metal competition at common root absorption sites, coincided with lower shoot PC levels. Also differences in metal uptake and xylary metal transport among the two plant species were reflected in corresponding differences in PC concentration. The observed direct relationship between shoot PC concentration and the degree of metal-induced growth inhibition makes the use of PC promising for the purpose tested for.
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    URL: http://dx.doi.org/10.1023/A:1004373700581
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    The relationship between green spot initiation and plantlet regeneration of wheat callus grown under short-term conditions (1997)
    Springer
    Plant cell, tissue and organ culture 50 (1997), S. 67-69 
    Details
    ISSN: 1573-5044
    Keywords: immature embryos ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Six wheat genotypes (three varieties and three whole chromosome substitution lines) were used to analyse the relationship between the initiation of green spots and plant regeneration under short-term tissue culture conditions. The highest percentage of green spot initiation was observed after one week culture on maintenance medium (M-Med.). The calluses producing green spots at the end of the first and second week on M-Med. were highest in regeneration frequency compared to late green spot producing ones. A significant positive correlation between green spot initiation and plantlet regeneration was observed for calluses showing green spots within the first two weeks on M-Med. and was decreased for calluses producing green spots afterwards. The results suggest that by selecting only calluses producing early green spots the experimental efficiency will be increased.
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    URL: http://dx.doi.org/10.1023/A:1005855912655
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    Comparison of two crossing and four selection schemes for yield, yield traits, and slow rusting resistance to leaf rust in wheat (1998)
    Springer
    Euphytica 100 (1998), S. 35-43 
    Details
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; Puccinia recondita ; leaf rust ; breeding ; resistance ; yield ; yield components
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The most important breeding objectives in crop improvement are improving grain yield, grain quality, and resistances to various biotic and abiotic stresses. The objectives of our study were to compare two crossing and four selection schemes for grain yield, yield traits, and slow rusting resistance to leaf rust (Puccinia recondita) based on additive genes in wheat (Triticum aestivum), and to identify the most efficient crossing and selection methodologies in terms of genetic gains and cost efficiency. Segregating populations were derived from 18 simple crosses and the same number of top (three-way) crosses. Half of the crosses were derived from Yecora 70 and the other half from Veery #10 as the common leaf rust susceptible parents. The four selection schemes were: pedigree, modified bulk (F2 and F1-top as pedigree, selected lines in F3, F4, F2-top, F3-top as bulk; and pedigree in F5 and F4-top populations), selected bulk (selected plants in F2, F3, F4, F1-top, F2-top and F3-top as bulk; and pedigree in F5 and F4-top populations), and nonselected bulk (bulk in F2, F3, F4, F1-top, F2-top and F3-top; and pedigree in F5 and F4-top populations). A total of 320 progeny lines, parents and checks were tested for grain yield, other agronomic traits and leaf rust resistance during the 1992/93 and 1993/94 seasons in Ciudad Obregon (Sonora State, Mexico) which represents a typical high yielding irrigated site. The influence of the type of cross and the selection scheme on the mean grain yield and other traits of the progenies was minimal. The selection of parents was the most important feature in imparting yield potential and other favourable agronomic traits. Moreover, the highest yielding lines were distributed equally. Progeny lines derived from Veery #10 crosses had significantly higher mean grain yield compared to those derived from the Yecora 70 crosses. Furthermore, a large proportion of the highest yielding lines also originated from Veery #10 crosses. Mean leaf rust severity of the top cross progenies was lower than that of the simple cross progenies possibly because two parents contributed resistance to top cross progenies. Mean leaf rust severity of the nonselected bulk derivatives was twice that of lines derived from the other three schemes. Selected bulk appears to be the most attractive selection scheme in terms of genetic gains and cost efficiency.
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    Production of polyhaploids of hexaploid wheat using stored pearl millet pollen (1998)
    Springer
    Euphytica 100 (1998), S. 253-259 
    Details
    ISSN: 1573-5060
    Keywords: hexaploid wheat ; pearl millett ; Pennisetum glaucum ; polyhaploid ; pollen storage ; Triticum aestivum ; wide crosses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of drying and freezing on viability of pearl millet pollen were examined with the aim of using stored pollen in polyhaploid production of hexaploid wheat. Freshly collected pollen of pearl millet line NEC 7006 with 55% water content, germinated at a frequency of 80%. Pollen that was dried for two hours to 6% water content showed 50% germination frequency and maintained similar frequencies after the freezing process. In crosses of hexaploid wheat variety Norin 61 with fresh pearl millet pollen, embryos were obtained at a frequency of 27.6%. In crosses with pollen stored at -196 °C, -80 °C and -20 °C for one month, embryo formation frequencies ranged from 27.5 to 17.4%. After five and twelve months of storage, the frequencies ranged from 29.7 to 14.6% at storage temperatures of -196 °C and -80 °C, and from 8.0 to 3.2% at -20 °C, indicating significant differences among storage temperatures. However, no significant frequency difference was found among pollen water contents at the time of collection. All plants regenerated from crosses with pearl millet pollen stored for five months were wheat polyhaploids. These results suggest that stored pearl millet pollen is an efficient medium for producing polyhaploids in hexaploid wheat.
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    Analysis of genetic profiles of winter wheats from Russia (1998)
    Springer
    Euphytica 100 (1998), S. 305-311 
    Details
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; winter wheat ; genetic diversity ; ancestors ; genetic profile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract With the aid of GRIS, the wheat genetic resources database, the retrospective analysis of winter wheat breeding programs in the ex-USSR during its existence, and modern Russia, was conducted. The dynamics of genetic diversity of released cultivars was studied. A significant tendency to reduce the use of local materials was discovered, although a stable set of original ancestors has prevailed over the last 40 years. The modern cultivar genes pool has increased as a result of the utilisation of North American semidwarf varieties. Breeding programs at different breeding centres are distinguished by varying levels of genetic diversity. The need to discover new sources of disease resistance and environmental adaptation are problems that remain.
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    URL: http://dx.doi.org/10.1023/A:1018357718307
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    Isolation, identification and characterization of disomic and translocated barley chromosome addition lines of common wheat (1997)
    Springer
    Euphytica 96 (1997), S. 289-296 
    Details
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; Hordeum vulgare ; wheat ; barley ; chromosome addition lines ; translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two disomic barley chromosome addition lines and five translocated chromosome addition lines of common wheat cultivar Shinchunaga were isolated. They were derived from a hybrid plant between Shinchunaga and cultivated barley Nyugoruden (New Golden) by backcrossing with wheat and self pollination. Barley chromosomes added to chromosome arms involved in the translocated chromosomes were identified by C-banding method and by crossing these lines with Chinese Spring/Betzes addition lines. Two disomic addition lines were identified to have chromosome 6 and 7 of barley, respectively. Two of the five translocated chromosome addition lines were clarified to have same chromosome constitution, 42 wheat chromosomes and a pair of translocated chromosomes constituted with a long arm of chromosome 5B of wheat and a short arm of chromosome 7 of barley. The other three lines could not be identified due to chromosome rearrangement. Performances of these seven lines on agronomic characters were examined. Addition of barley chromosome 7 induced early heading, and chromosome 6 showed lated heading. Almost all of the lines except that of chromosome 6 showed short culm length and all showed reduced number of tillers, spikelets and grains per ear, and low seed fertility. These lines would be useful for genetic analyses in wheat and barley and for induction of useful genes of barley into wheat.
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    URL: http://dx.doi.org/10.1023/A:1003081619338
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    Structuring genotype × environment interaction for quality traits in bread wheat, in two multi-location series of trials (1997)
    Springer
    Euphytica 97 (1997), S. 53-66 
    Details
    ISSN: 1573-5060
    Keywords: clustering procedure ; genotype × environment interaction ; multi-trait analysis ; quality ; wheat ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Structure of genotype × environment interaction was studied in two series of trials for three quality traits in bread wheat. Two kinds of environments were present in each series of trials: macro-environments defined as locations or location × year combinations and micro-environments induced by diversified cultural practices within each site. For each trait, a simultaneous clustering procedure was used to identify groups of environments which were homogeneous for interaction. An optimised series of trials was proposed from the clusters obtained. The cultural practice based on nitrogen fertilisation seemed to better diversify environments for interaction than use of fungicide, when all quality traits were considered. Determining an optimised series of trials simultaneously for the three traits led to keeping more environments than when one trait was considered. Suggestions for establishing a series of trials for a multi-trait analysis were proposed.
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    URL: http://dx.doi.org/10.1023/A:1003048720423
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    Characterization of Triticum aestivum/Psathyrostachys juncea derivatives by genomic in situ hybridization (1998)
    Springer
    Euphytica 99 (1998), S. 85-88 
    Details
    ISSN: 1573-5060
    Keywords: in situ hybridization ; Psathyrostachys juncea ; chromosome translocation ; translocation addition ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Using the genomic in situ hybridization (GISH) technique, one translocation line, seven translocation-addition lines, five translocation plus translocation addition lines and two ditelosomic addition lines were identified in backcross progenies of Triticum aestivum L. -Psathyrostachys juncea (Fisch.) Nevski intergeneric hybrids. No complete P. juncea chromosomes were detected in the 25 lines studied. The results suggest that intact P. juncea chromosomes may be difficult to isolate in a wheat background.
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    Genetic suppression of the cereal rye-derived gene Pm8 in wheat (1997)
    Springer
    Euphytica 93 (1997), S. 353-360 
    Details
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; Secale cereale ; powdery mildew ; Erysiphe graminis f.sp. tritici ; resistance ; suppression ; segregation distortion ; wheat ; rye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The location of wheat gene Pm8 for resistance to powdery mildew in the 1RS chromosome segment derived from cereal rye cultivar Petkus was confirmed. There was reduced transmission of the 1BL.1RS chromosome relative to its wheat homologue in four of the five crosses examined. Pm8 was not expressed in some wheat cultivars and selections which possessed the 1RS chromosome identified by the presence of relevant genes for resistance to the three rusts, due to the presence of a dominant suppressor gene(s) in the wheat genome. The frequency of suppression in 1BL.1RS wheats from Mexico was significantly higher than in a group of wheats (both local and exotic) introduced from China and was probably much higher than in European wheats.
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    The genetics of rachis fragility and glume tenacity in semi-wild wheat (1997)
    Springer
    Euphytica 94 (1997), S. 119-124 
    Details
    ISSN: 1573-5060
    Keywords: glume tenacity ; inheritance ; rachis fragility ; spelta ; semi-wild wheat ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The inheritance of rachis fragility and glume tenacity in semi-wild wheat was studied in an attempt to help establish the taxonomic status and genetic origin of semi-wild wheat. Progenies of crosses and backcrosses of semi-wild wheat with the cultivar Columbus (common wheat) indicated that the fragile rachis and non-free-threshing character of semi-wild wheat were dominant to the tough rachis and free-threshing character of common wheat. F2 and backcross data indicated that the rachis fragility and glume tenacity of semi-wild wheat were each controlled by a single gene in the cross of semi-wild wheat with Columbus. In the cross of semi-wild wheat with Triticum aestivum spp. spelta, the F2 and F3 population did not segregate for glume tenacity, but did segregate for rachis fragility. The F2 and backcross data suggest that three genes interact to control three types of rachis fragility, i.e. semi-wild wheat-type, spelta-type and the tough rachis of common wheat. Semi-wild wheat differs from common wheat in rachis fragility and glume tenacity. This wheat also differs from other wheats with fragile rachis and tenacious glumes (T. aestivum ssp. spelta, macha and vavilovii) in the pattern and degree of rachis disarticulation. We conclude that semi-wild wheat is likely a subspecies within T. aestivum at the same taxonomic level as spp. spelta, macha and vavilovii.
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    Effect of genome and ploidy on photosynthesis of wheat (1997)
    Springer
    Euphytica 94 (1997), S. 303-309 
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    ISSN: 1573-5060
    Keywords: photosynthesis ; hexaploid wheat ; A genome ; D genome ; polyploidy ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We assessed (1) the effects of addition and doses of the D genome from different sources and (2) the addition of either the A genome or the D genome on the photosynthesis of synthesized hexaploid wheats. On average, the increased doses of the D genome reduced photosynthesis, but the depression was dependent on the source of the D genome. Two accessions of Aegilops squarrosa had depressed photosynthetic rates, but not another accession of Ae. squarrosa. The D genome of cv. Thatcher did not contribute to depress photosynthetic rate. Triticum monococcum had considerably higher photosynthetic rates than Ae. squarrosa. However, addition of the A genome from T. monococcum did not increase the photosynthetic rates of hexaploids. Chlorophyll a : b ratio, functional photosystem II and the core complex of photosystem II did not account for the variation in photosynthetic rate among the genotypes studied. In our experiment, photosynthesis of polyploids was not dependent on photosynthesis rates of the donor genomes.
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    Variation in sterility among wheat (Triticum aestivum L.) genotypes in response to boron deficiency in Nepal (1997)
    Springer
    Euphytica 95 (1997), S. 21-26 
    Details
    ISSN: 1573-5060
    Keywords: Boron ; genotypic variability ; sterility ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two field experiments were carried out at the Khairanitar Farm, Nepal during the winter season of 1993 to investigate whether wheat genotypes differ in their sterility response to low soil boron and whether boron added to soil can correct sterility. A nursery consisting of 41 diverse genotypes from Nepal, India, Bangladesh, Thailand, China, Pakistan and CIMMYT/Mexico were evaluated in a plot where severe sterility had been observed in previous years. The second experiment involved six genotypes of known sterility responses to boron grown with or without an application of boron at 1 kg ha-1. Large differences were observed among genotypes in terms of number of grain set per ear (range 0.5 to 30 ) and sterility (5.5% to 97.5%). About one third of all the genotypes had 〈25% sterility and 16 of them suffered 〉75% sterility. The genotypes Fang-60, Sonalika, De Mai 6-22, BUC/FLK/MYNA/VL and HDW-234 were highly tolerant to boron deficiency with 〈10% sterility. In sharp contrast, genotypes BOW/BUT, SERI/THB, Glennson, SW-41, Yunmai-33 and UHU were highly susceptible and set virtually no grains in the boron deficient plots. Strong responses to boron application were observed and genotypic variations were evident. Boron at 1 kg ha-1significantly reduced the number of late ears, increased number of grains per ear and grain yield in boron-responsive genotypes. Tolerant genotypes were not influenced by added boron. Given these striking genetic differences, progress in breeding wheat for B-deficient soils in Nepal should be worthwhile.
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    Emission of water stress ethylene in wheat (Triticum aestivum L.) ears: effects of rewatering (1997)
    Springer
    Plant growth regulation 21 (1997), S. 121-126 
    Details
    ISSN: 1573-5087
    Keywords: Triticum aestivum ; water stress ; ethylene ; antioxidant enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In this work it has been found that ethylene production increased only slightly under conditions of a moderate or severe water stress. However, the rehydration of the plants at full turgor after desiccation caused a high emission of ethylene. The desiccation would not irreversibly inactivate the enzymes of the ethylene pathway, since rehydration made the synthesis recommence almost immediately. Water deficit also increased the free radical levels and the antioxidant scavengers, such as superoxide dismutase. Free radicals promote the conversion of 1-amino-cyclopropane-1-carboxylic acid to ethylene, then it is logical to think that both chemical species are involved in the phenomenon of the acceleration of the grain maturity before the plant collapses.
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    Evaluation of surgery procedures for tagging eel Anguilla anguilla with biotelemetry transmitters (1998)
    Springer
    Hydrobiologia 371-372 (1998), S. 107-111 
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    ISSN: 1573-5117
    Keywords: tagging ; surgery ; cyanoacrilate adhesive ; fish ; eel ; Anguilla anguilla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Externally attached telemetry transmitters are unsuitable to tag yellow eels Anguilla anguilla (L.), in streams where they exhibit cryptic life habits and hide in narrow cavities between rocks. We evaluated the adequacy of surgical implantation and closing procedures for tagging eels with biotelemetry transmitters. Epoxy dummy transmitters (18 × 8 mm, 1.6–1.7 g) were implanted in eels anaesthetised with 2-phenoxy-ethanol (0.9 ml l-1), through a 20 mm mid ventral incision made in the posterior quarter of their body cavity. The incision was either left open, or closed in different ways: stitches (absorbable or non absorbable suture material) or commercial-grade cyanoacrilate adhesive (LoctiteTM). Fish were stocked in a 4 m2 flow through tank (15–17 °C), controlled daily for mortality and weekly for evaluating the healing process. No transmitter was expelled over a 12-week period, even in eels with unclosed incisions, of which 50% healed within 28 days (t 50). Regardless of the nature of the filament, suturing induced skin and muscle necrosis, caused significantly higher mortality rates (60% after 10 weeks) and paradoxically slowed down the healing rate (40 and 45 d, respectively). Cyanoacrilate suppressed the inflammatory response and granted higher survival rate (90%), but did not permit to speed up the closing process (t_50 = 52 d), as eels actively bit and removed the adhesive within hours. This behaviour was suppressed when we applied a freshly cut fragment of the eel dorsal fin as a biological bandage over the drying cyanoacrilate. The adhesive remained in place for one to two days and permitted to substantially increase the healing rate (t 50 = 15 d). These results substantiate the efficiency of surgery techniques for tagging eels with radio transmitters, at least for units of small weight and bulk.
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    The status and distribution of lake sturgeon, Acipenser fulvescens, in the Canadian provinces of Manitoba, Ontario and Quebec: a genetic perspective (1997)
    Springer
    Environmental biology of fishes 48 (1997), S. 299-309 
    Details
    ISSN: 1573-5133
    Keywords: postglacial recolonization ; anthropogenic influences ; fish ; Acipenseridae ; conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic analysis of mitochondrial DNA sequence variation indicates that most of a sample of 396 lake sturgeon, Acipenser fulvescens, from the northern part of their range belonged to either one of two haplotypes. The vast majority of fish from the Great Lakes/St. Lawrence and Mississippi drainages were of a single haplotype while those from the Hudson/James Bay were composed of both haplotypes. This haplotypic distribution suggests that fish from one refugium (possibly Missourian) recolonized the Hudson-James Bay drainage while those from a second (possibly Mississippian) recolonized the Laurentian Great Lakes and St. Lawrence River. Lake sturgeon still inhabit much of their native postglacial distribution in Manitoba, Ontario and Quebec. However, the stresses of commercial overexploitation and habitat alteration, usually through hydroelectric dam construction and operation, have either singly or in tandem brought about the reduction, if not extirpation, of some populations within the range. The largest zone of extirpation and population reduction has occurred in the Lake Winnipeg drainage area, which covers more than one-third of Manitoba. Other areas where populations have been reduced to remnant levels, if not extirpated, include the lower Laurentian Great Lakes of Lake Ontario and Lake Erie. In northern Ontario, lake sturgeon populations whose riverine habitats have been fragmented by two or more dams are substantially reduced from their former levels. In Quebec, more attention has been paid to limiting the exploitive stresses on lake sturgeon populations. Combination of the genetic and status data suggests that both northern and southern populations of lake sturgeon (possibly from two glacial refugia) have been impacted severely from anthropogenic influences.
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    Weight-length relationship and condition of the characiform Triportheus guentheri (1997)
    Springer
    Environmental biology of fishes 50 (1997), S. 319-330 
    Details
    ISSN: 1573-5133
    Keywords: condition factor ; biometric indices ; Brazil ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sources of variations in the weight-length relationship parameters, and in the Fulton's, allometric, and relative condition factors (K) of the characiform fish Triportheus guentheri were investigated. The use of these indices as indicators of condition were also discussed. The 2899 females and 2491 males were captured with gill nets from January 1986 to March 1988 in Três Marias Reservoir (18° 15′ and 45° 15′ W), Brazil. Weight-length relationship parameters varied monthly in both sexes mainly due to the skewness of the relative frequency of the number of fish per body length. This suggests that a selective sample and/or the population length structure may strongly influence the estimate of those parameters. The K showed high correlations (r ≥ 0.99) among themselves. Their variations were ascribed to carcass weight in both sexes when analyzed by month, or to the ovary weights when analyzed by female gonad development intervals. The monthly weight-length relationship parameters of T. guentheri presented low or null correlation with K, except for the female's coefficient of regression. Problems using these parameters as indicators of condition suggested that they are not good indices to express condition. Some restrictions regarding the use of K are discussed.
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    Plasma concentrations of steroid hormones in male yellow perch, Perca flavescens: the effect of age and photothermal manipulation (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 97-105 
    Details
    ISSN: 1573-5133
    Keywords: fish ; 11-ketotestosterone ; testosterone ; estradiol ; sperm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plasma steroid concentrations in two and three year-old male yellow perch maintained under two different photothermal regimes were investigated. Initially, all fish kept indoors were exposed to the same water temperature (22 °C) and photoperiod (15L:9D). By the end of August, following the first sampling, fish were exposed to different photothermal regimes. Groups A2 (2 year old) and A3 (3 year old) were maintained under photothermal conditions similar to those of southern Ohio. Groups B2 (2 year old) and B3 (3 year old) were exposed to a condensed light/temperature regime designed to accelerate maturation. Testosterone (T) was the major circulating androgen in all groups. In regime A fish, plasma concentrations of 11-ketotestosterone (11KT) and T were very low in August, increased in October and remained elevated until March. In regime B plasma androgens were high until February and then dropped abruptly in March. The elevated circulating levels of 11KT and T were associated with production of sperm. The highest sperm concentration in the groups A3 and B3 was observed in February and December, respectively. There were no major differences in profiles and levels of plasma steroids between two age categories within each photothermal regime. These data indicate that the compression of the photothermal cycle accelerated both the occurrence of the low postspawning levels of circulating steroids and the completion of milt production. Higher sperm concentration observed in B3 group earlier in the season compared to A3 group also support the notion that the condensed photothermal cycle accelerated gonadal maturation. It appears that modification of the environmental cues may be a useful tool for manipulation of reproductive processes in male yellow perch.
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    Sex determination system of the rosy bitterling, Rhodeus ocellatus ocellatus (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 251-260 
    Details
    ISSN: 1573-5133
    Keywords: backcross ; crossover ; gynogenesis ; meiosis ; triploid ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rosy bitterling, Rhodeus ocellatus ocellatus, is the only fish species known in which artificial triploids are always male, regardless of the kind of polyploidization technique used. In order to elucidate the genetic sex determination system of the rosy bitterling, two kinds of gynogenesis were carried out: retention of the second polar body (GRSPB) and suppression of the first cleavage (GSFC). The sex ratio of progeny was nearly 7:1 (♂:♀) for both GRSPB and GSFC, while those of control and parental fish were almost 1:1. In backcrosses of female progeny by GRSPB and normal diploid males, male progeny were observed at low frequency (one or two individuals in each experiment), except in one experiment where the appearance rate of males was about 50%. From results of gynogenesis and backcrosses, the following conclusions can be made. The genetic sex determination system of the rosy bitterling is a heterogametic female system (ZW). Survival rate of superfemales (WW), produced by gynogenesis, is much lower than that of males (ZW).There is a possibility that crossovers between sex determining genes and a centromere occur in the first meiosis. With repect to the mechanism of unisexuality (male) of artificial triploids of the rosy bitterling, only males (ZZZ and ZZW) are presumed viable, while females (ZWW) are probably inviable.
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    Osteology of Zacco pachycephalus, sensu Jordan & Evermann (1903), with special reference to its systematic position (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 163-171 
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    ISSN: 1573-5133
    Keywords: Formosan cyprinid ; skeletal system ; Opsariichthys ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The skeletal system of Zacco pachycephalus, sensu Jordan & Evermann (1903), is described and compared with that of other related barilines to clarify its systematic position. Osteological characters fall generally into two categories in terms of apomorphic features. The first category is exemplified by autapomorphies such as lower jaw bone shape and the number of branchiostegal rays and hypurals. The latter characters are highly unusual among Cyprinidae. The second category consists of synapomorphies linking Z. pachycephalus and Opsariichthys uncirostris. Specialization of jaw bones for a piscivorous habit is also notable. The quadrate-pterygoid fenestra of Z. pachycephalus and O. uncirostris is considered derived. We conclude that Zacco pachycephalus should be transferred from Zacco to Opsariichthys based on the present osteological analysis.
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    Variations in age and size at maturity of female Nile tilapia, Oreochromis niloticus, populations from man-made lakes of Côte d'Ivoire (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 453-465 
    Details
    ISSN: 1573-5133
    Keywords: phenotypic plasticity ; reproductive style ; fish ; cichlid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reproductive characteristics of Oreochromis niloticus females were studied in two large hydroelectric dams and 6 small agropastoral reservoirs of Côte d'Ivoire, selected for their diversity of environmental conditions and sizes (6 to 80000 ha). Comparative analysis of age and size at maturity revealed large differences between the populations with early maturity, late maturity, and intermediate situations. All the populations matured in their first year, between 5.6 and 10 months. Age and size at maturity were positively correlated with the reservoir area. The range of variation in age at maturity between populations was far greater than that of size at maturity. However, size at maturity also appears to be very plastic as intra-population variations of 2 to 3 cm were found between consecutive years. A comparison of age at maturity for a population in 1994 and 1996 showed that this trait is also likely to vary significantly at the intra-population level. Environmental factors which could potentially affect age and size at maturity are discussed. Growth differences are the probable explanation for the observed patterns of variation between populations. Rapid changes in age and size at maturity at inter or intra-population levels suggest that the observed variations might be explained by differences in environmental variables (phenotypic plasticity) rather than by genetic differences.
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    Comparative ecology and historical biogeography of the genus Brachyrhaphis (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 117-127 
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    ISSN: 1573-5133
    Keywords: poeciliid ; area cladogram ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phylogenetic systematics was used to reveal micro-evolutionary processes and macro-evolutionary patterns that have resulted in the current distribution of species of the live-bearing fish genus Brachyrhaphis. A previously constructed molecular phylogeny for the genus determined that two distinct clades, deep-bodied and slender-bodied, exist within the genus. Micro-habitat variables were measured for all extant members of the genus. Water flow differed significantly between the clades and was converted to a discrete variable and, along with elevation and micro-habitat type, mapped onto the phylogeny for the genus. The evolution of micro-habitat choice was hypothesized using these results. A detailed distribution map was constructed to unveil biogeographic patterns and was also interpreted in light of the molecular phylogeny. The phylogeny was then used to construct an area cladogram. This cladogram was compared to the one derived from paleogeography. The molecular-based area cladogram adds to the growing database required to resolve the biogeography of the Caribbean.
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    Gastric evacuation rates and maximum daily rations of rainbow trout fed chironomid larvae at 7.8, 10.0 and 12.8°C (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 321-330 
    Details
    ISSN: 1573-5133
    Keywords: food consumption ; Salmo gairdneri ; Oncorhynchus mykiss ; fish ; stream population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gastric evacuation rate (GER) and maximum daily ration (CMAX) data for rainbow trout, Oncorhynchus mykiss, are scant, particularly those that apply to field populations of this species. We determined GERs and CMAXs of rainbow trout (approx. 160-300 mm TL, 40-300 g live weight), fed chironomid larvae at 7.8, 10.0 and 12.8°C. Primary GER and CMAX results are provided so they can be readily compared and combined with data from related studies. Disclosure of primary data should facilitate development of predictive equations for GER and CMAX that are applicable to the broad array of conditions under which rainbow trout exist. Our GERs at 10°C were intermediate to but different from most reported in other such studies of rainbow trout at this temperature where different food types were used. Our CMAX values for rainbow trout were substantially higher than those reported in a previous study, and we argue that our values are probably more appropriate for stream-dwelling populations. We also provide evidence that Elliott's (1972, 1975) equations for predicting GER and CMAX in brown trout, Salmo trutta, should not be applied to rainbow trout as has been done in some studies.
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    Life-history variations in the fluvial sculpin, Cottus nozawae (Cottidae), along the course of a small mountain stream (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 203-212 
    Details
    ISSN: 1573-5133
    Keywords: mark-and-recapture ; size at maturity ; age at maturity ; restricted movement ; individual growth ; sex ratio ; population density ; phenotypic plasticity ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Life-history variations in male and female fluvial sculpins, Cottus nozawae, were studied in a small mountain stream in Hokkaido, Japan, primarily by using capture-mark-recapture methods. At three study areas established along the stream course, the majority of marked sculpins were recaptured in their original location over one or more years, indicating their long-term occupation of each restricted habitat area. Sculpin densities increased toward the upstream habitats, whereas individual growth rates were more rapid downstream. In both sexes, sculpins distributed downstream matured at a larger body size and later in life than upstream sculpins, clearly demonstrating a clinal variation in these respects. A comparison of life-history variations in C. nozawae with those in amphidromous C. hangiongensis suggests that intrapopulational life-history variations in the former might be environmentally induced, and that one of the most important determinants for the variations in Cottus species might be population density.
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    Dyadic relationships in nesting males of the three-spined stickleback, Gasterosteus aculeatus (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 243-250 
    Details
    ISSN: 1573-5133
    Keywords: dyad ; aggressive interaction ; social relationships ; nesting males ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Multidimensional scaling analysis of nest site location, nesting interval, and aggressive and mating interactions revealed that male three-spined sticklebacks, Gasterosteus aculeatus, formed nesting clusters comprising five patterns of dyadic relationships. These patterns were defined by intervening variables such as size difference between the two males, nest site locations, synchronization of nesting cycles (egg presence in the nest), distance between two nests, and nest raiding behaviours. Several patterns of dyadic relationships were integrated among nesting males and their constellations indicated an expression of the social structure. Through an understanding the social structure, I described effects of social context or situations on individual reproductive success.
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    Daily spawning and development of sensitivity to gonadotropin and maturation-inducing steroid in the oocytes of the bambooleaf wrasse, Pseudolabrus japonicus (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 281-290 
    Details
    ISSN: 1573-5133
    Keywords: maturational competence ; protogyny ; teleost ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cycle of oocyte development of the bambooleaf wrasse, Pseudolabrus japonicus, was studied to elucidate the endocrinological mechanism of oocyte maturation in a marine teleost. A single female reared with two males spawned every day for 17 days in captivity, indicating that this species is a daily spawner. Ovarian histology revealed that germinal vesicle migration of the largest oocytes progressed from 12:00 to 3:00 h, and germinal vesicle breakdown (GVBD) was completed at 6:00 h. Ovulation and spawning occurred between 6:00 and 9:00 h. The effectiveness of human chorionic gonadotropin (HCG) and 17α,20β-dihydroxy-4-pregnen-3-one (17,20β-P), which is one of the most potent steroidal inducers of GVBD in bambooleaf wrasse oocytes, in inducing final oocyte maturation was examined at eight different times of the day. The responsiveness of the oocyte to HCG and steroid differed at different times of the day. The GVBD could be induced by HCG but not 17,20β-P at 9:00 h. Between 12:00 and 18:00 h, not only HCG but also 17,20β-P induced GVBD. Both GVBD and ovulation spontaneously occurred between 0:00 and 6:00 h without any hormonal treatment. These results clearly showed that the oocyte of the bambooleaf wrasse possessed a diurnal maturation cycle. Responsiveness of oocytes to HCG appeared earlier than responsiveness to 17,20β-P. This suggests that sensitivity to 17,20 β-P is induced by gonadotropic hormone (GTH).
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    Home range of the Japanese fluvial sculpin, Cottus pollux, in relation to nocturnal activity patterns (1998)
    Springer
    Environmental biology of fishes 53 (1998), S. 295-301 
    Details
    ISSN: 1573-5133
    Keywords: appearance ; residential tendency ; substratum use ; nocturnal activity ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Patterns of space use related to the activity of individual Japanese fluvial sculpins, Cottus pollux, were examined during the non-breeding season, in the upper reaches of the Inabe River, central Japan. Sculpins appeared more frequently at night than in daytime. Among 31 recaptured sculpins, 30 (96.8%) showed nocturnal activity patterns, there being no fish which exhibited an entirely diurnal activity pattern. Of 21 sculpins captured both in daytime and at night, the most common pattern of space use (n = 14, 66.7%) was that in which the nocturnal home range entirely encompassed the diurnal range. Overall, nocturnal home ranges were significantly larger than diurnal ranges. Active sculpins were rarely found on sand-associated substrata in daytime, but were seen more frequently on such substrata at night.
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    URL: http://dx.doi.org/10.1023/A:1007410519726
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    General response patterns of fish populations to stress: an evaluation using an individual-based simulation model (1997)
    Springer
    Journal of aquatic ecosystem stress and recovery 6 (1997), S. 15-31 
    Details
    ISSN: 1573-5141
    Keywords: contaminants ; fish ; general response patterns ; individual-based ; population dynamics ; simulation model ; yellow perch ; walleye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract General response patterns of fish populations tostress, originally proposed by Colby for fisheriesrehabilitation and later adapted by Munkittrick forcontaminants, were evaluated using an individual-basedsimulation model. General response patterns relatechanges in population-level variables to the type ofstress. The model follows the daily growth,mortality, and spawning of individual yellow perch andwalleye through their lifetime, and was corroboratedusing Oneida Lake data. Two versions of the model wereused: population (yellow perch only) and community(dynamic predation on yellow perch by walleye). Eightstresses were imposed on the population and communityversions of the model and 100-year simulations wereperformed. Response patterns were defined by changesin predicted yellow perch mean population abundance,mean age of adults, and mean adult growth (representedby mean length at age-7). Proposed response patternswere similar to those predicted using the populationversion of the model. Simulations using the communityversion of the model distorted the response patterns,either causing amplification, dampening, or reversalof many of the patterns. Predicted response patternsbecame unique when additional variables were included.Our model results suggest that caution is appropriatein interpreting general response patterns based onmean age, or when the population of interest plays amajor role in a relatively simple food web. The responsepattern approach may be better at identifying the lifestage impacted rather than the mechanism of the stress.
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    Development of community metrics to evaluate recovery of Minnesota wetlands (1998)
    Springer
    Journal of aquatic ecosystem stress and recovery 6 (1998), S. 217-234 
    Details
    ISSN: 1573-5141
    Keywords: wetlands ; land use ; biological integrity ; biological diversity ; ecosystem monitoring ; ecosystem recovery ; amphibians ; fish ; birds ; plants ; invertebrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Monitoring wetland recovery requires assessment tools that efficiently and reliably discern ecosystem changes in response to changes in land use. The biological indicator approach pioneered for rivers and streams that uses changes in species assemblages to interpret degradation levels may be a promising monitoring approach for wetlands. We explored how well metrics based on species assemblages related to land use patterns for eight kinds of wetlands in Minnesota. We evaluated land use on site and within 500 m,1000 m, 2500 m and 5000 m of riverine, littoral, and depressional wetlands (n = 116) in three ecoregions. Proportion of agriculture, urban, grassland, forest,and water were correlated with metrics developed from plant, bird, fish, invertebrate, and amphibian community data collected from field surveys. We found79 metrics that relate to land use, including five that may be useful for many wetlands: proportion of wetland birds, wetland bird richness, proportion of insectivorous birds, importance of Carex, importance of invasive perennials. Since very few metrics were significant for even one-half of the wetland types surveyed, our data suggest that monitoring recovery in wetlands with community indicators will likely require different metrics,depending on type and ecoregion. In addition, wetlands within extensively degraded ecoregions may be most problematic for indicator development because biotic degradation is historic and severe.
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    Characterization of molecular variants of GnRH, induction of spermiation and sex reversal using salmon GnRH-A and domperidone in the protogynous diandric fish, Synbranchus marmoratus Bloch, (Teleostei, Synbranchidae) (1997)
    Springer
    Fish physiology and biochemistry 16 (1997), S. 425-436 
    Details
    ISSN: 1573-5168
    Keywords: fish ; GnRH ; domperidone ; hermaphroditism ; protogynous ; diandric ; sex reversal ; spermiation ; Synbranchidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper studies the molecular variants of gonadotropin-releasing hormone (GnRH) present in the brain of the protogynous swamp eel, Synbranchus marmoratus, and the effects of the administration of salmon GnRH analogue (sGnRH-A) and the dopamine receptor antagonist, domperidone (DOM) on final maturation and gamete release in this species. Evidence for the presence of two GnRH variants, sGnRH and cIIGnRH were obtained by reverse phase high-pressure liquid chromatography (RP-HPLC) and radioimmunoassay with different antisera. The effects of treatment with sGnRH-A+DOM were checked by three ways: oocyte and milt release by stripping, histological analysis of the gonadal tissue, and androgen serum levels at different times throughout the experiment. In males, spermiation was induced after three weeks of treatment. In the female group, sGnRH-A+DOM did not induce ovulation at the end of the experiment. Histological analysis of the gonads from the female group showed evidence of sex reversal. All the treated fish had elevated androgen serum levels from the third week, with respect to control fish. In all cases, serum estradiol levels were undetectable. These results suggest that treatment with sGnRH analog and DOM induce sex reversal in female and spermiation in males.
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    URL: http://dx.doi.org/10.1023/A:1007772416539
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    Plasticity of the properties of mitochondria from rainbow trout red muscle with seasonal acclimatization (1997)
    Springer
    Fish physiology and biochemistry 16 (1997), S. 531-541 
    Details
    ISSN: 1573-5168
    Keywords: mitochondria ; muscle ; thermal acclimatization ; fish ; substrate preferences ; phospholipid fatty acid composition ; oxidative capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cold-acclimation of rainbow trout brings only limited changes in muscle metabolic capacities, but marked modifications in membrane composition. Thus, we examined whether the functional properties of mitochondria from trout red muscle were modified by seasonal temperature acclimatization. Mitochondria from fall-acclimatized trout had higher maximal capacities (state 3 rates) for the oxidation of pyruvate and acyl carnitines at 12 and 20 °C than mitochondria isolated from summer-acclimatized trout. For these substrates, the increased oxidative capacity completely compensated for the seasonal drop in temperature. Pyruvate and palmitoyl carnitine were consistently the preferred substrates, while decanoyl and octanoyl carnitine were oxidized at higher rates than glutamine, particularly in fall trout. State 4 rates of oxygen uptake (obtained when all ADP has been converted to ATP) differed less among substrates, but varied seasonally. State 4 rates at 12 and 20 °C were higher in mitochondria isolated from fall than summer trout. At low temperatures, the Q10 of both maximal and state 4 rates of substrate oxidation tended to be higher for mitochondria from fall trout. The apparent Arrhenius activation energy (Ea) for mitochondrial pyruvate oxidation was higher in fall than summer trout whereas the Ea’s for palmitoyl carnitine and decanoyl carnitine oxidation did not change. The fatty acids of mitochondrial phospholipids from fall trout were more polyunsaturated than those from summer trout, with 12% more double bonds occurring than in summer trout, suggesting that membrane restructuring may be involved in the observed compensatory responses.
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    URL: http://dx.doi.org/10.1023/A:1007708826437
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    Reproduction related immunoglobulin changes in rainbow trout (1997)
    Springer
    Fish physiology and biochemistry 17 (1997), S. 415-421 
    Details
    ISSN: 1573-5168
    Keywords: fish ; trout ; reproduction ; seasonal changes ; immunoglobulin ; testosterone ; estradiol-17β ; 11-ketotestosterone ; water temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Annual changes in plasma immunoglobulin (IgM) levels were investigated in three strains of rainbow trout Oncorhynchus mykiss which have different spawning periods, i.e., September–October, November–December, and January, reared under constant water temperature and natural day length. Plasma IgM levels decreased during the spawning season in all strains tested. The IgM changes became reversed in response to significant increases in plasma testosterone (T) and estradiol-17β in females and T and 11-ketotestosterone in males. Though the IgM decline showed a connection with suppressed immunocompetence, since many mature fish caught fungal diseases, no clear differences were observed in the plasma IgM levels between infected and noninfected fish during the spawning season. Incidentally, plasma IgM levels in infection prone fish were higher than in noninfection prone fish prior to the spawning season, whereas coincident differences in the plasma steroid levels were observed. Immature fish reared under lower water temperatures showed lower IgM levels. The effect of water temperature may have to be considered when analyzing the defense mechanism during the spawning season in rainbow trout.
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    Accumulation of mercury in estuarine food chains (1998)
    Springer
    Biogeochemistry 40 (1998), S. 235-247 
    Details
    ISSN: 1573-515X
    Keywords: fish ; invertebrates ; ligands ; mercury ; methylmercury ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract To understand the accumulation of inorganic mercury and methylmercury at the base of the estuarine food chain, phytoplankton (Thalassiosira weissflogii) uptake and mercury speciation experiments were conducted. Complexation of methylmercury as methylmercury-bisulfide decreased the phytoplankton uptake rate while the uptake rate of the methylmercury-cysteine and -thiourea complexes increased with increasing complexation by these ligands. Furthermore, our results indicated that while different ligands influenced inorganic mercury/methylmercury uptake by phytoplankton cells, the ligand complex had no major influence on either where the mercury was sequestered within the phytoplankton cell nor the assimilation efficiency of the mercury by copepods. The assimilation efficiency of inorganic mercury/methylmercury by copepods and amphipods feeding on algal cells was compared and both organisms assimilated methylmercury much more efficiently; the relative assimilation efficiency of methylmercury to inorganic mercury was 2.0 for copepods and 2.8 for amphipods. The relative assimilation is somewhat concentration dependent as experiments showed that as exposure concentration increased, a greater percentage of methylmercury was found in the cytoplasm of phytoplankton cells, resulting in a higher concentration in the copepods feeding on these cells. Additionally, food quality influenced assimilation by invertebrates. During decay of a T. weissflogii culture, which served as food for the invertebrates, copepods were increasingly less able to assimilate the methylmercury from the food, while even at advanced stages of decay, amphipods were able to assimilate mercury from their food to a high degree. Finally, fish feeding on copepods assimilated methylmercury more efficiently than inorganic mercury owing to the larger fraction of methylmercury found in the soft tissues of the copepods.
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    URL: http://dx.doi.org/10.1023/A:1005959211768
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    Transcriptional regulation of fish growth hormone gene (1997)
    Springer
    Fish physiology and biochemistry 17 (1997), S. 237-246 
    Details
    ISSN: 1573-5168
    Keywords: fish ; growth hormone gene ; thyroid hormone ; transcription ; DNA response element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcription of growth hormone (GH) genes in vertebrates depends, among other factors, on pituitary specific transcription factors (such as Pit-1) and on thyroid hormone (TH) and TH receptors. Gel retardation experiments indicated the presence of proteins in the carp pituitary nuclear extract that specifically bind the Pit-1 DNA response element and the adjacent putative TH DNA response element (TRE), on the Atlantic salmon (Salmo salar) GH proximal promoter. The putative TRE element competes effectively in vitro in gel retardation assays with 4×TREpal, a consensus TRE element, on zebrafish (Danio rerio) purified recombinant TH receptor (zfTHR). The zfTHR/TRE complex can also be further identified with antibodies to rat THR that causes the complex a supershift in gel retardation assay. Cross competition was observed in nuclear extracts between the TRE and Pit-1 sites. It was found that 100 molar fold excess of Pit-1 binding element can compete effectively with the TH binding element and reduce its binding activity. The endogenous TRE binding element, on the other hand, cannot effectively reduce the binding activity of the Pit-1 DNA binding element. This unexpected competition between the two sites was examined in the presence and absence of the hormones: TH, 9-cis retinal, and TH + 9-cis retinal. The addition of the two hormones together significantly increased the binding properties of the TH response element as compared to its binding in the absence of the hormones, and also improved its binding activity in the presence of the Pit-1 DNA competitor. In summary, the two adjacent sites that control GH gene transcription, Pit-1 and TRE, on the fish GH promoter exhibit some degree of interaction between their respective transcription factors, the Pit-1 protein and the thyroid/retinoic acid receptors.
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    URL: http://dx.doi.org/10.1023/A:1007762325604
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    A method for the external attachment of acoustic tags on roundfish (1998)
    Springer
    Hydrobiologia 371-372 (1998), S. 113-116 
    Details
    ISSN: 1573-5117
    Keywords: fish ; tagging ; telemetry ; heart rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The present paper proposes a new method for the external attachment of an acoustic tag on roundfish. The tag is placed in anterio-ventral position and attached with two wires passed around the pelvic girdle. This tagging method was tested on Atlantic cod and European sea bass using acoustic heart rate transmitters. Preliminary results concerning metabolic demand (oxygen consumption), heart rate and behaviour of free swimming individuals are presented and discussed.
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    URL: http://dx.doi.org/10.1023/A:1017017810099
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    Long-term changes in crustacean zooplankton and water quality in a shallow, eutrophic Chinese lake densely stocked with fish (1998)
    Springer
    Hydrobiologia 391 (1998), S. 193-201 
    Details
    ISSN: 1573-5117
    Keywords: crustacean zooplankton ; long-term changes ; water quality ; fish ; Lake Donghu ; China
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From surveys made in 1962–1963, 1973–1974, 1979–1996 at two Stations in Lake Donghu, a shallow eutrophic water body near Wuhan, P. R. China, the authors, derive long-term changes in species composition, standing crop and body-size of planktonic crustaceans. The species number decreased from the 1960s to the 1990s. The cladocerans dropped from 46 (1960s) to 26 (1980s) to 13 (1990s); the copepods decreased from 14 (1960s) to 10 (1980s) to 7 (1990s). From the mid-1980s on, the dominant crustaceans also changed: Daphnia hyalina and D. carinata ssp. were replaced by Moina micrura and Diaphanosoma brachyurum at Stations 1 and 2, respectively; Cyclops vicinus replaced Mesocyclops leuckarti. Densities and biomass of Cladocera decreased markedly after 1987. Annual average densities and biomass of cladocerans were statistically differences between 1962–1986 and 1987–1996 (P 〉 0.01). Annual average densities of Daphnia (Station 1 + Station 2) were negatively correlated with fish yield . Since the 1980s, annual average body length of Cladocera and Calanoida decreased, while annual average body length of Cyclopoida increased. In the same years, average body length of copepods was lower during May–October than during January–April and November–December. A 12-yr data analysis showed annual average concentration of chlorophyll-a (Chl-a) to be negatively correlated with annual average density of Daphnia, whilst lake transparency was positively correlated with annual average densities of Daphnia. The results imply that, since Daphnia feeds efficiently on phytoplankton, it could decrease concentration of Chl-a, and enhance water transparency.
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    Critical thermal maxima of diploid and triploid brook charr, Salvelinus fontinalis (1997)
    Springer
    Environmental biology of fishes 49 (1997), S. 259-264 
    Details
    ISSN: 1573-5133
    Keywords: triploidy ; thermal tolerance ; lethal limits ; brook trout ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The purpose of this experiment was to determine whether diploid and triploid brook charr, Salvelinus fontinalis, differ in their critical thermal maxima (CTM). Two age classes were tested (underyearlings, having average weight of 25 g, and yearlings, having average weight of 668 g) at two rates of temperature increase (2° C h-1 and 15° C h-1). No effect of ploidy on CTM was found. Fish exposed to the faster rate of temperature increase had higher CTM values than those exposed to the slower rate (underyearlings: 29.5 ± 0.1° C versus 29.1 ± 0.1° C in one trial and 29.8 ± 0.1° C versus 28.3 ± 0.1° C in a second trial; yearlings: 29.3 ± 0.1° C versus 27.7 ± 0.1° C in two trials, p 〈 0.001 in all cases). Underyearlings had higher CTM values than yearlings (29.2 ± 0.1° C versus 28.5 ± 0.1° C, p 〈 0.05). Female yearlings, which were immature, had higher CTM values than males, which had previously matured as one-year-olds (28.8 ± 0.1° C versus 28.3 ± 0.1° C, p 〈 0.001).
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    Predation of zebra mussels by round gobies, Neogobius melanostomus (1997)
    Springer
    Environmental biology of fishes 50 (1997), S. 267-273 
    Details
    ISSN: 1573-5133
    Keywords: exotic species ; laboratory experiment ; size selectivity ; Great Lakes ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Preliminary gut analysis of a recent Great Lakes invader, the round goby, Neogobius melanostomus (7.0–8.4 cm), collected from the Detroit River, showed that they ate zebra mussels (58%), snails (6%), and other invertebrates (36%), including aquatic insects (Hexagenia), softshelled crayfish, and zooplankton. Because zebra mussels, Dreissena polymorpha, predominated as prey, we investigated the ability of round gobies to consume different size classes of zebra mussels. In laboratory experiments, we examined feeding preferences of three size classes of round gobies (5.5–6.9 cm; 7.0–8.4 cm; 8.5–10.3 cm standard length) on four different size classes of zebra mussels (6.0–9.9 mm, 10.0–12.9 mm, 13.0–15.9 mm, 16.0–18.9 mm). All sizes of round gobies ate zebra mussels 〈 10.0 mm. Only the largest size class of round gobies ate larger zebra mussels (10.0–12.9 mm) when all prey sizes were presented. The association between the total mass of zebra mussels available and the amount consumed by round gobies increased positively up to about 6.5 g of available mussels and then levelled off. Round gobies consumed an average of 1.0 g of mussels in 24 h. There was a significant positive relationship between gape size and standard length of round gobies. Although larger round gobies (over the size range of fish in our study) are able to consume larger zebra mussels, small mussels were preferred. Our findings suggest that the preference of small zebra mussels by round gobies has the potential to alter the size structure of zebra mussel populations.
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    Arrival of an Australian anguillid eel in New Zealand: an example of transoceanic dispersal (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 1-6 
    Details
    ISSN: 1573-5133
    Keywords: biogeography ; Anguilla ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Anguilla reinhardtii, hitherto known from eastern Australia, New Caledonia, Norfolk Island, and Lord Howe Island, has recently been discovered in rivers of northern New Zealand. Identification, based on morphological and genetic characteristics, is unequivocal; eight consecutive year classes have been found. The only reasonable explanation of this occurrence is transoceanic dispersal to New Zealand, probably from subtropical oceanic spawning grounds north of New Zealand. This corroborates past hypotheses that the strongly diadromous freshwater fish fauna of New Zealand is derived by transoceanic dispersal of known marine life intervals.
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    URL: http://dx.doi.org/10.1023/A:1007326405148
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    Sound production during feeding in Hippocampus seahorses (Syngnathidae) (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 221-229 
    Details
    ISSN: 1573-5133
    Keywords: bioacoustics ; feeding behavior ; functional morphology ; fish ; cavitation ; stridulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract While there have been many anecdotal reports of sounds produced by Hippocampus seahorses, little is known about the mechanisms of sound production. We investigated clicking sounds produced during feeding strikes in H. zosterae and H. erectus. Descriptions of head morphology support the idea that feeding clicks may represent stridulatory sounds produced by a bony articulation between the supraoccipital ridge of the neurocranium and the grooved anterior margin of the coronet. Analysis of high-speed video and synchronous sound recordings of H. erectus indicate that the feeding click begins within 1-2 msec of the onset of the rapid feeding strike (4 msec mean duration). Surgical manipulations of the supraoccipital-coronet articulation resulted in a decreased proportion of feeding strikes that produced clicks. This study provides several lines of evidence in support of the hypothesis that feeding clicks in Hippocampus seahorses are stridulatory in origin and are produced by the supraoccipital-coronet articulation. Our results are not consistent with previous suggestions that sounds may be produced by cavitation due to rapid pressure changes within the buccal cavity during the feeding strike.
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    URL: http://dx.doi.org/10.1023/A:1007434714122
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    Simulating smallmouth bass reproductive success in reservoirs (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 161-174 
    Details
    ISSN: 1573-5133
    Keywords: Micropterus dolomieu ; reproduction ; predictive model ; Brownlee Reservoir ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An individual-based model of nesting smallmouth bass, Micropterus dolomieu, is used to predict the effects of water level fluctuations on reproductive success. The model simulates daily nest site selection, spawning, nest guarding, and development and survival of eggs, embryos, and larvae until dispersal. The model was configured for Brownlee Reservoir, Idaho-Oregon. Each reservoir bank is represented as a rectangular grid of cells, with each cell characterized by an assigned slope, substrate, and elevation, and by a water depth that varied daily. Nest site (cell) selection is determined from a habitat suitability index (HSI) based on substrate, slope, and depth. Development of young is temperature-dependent. Mortality of young occurs via attrition, abandonment by the guarding male, and probabilistic whole-nest catastrophe. Simulations were performed that used observed data for 1991 to 1996. Model predicted nest habitat selection and egg-to-dispersal survival rates were similar to observed values. Additional model simulations showed that: (1) nest habitat selection was best predicted when depth, slope, and substrate were considered together rather than singly, (2) egg-to-dispersal survival was related to the magnitude of water level fluctuations during the peak spawning period, (3) relating mortality to HSI values resulted in lower survival, while relating growth to HSI values resulted in higher survival, and (4) spawning habitat is not limiting in Brownlee Reservoir. Suggestions for future monitoring of reservoir-based smallmouth bass populations are discussed.
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    URL: http://dx.doi.org/10.1023/A:1007489627887
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    Arrival of an Australian anguillid eel in New Zealand: an example of transoceanic dispersal (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 1-6 
    Details
    ISSN: 1573-5133
    Keywords: biogeography ; Anguilla ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Anguilla reinhardtii, hitherto known from eastern Australia, New Caledonia, Norfolk Island, and Lord Howe Island, has recently been discovered in rivers of northern New Zealand. Identification, based on morphological and genetic characteristics, is unequivocal; eight consecutive year classes have been found. The only reasonable explanation of this occurrence is transoceanic dispersal to New Zealand, probably from subtropical oceanic spawning grounds north of New Zealand. This corroborates past hypotheses that the strongly diadromous freshwater fish fauna of New Zealand is derived by transoceanic dispersal of known marine life intervals.
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    URL: http://dx.doi.org/10.1023/A:1007326405148
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    Physiological tolerances of juvenile robust redhorse, Moxostoma robustum: conservation implications for an imperiled species (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 429-444 
    Details
    ISSN: 1573-5133
    Keywords: fish ; Catostomidae ; temperature ; salinity ; pH ; hypoxia ; conservation biology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The robust redhorse, Moxostoma robustum (Teleostei: Catostomidae), is an imperiled sucker native to large rivers of the Atlantic slope of the southeastern United States. Juvenile M. robustum were tested for tolerances to temperature, salinity, pH, and hypoxia in order to evaluate basic early life-history requirements. Static (acute) tests resulted in estimates of mean lower temperature tolerances (5.3–19.4 °C) that varied with prior thermal acclimation and indicated no apparent difference in tolerance among fish 30, 60, and 90 days old. Fish acclimated to 20 °C and 30 °C had significantly different mean critical thermal maxima (34.9 °C and 37.2 °C, respectively) and exhibited pronounced increased opercular ventilation rates with elevated temperatures. Fish exposed to acute and chronic increases in salinity showed unusual patterns of mortality above the isosmotic point (9 ppt) that reflected possible differences in body mass and prior acclimation conditions (i.e., water ionic composition); small fish and those held in soft water were the least tolerant of increased salinity. Abrupt exposure to extreme pH values resulted in greater than 50% mortality at pH values below 4.3 and above 9.5 within a 96-hour period. Fish exposed to progressive hypoxia utilized aquatic surface respiration at a mean oxygen concentration of 0.72–0.80 mg O2 l-1 (20 °C and 30 °C acclimated fish, respectively), and lost equilibrium at 0.54–0.57 mg O2 l-1. Juvenile M. robustum are moderately tolerant of a wide range of ambient physicochemical parameters, but further research is needed to determine how both abiotic and biotic factors have contributed to population decline and extirpation of this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007486632102
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  • 98
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    Generalists as sequential specialists: diets and prey switching in juvenile silver perch (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 445-454 
    Details
    ISSN: 1573-5133
    Keywords: planktivory ; insectivory ; pond fertility ; fish ; Bidyanus bidyanus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Diets of silver perch, Bidyanus bidyanus, in organically fertilised aquaculture ponds were dominated by chironomid larvae, Daphnia and calanoid copepods. Insects and crustaceans contributed approximately 80% and 20% by weight to the diet respectively. Classification of the stomach contents of individual fish revealed 8 diet groups, 4 of which were dominated by planktonic crustaceans and 4 by insects. Each diet group was strongly dominated by a different prey type. Fish from the same sample tended to belong to the same diet group and there was a non-random distribution of diet groups across ponds. Perch diets were influenced by the method of pond fertilisation (livestock effluent or pellet feed). Shifts in the representation of groups indicated that fish switched from one diet group to another over a 2–4 week period. The selection of planktonic prey by perch was related to prey densities in the ponds. Fish preferred Daphnia when these prey were common, but switched to calanoids and insects when Daphnia were scarce. A perfect rank correlation between the mean body size of planktonic prey and their contribution to the diet suggested that prey choice involved comparative decisions based on prey size. These findings indicate that, while classified as dietary generalists, silver perch exhibit consumption patterns which at the individual level are highly specialised at any given time. These patterns can be predicted, given information on prey densities in the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007489100809
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  • 99
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    Electronic Resource
    Use of substratum ripples for flow refuging by Atlantic cod, Gadus morhua (1998)
    Springer
    Environmental biology of fishes 51 (1998), S. 455-460 
    Details
    ISSN: 1573-5133
    Keywords: station-holding ; current ; trough ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ability to maintain position in a current without actively swimming (station-holding) was measured on substratum ripples for Atlantic cod, Gadus morhua, a bentho-pelagic fusiform species. The current velocities tested ranged from 0–111 cm sec-1. Ripples were sinusoidal, with twelve combinations of ripple wavelength (10, 25, 50, 125 cm) and ripple amplitude (1.0, 2.5, 5.0 cm). Ripple wavelengths were chosen to approximate 0.5, 1.0, 2.0 and 5.0 times fish total length. The potential of ripples to locally retard current and thereby provide a refuge from the flow was measured as a velocity ratio, utrough/ufree-stream, where utrough is the flow velocity measured at a height of 0.5 cm from the bottom of a trough and ufree-stream the flow velocity measured at a height of 10 cm above ripple crests. Cod usually swam steadily above substratum ripple crests in the free-stream flow. They used substratum ripples to hold station on only 3 of the 12 ripples tested by refuging from the flow in the ripple troughs (flow refuging). These ripples had wavelengths approaching twice the body length, with ripple amplitudes that produced velocity ratios of 0.44–0.65, thus providing at least a 35% flow reduction in the troughs. In addition, these ripples were only used at intermediate velocities starting at 49–78 cm sec-1 and ending at 81–109 cm sec-1 depending on the ripple morphology, suggesting there may be costs involved in flow refuging, probably in stability control. Flow refuging on substratum ripples could dramatically impact the physiology and ecology of cod in high current velocities by providing areas of retreat for energetic savings, but also offering opportunities for enhanced feeding and migration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007449630601
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  • 100
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    Electronic Resource
    Reproductive success in female Neolamprologus mondabu (Cichlidae): influence of substrate types (1998)
    Springer
    Environmental biology of fishes 52 (1998), S. 261-269 
    Details
    ISSN: 1573-5133
    Keywords: substrate brooder ; body size ; home range size ; habitat preference ; Lake Tanganyika ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Individual variation in body size, home range size, and reproductive success among Neolamprologus mondabu (Cichlidae) females were investigated with reference to substrate types in the littoral zone of northern Lake Tanganyika. Larger females occupied sandy substrates and smaller ones stony substrates. Female reproductive success, estimated as the number of offspring successfully released per month, was higher on sandy substrates than on stony substrates. This may be attributable to higher spawning intensity and better protection of broods against predators in open, sandy habitats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007380431013
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