Showing papers on "Rust published in 1998"

Characterization of Iron Oxides Commonly Formed as Corrosion Products on Steel

Abstract: For fundamental studies of the atmospheric corrosion of steel, it is useful to identify the iron oxide phases present in rust layers. The nine iron oxide phases, iron hydroxide (Fe(OH)2), iron trihydroxide (Fe(OH)3), goethite (α-FeOOH), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH), feroxyhite (δ-FeOOH), hematite (α-Fe2O3), maghemite (γ-Fe2O3) and magnetite (Fe3O4) are among those which have been reported to be present in the corrosion coatings on steel. Each iron oxide phase is uniquely characterized by different hyperfine parameters from Mossbauer analysis, at temperatures of 300K, 77K and 4K. Many of these oxide phases can also be identified by use of Raman spectroscopy. The relative fraction of each iron oxide can be accurately determined from the Mossbauer subspectral area and recoil-free fraction of each phase. The different Mossbauer geometries also provide some depth dependent phase identification for corrosion layers present on the steel substrate. Micro-Raman spectroscopy can be used to uniquely identify each iron oxide phase to a high spatial resolution of about 1 µm.

Lr68: a new gene conferring slow rusting resistance to leaf rust in wheat

Abstract: The common wheat cultivar Parula possesses a high level of slow rusting, adult plant resistance (APR) to all three rust diseases of wheat. Previous mapping studies using an Avocet-YrA/Parula recombinant inbred line (RIL) population showed that APR to leaf rust (Puccinia triticina) in Parula is governed by at least three independent slow rusting resistance genes: Lr34 on 7DS, Lr46 on 1BL, and a previously unknown gene on 7BL. The use of field rust reaction and flanking markers identified two F6 RILs, Arula1 and Arula2, from the above population that lacked Lr34 and Lr46 but carried the leaf rust resistance gene in 7BL, hereby designated Lr68. Arula1 and Arula2 were crossed with Apav, a highly susceptible line from the cross Avocet-YrA/Pavon 76, and 396 F4-derived F5 RILs were developed for mapping Lr68. The RILs were phenotyped for leaf rust resistance for over 2 years in Ciudad Obregon, Mexico, with a mixture of P. triticina races MBJ/SP and MCJ/SP. Close genetic linkages with several DNA markers on 7BL were established using 367 RILs; Psy1-1 and gwm146 flanked Lr68 and were estimated at 0.5 and 0.6 cM, respectively. The relationship between Lr68 and the race-specific seedling resistance gene Lr14b, located in the same region and present in Parula, Arula1 and Arula2, was investigated by evaluating the RILs with Lr14b-avirulent P. triticina race TCT/QB in the greenhouse. Although Lr14b and Lr68 homozygous recombinants in repulsion were not identified in RILs, γ-irradiation-induced deletion stocks that lacked Lr68 but possessed Lr14b showed that Lr68 and Lr14b are different loci. Flanking DNA markers that are tightly linked to Lr68 in a wide array of genotypes can be utilized for selection of APR to leaf rust.

Genetic Progress in Reducing Losses to Leaf Rust in CIMMYT-Derived Mexican Spring Wheat Cultivars

Abstract: Leaf rust, caused by Puccinia recondita Roberge ex Desmaz., is an important disease of wheat (Triticum aestivum L.) worldwide. To estimate the genetic progress in reducing grain yield losses through breeding for resistance to leaf rust, replicated trials including 15 popular CIMMYT germplasm-derived wheat cultivars released between 1966 and 1988 in northwestern Mexico were sown in that same area; normal and late planting dates were used for four and two seasons, respectively. Leaf rust epidemics were established by inoculating spreader rows planted adjacent to plots of the cultivars which were not protected by fungicide. Average losses in grain yields of the cultivars due to leaf rust ranged between 6.6 and 62.7% and were highly correlated with final disease severity (r = 0.898, P < 0.01) and relative area under the disease progress curve (r = 0.917, P < 0.01). The losses in grain yield were mostly due to reductions in kernel weight, kernels per square meter, and grain fill rate. Grain yield losses (7.7-10.4%) in slow rusting cultivars Cocoraque 75, Nacozari 76, Opata 85, and Bacanora 88 were similar to those observed in the immune 'Oasis 86' (6.6%) or resistant 'Ciano 79' (10.2%). The average annual progress in grain yield potential achieved through breeding averaged over the six trials was estimated to be 0.48% (r 2 = 0.38, P < 0.01) for fungicide protected and 2.21% (r 2 = 0.47, P< 0.01) when not protected by fungicide. We conclude that while the grain yield potential of CIMMYT-derived cultivars has increased significantly over the years, progress in protecting this yield potential through the incorporation of genes that confer slow rusting resistance has been more dramatic.

Structure of Protective Rust Layers Formed on Weathering Steels by Long-term Exposure in the Industrial Atmospheres of Japan and North America

Abstract: A protective and adherent rust layer develops on weathering steels during outdoor exposure. This layer acts as a barrier which slows further corrosion, thus enabling weathering steel to be used in structural applications without painting. To aid in understanding the mechanism of protective rust formation, studies have been made on the composition and microstructure of these layers. The present study was jointly conducted on Japanese weathering steel exposed in the industrial environment of Amagasaki, and US weathering steel exposed in the industrial environment of Bethlehem. The rust layers were studied by use of optical microscopy, electron microscopy with X-ray fluorescence, X-ray diffraction, and micro-Raman spectroscopy. The results of this collaboration show that, in general, the rust layers formed during long-term exposure are composed of one or more alternating layers of goethite and lepidocrocite, with scattered patches of maghemite and/or magnetite.

Association of leaf rust and powdery mildew resistance in a recombinant derived from a Hordeum vulgare × Hordeum bulbosum hybrid

Abstract: While studying powdery mildew resistance in a recombinant line (code 81882 derived from a Hordeum vulgare (cv. 'Vada') × Hordeum bulbosum hybrid, a low infection type of resistance to leaf rust was observed. To determine the mode of inheritance of the leaf rust resistance and whether there was linkage between the two resistances, F 2 and F 3 progenies from crosses between 81882 and 'Vada' were inoculated with the leaf rust and powdery mildew pathogens. Southern blots were prepared using restricted DNA extracted from leaves of 82 F 2 plants and four chromosome 2HS sequences were hybridized with the blots to define the length of the introgression. The leaf rust resistance appears to be inherited as a single dominant gene on chromosome 2HS, which co-segregates with the powdery mildew resistance. There was an almost complete association between the resistances and the respective molecular markers, but it is likely that the strong linkage results from the frequent inheritance of the introgressed H. bulbosum DNA as an intact segment of chromatin with only low levels of recombination within the segment.

Effects of bean line pattern mosaic virus on the monocyclic components of rust and angular leaf spot of Phaseolus bean at different temperatures

Abstract: Monocyclic components (development rate during the incubation period or latent period, lesion density, lesion size and disease severity) of rust (Uromyces appendiculatus) and of angular leaf spot (Phaeoisariopsis griseola) in two bean (Phaseolus vulgaris) cultivars (Rosinha G-2 and Carioca), pre-infected or not with bean line pattern mosaic virus (BLPMV), were determined. Trials were conducted at temperatures in the range from 9 to 27°C for rust and from 12 to 30°C for angular leaf spot. Regardless of viral pre-infection, the effect of temperature on the four monocyclic components followed an optimum curve and could be described by a generalized beta function. Generally, angular leaf spot was favoured by higher temperatures with an optimum for disease severity between 24.2 and 28.3°C compared with 15.9–18.5°C for rust. Pre-infection with BLPMV did not change the shape of the optimum curves for all components, but significantly reduced lesion density and disease severity on both cultivars. The development rates during incubation and latent periods for both fungal diseases were not affected by BLPMV. Pre-infection with virus did not alter the ranking of cultivars with respect to resistance to both fungal diseases.

Nitrogen‐induced reduction in leaf phenolic level is not accompanied by increased rust frequency in a compatible willow (Salix myrsinifolia)‐Melampsora rust interaction

Abstract: Phenolic compounds are potential antimicrobial agents in willows (Salix spp.). However, little is known about their role in willow-pathogen interactions. Earlier studies have shown that phenolic levels may vary depending on genotype and environmental factors (such as nutrient availability). In the present study, the combined effects of nitrogen fertilization and infection by pathogenic rust (Melampsora sp.) on phenolics and growth in willow (salix myrsinifolia) clones were investigated. Cutting-propagated plants of eight willow clones were subjected to low and optimum levels of nitrogen fertilization and inoculated with rust urediniospores or mock-inoculated with water. The plants were harvested 20 days after the inoculations and the dry weight of the leaves, stems and roots determined. Phenolics were analysed from leaf material using HPLC. The willow clones differed significantly in their phenolic content, rust frequency and phytomass production. Plants under optimum nitrogen availability showed increased shoot phytomass production and reduced root production. Rust infection increased the root phytomass of willow under both fertilization treatments, but had no consistent effect on the shoot growth of the clones. Low nitrogen availability increased the phenolic levels in willow leaves, but the rust frequency did not differ significantly between plants grown at low and optimum levels of nitrogen fertilization. In several clones, rust infection increased the concentrations of individual phenolic compounds, but there were no significant correlations between phenolic concentrations and the level of rust infection. The results indicate that resistance in compatible willow-rust interactions may not be directly governed by phenolic compounds.

Ion Selective Properties of Rust Membranes and Protective Effect of Stable Rust Layer Formed on Weathering Steel

Abstract: In order to elucidate the mechanism for the protective ability of final stable rust layer formed on a weathering steel by atmospheric corrosion, the ion selective property of rust layer was studied by the use of synthetic iron rust membranes. Anion selective property was increased in this order: Fe3O4<ƒ¿-Fe2O3<ƒ¿-FeOOH<ƒÁ-FeOOH<ƒÀ-FeOOH. Fe3O4 has little effect on the ion selective property. Anion selective property decreased with increasing Cr content in a(Fe1-x, Crx) OOH (Cr-substituted goethite), cation selective property came out when the Cr content exceeds 3.8 mass %. As the effect of adsorbed oxyanions, all of PO43-, MoO42and SO42reduced the anion selective property or changed to cation selective property. Among these anions, PO43has significant effect on the ion selective

Wheat Leaf Rust Severity as Affected by Plant Density and Species Proportion in Simple Communities of Wheat and Wild Oats

Abstract: While it is generally accepted that dense stands of plants exacerbate epidemics caused by foliar pathogens, there is little experimental evidence to support this view. We grew model plant communities consisting of wheat and wild oats at different densities and proportions and exposed these communities to Puccinia recondita to induce wheat leaf rust. Wild oats was included because it is a common competitor of wheat and may act as a barrier to the dispersal of P. recondita spores among wheat plants. Disease severity was estimated as percentage of wheat flag leaves covered by rust lesions. Seeding density rarely had a significant influence on rust severity, probably because of compensation due to increased tillering at low seeding densities. In contrast, increasing the proportion of wheat in mixtures with wild oats consistently increased wheat leaf rust severity. Regression parameters describing wheat leaf rust severity as a function of wheat seeding density did not differ significantly between pure...

Genetics of Stem Rust Resistance in Wheat Cvs. Pasqua and AC Taber

Abstract: Liu, J. Q., and Kolmer, J. A. 1998. Genetics of stem rust resistance in wheat cvs. Pasqua and AC Taber. Phytopathology 88:171-176. Canadian wheat cvs. Pasqua and AC Taber were examined genetically to determine the number and identity of stem rust resistance genes in both. The two cultivars were crossed with stem rust susceptible line RL 6071, and sets of random F6 lines were developed from each cross. The F 6 lines, parents, and tester lines with single stem rust resistance genes were grown in a field rust nursery, inoculated with a mixture of stem and leaf rust races, and evaluated for rust resistance. The same wheat lines were tested by inoculation with specific stem rust races in seedling tests to postulate which Sr genes were segregating in the F 6 lines. Segregation of F6 lines indicated that Pasqua had three genes that conditioned field resistance to stem rust and had seedling genes Sr5, Sr6, Sr7a, Sr9b, and Sr12. Leaf rust resistance gene Lr34, which is in Pasqua, was associated with adult-plant stem rust resistance in the segregating F 6 lines. Adultplant gene Sr2 was postulated to condition field resistance in AC Taber, and seedling genes Sr9b, Sr11, and Sr12 also were postulated to be in AC Taber. Additional keywords: CIMMYT germ plasm, Puccinia graminis f. sp. tritici, specific resistance, Thatcher wheat.

Method for forming a rust proof film

Abstract: A method for forming a rust proof film on a metal substrate comprising the step of immersing the metal substrate in a liquid rust proof film-forming composition which comprises (A) an oxidative substance, (B) a silicate and/or silicon dioxide and (C) at least one member selected from the group consisting of metal cations of Ti, Zr, Ce, Sr, V, W and Mo; and oxymetal anions and fluorometal anions thereof.

Adult plant response of near-isogenic lines and stocks of wheat carrying specific Lr genes against leaf rust

Abstract: Near-isogenic lines and stocks of common wheat carrying specific Lr genes were screened for adult plant resistance against leaf rust (Puccinia recondita f. sp. triticl) pathotypes prevailing in the Nilgiris (South India) under natural and artificial epiphytotic conditions for a period of 10 years (1985-1995). AI;en genes, namely, Lr9, Lr19, Lr14, Lr25, Lr28, Lr32 and Lr37 conferred a high degree of adult plant resistance (APR), while Lr18, Lr21, Lr22a, Lr35 and Lr36 exhibited moderate resistance to leaf rust. However, wheats carrying LrUb, Lr31 + Lr27 and Lr34 conditioned moderate susceptibility. Gene Lr26 from SecaJe cereale and Agropyron elongatum-derived gene Lr29 were ineffective. Adult plant response of these stocks against stem and stripe rusts was also recorded. The backcross improved lines carrying genes Lr19 and Lr14 also showed APR to leaf rust.

Direct and Indirect Effects of Full-Sib Recurrent Selection for Resistance to Common Rust (Puccinia sorghi Schw.) in Three Sweet Corn Populations

Abstract: Common rust (Puccinia sorghi Schw) is a major pathogen of sweet corn (Zea mays L) Recurrent selection may be useful for improving resistance to common rust The objectives of this study were to (i) evaluate three sweet corn populations (Minnll, Minn14, NECDR) after three cycles of full-sib recurrent selection for resistance to common rust evaluated 40 d after pollination (DAP), (ii) determine if selection increased resistance 21 DAP, and (iii) determine if selection affected agronomic traits related to plant architecture, maturity, and yield Cycles 0 to 3 from each population were evaluated under artificial rust infestation in 1989, 1990, 1993, 1994, and 1995, and without infestation in 1994 and 1995 Percent leaf area infected declined linearly from 370 to 82% in Minnll (R 2 = 098) and 570 to 99% in NECDR (R 2 = 098) evaluated 40 DAP, and from 225 to 78% in Minnll (R 2 = 089) and from 228 to 100% in NECDR (R 2 = 091) evaluated 21 DAP Population Minn14 tended to have decreased percent leaf area infected over cycles, but the response was not significant because of cycle x year interactions in each experiment Most agronomic traits decreased linearly over cycles except for ear weight/ stover weight ratio in Minnll and NECDR, and silk delay in Minn14, which increased linearly In general, plants tended to be more compact and flower earlier over cycles Selection for plant type, ear weight, and flowering time should accompany selection for resistance to common rust

Aqueous dispersion composition process for preparing the same, rust preventive, rust prevention method, and rust-proofed metallic products

Abstract: An aqueous dispersion composition comprising an ionomer resin (A) neutralized with a divalent metal and water, which can satisfactorily meet a requirement for higher performance in various applications and is suitable particularly as a heat sealing agent for aluminum foils, films, and papers, metal coating agents, various emulsion modifiers, paints, adhesives, rust preventives, and the like; a process for preparing the aqueous dispersion composition with a high efficiency; a rust preventive for metallic surfaces which can form a rust preventive layer having excellent corrosion resistance and excellent adhesion to a topcoating; a rust prevention method using the rust preventive; and rust-proofed metallic products.

Impact of apple rust mite (Acari: Eriophyiidae) feeding on apple leaf gas exchange and leaf color associated with changes in leaf tissue

Abstract: The impact of the apple rust mite, Aculus schlechtendali (Nalepa), on net CO 2 exchange, transpiration rate, and leaf color of field-grown Jonagold and Golden Delicious apples was investigated. Apple rust mite feeding causes leaf browning. Changes in leaf color were measured to assess the cumulative leaf damage. Significant negative relationships were found between cumulative leaf damage and single-leaf net CO 2 exchange as well as transpiration rate, The same trends were observed on both varieties, but the effect of apple rust mite feeding was more severe on Jonagold than on Golden Delicious. Leaftissue injury was analyzed by cryoscanning electron microscopy and light microscopy. The pictures show that apple rust mites penetrate epidermal cells with their stylets, causing multiple puncture wounds. On heavily infested leaves, apple rust mite feeding causes desiccation of the epidermis and the spongy parenchyma. The resulting malfunction of the stomata and problems in gas exchange within the spongy parenchyma are likely to be the main reason for the reduction of gas exchange.

Connection terminal of fitting type

Abstract: PROBLEM TO BE SOLVED: To provide a connection terminal of fitting type which is given sufficient corrosion resistance as well as reduces the inserting force. SOLUTION: A rust preventive-lubricant of organoamine and paraffin wax dissolved in an organic solvent or water is generated, a male terminal 10 and a female terminal 20 are immersed in the rust preventive-lubricant and dried, or a contacting part of both terminals 10 and 20 is sprayed with the solvent. In the initial state that the rust preventive-lubricant is sprayed on the terminals of a tinning thickness of 0.1 μm, they can maintain contact resistance of the same degree as that of the terminal which is not sprayed. Also, the contact resistance after a corrosion test after spraying the rust preventive-lubricant on the terminals of a timing thickness of 0.1 μm can be reduced to the same degree as the contact resistance after a corrosion test of the terminals of a timing thickness of 0.1 μm. Further, as the wax contained in the rust preventive- lubricant has also lubricity, the effect which reduces the inserting force further can be also obtained.

Triazinethiol-containing anticorrosive coating, anticorrosion treatment method, and anticorrosion treated metal materials

Abstract: A solution and a process for non-chromium rust proof coating is disclose. The rust proof coating solution includes a composite of which the main components are an aqueous resin and water, with 0.2-20 g/l of triazine thiol compound and 0.1/5 g/l phosphoric acid contained therein. The rust proof process is a process for coating a zinc-coated steel or a non-coated steel with the rust proof coating solution as described above.

Rust scorings in a plantation of Salix viminalis clones during ten consecutive years

Abstract: Summary Among pests and diseases occurring in coppiced willow plantations established to produce biofuel, Melampsora rust is the most widespread and severe. In the present study, the variation in rust attacks in a set of Salix viminalis clones was investigated. The aim was to look for trends possibly arising from changes in rust genotype composition, to get some idea about the risks of rust overcoming resistance bred into new willow varieties. Rust levels on 92 S. viminalis clones belonging to 18 different families were scored once each year during 1987–96 in a plantation in southern Sweden. Rust scorings in 1993 deviated most from the average scoring pattern of the clones. Furthermore there was a successive change, such that the longer the time interval between scorings the lower was the correlation between rust scores. Willow families were identified that deviated from the others over time. Various explanations for inconsistency in rust scores over time are discussed.

Introgression of alien genes for leaf rust (Puccinia recondita) resistance into bread wheat (Triticum aestivum) cultivars

Abstract: A study Was conducted during 1983-96 to produce backcross lines. Nineteen bread wheat (Triticum aestivum L, emend, Fiori & Paol.) cultivars susceptible to leaf rust (Puccinia recondita Rob, ex Desm, f. sp tritici) were chosen for incorporating resistance genes of alien origin, viz Lr 9, Lr 19, Lr 24 and Lr 28 . Six to eight backcrosses were given. The evaluation of these backcross improved lines along with their recurrent parents under natural and artificial epiphytotic conditions revealed that they confer adult plant resistance to leaf rust pathotypes prevailing in the Nilgiri hills. Seedling test against selected Indian leaf rust pathotypes of 19 lines provided an evidence that they carry Lr 24 . The backcross derived lines carying Lr 9, Lr 19 and Lr 28 exhibited variable pattern of infection type at seedling stage against leaf rust pathotypcs 77-1 and 77-5 indicating the difference among the type of resistance imparted by these genes. Seedling test against stem rust pathotypes 40 A and 40-1 of backcross lines carrying Lr 24/Sr 24 exhibited resistance to 40A but susceptibility to 40-1, those carrying Lr 19/Sr 25 showed resistance to both pathotypes while those carrying Lr 28 showed susceptibility. The rust reaction taken at different stages of plant growth of backcross lines carrying Lr 19/Sr' 25 indicated that Sr 25 provides adult plant resistance to the stem rust pathotypes occurring in the Nilgiris. The availability of the above alien genes in the background of adapted wheat cultlvars will enhance the exploitation in wheat breeding in India and elsewhere in agriculture and that they could be blended to constitute multilines.

Study on rust layers on steel in different marine corrosion zone

Abstract: The Mossbauer spectra for corrosion products formed on A3 carbon steel and low alloy 16Mn steel exposed in the Chengdao sea area for 2 years by the electro-connected method were determined. The phase composition and content of the rust layers on the two steels in four marine corrosion zones were analyzed and studied. Although the phase composition of the two steels were different, their main phase was β-FeOOH. The different content of FeOOH and Fe3O4 in the rust layers illustrated that FeOOH in the inner rust layer participated in the cathodic process as an oxidant accelerating the corrosion rate of steel under wet/dry cycle condition. Moreover, for the alloy elements in 16Mn steel, the rust layers with simple composition and fine and close texture formed a good barrier layer lowering the corrosion rate of low alloy steel.

Rust preventive coating and method for forming the same

Abstract: (1) An undercoat layer is formed on a surface of a substrate mainly composed of iron by coating the substrate with at least one metal selected from the group consisting of zinc, tin, lead, aluminum, chromium, nickel and copper by hot dipping, electroplating, penetration plating, thermal spraying or chemical plating, or a paint containing at least one rust preventive pigment selected from the group consisting of zinc dust, zinc chromate, minium, basic lead chromate, strontium chromate and lead chromate, and then, (2) the undercoat layer is coated with a paint composition mainly composed of (a) 100 parts by weight of an inorganic filler, (b) 5 to 30 parts by weight of a binder in terms of solid content, and (c) 10 to 100 parts by weight of water and/or a hydrophilic organic solvent, and the composition is hardened by drying at ordinary temperature or heat drying at low temperature to form an overcoat layer, thereby obtaining a rust preventive coating good in hydrophilic properties, air permeability and drying properties, and excellent in corrosion resistance.

Textile composite with iron oxide film

Abstract: A colored textile composite is produced by forming an iron (III) oxide film on a textile surface. This is accomplished by contacting the textile with an aqueous solution having an iron (II) or iron (III) species present. The iron (II) ion resulting from the dissociated iron (II) salt, if an iron (II) salt is utilized, is first hydrolyzed within the aqueous solution and then oxidized under controlled conditions to form iron (III) oxide (hydroxide). The iron (III) ion resulting from the dissociated iron (III) salt, if an iron (III) salt is utilized, is only hydrolyzed under controlled condition to form iron (III) oxide (hydroxide). The iron (III) oxide is then nucleated and forms a smooth and coherent iron (III) oxide film or coating on the surface of the textile without forming an insoluble iron (III) hydroxide precipitate in the solution. This reaction occurs because the reaction conditions are controlled in such a manner as to form sub-colloidal sized iron oxide particles which, in turn, permits a faster rate of adsorption of the iron (III) oxides onto the substrate surface than the rate of formation of the same particles. The iron (III) oxide formed may be goethite, hematite, or magnetite or any mixture thereof. Varying the type of oxide formed allows control over the color shade and other properties of the treated textile composite.