bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing the depth of soil disturbance increases yields of direct drilled wheat on the sandplain soils of Western Australia
Authors: Schmidt CP , Belford RK
Published: March 2005

We evaluated on sandplain soils in the northern wheatbelt of Western Australia in 1990 and 1991 the effect on wheat yields (Triticum aestivum) of increasing the depth of soil disturbance (4-40 cm) while direct drilling. These sandplain soils are easily compacted and eroded by wind, but yields after direct drilling with tined implements are frequently poorer than yields after cultivation. Direct drilling with a tined seeder was compared with: (i) direct drilling with a modified seeder on which the front 3 rows of cultivating tines could be lowered relative to the rear 3 rows of seeding tines; and (ii) with direct drilling followed immediately by deep ripping. Progressively increasing the depth of disturbance reduced soil strength and generally increased grain yields of wheat. Effects on yield were more pronounced in the wetter year of 1991 on an experimental site that had not been previously ripped; responses of 32 kg/ha for each centimetre increase in depth of disturbance were recorded. The highest yields followed deep ripping (3429 kg/ha), and the lowest yields followed minimal soil disturbance using narrow (5 cm) seeding tines working to seeding depth only (2144 kg/ha). These results confirmed that it is possible to use a modified direct drilling technique (thus retaining the advantages of timely sowing after rainfall and lowered risk of wind erosion) and raise yields above those normally expected from direct drilling on these soils.
Breeding improved rice cultivars for temperate regions: a case study
Authors: McKenzie KS , Johnson CW , Tseng ST , Oster JJ , Brandon DM
Published: March 2005

An accelerated rice-breeding program was initiated in 1969 at the California Rice Experiment Station. The program is broad in scope, developing cultivars in all US market classes (long, medium, and short grains) and special purpose types (waxy and aromatics). This grower-funded rice-breeding program has released 27 new cultivars as well as improved germplasm lines. Statewide paddy rice yields have risen from 6.2 to 9.3 t/ha since 1978. The incorporation of semi-dwarfing genes, earlier maturity, and increased yield potential have contributed significantly to increases in grain yield. High experimental yields (>I1 t/ha) are routine and achieving increased increments of yield will become more difficult. After the initial shift to semi-dwarf cultivars, increasing efforts were directed toward improving adaptation to environmental stresses and grain quality. Screening and selection for cold tolerance in the form of seedling vigour for water seeding and resistance to cool temperature induced sterility at the reproductive stage are integral parts of the rice-breeding program. Progress is being made on incorporation into California rice cultivars of resistance to stem rot (Sclerotiurn oryzae Cattaneo) and aggregate sheath spot [Rhizoctonia oryzae-sativae (Swada) Mordue] from wild species and tolerance to rice water weevil (Lissorhoptus oryzophilus Kuschel). New restrictions and regulations of agronomic management practices may negatively impact rice production, creating problems in stand establishment, soil fertility, and weed, disease, and insect control. Breeding efforts to help minimise the adverse effect of these restrictions on yield and quality will increase in the future. Increased emphasis is being placed on improving milling yield and cooking and processing characteristics, and new laboratory methods are being explored to aid in evaluation and selection for grain quality.
The life cycle and ecology of Cyperus difformis (rice weed) in temperate Australia: a review
Authors: Sanders BA
Published: March 2005

The almost exclusive use of aerial sowing of rice in Australia and the concomitant reliance upon the herbicide bensulfuron-methyl to control Cyperus difformis has not been matched with an increase in the understanding of the biology of this major weed. Of great significance i s the recent discovery of C. difformis biotypes in California which are resistant to bensulfuron-methyl. Although Australian rice agroecosystems employ longer rotations than the intensive Californian systems, it is only a matter of time until resistant biotypes are identified in Australia. This paper identifies the life cycle characteristics of C. difformis that we need to understand for its future management.
Honeybee pollination of white clover (Trifolium repens L.) cv. Haifa
Authors: Goodman RD , Williams AE
Published: March 2005

The role of honeybees (Apis mellifera) in the pollination of white clover cv. Haifa was studied in a commercial planting at Mount Mercer, Victoria. Honeybees comprised 88% of all insect visitors to this crop. The activity of honeybees and native bees (Lasioglossum sp.) increased seed yield from 1.3 g/plot (plots closed to bees) to 40.3 g/plot (plots open to bees). The caging of plots for part of the flowering period to simulate the non-availability of bees for pollination resulted in lower seed yields than those from uncaged plots.
Sustaining productivity of a Vertisol at Warra, Queensland, with fertilisers, no-tillage, or legumes. 1. Organic matter status
Authors: Dalal RC , Strong WM , Weston EJ , Cooper JE , Lehane KJ , King AJ , Chicken CJ
Published: March 2005

Management practices involving legume leys, grain legumes, and no-tillage and stubble retention, along with nitrogen (N) fertiliser application for wheat cropping, were examined for their effectiveness in increasing soil organic matter (0-10 cm depth) from 1986 to 1993 in a field experiment on a Vertisol at Warra, Queensland. The treatments were (i) grass + legume leys (purple pigeon grass, Setaria incrassata; Rhodes grass, Chloris gayana; lucerne, Medicago sativa; annual medics, M. scutellata and M. truncatula) of 4 years duration followed by continuous wheat; (ii) 2-year rotation of annual medics and wheat (Triticum aestivum cv. Hartog); (iii) 2-year rotation of lucerne and wheat; (iv) 2-year rotation of chickpea (Cicer arietinum cv. Barwon) and wheat; (v) no-tillage (NT) wheat; and (vi) conventional tillage (CT) wheat. Fertiliser N as urea was applied to both NT wheat and CT wheat at 0,25, and 75 kg N/ha. year. The CT wheat also received N at 12.5 and 25kg N/ha. year. After 4 years, soil organic carbon (C) concentration under grass + legume leys increased by 20% (650 kg C/ha. year) relative to that under continuous CT wheat. Soil total N increased by 11, 18, and 22% after 2, 3, and 4 years, respectively, under grass + legume leys relative to continuous CT wheat. These increases in soil organic matter were mostly confined to the 0-2.5 cm layer. After the start of wheat cropping, organic C and total N levels declined steadily but were still higher than under CT wheat and higher than initial values in December 1985. Although 2-year rotations of lucerne-wheat and medic-wheat had a small effect on soil organic C, soil total N concentrations were higher than in the chickpea-wheat rotation and continuous CT wheat from November 1990 to November 1992. Soil under chickpea-wheat rotation had organic C and total N concentrations similar to continuous CT wheat, although from the former, about 70 kg/ha. year of extra N was removed in the grain from 1989 to 1993. No-tillage practice had a small effect on soil organic C, although total N concentration was higher than under CT wheat in November 1993. These effects were mainly confined to the surface 0-2.5 cm depth. The C to N ratio was only affected in soil under grass + legume leys, and no-tillage treatments. These data show that restoration of soil organic matter in Vertisol requires grass + legume leys, primarily due to increased root biomass, although soil total N can be enhanced by including legume leys for longer duration in cropping systems in the semi-arid and subtropical environment.
Wheat yield response to rainfall in a long-term multi-rotation experiment in the Victorian Wimmera
Authors: Hannah MC , O'Leary GJ
Published: March 2005

Seventy-six years of wheat yield data from a long-term rotation experiment at Dooen in the Victorian Wimmera were analysed to describe the response of wheat yield to seasonal rainfall, crop sequence, and time. Wheat yields from 7 different 1- to 4-course rotations involving wheat, barley, oat, field pea, grass pasture and fallow were compared as a function of growing-season (May-November) rainfall. The field layout had no within-year replication, but each phase of each rotation was represented once in each year. An approximate quadratic response of wheat yield to both current year and previous year May-November rainfall was observed for each rotation. Previous year May-November rainfall boosted wheat yields grown on fallow, but decreased the yield of wheat grown on field pea or wheat stubble. Highest wheat yields followed fallow preceded by pasture, high yields followed fallow preceded by a cereal, moderate yields followed field pea, and low yields occurred for continuous wheat. Long-term trends in wheat yields adjusted for rainfall depended on crop sequence and fluctuated more in the non-fallow, 3-course rotations. Over the 76 years, average yield declined in all rotations except the continuous wheat, which was always low, but there was evidence that yield of all continuous cropped rotations had increased during the last 2 decades.
Application of AGNPS to model nutrient generation rates under different farming management practices at the Gunnedah Research Centre catchment
Authors: Foerster J , Milne-Home WA
Published: March 2005

Data collected at a conservation tillage trial site operational between 1971 and 1986 were used to assess the performance of the Agricultural Non-Point Source model (AGNPS). Eight trial plots, each of about 1 ha (average slope of 3.8%), were established on the black earths of paddock 2 at the Gunnedah Research Centre, New South Wales. The plots were subjected in pairs to stubble-burning, stubble incorporation, stubble-mulching, and no-tillage treatments. Runoff and peak flow rate from the plots, resulting from 5 rainfall events between 1982 and 1986, were used to calibrate the hydrology module of AGNPS. Hydrologic simulations for each plot and associated tillage treatment performed after calibration showed that conservation farming practices could effectively reduce runoff and peak flow rate. AGNPS was also used to simulate nutrient generation rates, defined as the transport of soluble and sediment-adsorbed nitrogen and phosphorus in runoff and sediment discharge, for the whole catchment for a number of rainfall events. The model predicted that nutrient movement could be reduced using best management practices, including the implementation of contour banks, contour cultivation, and no tillage. Additional information related to soil chemical properties and pore/surface water nutrient content could improve model performance.
Factors in conservation farming that reduce erosion
Authors: Malinda DK
Published: March 2005

A medium-term (10 years) stubble x tillage field experiment was established in 1984 on a red-brown earth at Tarlee, 70 km north of Adelaide, to develop a suitable system for sustaining the soil resource. Measurements of infiltration capacity, soil detachment rate, and erosion were taken in summer, autumn, winter, and spring 1989-90. The rotation was wheat-barley-grain legume, and treatments included 3 levels of stubble retention (0.5, 3.0, 5.0 t/ha.year) and 4 types of tillage [no-tillage (NT), direct drill (DD), reduced tillage (RT), conventional cultivation (CC)]. NT was seeded with narrow points (30 mm) and the other tillage treatments with wide shares (150 mm). The Northfield rainfall simulator with an erosive rainfall of 100 mm/h and an energy of 28.6 J/ m2.mm was used to measure runoff and soil and nutrient loss. This paper reports on erosion from this experiment. The results show that runoff was reduced through farming practices such as the retention of adequate stubble residue (about 3-5 t/ha.year of cereals), NT, or a combination of these factors. Increasing the average - - - annual stubble retention decreased runoff and soil loss linearly. The greater the amount of stubble retained annually, the less the runoff and soil loss, whether or not the soil surface was protected. The significant sediment release and soil loss from bared soil is inversely related to soil stability measured by a reduction in soil organic matter. Crop type also influenced erosion; for example, soil was more vulnerable to erosion after peas than after cereal. The amount of stubble after harvest was usually greater with cereals than with grain legumes. Runoff as a percentage of applied rain, and soil loss, ranged from 26 to 60% and 0.52 to 1 .I t/ha for 0.5 t/ha. year stubble (means of all treatments) for April 1989 and August 1990, respectively, and from 5 to 35% and 0.03 to 0.8 t/ha for 5.0 t/ha.year stubble for the same simulation period. Runoff rates in the last 3 min of 18 min simulation ranged from 0.4 to 1.1 mm/min for 5.0 t/ha.year stubble and from 0.8 to 1.7 mm/min for 0.5 t/ha.year stubble. The runoff rates recorded at the 18th minute of simulation ranged from 0.5 to 1.2 mm/min for NT and 0.7 to 1.5 mm/min for CC.
Effects of tillage, stubble, gypsum, and nitrogen fertiliser on cereal cropping on a red-brown earth in south-west Queensland
Authors: Thomas GA , Gibson G , Nielsen RGH , Martin WD , Radford BJ
Published: March 2005

We describe effects of a range of fallow and crop management practices on soil properties and crop growth in wheat and grain sorghum on a red-brown earth in south-west Queensland. Results from the first 4 years of the experiment, which commenced in 1983, have been published. This paper reports results from the next 6 years. No tillage (NT) and reduced tillage (RT), combined with stubble retention, resulted in better soil-water storage during fallow but less soil nitrate-nitrogen (N) at sowing than observed with more frequent and aggressive mechanical tillage treatments such as discing, and stubble removal. In drier growing seasons, when N application often resulted in yield reductions in wheat, NT and RT with stubble retention resulted in higher grain yields than other treatments in both crops. In a wetter growing season, when N application resulted in yield increases, wheat yields under NT and RT with stubble retention were lower than those of other treatments, even at the highest rate of N application, indicating that factors such as plant disease were also affecting yields. With stubble retention, average yields of 6 wheat crops were 12% higher under NT and reduced blade tillage, and average yields of 4 sorghum crops were 20-30% higher under NT, than other tillage treatments. Gypsum application resulted in an average yield increase of 15% in both crops under conventional disc tillage with stubble retention. In wheat, NT and RT with stubble retention were generally associated with lower grain protein concentration, and N application was necessary to maximise profitability of these practices.
Effects of rainfall, moisture stress, and stocking rate on the persistence of white clover over 30 years
Authors: Hutchinson KJ , King KL , Wilkinson DR
Published: March 2005

The effects of spring rainfall, critical levels of summer moisture stress, and sheep stocking rates on the persistence of white clover (Trifolium repens cv. Huia) have been evaluated in a 30-year experiment (1964-93) based on sown, well-fertilised pasture. Plant species presence was measured each year as basal cover using a vertical 10-pin frame. Hits at ground level from 800 points/plot were recorded in late September on duplicate plots, which were set-stocked at 3 rates (10, 20 reduced to 15, 30 reduced to 20 d.s.e./ha). A soil-water model based on rainfall and tank evaporation was calibrated against on-site soil water measurements (0-260 mm) and used to predict soil water (mm) for weekly time steps over 30 years. Smoothing of long-term rainfall data (SYSTAT, Lowess) showed an overall decline in warm-season rainfall (October-March), which was punctuated by above-average (1969-74) and average runs of years (1983-90). Flexible smoothing splines (SAS) were used to indicate patterns of yearly white clover presence. For all stocking treatments, there were significant declines in the presence of white clover over 3 decades. At the highest stocking rate, the recovery of white clover following the 1965 drought was poor. Late summer (January-March) moisture stress, defined as the number of weeks when soil water (0-260 mm) was <15 mm, was critical in determining white clover presence in the following spring (September). Rainfall received from October to December generally had a positive effect. These climate-based relationships reinforce the importance of stolon growth and survival as a regenerative strategy for white clover. However, over the 30 years, the species showed decreasing resilience post drought, which suggests a long-term failure of seed-based regeneration. Annual rates of soil nitrogen build-up ranged from 29 to 54 kg N/ha.year and were poorly related to white clover presence in the stocking treatments. Governing mechanisms, based on interactions between seasonal moisture stress, sheep stocking rate, interspecific plant competition, and seed pool dynamics, are proposed to explain the nature of long-term decline in white clover presence in well-fertilised, sown pastures in the Northern Tablelands of New South Wales.
Differences in mineral concentration among diploid and tetraploid cultivars of rhodesgrass (Chloris gayana)
Authors: Jones RJ , Loch DS , LeFeuvre RP
Published: March 2005

Mineral composition of a range of rhodesgrass cultivars was measured to assess if levels were suitable for cattle growth. Leafy regrowth of 11 rhodesgrass cultivars and lines was analysed for a range of elements in 2 replicated field experiments near Gympie in southern Queensland. Experiment 1 comprised 2 diploid and 2 tetraploid cultivars, while 7 diploids and 3 tetraploids were compared in experiment 2.Overall, the tetraploids had higher nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) concentrations but lower sodium (Na) and boron (B) concentrations than the diploids. Concentrations of potassium (P), copper (Cu) and aluminium (Al) for the 2 groups were similar and showed no significant cultivar differences. Results for sulfur (S), zinc (Zn) and iron (Fe) varied between experiments, either with no significant ploidy and cultivar differences or with higher concentrations in the tetraploids (S in experiment 2, Zn in experiment 1). The tetraploids had significantly higher concentrations of Mn in experiment 2. The Na concentration found in cultivar Boma was lower (0.02%) than the other cultivars in experiment 2. Similarly, cultivar Samford in experiment 1 had a lower Na concentration than the other 3 cultivars. Both Boma and Samford, however, had the highest Mg concentrations in their respective experiments. K/(Ca+ Mg) equivalent ratios in the 2 experiments were in the range 0.40-1.50. This is well below the accepted critical value of 2.2 above which grass tetany in ruminants could become a problem.
Gibberellic acid detection of dwarf offtypes in micropropagated Cavendish bananas
Authors: Damasco OP , Godwin ID , Smith MK , Adkins SW
Published: March 2005

Detection of dwarf offtypes produced by micropropagation of Cavendish bananas (Musa spp.) cultivars New Guinea Cavendish and Williams was achieved by spraying gibberellic acid (GA3) solution (289 pmol/L) onto deflasked plants and measuring various plantlet responses. The most useful identification criterion was elongation of the sheath of the first leaf to form after GA3 application. Elongation of this structure was about 2-fold greater in normal plants than observed in dwarfs. Similar measurements taken earlier during in vitro culture or later during plant establishment in soil were not as useful in discriminating between normals and dwarfs as the measurements made at deflasking. The similar GA3-induced elongation response of the dwarf offtype and that of the naturally occurring dwarf cultivar Dwarf Parfitt suggests that the mechanism for dwarfism could be the same in the 2 cases.
Effect of ethylene on postharvest quality of green beans
Authors: Wills RBH , Kim GH
Published: March 2005

Green beans were stored at 0,5 and 20�C in air containing ethylene at concentrations in the range 0.005-10 �L/L. The quality of individual beans was scored at regular intervals and the time for each treatment unit to deteriorate to an unacceptable quality score was calculated. Reducing the ethylene concentration in the atmosphere was found to significantly extend the storage life at all temperatures. The maximum storage life achieved at an ethylene concentration of 0.005 �L/L was 29, 20 and 11 days at 0, 5 and 20�C, respectively. For each temperature, this was about twice the storage life of beans held in 0.1-1.0 �L/L ethylene. The amount of ethylene in the atmosphere around beans held in commercial markets was found to range from 0.17 to 1.17 �L/L suggesting that the useful marketing period of beans could be greatly extended by better control over ethylene accumulation.
Comparison of α -tocopherol acetate preparations given as single intraperitoneal or subcutaneous doses for increasing plasma and liver α -tocopherol in sheep fed a low vitamin E diet
Authors: Smith GM , Fry JM , Ilett KF
Published: March 2005

This experiment examined the efficacy of a single dose of �-tocopherol acetate (2000 IU) in either an aqueous or oily formulation, given as an intraperitoneal (i.p.) or subcutaneous (s.c.) injection or orally as an aqueous formulation, at raising a-tocopherol concentrations in blood plasma and liver of young sheep with low vitamin E. Maximum plasma concentrations (Cmax) were greatest in sheep supplemented by the s.c.-aqueous method or orally (4.83 and 3.49 mg/L respectively). These values were 3.0-5.7 times the C, values of the other treatment groups. Also, the time taken to reach Cmax (Tmax) was far shorter in these 2 treatments than in the other treatments (Tmax values were 0.70 and 0.65 days respectively). Tmax values were greatest for the oily formulation (42 and 73 days for the i.p. and S.C. injections, respectively). The area under the plasma a-tocopherol concentration-time curve (AUC(0-85d)), was greatest for the s.c.-aqueous group (median of 2066 mg.h/L). Six of the sheep in the i.p.-aqueous group had AUC(0-85d) values similar to the controls whereas the rest were similar to the s.c.-aqueous group. Plasma �-tocopherol acetate was only consistently detected in sheep in the s.c.-aqueous group (Cmax of 25.25 � 3.14 mg/L and Tmax of 0.24 � 0.03 days). Pharmacokinetic modelling of the plasma data obtained from sheep in the s.c.-aqueous group was helpful in understanding the factors which controlled the appearance and disappearance rates of plasma �-tocopherol in this group. In contrast to plasma data, liver concentrations of �-tocopherol at days 24 and 57 were greatest in sheep supplemented by the i.p.-oily method. The s.c.-aqueous was the second most effective method at raising concentrations in the liver. The results suggest that supplementation by s.c. injection of an aqueous formulation may be an effective means of administering vitamin E to sheep.
Plant population dynamics in subterranean clover and murex medic swards. 3. Effect of pod burial, summer grazing and autumn cultivation on emergence
Authors: Blumenthal MJ , Ison RL
Published: March 2005

Murex medic (Medicago murex Willd.) seedling recruitment is more sensitive to soil water at the time of emergence than subterranean clover (Trifolium subterraneum L.). Murex medic pods normally lay on the soil surface. Shallow burial of pods may be beneficial when soil moisture is marginal for germination and emergence. In addition, the tightly coiled structure of murex medic pods may also act as a barrier to water uptake by the seed. Two methods of burying murex medic pods were investigated in the field: (i) trampling by sheep hooves through summer grazing; and (ii) through light cultivation in autumn. A glasshouse experiment was also conducted to examine the interaction between the length of time that the soil stays moist and pod burial for CD26 and CD53 murex medic and Dalkeith, Junee, Seaton Park and Woogenellup subterranean clover. In the glasshouse, pod burial was important for the attainment of maximum emergence in all genotypes when soil water was limiting. However, pod structure did not appear to have a limiting role in germination and emergence in murex medic. When tested in the field, pod burial by sheep trampling through summer grazing improved emergence in CD26, possibly because the smaller more open pod was more easily trampled than that of CD53. Summer grazing in CD53 and Dalkeith and autumn cultivation in all genotypes did not improve emergence; possible reasons for this are discussed so to is the role of murex medic in ley farming systems in eastern Australia.
Production and composition of milk by dairy cows fed common vetch or lupin grain as protein supplements to a silage and pasture-based diet in early lactation
Authors: Valentine SC , Bartsch BD
Published: March 2005

Milk production and composition were measured for 49 days in early lactation in 40 Holstein-Friesian cows fed 8 kg/day (fresh weight) of 1:1 mixtures of either rolled barley-lupin grain (Lupinus angustifolius L. cv. Gungurru) or barley-common vetch grain (Vicia sativa L. cv. Blanche Fleur). All cows were fed 1 kg/day of a pelleted concentrate containing minerals and vitamins, and wilted perennial ryegrass-subterranean clover pasture silage was available ad libitum with restricted grazing of perennial ryegrass-subterranean clover pasture. Cows ate all of the barley-lupin grain and barley-vetch grain mixtures. Mean daily dry matter intakes of silage (kg/cow.day) were 9.9 and 9.8 for cows fed the barley-lupin grain and barley-vetch grain mixtures respectively. Estimated pasture DM intake was 3.0 kg/cow.day. Mean daily yields of milk (L), fat (kg) and protein (kg) were significantly (P<0.001) greater for cows fed the barley-lupin grain mixture (30.3, 1.30 and 0.92 respectively) than for those fed the barley-vetch grain mixture (27.7, 1.23 and 0.87 respectively). Cows fed the barley-vetch grain mixture gained 0.2 kg/day more liveweight than those fed the barley-lupin grain mixture. Although both common vetch grain and lupin grain were readily eaten by dairy cows, when fed as protein supplements to a high quality silage and pasture-based diet in early lactation, cows fed the vetch grain produced less milk and milk components. This may be related to the greater partitioning of nutrients to liveweight gain rather than to toxicity problems in the cows fed vetch grain.
Effect of sowing point design and tillage practice on the incidence of Rhizoctonia root rot, take-all and cereal cyst nematode in wheat and barley
Authors: Roget DK , Neate SM , Rovira AD
Published: March 2005

Effect of tillage treatments on the cereal root diseases, rhizoctonia root rot, take-all and cereal cyst nematode, and on grain yield of cereals were tested in 4 field experiments over 3 years. Conventionally cultivated treatments were compared with a range of direct-drill treatments using either a standard tined seed drill equipped with 10 cm sowing points, a specialised drill designed to give minimal soil disturbance or a standard tined seed drill equipped with a range of commercial or modified narrow points designed to provide soil disturbance from 0 to 5.0 cm below seed depth. Direct-drilled treatments that disturbed the soil below seed depth (DDD) and treatments that included 1 cultivation prior to sowing (CPS) resulted in a reduction of rhizoctonia root rot when compared with direct-drilled treatments that did not disturb the soil below seed depth (DDN). When seasonal conditions encouraged volunteer plant growth before sowing, a chemical fallow treatment applied 3 weeks before sowing significantly reduced rhizoctonia root rot in all direct-drilled plots. This was a significant factor in DDD treatments providing effective control of rhizoctonia root rot. Take-all was present in 3 of the 4 experiments. In 2 experiments, take-all was significantly higher in plots following DDN treatments than DDD or CPS treatments and in 1 experiment there was no effect of tillage. Cereal cyst nematode was present in 1 of the 4 experiments. The level of root damage from cereal cyst nematode was least in plots following DDN treatments, higher following DDD treatments and highest following CPS treatments. The influence of tillage practice on grain yield was closely related to the effect of tillage on cereal root disease when levels of disease were moderate to high. Where the incidence of root disease was low, grain yield differences due to tillage treatments were generally related to agronomic factors such as seed depth and seedbed condition.
Transcriptome analysis of the aphid bacteriocyte, the symbiotic host cell that harbors an endocellular mutualistic bacterium,
Buchnera
Authors: Nakabachi Atsushi , Shigenobu Shuji , Sakazume Naoko , Shiraki Toshiyuki , Hayashizaki Yoshihide , Carninci Piero , Ishikawa Hajime , Kudo Toshiaki , Fukatsu Takema
Published: March 2005

Aphids possess bacteriocytes, cells specifically differentiated to harbor obligatory mutualistic bacteria of the genus
Buchnera
, which have lost many genes that are essential for common bacterial functions. To understand the host's role in maintaining the symbiotic relationship, bacteriocytes were isolated from the pea aphid,
Acyrthosiphon pisum
, and the host transcriptome was investigated by using EST analysis and real-time quantitative RT-PCR. A number of genes were highly expressed specifically in the bacteriocyte, including (
i
) genes for amino acid metabolism, including those for biosynthesis of amino acids that
Buchnera
cannot produce, and those for utilization of amino acids that
Buchnera
can synthesize; (
ii
) genes related to transport, including genes for mitochondrial transporters and a gene encoding Rab, a G protein that regulates vesicular transport; and (
iii
) genes for putative lysozymes that degrade bacterial cell walls. Significant up-regulation of
i
clearly indicated that the bacteriocyte is involved in the exchange of amino acids between the host aphid and
Buchnera
, the key metabolic process in the symbiotic system. Conspicuously high expression of
ii
and
iii
shed light on previously unknown aspects of the host–
Buchnera
interactions in the symbiotic system.
Quantitative SUMO-1 Modification of a Vaccinia Virus Protein Is Required for Its Specific Localization and Prevents Its Self-Association
Authors: Palacios Silvia , Perez Laurent H. , Welsch Sonja , Schleich Sibylle , Chmielarska Katarzyna , Melchior Frauke , Locker Jacomine Krijnse
Published: March 2005

Vaccinia virus (VV), the prototype member of the Poxviridae, a family of large DNA viruses, carries out DNA replication in specialized cytoplasmic sites that are enclosed by the rough endoplasmic reticulum (ER). We show that the VV gene product of A40R is quantitatively modified by SUMO-1, which is required for its localization to the ER-enclosed replication sites. Expression of A40R lacking SUMO-1 induced the formation of rod-shaped cytoplasmic aggregates. The latter likely consisted of polymers of nonsumoylated protein, because unmodified A40R interacted with itself, but not with the SUMO-1–conjugated protein. Using a bacterial sumoylation system, we furthermore show that unmodified A40R is mostly insoluble, whereas the modified form is completely soluble. By electron microscopy, the A40R rods seen in cells were associated with the cytosolic side of the ER and induced the apposition of several ER cisternae. A40R is the first example of a poxvirus protein to acquire SUMO-1. Its quantitative SUMO-1 modification is required for its proper localization to the viral “mini-nuclei” and prevents its self-association. The ability of the nonsumoylated A40R to bring ER membranes close together could suggest a role in the fusion of ER cisternae when these coalesce to enclose the VV replication sites.
Association of the Leukocyte Plasma Membrane with the Actin Cytoskeleton through Coiled Coil-mediated Trimeric Coronin 1 Molecules
Authors: Gatfield John , Albrecht Imke , Zanolari Bettina , Steinmetz Michel O. , Pieters Jean
Published: March 2005

Coronin 1 is a member of the coronin protein family specifically expressed in leukocytes and accumulates at sites of rearrangements of the F-actin cytoskeleton. Here, we describe that coronin 1 molecules are coiled coil-mediated homotrimeric complexes, which associate with the plasma membrane and with the cytoskeleton via two distinct domains. Association with the cytoskeleton was mediated by trimerization of a stretch of positively charged residues within a linker region between the N-terminal, WD repeat-containing domain and the C-terminal coiled coil. In contrast, neither the coiled coil nor the positively charged residues within the linker domain were required for plasma membrane binding, suggesting that the N-terminal, WD repeat-containing domain mediates membrane interaction. The capacity of coronin 1 to link the leukocyte cytoskeleton to the plasma membrane may serve to integrate outside-inside signaling with modulation of the cytoskeleton.
Mining SARS-CoV protease cleavage data using non-orthogonal decision trees: a novel method for decisive template selection
Authors: Yang Zheng Rong
Published: March 2005

Motivation

Although the outbreak of the severe acute respiratory syndrome (SARS) is currently over, it is expected that it will return to attack human beings. A critical challenge to scientists from various disciplines worldwide is to study the specificity of cleavage activity of SARS-related coronavirus (SARS-CoV) and use the knowledge obtained from the study for effective inhibitor design to fight the disease. The most commonly used inductive programming methods for knowledge discovery from data assume that the elements of input patterns are orthogonal to each other. Suppose a sub-sequence is denoted as P2P1P1′P2′, the conventional inductive programming method may result in a rule like ‘if P1 = Q, then the sub-sequence is cleaved, otherwise non-cleaved’. If the site P1 is not orthogonal to the others (for instance, P2, P1′ and P2′), the prediction power of these kind of rules may be limited. Therefore this study is aimed at developing a novel method for constructing non-orthogonal decision trees for mining protease data.

Result

Eighteen sequences of coronavirus polyprotein were downloaded from NCBI (http://www.ncbi.nlm.nih.gov). Among these sequences, 252 cleavage sites were experimentally determined. These sequences were scanned using a sliding window with size k to generate about 50 000 k-mer sub-sequences (for short, k-mers). The value of k varies from 4 to 12 with a gap of two. The bio-basis function proposed by Thomson et al. is used to transform the k-mers to a high-dimensional numerical space on which an inductive programming method is applied for the purpose of deriving a decision tree for decision-making. The process of this transform is referred to as a bio-mapping. The constructed decision trees select about 10 out of 50 000 k-mers. This small set of selected k-mers is regarded as a set of decisive templates. By doing so, non-orthogonal decision trees are constructed using the selected templates and the prediction accuracy is significantly improved.

Availability

The program for bio-mapping can be obtained by request to the author.

Contact

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Genetic variation for an aphid wing polyphenism is genetically linked to a naturally occurring wing polymorphism
Authors: Braendle Christian , Friebe Ilvy , Caillaud Marina C , Stern David L
Published: March 2005

Many polyphenisms are examples of adaptive phenotypic plasticity where a single genotype produces distinct phenotypes in response to environmental cues. Such alternative phenotypes occur as winged and wingless parthenogenetic females in the pea aphid (
Acyrthosiphon pisum
). However, the proportion of winged females produced in response to a given environmental cue varies between clonal genotypes. Winged and wingless phenotypes also occur in males of the sexual generation. In contrast to parthenogenetic females, wing production in males is environmentally insensitive and controlled by the sex-linked, biallelic locus,
aphicarus
(
api
). Hence, environmental or genetic cues induce development of winged and wingless phenotypes at different stages of the pea aphid life cycle. We have tested whether allelic variation at the
api
locus explains genetic variation in the propensity to produce winged females. We assayed clones from an F
2
cross that were heterozygous or homozygous for alternative
api
alleles for their propensity to produce winged offspring. We found that clones with different
api
genotypes differed in their propensity to produce winged offspring. The results indicate genetic linkage of factors controlling the female wing polyphenism and male wing polymorphism. This finding is consistent with the hypothesis that genotype by environment interaction at the
api
locus explains genetic variation in the environmentally cued wing polyphenism.
The distributions of the duplicate oestrogen receptors ER-βa and ER-βb in the forebrain of the Atlantic croaker (Micropogonias undulatus): evidence for subfunctionalization after gene duplication
Authors: Hawkins M.B , Godwin J , Crews D , Thomas P
Published: March 2005

Teleost fishes have three distinct oestrogen receptor (ER) subtypes: ER-α, ER-βa (or ER-γ) and ER-βb. ER-βa and ER-βb arose from a duplication of an ancestralER-βgene early in the teleost lineage. Here, we describe the distribution of the three ER mRNAs in the hypothalamus and cerebellum of the Atlantic croaker to address two issues: the specific functions of multiple ERs in the neuroendocrine system and the evolution and fate of duplicated genes. ER-α was detected in nuclei of the preoptic area (POA) and hypothalamus previously shown to possess ER-αs in teleosts. AcER-βb, but not ER-βa, labelling was detected in the magnocellular neurons of the POA, nucleus posterior tuberis, the nucleus recessus posterior and cerebellum. By contrast, acER-βa, but not ER-βb, was detected in the dorsal anterior parvocellular POA and suprachiasmatic nucleus. Both ER-βs were found in posterior parvocellular and ventral anterior POA nuclei, the ventral hypothalamus, and periventricular dorsal hypothalamus. The differences we observed in ER subtype mRNA distribution within well-characterized brain nuclei suggest that ER-βa and ER-βb have distinct functions in the neuroendocrine control of reproduction and behaviour, and provide evidence that the teleostER-βparalogues have partitioned functions of the ancestralER-βgene they shared with tetrapods.
The silvering process of Anguilla anguilla: a new classification from the yellow resident to the silver migrating stage
Authors: Durif C. , Dufour S. , Elie P.
Published: March 2005

The identification of five stages for female and two stages for male eels Anguilla anguilla using multivariate analysis was carried out on a large sample of individuals collected at six different locations in France. Stages corresponded to a growth phase (stages I and II), a pre‐migrant phase (III) and two migrating phases (IV and V). It is likely that an important period of growth triggered silvering through the production of growth hormone (GH) in stage III eels. In migrating eels gonad development, gonadotropin hormone (GTH‐II) production and increase of eye surface were similar at all sites. Differences among locations were found in gut regression and pectoral fin length. As variability for these increased with the size of the watershed and values were highest for the most downstream locations, fin length and gut regression may indicate the time since an eel started its migration.
7 cases of hydrofluoric acid burn in which calcium gluconate was effective for relief of severe pain
Authors: Ohata Utako , Hara Hiroyuki , Suzuki Hiroyuki
Published: March 2005

We report 7 cases of chemical burns due to hydrofluoric acid (HF). The patients suffered from severe pain. However, the pain was relieved after treatment with calcium gluconate. 6 out of the 7 cases were men. At the accidental exposures, all the patients had been engaged in washing or cleaning work and received burns on their hands and/or fingers. In one case, the forearm was also involved. During such work, all the patients had used rubber gloves, but the gloves had pinholes. For the treatments, 4% calcium gluconate jelly was applied in 5 cases and 4 of 7 were subcutaneously injected with 8.5% calcium gluconate. The involved nails were removed in 5 cases. It is concluded that physicians should provide calcium gluconate jelly and subcutaneous injections to treat an HF burn and should not hesitate to remove the involved nails. To prevent chemical burn due to HF, education and reeducation of workers regarding the hazard of this chemical are necessary.
Contact allergy to methyldibromo glutaronitrile – data from a ‘front line’ network
Authors: Johansen Jeanne D. , Veien Niels K. , Laurberg Grete , Kaaber Knud , Thormann Jens , Lauritzen Martin , Avnstorp Christian ,   on Behalf Of The Danish Contact Dermatitis Group
Published: March 2005

The preservative methyldibromo glutaronitrile (MDBGN) has caused an epidemic of contact allergy in Europe. However, most data concerning contact allergy comes from hospital departments of dermatology. As a part of the primary health care sector, Danish dermatologists in private practice provide the front line of care for patients with skin diseases. Data from this source may therefore better reflect trends in the general population than material from hospital departments of dermatology. In this study, the frequency of MDBGN allergy and the characteristics of patients seen by dermatologists in private practice were studied. In 1 year, 2146 patients were patch tested by the participating dermatologists from 4 clinics in various parts of Denmark. 5% (110) had positive patch tests to MDBGN, with no difference between the sexes. After adjustment was made for other background variables, multivariate analysis using logistic regression showed a significant association between hand eczema and MDBGN allergy (OR 2.5, P < 0.001). In 53 cases (52.4%), the patch test reaction to MDBGN was judged to be of current relevance. Creams and lotions accounted for 31% of the identified causative products and liquid soaps for 23%. It is concluded that contact allergy to MDBGN is frequent among patients seen by dermatologists in private practice. This is consistent with results from hospital departments of dermatology in Europe and indicates a general trend and ongoing epidemic in the general population. The significant relationship between hand eczema and MDBGN allergy is of concern, and the finding that wash‐off products, especially liquid soaps, play a significant role in MDBGN allergy calls for a revision of the safety assessment of MDBGN in wash‐off products.
Airborne irritant contact dermatitis due to synthetic fibres from an air‐conditioning filter
Authors: Patiwael Jiska A. , Wintzen Marjolein , Rustemeyer Thomas , Bruynzeel Derk P.
Published: March 2005

We describe 8 cases of occupational airborne irritant contact dermatitis in intensive care unit (ICU) employees caused by synthetic (polypropylene and polyethylene) fibres from an air‐conditioning filter. Not until a workplace investigation was conducted, was it possible to clarify the unusual sequence of events. High filter pressure in the intensive care air‐conditioning system, maintained to establish an outward airflow and prevent microorganisms from entering the ward, probably caused fibres from the filter to become airborne. Upon contact with air‐exposed skin, fibres subsequently provoked skin irritation. Test periods in the ICU with varying filter pressures, in an attempt to improve environmental conditions, led to even higher filter pressure levels and more complaints. The sometimes‐very‐low humidity might have contributed to development of skin irritation. The fact that most patients recovered quickly after treatment with emollients and changing the filters made it most likely that the airborne dermatitis was of an irritant nature.
Pustular psoriasis and the Köbner phenomenon caused by allergic contact dermatitis from zinc pyrithione‐containing shampoo
Authors: Jo Ju‐Hyun , Jang Ho‐Sun , Ko Hyun‐Chang , Kim Moon‐Bum , Oh Chang‐Keun , Kwon Yoo‐Wook , Kwon Kyung‐Sool
Published: March 2005

Zinc pyrithione is a shampoo ingredient that has been shown to be safe and effective for dandruff and scalp psoriasis. It is thought to decrease the cell turnover rate in hyperproliferative dermatoses such as psoriasis, and also has fungistatic and antimicrobial activity, although its exact mode of action is unknown. In psoriasis, external factors, such as trauma, infection and drugs, may provoke aggravated manifestations of psoriatic skin lesions. Rarely, irritant or allergic mechanisms are likely causes of psoriatic flare and Köbnerization. A patient had had stable psoriasis for 25 years and no any other skin disease. Within 20 days, she developed an aggravated scaly erythematous patch on the scalp, where a shampoo had been applied, and simultaneously developed pustular psoriasis on both forearms. Patch testing showed a relevant sensitization to zinc pyrithione, and we observed symptomatic aggravation by provocation testing with zinc pyrithione shampoo. We report a rare case of psoriasis aggravated by the induction of allergic contact dermatitis from zinc pyrithione after using antidandruff shampoo.
‘Black henna’ tattoos: an occult source of natural rubber latex allergy?
Authors: Martin J. A. , Hughes T. M. , Stone N. M.
Published: March 2005

Temporary ‘black henna’ tattoos are an increasingly popular body decoration with a growing incidence of associated adverse events. We report the case of a 14 year old girl presenting with an acute allergic contact dermatitis to hair dyes. Some years previously she had a ‘black henna’ tattoo with prior application of a tacky transfer to the skin to outline the design followed some days later by an acute localised blistering reaction. Patch testing to an extended British Contact Dermatitis Society standard series showed relevant positive reactions to paraphenlyenediamine (PPD) and thiuram mix, as well as to several of the azo disperse dyes. We went on to perform prick testing to natural rubber latex (NRL), showing a positive reaction to the commercial HEP 100 concentration. We propose that through the initial acute reaction caused by PPD in the ‘black henna’ our patient was not only sensitized to PPD, but also to thiuram and natural rubber latex which may have been present in the tacky transfer applied prior to ‘tattooing.’ We would add that temporary ‘black henna’ tattoos may have more important consequences than previously thought on patients’ future health by sensitization to NRL.