bluuebunny/crossref_metadata_2025 huggingface dataset:
Blue Tit song repertoire size, male quality and interspecific competition
Authors: Doutrelant Claire , Blondel Jacques , Perret Philippe , Lambrechts Marcel M.
Published: November 2004

A recent hypothesis suggested that bird song repertoire size is a reliable indication of male quality because the number of songs emitted by an individual and the expression of many traits important for fitness are highly dependent on developmental conditions. To test this hypothesis, we studied the relationship between song repertoire size and a trait known to be strongly affected by developmental conditions: tarsus length of Blue Tits Parus caeruleus. We studied this relationship
in three populations presenting differences in density, quantity of food
available and relative and absolute densities of Great Tits Parus
major. Great Tit density may be an important factor because this species is supposed to be in competition for acoustic space with the Blue Tit. We found a positive correlation between Blue Tit dawn repertoire size and tarsus length in the three study populations which is consistent with the tested hypothesis. However, this correlation was only significant in the population with the lower Great Tit density. We discuss the significance of this variation and propose that interspecific competition may limit the action of sexual selection on song repertoire size.
Territorial song and song neighbourhoods in the Scarlet Rosefinch Carpodacus erythrinus
Authors: Martens Jochen , Kessler Philipp
Published: November 2004

Throughout the range of the Scarlet Rosefinch, its territorial song consists of 3–9 (usually 4–5) elements, of which there are 5 different types. The differences lie in the way the pitch of the element changes in time (frequency “slope”) and the width of the frequency band. Within a given type of song, the various elements can be present in almost any combination. Therefore, so many song types can be formed that the songs in even small parts of the species’ area are clearly distinct from one another. Despite this capacity for variation, however, by chance identical songs may be sung in widely separated parts of the area, in some cases by different subspecies.  The species has not developed large‐scale dialects or regiolects based on a song tradition acquired during an early imprinting phase. Scarlet Rosefinches tend to breed in small colonies, groups of up to about 15 pairs characterized by the same type of song (song neighbourhoods, formed by the development of a microlect).  Microlects develop by a founder effect. When males, near one‐year old or older, join one another to form isolated colonies after arrival in the breeding region, they adopt (“learn”) the song type that will eventually characterize the colony from the first male to arrive at the site. After the colony has been founded, in most cases each male uses only one type of song during a breeding season, with practically no variation of the temporal and frequency parameters.  Singing the same type of song, the members of a colony accept one another sufficiently to allow the breeding territories to be closely packed. It appears that a long‐lasting capacity for acoustic learning, in combination with colony‐like breeding and great ecological flexibility, has allowed the Scarlet Rosefinch to become the most successful species of the genus Carpodacus.
Density dependence of avian clutch size in resident and migrant species: is there a constraint on the predictability of competitor density?
Authors: Both Christiaan
Published: November 2004

The presence of density dependence of clutch size is tested in 57 long‐term population studies of 10 passerine bird species. In about half of the studies of tit species Parus spp. density dependence of
clutch size was found, while none was found in studies of two flycatcher
species Ficedula spp. One hypothesis explaining this difference is
that migrants are less able to predict the final competitor density,
because new pairs are still settling when the first females start laying
eggs. Such unpredictability is only a problem for early laying females.
If this explanation is true, the commonly observed negative correlation
between clutch size and laying date should be stronger in high‐density
years. I tested this prediction in three populations of Pied Flycatcher
Ficedula hypoleuca, and compared the results with three
populations of Great Tit Parus major. In none of the six populations was there a significant correlation between the strength of the seasonal decline in clutch size and population density. Thus the lack of density dependence of clutch size in Pied Flycatchers was not consistent with the idea that this is caused by the unpredictability of final density at the time of egg‐laying of the earliest females in the population. Furthermore, density does not have any adverse effect on reproductive output of Pied Flycatchers, and therefore they do not adjust clutch size to density.
Hyoid position, pharyngeal airway and head posture in relation to relapse after the mandibular setback in skeletal Class III
Authors: Gu Gaoman , Gu Gaoman , Nagata Junko , Suto Masato , Anraku Yue , Nakamura Keisuke , Kuroe Kazuto , Ito Gakuji
Published: November 2004

This study evaluates the process of relapse after mandibular setback surgery by an analysis of the role of craniofacial morphology, hyoid position, pharyngeal airway and head posture. Subjects examined were 62 patients who received the sagittal split ramus osteotomies (SSRO). Changes of the craniofacial and related structures were evaluated from the serial cephalograms up to 3 years after the surgery. Results indicated that mandibular relapse represented by Pg occurred mostly within 6 months after the surgery. A net setback of the mandible was 9.1 mm and the superior move was 1.7 mm, with a reduction of 7.2 mm in mandibular length, 4.2 mm in ramus height, 3.7 mm in posterior face height, 2.6° in gonial angle, an increase of 2.9° in mandibular plane angle (MPA) by the last examination. Hyoid bone moved backward and downward and head posture was raised. The forward relapse of Pg was correlated with the changes of ANB, MPA, ramus height and hyoid position. Only hyoid position was predictably correlated with mandibular morphology and head posture. These findings suggest that mandibular setback alters the relationship among the hyoid position, pharyngeal airway and the head posture. It might be critical, therefore, relapse is closely monitored and controlled before the full healing of fragments and new muscular balance is established.
Three‐dimensional simulation and prediction of craniofacial surgery
Authors: Meehan M , Teschner M , Girod S
Published: November 2004

Authors– Meehan M, Teschner M, Girod S

The treatment of patients with complex facial deformities is one of the most challenging multidisciplinary tasks in plastic surgery. Due to advancements in medical technology and surgical techniques in the last 20 years correction of severe malformations has become possible and is performed by highly specialized teams frequently in a single operation. Recent developments in three‐dimensional (3‐D) imaging techniques have already greatly facilitated diagnosis of complex craniofacial deformities. Computer‐based simulation methods for surgical procedures that are based on imaging data have the potential to improve surgical treatment by providing the ability to perform ‘virtual surgery’ preoperatively and thus reduce patient risk and morbidity intraoperatively. A method is presented for interactive computer‐assisted craniofacial plastic surgery planning and visualization, especially simulation of soft tissue changes using an experimental Craniofacial Surgery Planner. The system computes non‐linear soft‐tissue deformation because of bone realignment. It is capable of simulating bone cutting and bone realignment with integrated interactive collision detection. Furthermore, soft‐tissue deformation and cutting due to surgical instruments can be visualized. Simulation processes are based on an individual patient's preoperative 3‐D computed tomography and on a 3‐D, photo‐realistic model of the patient's preoperative appearance obtained by a laser range scanner. Very fast and robust prediction of non‐linear soft‐tissue deformation is computed by optimizing a non‐linear cost function.
Video reconstructions in dentistry
Authors: Farag AA , Eid A
Published: November 2004

Structured Abstract

Authors –
Farag AA, Eid A

Objectives – To present two practical techniques for three‐dimensional (3D) modeling of the human jaw from a sequence of intra‐oral images.

Design – A data acquisition system consists of: 3D digitizing arm, CCD camera and a laser projector in addition to a software module of two 3D modeling techniques; shape from shading (SFS) and space carving (SC).

Setting and sample population – Several experiments have been conducted on a sample of students at the Computer Vision and Image Processing (CVIP) Laboratory at the University of Louisville, Louisville, KY. Other experiments were performed on solid models of human jaw.

Experimental variable – The SFS technique, using perspective projection and camera calibration, extracts the 3D information from a sequence of two‐dimensional images of the jaw. Data fusion of range data and 3D registration techniques develop the complete jaw model. The SC approach is implemented on a sequence of calibrated images. On the two reconstructions, we fit a mesh model to the data, in order to create a solid 3D model.

Outcome measure – The accuracy of the reconstructed 3D model of human jaw is calculated based on the measurements on real jaws.

Results – The SFS‐based technique seems to provide more faithful information about the shape of the tooth tops. However, the SC algorithm successfully reconstructed 3D models of the human jaw with sub‐millimeter accuracy, which is as accurate as (or even better than) the first technique without using any range measurements or laser projectors. The average error in distance calculation was found to be 0.74 mm, which is an acceptable resolution for many orthodontics and maxillofacial applications.

Conclusion – Accurate 3D reconstruction of the human jaw enables many orthodontics and dental imaging research findings to be applied directly to a digital jaw model – not to a cast – using computer vision and medical imaging tools.
A three‐dimensional evaluation of the upper airway in adolescents
Authors: Aboudara CA , Hatcher D , Nielsen IL , Miller A
Published: November 2004

Authors– Aboudara CA, Hatcher D, Nielsen IL, Miller A

The link between the facial growth and airway function has been a subject of controversy in orthodontics for many years. This study investigates how well lateral cephalometric headfilms depict three‐dimensional upper airway structures. Subjects are 11 normal adolescent children, ages 7–16 years old. Airway information over the same anatomic area in the nasopharynx is compared between lateral cephalometric headfilms and three‐dimensional cone beam computed tomography (CT) scans. Intra‐subject proportion of airway volume to area shows moderate variability. CT airway volume shows more variability than corresponding headfilm airway area.
Propagule banks, herbivory and nutrient supply control population development and dominance patterns in macroalgal blooms
Authors: Lotze Heike K. , Worm Boris , Sommer Ulrich
Published: November 2004

Destructive macroalgal mass blooms threaten estuarine and coastal ecosystems worldwide. We asked which factors regulate macroalgal bloom intensity, distribution and species composition. In field experiments in the Baltic Sea, we analyzed the relative effects of nutrients, herbivores and algal propagule banks on population development and dominance patterns in two co‐occurring bloom‐forming macroalgae, Enteromorpha
intestinalis and Pilayella littoralis. 
Both species were highly affected by the combined effects of a propagule
bank, herbivory and nutrients. The magnitude of effects varied with
season. The propagule bank was an important overwintering mechanism for
both algae, and allowed for recruitment two months earlier than
recruitment via freshly dispersed propagules. This provided a seasonal
escape from intense herbivory and nutrient limitation later in the year.
Favored by massive recruitment from the propagule bank,
Enteromorpha was the superior space occupier in early spring,
thereby reducing recruitment of Pilayella. Elimination of the
propagule bank and recruitment via freshly dispersed propagules favored
Pilayella. Strong and selective herbivory on Enteromorpha
supported Pilayella in the presence, but not in the absence of the
propagule bank. Nutrient enrichment in summer counteracted herbivore
pressure on Enteromorpha, thereby negatively affecting
Pilayella. Herbivore and nutrient effects were more pronounced for early life stages than adult algae.  These results show that recruitment processes and forces affecting early life stages at the beginning of the vegetation period determine development and dominance patterns of macroalgal blooms. Herbivores naturally suppress blooms but increasing nutrient enrichment can override this important control mechanism. The propagule bank plays a previously unrecognized role for population and community dynamics.
Are predators rare?
Authors: Spencer Matthew
Published: November 2004

Predators are usually thought to be rarer (in the sense of having lower population densities) than non‐predators. Recent analyses have suggested that this is not the case because a decline in species richness compensates for the well‐known decline in number of individuals with increasing trophic rank. I show that a variety of invertebrate communities contain more species of predators than would be expected from the number of predatory individuals. This is not due to differences in dominance or taxonomic resolution between predatory and non‐predatory guilds, and implies that predators are indeed relatively rare. I suggest that patterns of energy flow and body size make it likely that there will be a higher proportion of predatory species than individuals in a community, provided that predators have moderately specialized diets.
Schooling, dusk flight and dance: social organisations as amplifiers of individual quality?
Authors: Barber Iain , Folstad Ivar
Published: November 2004

One striking aspect of certain types of animal assemblages, for example fish schools or bird flocks, is the level of synchrony and spatial regularity that group members achieve. Although the evolutionary mechanisms leading to the formation of animal aggregations appear to be understood reasonably well, the evolution of spatial regularity and the high levels of synchrony that typify the groups in which certain animals move are less clear. Traditional explanations have generally focused on benefits gained during interspecific interactions, particularly the improvement of antipredator responses, or have suggested aero‐ or hydrodynamic advantages during locomotion. However, since the latter benefits of structural regularity may be largely rejected on theoretical grounds, and because many examples of spatially regular, synchronous groupings – such as dusk‐flying flocks of some birds – may occur in the absence of predators, we suggest that these behaviours may not be explained solely in terms of locomotory efficiency or performance in predator‐prey interactions. Instead, we suggest that the maintenance of regular spatial positions and the level of synchrony achieved within certain social groups may reveal honest information about an individual's neurosensory or locomotory performance, and that these behaviours may have evolved as amplifiers of individual quality. The evolution of such behaviour therefore need not have occurred as a result of interspecific interactions, but could have happened in the arena of conspecific evaluation.
On the usage and measurement of landscape connectivity
Authors: Tischendorf Lutz , Fahrig Lenore
Published: November 2004

This paper examines the usage and measurement of “landscape connectivity” in 33 recent studies. Connectivity is defined as the degree to which a landscape facilitates or impedes movement of organisms among resource patches. However, connectivity is actually used in a variety of ways in the literature. This has led to confusion and lack of clarity related to (1) function vs structure, (2) patch isolation vs landscape connectivity and, (3) corridors vs connectivity. We suggest the term connectivity should be reserved for its original purpose. We highlight nine studies; these include modeling studies that actually measured connectivity in accordance with the definition, and empirical studies that measured key components of connectivity. We found that measurements of connectivity provide results that can be interpreted as recommending habitat fragmentation to enhance landscape connectivity. We discuss reasons for this misleading conclusion, and suggest a new way of quantifying connectivity, which avoids this problem. We also recommend a method for reducing sampling intensity in landscape‐scale empirical studies of connectivity.
Effects of defoliation intensity on soil food‐web properties in an experimental grassland community
Authors: Mikola Juha , Yeates Gregor W. , Barker Gary M. , Wardle David A. , Bonner Karen I.
Published: November 2004

We established a greenhouse experiment based on replicated mini‐ecosystems to evaluate the effects of defoliation intensity on soil food‐web properties in grasslands. Plant communities, composed of white clover (Trifolium repens), perennial ryegrass (Lolium perenne) and plantain (Plantago lanceolata) with well‐established root and shoot systems, were subjected to five defoliation intensity treatments: no trimming (defoliation intensity 0, or DI 0), and trimming of all plant material to 35 cm (DI 1), 25 cm (DI 2), 15 cm (DI 3) and 10 cm (DI 4) above soil surface every second week for 14 weeks. Intensification of defoliation reduced shoot production and standing shoot and root mass of plant communities but increased their root to shoot ratio. Soil microbial activity and biomass decreased with intensification of defoliation. Concentrations of NO3–N in soil steadily increased with intensifying defoliation, whereas NH4–N concentrations did not vary between treatments. Numbers of microbi‐detritivorous enchytraeids, bacterial‐feeding rotifers and bacterial‐feeding nematodes steadily increased with intensifying defoliation, while the abundance of fungal‐feeding nematodes was significantly enhanced only in DI 3 and DI 4 relative to DI 0. The abundance of herbivorous nematodes per unit soil mass was lower in DI 3 and DI 4 than in DI 0, DI 1 and DI 2, but when calculated per unit root mass, their abundance tended to increase with defoliation intensity. The abundance of omnivorous and predatory nematodes appeared to be highest in the most intensely defoliated systems. The ratio of abundance of fungal‐feeding nematodes to that of bacterial‐feeding nematodes was not significantly affected by defoliation intensity. The results infer that defoliation intensity may significantly alter the structure of soil food webs in grasslands, and that defoliation per se is able to induce patterns observed in grazing studies in the field. The results did not support hypotheses that defoliation per se would cause a shift between the bacterial‐based and fungal‐based energy channels in the decomposer food web, or that herbivore and detritivore densities in soil would be highest under intermediate defoliation. Furthermore, our data for microbes and microbial feeders implies that the effects of defoliation intensity on soil food‐web structure may depend on the duration of defoliation and are therefore likely to be dynamic rather than constant in nature.
How does landscape structure influence landscape connectivity?
Authors: Goodwin Brett J. , Fahrig Lenore
Published: November 2004

We investigated the impact of landscape structure on landscape connectivity using a combination of simulation and empirical experiments. In a previous study we documented the movement behaviour of a specialized goldenrod beetle (Trirhabda borealis Blake) in three kinds of patches: habitat (goldenrod) patches and two types of matrix patch (cut vegetation and cut vegetation containing camouflage netting as an impediment to movement). In the current study, we used this information to construct simulation and experimental landscapes consisting of mosaics of these three patch types, to study the effect of landscape structure on landscape connectivity, using the T. borealis beetle as a model system. In the simulation studies, landscape connectivity was based on movements of individual beetles, and was measured in six different ways. The simulations revealed that the six measures of landscape connectivity were influenced by different aspects of landscape structure, suggesting that: (1) landscape connectivity is a poorly defined concept, and (2) the same landscape may have different landscape connectivity values when different measures of landscape connectivity are used. There were two general predictions that held over all measures of landscape connectivity: (1) increasing interpatch distance significantly decreased landscape connectivity and (2) the influence of matrix elements on landscape connectivity was small in comparison to the influence of habitat elements. Empirical mark‐release‐resight experiments using Trirhabda beetles in experimental landscapes supported the simulation results.
Direct interference or indirect exploitation? An experimental study of fitness costs of interspecific competition in voles
Authors: Eccard Jana A. , Ylönen Hannu
Published: November 2004

Studies on competing mammalian species in the past have focused mainly on the competitive exclusion of one species from the preferred habitat of the other. Investigations on effects of competition and coexistence on individual fitness are rare.In this study we were able to measure effects of interspecific competition on major fitness components, using a system with two vole species in asymmetric competition. Survival, reproduction and space use of bank voleClethrionomys glareolusfemales were monitored in 32 enclosed populations over four replicates of eight parallel run enclosures. Into half of the enclosures we introduced an additional number of field volesMicrotus agrestis, a dominant competitor.

Survival of bank vole females was lower under competitive conditions. Total number of breeding females was lower in populations coexisting with competitors. Territory size of bank vole females decreased. Females body weight and litter size bank vole litters conceived during the experiment were not affected by interspecific competition. These characteristics should respond to differences in food resources, and territory size should increase if food was scarce, thus we found no indication of direct exploitation competition between the two species. Space use was overlapping between the species, but individuals of both species were never caught together in the same trap, indicating avoidance behaviour.

We conclude that adult bank vole females do suffer fitness consequences through interference competition with field voles, probably basing on increased number of aggressive encounters in the presence of the dominant species. Our results suggest, that direct interference rather than indirect exploitation competition may be the cause for observed fitness decrease in bank vole females.
Correlations between small aperture skin suction parameters: statistical analysis and mechanical model
Authors: Schlangen L. J. M. , Brokken D. , Van Kemenade P. M.
Published: November 2004

Background/aims: Skin suction experiments are widely used in order to evaluate the effects of skin treatments, both for cosmetic and for dermatological purposes. Classically, the elevation of the skin is measured at different discrete time instances after the pressure has been changed. Relations between the classical parameters – Uv, Ur, Ue and Uf – have been investigated and used in order to develop a new model for interpreting the mechanical properties of the skin.

Methods: Within a group of 68 female subjects – aged between 37 and 68 – a Cutometer has been used in order to determine classical skin suction parameters on the female facial skin. Each skin suction measurement consists of three consecutive underpressure cycles. Within the resulting parameter set, a statistical analysis has been performed to investigate interparameter relations.

Results: Strong interparameter correlations have been found within a set of 12 classical skin suction parameters. The set contains three independent groups of interrelated parameters. Based on this observation, a one‐dimensional mechanical model – consisting of springs and dampers – is constructed. When two extra independent parameters are included in the model, the elevation versus time curves as recorded during three consecutive underpressure cycles can be fully described. The model reveals that typical skin suction data can be described in terms of a quick and a slow deformation process. The two characteristic time scales are 0.1 and 7 s approximately. The 0.1 s‐value matches the response time of the device used. In reality, the quick deformation process in the skin may have a shorter time scale.

Conclusions: In skin suction data, each underpressure cycle is usually characterized by four classical parameters – Uv, Ur, Ue and Uf. Within the 12 parameters of a three‐cycle measurement, three independent groups of interrelated parameters have been found. These groups can be represented by the parameters Uv1, Ur1 and Uf1 of the first underpressure cycle.

A model that is based on these three independent groups and two other independent parameters is proposed. The model provides an accurate description of the skin deformation as recorded during a measurement involving three underpressure cycles. The model is an improvement over classical interpretations of skin suction data where interrelated parameters are used. Moreover, the five‐parameter model accounts for well‐known mechanical characteristics of the skin such as preconditioning and visco‐elastic behavior.
Colour analysis of skin lesion regions for melanoma discrimination in clinical images
Authors: Chen Jixiang , Stanley R. Joe , Moss Randy H. , Van Stoecker William
Published: November 2004

Background: Skin lesion colour is an important feature for diagnosing malignant melanoma. Colour histogram analysis over a training set of images has been used to identify colours characteristic of melanoma, i.e., melanoma colours. A percent melanoma colour feature defined as the percentage of the lesion pixels that are melanoma colours has been used as a feature to discriminate melanomas from benign lesions.

Methods: In this research, the colour histogram analysis technique is extended to evaluate skin lesion discrimination based on colour feature calculations in different regions of the skin lesion. The colour features examined include percent melanoma colour and a novel colour clustering ratio. Experiments are performed using clinical images of 129 malignant melanomas and 129 benign lesions consisting of 40 seborrheic keratoses and 89 nevocellular nevi.

Results: Experimental results show improved discrimination capability for feature calculations focused in the lesion boundary region. Specifically, correct melanoma and benign recognition rates are observed as high as 89 and 83%, respectively, for the percent melanoma colour feature computed using only the outermost, uniformly distributed 10% of the lesion's area.

Conclusions: The experimental results show for the features investigated that the region closest to the skin lesion boundary contains the greatest colour discrimination information for lesion screening. Furthermore, the percent melanoma colour feature consistently outperformed the colour clustering ratio for the different skin lesion regions examined. The clinical application of this result is that clustered colours appear to be no more significant than colours of arbitrary distribution within a lesion.
Granular cells in oral lichen planus
Authors: Van Der Meij EH , Van Der Waal I
Published: November 2004

OBJECTIVE AND DESIGN: Three cases of granular cells associated with oral lichen planus (OLP) have been reported to date, which prompted us to look for the presence of granular cells in a consecutive series of 250 cases of OLP in the period 1996–1998.

RESULTS: Only one case with granular cell changes was encountered in that series. H&E stained slides as well as direct immunofluorescence examination showed characteristics compatible with OLP. Part of the subepithelial connective tissue was replaced by a granular cell proliferation; S‐100 protein was diffusely expressed in all granular cells, whereas no expression of smooth muscle actin was observed.

CONCLUSION: Based on these findings it seems unlikely that the granular cells in the present case represent a so‐called ‘oral ceroid granuloma’. The presence of granular cells might rather have been a reactive phenomenon triggered by the inflammatory infiltrate or a granular cell tumour (GCT). Whether the simultaneous presence of a GCT and OLP in this particular case was based on a causal relationship or on coincidence still remains unknown.
Prediction of durum-wheat quality from gliadin-protein composition
Authors: Cros DLdu , Wrigley CW , Hare RA
Published: November 2004

The possible use of gel electrophoresis of grain proteins to select for pasta-making quality in breeding durum wheats was studied in Australian durum cultivars and in 103 crossbred lines. Computer-based pattern analysis was used to compare gliadin electrophoregrams (38 band positions, each at three levels of intensity) and dough strength (considered as four quantitative estimates from mixograph testing). Close relationships were found between dough strength and a group of gliadin proteins (including band 43, and between dough weakness and a different group of gliadins (including band 42). All 27 breeding lines with weak dough had band 42 and its associated bands, while 90% of the strong-dough lines had gliadin 45. These relationships were shown not to be due to similarities in pedigree. The results indicate gel electrophoresis to be a valuable means of screening for grain quality at early generation in durum-wheat breeding.
Effect of defoliation on Virginia Bunch peanuts at Camden, N.S.W
Authors: Santos RB , Sutton BG
Published: November 2004

It is not at all usual to defoliate peanuts; however, the low harvest index (less than 0.34) and high vegetative yield (> 5 t ha-1) at Camden, N.S.W., suggested there might be foliage which could be harvested as forage. Accordingly, the ability of peanuts to sustain kernel yield after defoliation to 10 cm was examined using the cultivar Virginia Bunch at Camden. Defoliation up to early pod formation (10 weeks from sowing) caused no reduction in kernel yield, in contrast to later treatments where yield reductions of up to 40% were observed. The top dry matter so removed provides an additional useful forage product from the crop, with an in vitro dry matter digestibility of 79% and average nitrogen concentration of 2.4 g nitrogen/100 g at age 10 weeks. The reasons for the increased sensitivity to defoliation of older plants (> 10 weeks) are explored.
A case for unreplicated plots for multi-site yield testing in wheat
Authors: Bhatt GM , Ellison FW , Marshall DR
Published: November 2004

The effectiveness of unreplicated multi-site yield tests was evaluated by using data from 82 trials involving 16 sets of entries including cultivars or advanced breeding lines each grown on four-seven sites per year over an 11-year period. For each data set, entry means and ranks over sites were calculated using, first, all replications (usually four, but sometimes three) at each site; and, second, one of the four (or three) replications selected at random at each site. The estimates of entry mean yields over sites by using only one replicate were highly and positively correlated with estimates using all available data. The correlations varied from +0.88 to +0.98 with a mean, over all 16 data sets, of +0.94. In addition, if the 10 highest yielding entries were selected on the basis of unreplicated trials at several sites, the top five entries according to multi-replicate trials were invariably retained. It is concluded that unreplicated multi-site tests offer breeders an effective and efficient means of identifying high yielding genotypes, particularly early in the breeding program when seed supplies are limited.
The influence of nitrogen level, rainfall, seed pools, and pasture biomass on the botanical composition of annual pastures
Authors: Arnold GW , Anderson GW
Published: November 2004

The influence of nitrogen level, rainfall, seed pools and pasture biomass on the botanical composition of annual pastures was examined over five years at two sites at Baker's Hill in the south-west of Western Australia. At the first site a pasture that had declined in content of Trifolium subterraneum to 5% remained at this level over five years when receiving 100 kg ha-1 of nitrogen fertilizer. On plots not receiving nitrogen fertilizer, but grazed to the same level, Trifolium seedling numbers in autumn increased from 5 dm-2 to a maximum of 60 dm-2, but Trifolium content of the pastures in October only increased to 15%. At the second site, established pasture was resown to different annual pasture species. Plots resown to Trifolium had 30% of Trifolium in October of the reseeding year, but only 5% three years later. Trifolium seedling numbers in autumn were >70 dm-2 in three of four years. The Trifolium was replaced by Arctotheca calendula. Plots sown to Arctotheca maintained c. 50% of this species, whilst plots sown to Erodium botrys also maintained a high level of this species but had very little Arctotheca. Plots sown to the grass Lasiochloa echinata developed a progressively higher content of Arctotheca. Annual grasses (Bromus diandrus, Vulpia myuros, Hordeum leporinum and Lolium rigidum) occurred in all plots, but their contents showed no specific trend with time. The major species were found to have different adaptive characteristics. Whilst seedling number in autumn was a major determinant of the content of a species in the pastures in August, Trifolium content was enhanced by high autumn rainfall and low winter biomass. The contribution of each Trifolium seedling to clover content in August was much less than that of each Arctotheca seedling to the capeweed content at that time. The pasture composition in October was mainly determined by cornposirim in August, although heavy rain in October favoured Arctotheca and light rain favoured the grass species.
Diallel crosses of honeybees. II A note presenting an estimate of the heritability of honey production under Australian conditions
Authors: Oldroyd BP , Moran C , Nicholas FW
Published: November 2004

A partial diallel cross of honeybees (Apis mellifera L.) was formed. Combining ability analysis of variance was used to estimate additive and non-additive genetic variance in seasonal colony weight gain for the artificial 'population' studied. The values determined were: general combining ability variance, 12.14 kg2 (s.e., 11.42); specific combining ability variance, 11 -96 kg2 (s.e., 13.71); environmental variance, 21.65 kg2 (s.e., 8.84); heritability of honey production, 0.42 (s.e., 0.24). The phenotypic standard deviation was 7.6 kg.The results suggest that selection for colony weight gain would be successful.
Predicting phenological development for Australian wheats
Authors: Perry MW , Siddique KHM , Wallace JF
Published: November 2004

Dates of ear initation and anthesis were recorded for 16 wheat cultivars at a wide range of sowing dates in four field experiments conducted over four years.In general for the majority of cultivars number of days from sowing to ear initiation increased as sowing was delayed through May and then declined with sowings after June. The effects of sowing date and cultivar on anthesis were similar to those observed for ear initiation. Maximum time to anthesis was observed from sowings in early May.A linear regression model relating rate of development to mean temperature and photoperiod accounted for 47-98% of the variation in rate of development from sowing to ear initiation and from 68 to 98% of the variation from ear initiation to anthesis. A five-parameter non-linear model was also tested but was not superior. Observations in a single year were sufficient to characterize a cultivar provided the range of mean temperature and photoperiod was large.Comparison with data from other field sites of ear initiation and anthesis showed that the regression equations gave a good fit to the occurrence of these events when used in the incremental sense, that is, by summing increments of development rate calculated from daily temperature and photoperiod.The prediction model is discussed in relation to its application in simulation models of crop growth, analysis of cultivar adaptation to environments and in day-to-day crop management.
Variation among soybean (Glycine max (L.) Merr.) accessions in epidermal conductance of leaves
Authors: Paje MCM , Ludlow MM , Lawn RJ
Published: November 2004

Significant variation in epidermal conductance was obtained among the 74 soybean accessions tested. When six accessions representing high, medium and low epidermal conductance groups were grown under different environments, it was found that epidermal conductance was sensitive to changes in temperature, relative humidity and water stress. However, analysis of these responses showed that genotypic differences were consistent, although the six accessions possessed varying levels of stability of expression of the trait. Epidermal conductance, therefore, appears to be a physiological trait which might well be utilized in a plant-breeding program for improvement of drought resistance in soybean, should further studies establish its utility for that purpose.
Some effects of stripe rust infection in wheats with adult plant resistance
Authors: Park RF , Rees RG , Platz GJ
Published: November 2004

Effects of early and full season epidemics by stripe rust (Puccinia striiformis f. sp. Tritici) were examined in 12 wheat cultivars with different levels of adult plant resistance (APR). The APR in Cook, Bass, Banks, Kite, and Suneca was generally effective in preventing detectable yield losses due to stripe rust infection. Cultivars with lower levels of APR experienced yield losses of 15-25%, compared with 45-50% reduction for the susceptible cultivar Teal. Severe stripe rust infection early in the season, prior to node formation, resulted in significant yield reductions only in the more susceptible cultivars. Yield reductions were usually associated with reduced grain weight, and no reduction in tillering was detected in diseased plants. Severe stripe rust infection did not significantly affect the concentration of grain phosphorus, but did result in reduced grain nitrogen concentration in the more susceptible cultivars.
Comparison of the effects of continuous and relieved water stress on nitrogen nutrition of grain sorghum
Authors: Rego TJ , Grundon NJ , Asher CJ , Edwards DG
Published: November 2004

A solution culture experiment was conducted to study the effects of continuous and relieved water stress and of nitrogen (N) supply on growth and N content of grain sorghum cv. Texas 610SR. Polyethylene glycol-6000 was used to impose solution osmotic potentials of -0.1, -0.4, and -1.1 MPa over 9 days beginning on day 21. On day 30, half the plants in the -0.4 and -1.1 MPa treatments were returned to solutions with osmotic potentials of -0.1 MPa (relieved water stress regime), while the other half remained at solution osmotic potentials of -0.4 and -1.1 MPa until harvest (continuous water stress regime). Plants were harvested on day 43. Dry matter yields, total plant N content, mean rate of N uptake per unit root weight, and the number of leaves expanded after imposition of solution osmotic potential treatments were decreased significantly by decreases in N supply and solution osmotic potential in the continuous water stress regime. Decreasing the solution osmotic potential in the continuous water stress regime had no effect on mean N concentrations in expanded leaves or in shoots, but increased N concentrations in roots and in stem plus immature leaves. Plants in the relieved water stress regime produced more dry matter, expanded more leaves after day 21, had higher N contents, N concentrations and mean N uptake rates per unit root weight than plants in the continuous stress regime at equivalent levels of solution osmotic potential. Relationships between leaf N concentrations and relative yield of shoots were non-asymptotic for all three index leaves (youngest emerged blade and the two blades immediately below), and this prevented the calculation of meaningful critical N concentrations in any treatment. The results are discussed in relation to effects of intermittent water stress on rainfed sorghum in the field.
Heterosis and combining ability effects on cotton. II. Heterosis
Authors: Thomson NJ , Luckett DJ
Published: November 2004

The yield and quality of a diverse range of cotton hybrids was measured in one, or more, of a number of experiments conducted in the Ord River valley, Western Australia (15�S.) and the Namoi River valley, New South Wales (30�S.). Two of the experiments were diallels, one involving nine parents, the other thirteen parents. In both the plant and subsequent ratoon crops, mean yield of the hybrids was significantly greater than the mean yield of the parents, and the hybrids had significantly longer and stronger fibre. A few hybrids in both diallels significantly outyielded commercial controls by between 15 and 35% in both the plant and ratoon crops. Subsequently, in other experiments including one with near-commercial large plots, the high performers from the diallel experiments were inconsistent for yield, usually exhibiting little or no heterosis above that of the best commercial cultivars. Other hybrids tested in these experiments also generally failed to outyield the commercial controls, although a number had higher-quality fibre. It was concluded the heterosis for yield is not consistent enough under high-yielding Australian conditions to warrant the commercial production of hybrid cotton seed. Some hybrids, however, especially the interspecific G. hirsutum x G. barbadense ones, have the stronger, finer fibre that appears better suited to cotton spinning equipment now being developed, and this aspect could justify reappraisal of this conclusion in the future.
The intake and utilization of urea-treated rice straw by sheep differing in body condition
Authors: Djajanegara A , Doyle PT
Published: November 2004

Prior to the experiment two groups of 10 sheep were fed to either gain (group F) or lose (group T) weight. At the beginning of the experiment group F sheep weighed on average 57.7 kg fleece-free liveweight (W) and had a total body fat (TBF) content of 154 kg, while group T sheep weighed 42.6 kg and had a TBF content of 9.7 kg. During the experiment all sheep were given a urea-treated rice straw-based diet ad libitum for 56 days with an intra-ruminal infusion of urea and sodium sulfate. Measurements were made of feed intake and digestibility and of the amounts and composition of digesta in the reticula-rumen (ReRu) and flowing through the abomasum.Group T sheep consumed more feed (dry matter intake 1 170 v. 1040 g day-1, 24.9 v. 19.1 g kg W-1) and spent more time chewing (16.5 v. 14.1 h day-1) than group F sheep. There were no differences in the digestibility of dietary constituents.Associated with the greater feed intakes by group T sheep were increased amounts of total digesta (8.59 v 7.67 kg) and of dry matter (DM) (1040 v. 960 g), organic matter (OM) (820 v. 750 g) and neutral detergent fibre (NDF) (690 v. 620 g) in the ReRu. Flows of total digesta (22.45 v. 18.64 kg day-1), DM (910 v. 800 g day-1), OM (600 v. 510 g day-1) and NDF (330 v. 270 g day-1) through the abomasum were also greater in group T sheep. However, there were no differences between treatments in the proportion of digestion which occurred in the ReRu, in the fractional digestion rate of NDF in the ReRu or in the fractional passage rate of NDF from the ReRu.Group T sheep generally maintained weight (-4 g day-1) throughout the experiment and their TBF only declined from 9.7 to 9.1 kg. In contrast, group F sheep lost weight at 74 g day-1 and TBF declined from 15.8 to 14.1 kg.It is concluded that removal of limitations of essential nutrients enabled sheep in poor condition to consume more of this straw-based diet than those in good condition.
Growth responses of cultivars of subterranean clover to temperature, plant density and nitrate supply
Authors: Silsbury JH , Hancock TW
Published: November 2004

Six cultivars of subterranean clover were compared for growth as swards under controlled conditions in six separate experiments. Conditions common to all experiments were: 400 8mol quanta m-2 s-1 and 12 h day: 12 h night. The variable regimens were: 2 000 or 12 000 plants m-2 ('low' and 'high' density), 10 to 20�C; and no mineral N (0 mM) or N supplied as a 7.5 mM NO3- solution. Growth responses to these conditions were tested by sequential harvesting for dry matter and the fitting of linear and quadratic regression models. Special attention was given to testing for differential responses by cultivars to temperature. All cultivars except 'Woogenellup' grew about 20% faster when NO3- was supplied in the nutrient solution than when the N was derived entirely from N2 fixation under the 0mM treatment. Crop growth rate at 20�C was about double that at 10�C at low density, but at high density the rate at 20�C was 90-95% of that at 10�C. Cultivars differed significantly in growth rate but over all conditions, there was a hierarchical order from the highest to the lowest of: 'Clare', 'Woogenellup', 'Yarloop', 'Mt. Barker', 'Daliak' and 'Geraldton'. There was very little evidence of any cultivar by temperature interaction except for 'Woogenellup, which responded to a low temperature of 10�C compared with a 'high' of 20�C better than the other cultivars. The importance of seed size as a factor influencing the early growth of a subterranean clover sward was emphasized where swards established from large seeds of 'Mt. Barker' grew faster than where small seeds were used. 'Clare' was a highly productive cultivar under all growth conditions. It is concluded that the growth rates of swards of subterranean clover established at seedling densities in excess of 5000 plants m-2 are less sensitive to a low temperature of 10�C than are those established at more conventional densities.
The effect of nitrogen supply on the early growth and nodulation of several annual Medicago species
Authors: Ewing MA , Robson AD
Published: November 2004

Differences in nodulation amongst species of annual Medicago (medics) on moderately acid soils could be explained by differences in response to the form or level of nitrogen supply. We compared the growth and bulk soil pH changes when four annual medic species (M. truncatula, M. littoralis, M. polymorpha and M. murex) were supplied with ammonium, nitrate or biologically fixed nitrogen. Growth and nodule number were measured for M. polymorpha grown in solution culture at constant nitrogen supply (1 mM) but variable ammonium to nitrate ratio (1:0, 3:1, 1:1, 1:3, 0:1). Similar measurements were also made on M. truncatula, M. polymorpha and M. murex exposed to different concentrations of nitrate (0, 0.1, 1.5, 10 mM) during nodulation. When uninoculated, all medic species grew at the same rate when given equivalent levels of inorganic nitrogen as either ammonium or nitrate. All species similarly decreased the pH of soil around their roots when supplied with ammonium, and increased pH when supplied with nitrate. Nutrient solutions were acidified when M. polymorpha was supplied with ammonium and neutralized when nitrate was supplied. However, when ammonium and nitrate were added simultaneously solutions acidified, indicating a more rapid uptake of ammonium than nitrate. Nodule number of all medic species was reduced by nitrate concentrations in solution as low as 0.1 mM. M. truncatula formed fewer nodules than M. polymorpha and M. murex at all concentrations of nitrate.