bluuebunny/crossref_metadata_2025 huggingface dataset:
Construction of three linkage maps in bread wheat, Triticum aestivum
Authors: Chalmers K. J. , Campbell A. W. , Kretschmer J. , Karakousis A. , Henschke P. H. , Pierens S. , Harker N. , Pallotta M. , Cornish G. B. , Shariflou M. R. , Rampling L. R. , McLauchlan A. , Daggard G. , Sharp P. J. , Holton T. A. , Sutherland M. W. , Appels R. , Langridge P.
Published: September 2002

Genetic maps were compiled from the analysis of 160–180 doubled haploid
lines derived from 3 crosses: Cranbrook Halberd, CD87 Katepwa, and Sunco
Tasman. The parental wheat lines covered a wide range of the germplasm used in
Australian wheat breeding. The linkage maps were constructed with RFLP, AFLP,
microsatellite markers, known genes, and proteins. The numbers of markers
placed on each map were 902 for Cranbrook Halberd, 505 for CD87 Katepwa, and
355 for Sunco Tasman. Most of the expected linkage groups could be determined,
but 10–20% of markers could not be assigned to a specific linkage
group. Homologous chromosomes could be aligned between the populations
described here and linkage groups reported in the literature, based around the
RFLP, protein, and microsatellite markers. For most chromosomes, colinearity
of markers was found for the maps reported here and those recorded on
published physical maps of wheat. AFLP markers proved to be effective in
filling gaps in the maps. In addition, it was found that many AFLP markers
defined specific genetic loci in wheat across all 3 populations.
The quality of the maps and the density of markers differs for each
population. Some chromosomes, particularly D genome chromosomes, are poorly
covered. There was also evidence of segregation distortion in some regions,
and the distribution of recombination events was uneven, with substantial
numbers of doubled haploid lines in each population displaying one or more
parental chromosomes. These features will affect the reliability of the maps
in localising loci controlling some traits, particularly complex quantitative
traits and traits of low heritability.
The parents used to develop the mapping populations were selected based on
their quality characteristics and the maps provide a basis for the analysis of
the genetic control of components of processing quality. However, the parents
also differ in resistance to several important diseases, in a range of
physiological traits, and in tolerance to some abiotic stresses.
PCR-based molecular marker for the Bdv2 Thinopyrum intermedium source of barley yellow dwarf virus resistance in wheat
Authors: Stoutjesdijk P. , Kammholz S. J. , Kleven S. , Matsay S. , Banks P. M. , Larkin P. J.
Published: September 2002

Because of the importance of BYDV in wheat production worldwide, and given the
difficulties of bioassaying for resistance, a molecular marker was developed
for the resistance known as Bdv2 that originates on the
long arm of chromosome 7Ai1 of Thinopyrum intermedium.
This resistance was identified in a partial amphiploid line TAF46, a disomic
addition line to wheat (L1), a telosomic addition line (7Ai1 L), and a series
of recombinants and translocations. A RAPD (random amplified polymeric DNA)
marker for the resistant germplasm was cloned and sequenced, and primers were
designed against that sequence to produce a sequence characterised amplified
region (SCAR) marker. A single PCR product is produced only with genotypes
carrying the resistance from any of the available recombinants. The cloned
sequence, recommended primers, and PCR protocols are described. The usefulness
of the marker has been demonstrated for following Bdv2
in segregating wheat breeding germplasm, with the imminent release of a
BYDV-resistant cultivar.
Differences in symptom development in subterranean clover infected with Kabatiella caulivora Race 1 and Race 2 are related to host resistance
Authors: Bayliss K. L. , Kuo J. , Sivasithamparam K. , Barbetti M. J. , Lagudah E. S.
Published: September 2002

Clover scorch (Kabatiella caulivora) is a severe fungal
disease of Trifolium spp. contributing to the collapse
of pasture swards across southern Australia during warm, humid spring weather.
Host plant responses associated with resistance to the disease were determined
in 2 cultivars of subterranean clover (T. subterraneum)
separately inoculated with K. caulivora Race 1 or Race
2. Germination of conidia of both races reached a maximum 5 days
post-inoculation on cv. Woogenellup (susceptible to both races) and 4 days
post-inoculation on cv. Daliak (resistant to Race 1 but susceptible to Race
2). Germ tube growth of Race 1 was inhibited on cv. Daliak and the percentage
of conidia penetrating leaf surfaces was lowest on this race–cultivar
combination. Susceptibility was characterised by large petiole lesions, with
invasive hyphae extending through the mesophyll tissue into the pith and then
through the phloem tissue of vascular bundles, eventually causing the petioles
to collapse. Resistance was characterised by small, black lesions with
invasive hyphae extending no further than the fourth layer of mesophyll cells.
A suberin-based material was observed beneath infected mesophyll cells in the
incompatible interaction, beyond which no further growth of hyphae occurred.
Race 2 caused a faster rate of host tissue necrosis than Race 1 and also the
breakdown of starch grains in uninvaded petiole tissues. Starch grains in
plants infected with Race 1 were evenly distributed in uninvaded tissue.
Sporulation was rarely observed in the incompatible interaction but was common
in compatible interactions within 15 days post-inoculation. These responses to
K. caulivora can now be used as a breeding tool in
evaluating and selecting improved resistance to clover scorch disease among
breeding lines of subterranean clover.
Mineral nutrient uptake and removal by canola, Indian mustard, and Linola in two contrasting environments, and implications for carbon cycle effects on soil acidification
Authors: Santonoceto C. , Hocking P. J. , Braschkat J. , Randall P. J.
Published: September 2002

Field studies of the oilseed crops canola, Indian mustard, and
linseed/Linola were conducted over 2 seasons at 2 contrasting sites in the
cropping regions of central and southern NSW to determine the uptake of
mineral nutrients and quantities removed in seed. The sites were in the Junee
region where production of these oilseeds is common, and at Condobolin, which
is regarded as marginal for production of the crops. The 2 rates of nitrogen
(N) fertiliser applied were either none or rates that growers in the
Condobolin and Junee regions would apply to achieve high seed yields after a
cereal crop in the rotation when soil mineral N is low. Concentrations of
total N, the major cations (K, Ca, Mg, Na) and major anions (P, S, Cl), and
the micronutrients Fe, Mn, Zn, and Cu were determined in shoots harvested at
flowering and maturity. Nitrate and sulfate were also measured, and estimates
were made of excess cation concentrations in the plant material. The ranges of
concentrations of excess cations in shoots of the oilseeds at flowering were
83–206 cmolc/kg and 43–121 cmolc/kg
for straw at maturity. Linola had lower concentrations of excess cations in
vegetative material (83–108 and 43–82
cmolc/kg at flowering and maturity, respectively)
than canola or Indian mustard. Concentrations of excess cations in seed of the
crops were lower than for vegetative material, and ranged from 30 to 49
cmolc/kg. Nitrogen fertiliser had relatively little effect on
concentrations of mineral nutrients or excess cations in either shoots at
flowering and maturity, or in seed. However, N fertiliser increased the growth
and seed yields of the crops, and thus the amounts of mineral nutrients and
excess cations in shoots and seed. The results are discussed in the context of
the depletion of soil nutrients due to their removal in harvested seed of the
N-fertilised crops. The contribution of excess cation removal in seed to soil
acidification is also discussed. It is estimated that the quantity of lime
required to neutralise the acidity resulting from removal of 1 t seed is 22.4
kg for canola, 17.0 for Indian mustard, and 20.8 for linseed/Linola.
Estimates of the relative contributions of seed removal and N fertiliser to
soil acidification are presented.
Growth and P uptake by wheat genotypes supplied with phytate as the only P source
Authors: Osborne L. D. , Rengel Z.
Published: September 2002

In many soils, organic P is the major component of the total P pool. Genotypic differences in wheat for P acquisition from organic P in the form of phytate, a common organic phosphorus component in soil, were investigated in a glasshouse experiment. Twenty genotypes differing in the ability to utilise poorly soluble phosphate sources were grown in P-deficient brown sand amended with phytate or inorganic phosphate. The P efficiency of wheat genotypes was evaluated by 3 criteria: growth at low phytate-P supply; growth at low phytate-P supply relative to growth at the same rate supplied as soluble inorganic P; and phosphorus acquision efficiency (PAE), calculated as the amount of P in the plant divided by the amount of P supplied in the soil.

All wheat genotypes tested were able to utilise phytate as a source of P, albeit at a lower efficiency than soluble inorganic phosphate. Across the genotypes tested, plants supplied with 20 mg P as phytate produced only 23% of the shoot biomass of plants supplied with 20 mg P as inorganic P. When P supply was increased to 100 mg P as phytate, this increased to 88%. There was a significant variation in wheat genotypes in the ability to acquire P from phytate. Genotypes more efficient in acquiring P from sparingly water-soluble Fe phosphates were also more efficient in taking up P from phytate-amended soil. The genotypes Cadoux, Blade, ES8, Chinese 80-55, Wawht 2066, and Wawht 2128 were rated as efficient, whereas Janz, Machete, Kalingri, and Spear were rated inefficient on all 3 criteria.
Genetic control of quality traits of lucerne (Medicago sativa L.)
Authors: Guines F. , Julier B. , Ecalle C. , Huyghe C.
Published: September 2002

An important objective in lucerne breeding is the improvement of feeding
value. An understanding of the inheritance of digestibility and cell wall
related traits would facilitate the breeding of varieties with higher feeding
value. The aim of this experiment was first to determine the genetic control
of dry matter digestibility and related biochemical and morphological traits,
and to assess phenotypic and genetic correlations between these traits.
Quantitative genetic parameters were estimated for enzymatic solubility,
neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent
lignin (ADL), protein content, plant height, and leaf-to-stem ratio. A 7
× 7 diallel design with reciprocals and without selfing among parents
from different populations and a 7 × 7 factorial design within the
‘Flamande’ population were studied. In the diallel study, effects
due to general combining ability (GCA) were higher than those due to specific
combining ability (SCA) for all characters tested. In the factorial study, the
F1 progeny effect was significant for all characters. The male effect was
highly significant for all traits and higher than the female effect except for
plant height. The additive variance was higher than the dominance variance for
all characters except for plant height. The inheritance was predominantly
additive. The highest narrowsense heritabilities were found for NDF and ADF
and leaf-to-stem ratio. As a consequence, NDF or ADF would be more efficient
selection criteria than enzymatic solubility in a breeding program for
improved feeding value. In both mating designs, NDF, ADF, and ADL were
positively correlated with one another and negatively with enzymatic
solubility and protein content.
The performance of subterranean vetch (Vicia sativa ssp. amphicarpa) in a cereal/pasture rotation in north-west Syria
Authors: Street K. A. , El Moneim A. M. Abd , Cocks P. S.
Published: September 2002

The aim of this study was to determine if subterranean vetch can persist in a
cereal–legume ley farming system and to determine when it is most
susceptible to grazing. Grazing treatments were applied to a series of plots
containing subterranean vetch during the establishment year. Thereafter the
plots were alternately sown to barley or left for the vetch to regenerate.
Early grazing caused a seed yield reduction of about 75%. Later grazing
treatments had no effect on seed yield, which were between 1000 and 1400
kg/ha. The first cereal phase caused a 6–10-fold reduction in seed
bank size. During the 2 years following the first barley year, the seed bank
increased to about 900 kg/ha. The second barley year caused a 4-fold
reduction in the soil seed bank.
Although subterranean vetch managed to persist for 5 years, the dramatic
reduction in the seed bank after the barley years indicates that subterranean
vetch will not persist at a useful density in a system where 2 or more
cropping years run successively. However, other studies have shown that there
are enough genotypes with the necessary levels of hardseededness to fit the
ley system.
Identity and genetic diversity of the sorghum ergot pathogen in Australia
Authors: Komolong Birte , Chakraborty Sukumar , Ryley Malcolm , Yates David
Published: September 2002

Sorghum ergot was first discovered in Australia in 1996. It affects seed production and grain usage in stock feed due to concerns of animal toxicity. Three species of Claviceps are known to cause ergot of sorghum with different epidemiological, animal toxicity, and management implications. Claviceps africana was identified as the causal agent but morphological differences between isolates raised the possibility of more than one species being involved. The major aim of this study was to identify the Claviceps species causing sorghum ergot and to determine the genetic diversity among isolates of the ergot pathogen from Australia and overseas. Symptom development, sequencing of the ITS1 region, and radiolabelled DNA amplification fingerprints (RAF) were used to confirm that ergot of sorghum in Australia is caused by C. africana. The morphology of sphacelia, microconidia, macroconidia, and secondary conidia of all 36 Australian isolates studied matched the description for C. africana and the DNA sequence of the ITS1 region of 2 selected Australian isolates was identical to that of C. africana. Based on RAF analysis of 110 Australian and overseas isolates of Claviceps spp., C. africana isolates could be clearly distinguished (<40% similarity) from C. pusilla, C. sorghicola, C. sorghi, and a Claviceps sp. isolated from Panicum maximum. The C. africana isolates formed 2 distinct clusters. Cluster 1 contained 72 Australian isolates and all 21 overseas isolates of C. africana. The 13 isolates in Cluster 2 were all from Australia and more diverse than those in Cluster 1. The high level of genetic diversity of C. africana isolates in Australia is unexpected given that ergot has only been reported recently. The most likely source of this diversity points to introductions from countries such as India.
Macadamia nut size and maturity influenced by lime and nitrogen applications
Authors: Stephenson R. A. , Gallagher E. C. , Gogel B. J.
Published: September 2002

A long-term study of the effects of lime and nitrogen on a young macadamia orchard included acidifying sulfate of ammonia treatments to separate pH and Ca effects of lime applications. Lime, per se, had no influence on yield, quality, or trunk girth growth. Annual nitrogen applications (with or without neutralising applications of lime), however, consistently depressed the size of nuts and kernels and the percentage of first grade kernels, but had no effect on yield or other quality characteristics. More nuts developed with N treatments but failed to fill effectively.
Application of spatial analysis techniques to adjust for fertility trends and identify interplot competition in early stage sugarcane selection trials
Authors: Stringer J. K. , Cullis B. R.
Published: September 2002

Most sugarcane breeding programs in Australia use large unreplicated trials to evaluate clones in the early stages of selection. Commercial varieties that are replicated provide a method of local control of soil fertility. Although such methods may be useful in detecting broad trends in the field, variation often occurs on a much smaller scale. Methods such as spatial analysis adjust a plot for variability by using information from immediate neighbours. These techniques are routinely used to analyse cereal data in Australia and have resulted in increased accuracy and precision in the estimates of variety effects. In this paper, spatial analyses in which the variability is decomposed into local, natural, and extraneous
components are applied to early selection trials in sugarcane. Interplot competition in cane yield and trend in sugar
content were substantial in many of the trials and there were often large differences in the selections between the
spatial and current method used by the Bureau of Sugar Experiment Stations. A joint modelling approach for tonnes
sugar per hectare in response to fertility trends and interplot competition is recommended.
Pedigree analysis of selected lines of Merino sheep. 2. Gene contributions
Authors: Safari E. , James J. W.
Published: September 2002

Four pairs of selection lines of Merino sheep consisting of 100 ewes and 5 rams were established at the Trangie Agricultural Research centre in 1951. Each line was selected (mass selection) for the appropriate character and direction (Plus or Minus) for a period of 18 years (5 generations). Pedigree analysis of these selected lines in terms of gene contributions revealed different patterns in means and standard deviations of gene contributions of male and female founders. Female founders showed a consistent pattern in all of the selected lines, with an increasing trend for the first 5-6 years in both parameters, and then stabilised. Fleece Plus showed the smallest variation, with an average coefficient of variation of 163%, whereas Folds Plus showed the highest variation with 213%. In the mean contributions, male founders showed a declining pattern for the first 5-6 years and finally stabilised. In the standard deviations, Weight and Folds flocks showed an increasing pattern in the first 1-2 years, whereas Fleece and Crimp flocks showed a declining pattern for the first 3-6 years before stabilising. Male founders showed smaller variation in mean contribution than female founders. In the Weight and Folds flocks, coefficients of variation were in the range of 55-88%, whereas in the Fleece and Crimp flocks they ranged from 98% to 156%. On average, 71% of genes were contributed by female founders and 29% by male founders. A good agreement (>90%) was found between observed and estimated inbreeding from Wray and Thompson (1990) expression in all flocks except Weight Plus and Fleece Minus lines. Effective numbers of male, female, and both male and female founders showed a consistent pattern of early fluctuation, with a trend towards increasing, and eventually stabilised in all the lines. Fleece Plus and Folds Plus lines showed the smallest and highest effective numbers for male, female, and both male and female founders, respectively, which is consistent with the pattern of observed inbreeding. During the first and second year there was a major reduction in the effective number of female founders, which is an indication of marked decrease in the genetic variability at the beginning.
Asparagus in tropical Australia — the first fifteen years
Authors: Bussell W. T. , Olsen J. K. , Robinson C. , Bright J. D.
Published: September 2002

Location, climate, soil, crop establishment, cultural practice, and harvest information are given from 13 commercial plantings and 11 replicated trials of asparagus grown in tropical Australia since 1985. Both commercial plantings and trials have had a short life and low yields compared with plantings in subtropical and temperate parts of Australia. The unsuccessful outcomes to date are primarily because of the lack of experience in growing a perennial temperate vegetable crop in a tropical climate with high humidity during the wet season. After carefully considering poor results to date (attributed particularly to unsuitable soil type, insufficient disease control in the wet season, and inadequate carbohydrate reserves at harvest time) and reviewing current practices in relevant places elsewhere (especially the use of drought-induced dormancy), the chances of boosting average yields and having a prosperous industry in tropical Australia are considered good.
Seasonal changes and the effect of temperature and leaf moisture content on intrinsic shear strength of leaves of pasture grasses
Authors: Henry D. A. , Simpson R. J. , Macmillan R. H.
Published: September 2002

The intrinsic shear strength of leaves of 6 temperate pasture grasses was
measured using a guillotine. The intrinsic shear strength of the leaves was
represented as the force required to shear a leaf corrected for the length of
cutting blade in contact with the material. When green leaves were maintained
at 100% relative humidity, their moisture content was maintained and
their intrinsic shear strength remained constant over a 24-h period. Shear
strength increased when leaves were allowed to dehydrate.
Shear strength varied significantly over a growing season, with strength
generally higher in summer and lower in winter. When grown in a constant
regime with day/night temperatures ranging from 14/6˚C to
34/26˚C, no consistent effects of temperature on shear strength were
observed across species; however, higher temperatures did increase lignin
content of the leaves and decreased in vitro dry matter
digestibility. Any one chemical constituent of the leaves (e.g. lignin,
cellulose) did not appear to contribute significantly to their strength.
The intrinsic shear strength of senescent leaves of
Phalaris aquatica was significantly higher than that of
green leaves, but there was no correlation between the strength of green
leaves and that of senescent leaves. Hence, mature forages during the summer
period will exhibit increased intrinsic shear strength at a time of the year
when the digestibility of the feed also declines and the quality of feed
begins to limit animal production.
Sustained growth promotion, carcass characteristics, and meat quality of steers treated with oestradiol-17b
Authors: Hunter R. A. , Magner T. , Allingham P. G.
Published: September 2002

The experiment measured the effect of 2 hormonal growth promotion strategies
on growth rate, carcass characteristics, and some objective measurements of
meat quality of steers. Bos indicus ×
Bos taurus crossbred steers grazing improved tropical
pastures were divided into 3 treatment groups: unimplanted controls,
implantation once with a long-acting formulation containing 45 mg
oestradiol-17β (Compudose 400, Elanco Animal Health, West Ryde, NSW),
implantation every 105 days with a shorter acting formulation containing 20 mg
oestradiol-17β (Compudose 100) (4 implantations).
Over a 420-day experimental period, steers implanted several times with
oestradiol gained significantly (P < 0.001) more
weight (279 kg) than those implanted once (251 kg) and the controls (230 kg).
Respective carcass weights were 270, 255, and 244 kg. At the same carcass
weight, oestradiol treatment had no significant effect on beef yield or
carcass fatness. Increased total beef yields from implanted steers were
associated with increased carcass weight, rather than significant modification
of carcass composition.
Treatment had no significant effect on any of the objective measures of meat
quality studied, including ultimate pH, peak force, compression, and adhesion.
The occurrence of root-infecting fungi and parasitic nematodes in annual Medicago spp. in Western Australian pastures
Authors: You M. P. , Sivasithamparam K. , Riley I. T. , Barbetti M. J.
Published: September 2002

Asurvey of 30 medic pastures for root-rots was undertaken in Western Australia
and pathogenicity tests of representative fungal isolates from roots sampled
were conducted to determine the main factors contributing to medic decline and
the association between those factors. In particular, the contribution of
pathogenic fungi and nematodes to medic root-rot in Western Australia was
studied. From a total of 30 000 pieces of root plated, 3836 fungal isolates
were obtained and identified at least to genus level. Four hundred and
seventy-two representative isolates were tested for
in vitro pathogenicity in
Medicago sphaerocarpos cv. Orion. Of these, 32 were
further tested in the glasshouse. The pathogenicity tests indicated that
56% of isolates were capable of causing significant damage to the root
system and it is likely that pathogenic fungi are largely responsible for
medic root-rot in the field. In contrast, the number of
Pratylenchus spp. in the roots was not found to relate
to disease symptoms. It is concluded that soil-borne pathogenic fungi such as
species of Pythium, Fusarium, and
Phoma contribute significantly to medic pasture decline
in Western Australia.
Evaluation of a new cropping option using a participatory approach with on-farm monitoring and simulation: a case study of spring-sown mungbeans
Authors: Robertson M. J. , Carberry P. S. , Lucy M.
Published: September 2002

In the northern Australian cropping region, mungbean is commonly sown as an
opportunity crop, usually on low soil water after a winter cereal, and
consequently has a reputation for being a low yielding, high risk crop. Yield
prospects could be improved and risks reduced if it was sown on soils with a
higher soil water content, for instance in spring after a winter fallow.
However, there is a lack of experience and confidence in alternative roles for
mungbean in the farming system. This paper describes a research approach
involving researchers, farmers, advisers, and grain traders in which on-farm
monitoring of spring-sown commercial crops and cropping systems simulation
with APSIM were used to explore yield prospects for a spring-sown crop after a
winter fallow. The key elements of the approach are: (1) identification of
possible options through simulation of scenarios, (2) testing the new practice
with innovative farmers, and (3) monitoring of the management and performance
of commercial crops and comparing yields with benchmarks estimated with a
model. In this case, after 2 years of on-farm testing, spring-sown mungbean
has been shown to have a potential for high returns in the northern cropping
systems.
Prediction of weather damage of mungbean seed in tropical Australia. II. Model application
Authors: Yeates S. J. , Lawn R. J. , Adkins S. W.
Published: September 2002

To demonstrate a model to simulate the risk of weather damage of mungbean,
application studies were undertaken using 27 years of climatic data collected
at Katherine, Northern Territory, Australia. In terms of the risk of weather
damage, the transition from high risk to low risk occurred after mid-February
but before 20 March. High quality seed could be expected in 70% of
seasons for a crop that matured after 20 March. For planting dates prior to 25
January, the chance of producing premium quality seed was enhanced to
40–70% of seasons by sowing a cultivar that matured 2 weeks later
and by harvesting promptly (4 days after maturity). There was no benefit from
later maturity or harvest promptness where sowing was made after 25 January,
because maturity occurred after the wet season was complete. In contrast,
yield was optimised at early January sowing dates. Calculating gross margins
by combining yield and weather damage simulations identified an optimum sowing
date between the optimum for yield and seed quality. It was shown that later
maturity combined with photoperiod sensitivity increased the sowing window
from 10 to 29 days compared with a short duration variety that was insensitive
to photoperiod. The relative merits of modelling and field experimentation in
assessing the cropping potential for mungbean in a new region are discussed.
The need to be able to simulate the yield of the second flush of flowers was
acknowledged as a future research requirement.
The influence of dietary magnesium supplement type, and supplementation dose and duration, on pork quality and the incidence of PSE pork
Authors: D'Souza D. N. , Warner R. D. , Leury B. J. , Dunshea F. R.
Published: September 2002

Ninety crossbred (Large White × Landrace) female pigs were used to
compare the effects on ultimate pork quality of different magnesium (Mg)
compounds [magnesium aspartate (MgAsp) and magnesium sulfate
(MgSO4)], Mg dose (1.6 and 3.2 g elemental Mg), and
Mg supplementation period (2 and 5 days) in pigs subjected to an acute
stressor pre-slaughter. Pigs fed the Mg-supplemented diets had lower muscle
lactic acid concentrations at 24 h post-slaughter than pigs fed the control
diet. There were no significant differences in muscle glycogen concentrations
in the Longissimus thoracis (LT) at 5 min, 40 min, or 24
h post-slaughter between the control and Mg-supplemented diets. Pigs fed the
Mg-supplemented diets produced less pale colour pork (i.e. darker colour) and
had reduced drip loss and reduced incidence of pale, soft, exudative (PSE)
pork in the LT muscle compared with pigs fed the control diet. Within the Mg
diets, pigs fed the MgAsp-supplemented diet produced less pale LT muscle
colour than pigs fed the MgSO4-supplemented diet. There
were no significant differences in LT pork quality parameters (colour and
percent drip loss) regardless of whether the high or low Mg dose or the 2- or
5-day supplementation period was used. This experiment has shown that the use
of dietary MgAsp supplementation at a dose of 1.6 g elemental Mg (20 g MgAsp)
for 2 days prior to slaughter significantly improved pork quality and reduced
the incidence of PSE pork.
The roles of thyroid hormones and prolactin in the control of fibre moult and associated changes in hair follicle activities in cashmere goats
Authors: Villar D. , McMillen S. R. , Dicks P. , Rhind S. M.
Published: September 2002

Five groups of 8 adult male castrated goats were used in an 8-month study. For
a 6-month period commencing in November, goats of one group were dosed with
propylthiouracil (PTU), a drug which reduces the rate of conversion of
thyroxine (T4) to triiodothyronine
(T3) in peripheral tissues. Animals of a second group
were treated with bromocriptine (Br), a drug which reduces the circulating
concentrations of prolactin. Animals of other groups were treated with PTU
+ Br, PTU + triiodothyronine (PTU + T3),
or vehicle only (control). The mean date of moult onset was later in animals
of the PTU + T3 (P <
0.05), PTU + Br (P < 0.05), and Br (P < 0.01)
groups than in control animals. PTU + T3 , PTU
+ Br, and Br animals also exhibited lower minimum levels of primary
follicle activity than control animals (P < 0.01). On
the basis of a periodic function applied to the data, there was a trend
towards a later nadir of both primary and secondary follicle activity. There
were no significant effects of treatment on profiles of thyroxine
(T4), triiodothyronine (T3),
growth hormone (GH), insulin-like growth factor-1, or insulin but a
significant (P < 0.001) seasonal increase in mean
concentration occurred between November and March–April in all except GH
profiles. It is concluded that PTU and Br did not act additively or
synergistically on follicle activity or moult. Nevertheless, it is further
concluded that the mechanisms of action of the thyroid hormones and prolactin
are not independent and that future studies of their effects on follicle
function should address their interactions with other hormones and changes in
thyroid hormone receptor activity within the follicles.
Blood prolactin depression in growing pigs fed sorghum ergot (Claviceps africana)
Authors: Blaney B. J. , Kopinski J. S. , Magee M. H. , McKenzie R. A. , Blight G. W. , Maryam R. , Downing J. A.
Published: September 2002

The toxicity of sorghum ergot (Claviceps africana) was
assessed in young pigs over 28 days. Forty-eight pigs of both sexes and 2
breeds (Large White and Duroc) were allocated across 6 grower diets, balanced
for fibre and predicted digestible energy, and containing 0, 0.3, 0.6, 1.3,
2.5, or 5% ergot sclerotia [the 5% sclerotia diet contained
70 mg alkaloids/kg (>90% dihydroergosine)]. Blood samples
taken on Days 0 and 28 were analysed for prolactin and clinical, biochemical,
and haematological indices of health. Feed consumption and liveweight were
individually monitored. There were no clinical signs of illness attributable
to ergotism in the pigs. Blood prolactin concentrations were significantly
depressed in pigs receiving 9 mg alkaloids/kg (0.6% sclerotia) and
by >80% in pigs receiving 35 and 70 mg alkaloids/kg, clearly
indicating a potential to interfere with lactation in sows. Reductions in feed
intake and poor feed conversion were observed over the first 7 days with >9
mg alkaloids/kg, but some tolerance developed later. Feed refusal was more
pronounced for pigs of the Duroc breed. Over the full trial period, growth was
reduced by about 30% in pigs receiving 70 mg alkaloids/kg, as a
result of poor feed intake and feed conversion. Digestible energy of diets
containing ergot was later found to be lower than predicted, which contributed
to this result.
Cultivar and environmental effects on quality characters in wheat. II. Protein
Authors: Panozzo J. F. , Eagles H. A.
Published: September 2002

Glutenins and gliadins are the major components of the storage protein in
wheat and make a significant contribution to dough rheology and baking
quality. Qualitative differences in these proteins are known to be important
for dough rheology, particularly for glutenins, but much less is known about
quantitative differences, especially as influenced by field environment.
Flour protein, the proportion of glutenin and gliadin in flour protein, loaf
volume, and the dough rheological characters dough development time, dough
breakdown, dough extensibility, and maximum dough resistance (Rmax) were
determined for 7 cultivars grown in 15 diverse environments. The proportion of
glutenin in flour protein was highly dependent on cultivar, whereas, although
cultivar was still important, environmental variation was greater than
cultivar variation for gliadin. Environmental variation was greater than
cultivar variation for the dough rheological characters. Across environments,
the proportion of gliadin increased with increasing flour protein, whereas the
proportion of glutenin decreased. An index of accumulated temperatures above
30˚C during the first 14 days after anthesis explained a significant
proportion of the increase in gliadin, and, to a lesser extent, the decrease
in glutenin. Increasing Rmax and dough development time, and more rapid dough
breakdown, were also associated with this index. The rate of increase of Rmax
with the temperature index was greater for cultivars with the
Glu-D1a allele than those with the
Glu-D1d allele, suggesting that the relative performance
of cultivars with different alleles at this locus depends on environment.
Phenotypic variation for in sacco dry matter and fibre degradation kinetics in lucerne
Authors: Julier B. , Emile J. C. , Lila M. , Huyghe C.
Published: September 2002

Energy content is an important criterion for evaluation in lucerne breeding.
The in sacco method was used to investigate the
phenotypic variation in the kinetics of degradation of dry matter and fibre
for 15 lucerne cultivars grown in one location, and to compare these kinetic
parameters with laboratory analyses of dry matter solubility, fibre content
(NDF, neutral detergent fibre), and fibre solubility. Bags containing forage
samples were incubated for 2, 4, 8, 12, 24, 48, and 72 h in 3 fistulated
Holstein cows. Dry matter and NDF degradation curves were modelled with a
sigmoid curve with 3 parameters. Phenotypic variations were observed for dry
matter and NDF disappearance at each time interval, and for the parameters of
the degradation kinetics. For both dry matter and NDF, the totally degraded
fraction was correlated with the solubility measured by wet chemistry, but the
rate of degradation of the slowly degraded fraction was not correlated with
chemical analyses. The effect of the variations in the parameters of dry
matter and fibre degradation on ruminant performance needs to be studied
further.
Diet selection by sheep grazing Phalaris aquatica L. pastures of differing water-soluble carbohydrate content
Authors: Ciavarella T. A. , Dove H. , Leury B. J. , Simpson R. J.
Published: September 2002

A short-term shading treatment was used to create a
Phalaris aquatica L. pasture with alternating strips of
‘low’ [62 mg/g dry matter (DM)] and
‘high’ (126 mg/g DM) water-soluble carbohydrate (WSC)
concentration. Analyses showed that starch and all components of the WSC were
reduced in concentration by shading. The shaded and unshaded pasture strips
did not differ significantly in in vitro DM
digestibility (84% DM), nitrogen (3.1% DM), or neutral detergent
fibre concentration (42.4% DM). Synthetic alkanes were applied to the
pasture strips as markers to measure the selection of the shaded and unshaded
pasture by sheep. When 12–13-month-old Merino wethers were given
simultaneous access to both pasture treatments, they selected 2.6-fold more
unshaded (high WSC) pasture than shaded pasture. The results indicate the
involvement of herbage total WSC and its components in the process of diet
selection by sheep, and suggest that in future studies, more attention should
be paid to reporting data for total WSC concentration.
Morphological characteristics and agronomic merit of white clover (Trifolium repens L.) populations collected from northern New South Wales
Authors: Lane L. A. , Ayres J. F. , Lovett J. V. , Murison R. D.
Published: September 2002

Aset of white clover (Trifolium repens L.) populations
collected from old pasture sites in northern New South Wales was characterised
in situ at the collection sites and under uniform glasshouse conditions, and
then evaluated for agronomic merit in the field. The data were examined to
determine whether ecotype development through genetic differentiation had
occurred in these white clover populations, and to assess their potential
value for future breeding. Environmental conditions at the collection sites
represented a wide diversity of rainfall, altitude, soil type, companion
grass, and grazing intensity conditions. The populations generally were found
to be medium-leaf and mid- to late-flowering and derived from early New
Zealand introductions to Australia. The populations showed significant
(P < 0.05) variation in morphological characteristics
(leaf size and stolon characters) and this variation was expressed in all 3
environments. It was concluded that significant genetic differentiation
affecting stolon and flowering characteristics had occurred, with implications
for agronomic value. A small cluster of the populations was found to possess
useful characteristics for white clover breeding where persistence in dryland
environments is the primary breeding objective.
Response of lambs fed low quality roughage to supplements based on urea, cereal grain, or protein meals
Authors: Dixon R. M. , Egan A. R.
Published: September 2002

The intake and growth responses of lambs fed barley straw to a range of
supplements provided on a 3- or 4-day cycle were examined. Supplements were
urea and sulfur (N/S) added to the straw, or 3 increments of each of 3
approximately isonitrogenous supplements consisting of barley grain mixed with
urea and sulfur (Bar/N), cottonseed meal (CSM), and a 0.4 : 0.6 mixture of
fishmeal and lucerne hay (FM/L). Lambs fed straw alone consumed 38.3 g dry
matter (DM)/kg W0.75 day of straw and an estimated
2.54 MJ metabolisable energy (ME)/day, and lost 20 g liveweight
(LW)/day. Supplementation with N/S increased estimated ME intake by
32%. Substitution rates of Bar/N, FM/L, and CSM supplements for
straw were 0.50, 0.36, and 0.25 g/g, respectively, but these rates did not
differ (P > 0.05) between supplements.
Digestibilities of organic matter (OM) and neutral detergent fibre (NDF) were
affected differently depending on both the type and amount of supplement.
Estimated ME intake was increased 7.1, 7.9, and 8.6 kJ/g supplement DM by
Bar/N, FM/L, and CSM, respectively. LW gain and wool growth were
increased (P < 0.01) by consecutive increments of
each of the supplements, and were increased more (P <
0.01) by the FM/L and CSM than by the Bar/N supplement. The slopes of
the linear relationships between LWgain and estimated ME intake were greater
(P < 0.05) for CSM and FM/L than for Bar/N
supplement, ingested ME being used with about twice the efficiency for LW gain
when the protein meal supplements rather than the cereal grain–urea
supplement was fed. However, across all supplement treatments, LW gain was
correlated (r = 0 .9 1 ; P
< 0.001) with the absorbed amino acid supply as estimated from feeding
standards. In conclusion, although supplements based on either cereal grain or
protein meals increased LW gain in these young lambs, there were much greater
responses to the protein meals due principally to more efficient utilisation
of ingested ME for LW gain.
Effects of shallow water table on capillary contribution, evapotranspiration, and crop coefficient of maize and winter wheat in a semi-arid region
Authors: Kang Shaozhong , Zhang Fucang , Hu Xiaotao , Jerie Peter , Zhang Lu
Published: September 2002

A lysimeter experiment was conducted during 19866—96 to study the
impacts of groundwater tables on the capillary contribution,
evapotranspiration, and crop coefficient of maize and winter wheat grown in a
semi-arid region in loess loam soils. The depth of groundwater table was set
to 0.5, 0.8, 1.0, 1.2, 1.5, 2.0, and 2.50 m, respectively. The results showed
that the rate of capillary contribution from groundwater to crop root-zone was
influenced mainly by the depth of the water tables. The daily variation in
capillary contribution was not the same as pan evaporation; the peak was
delayed when the water table was >0.8 m, and the time of delay increased
with the depth of water table. The crop evapotranspiration was decreased with
increasing groundwater table in the early growth period and harvest period.
The maximum evapotranspiration occurred at 1.2 m groundwater table in the
other periods. Values of crop coefficients (K c ) were
estimated based on the measured evapotranspiration (ET) and reference crop ET
computed by the modified Penman method. The estimated K c was significantly
different from the values computed and used in the region in the absence of
groundwater table effects, and it varied markedly with groundwater tables.
Relationships between the crop coefficient and the depth of groundwater table
were developed using mean crop coefficients derived from multi-year data. It
was found that linear model was better for the period
Octobermp;mdash;February in the winter wheat growing season and June in the
summer maize growing season. The polynomial model was suitable for the period
March;mdahs;June in the winter wheat growing season and from July to
October in the summer maize growing season.
H I Emission and Absorption in the Southern Galactic Plane Survey
Authors: McClure-Griffiths N. M. , Dickey John M. , Gaensler B. M. , Green A. J. , Haynes R. F. , Wieringa M. H.
Published: September 2002

We present preliminary results from the Southern Galactic Plane Survey (SGPS) Test Region and Parkes data. As part of the pilot project for the Southern Galactic Plane Survey, observations of a Test Region (325·5° ≤l ≤ 333·5°; −0·5° ≤ b ≤ 3·5°) were completed in December 1998. Single-dish observations of the full survey region (253° ≤ l ≤ 358 ° |b| ≤ 1°) with the Parkes Radio Telescope were completed in March 2000. We present a sample of SGPS H I data, with particular attention to the smallest-and largest-scale structures seen in absorption and emission, respectively. On the large scale, we detect many prominent H I shells. On the small scale, we note extremely compact, cold clouds seen in H I self-absorption. We explore how these two classes of objects probe opposite ends of the H I spatial power spectrum.
Frequency Dependent Ray Paths in Local Helioseismology
Authors: Barnes G. , Cally P. S.
Published: September 2002

The surface of the Sun is continually oscillating due to sound waves encroaching on it from the interior. Measurements of the surface velocity are used to infer some of the properties of the regions through which the sound waves have propagated. Traditionally, this has been done by using a modal decomposition of the surface disturbances. However, the use of ray descriptions, in the form of acoustic holography or time–distance helioseismology, provides an alternative approach which may reveal more detailed information about the properties of local phenomena such as sunspots and active regions. Fundamental to any such treatment is determining the correct ray paths in a given atmosphere. In the simplest approach, the ray paths are constructed to minimise the travel time between two points (Fermat's principle). However, such an approach is only valid in the high frequency limit, ω » ωc, N, where ωc is the acoustic cut-off and N the Brunt-VÄisÄlÄ frequency. Although ωc is often included in time– distance calculations, and N occasionally, the same is not true of acoustic holography. We argue that this raises concerns about image sharpness. As illustrations, representative ray paths are integrated in a realistic solar model to show that the Fermat approximation performs poorly for frequencies of helioseismic interest. We also briefly discuss the importance of the Brunt-VÄisÄlÄ frequency to the time–distance diagram.
Image Processing for the Sydney University Molonglo Sky Survey (SUMSS)
Authors: Chan B. H. P. , Cram L. E.
Published: September 2002

The Sydney University Molonglo Sky Survey (SUMSS) is a deep radio survey at 843 MHz, covering the region south of −30° declination. Designed to be a southern counterpart of the northern NRAO VLA Sky Survey (NVSS), SUMSS is over 40% complete, and it is now time to devise ways to generate the source catalogue for the survey. We describe here new methods to deal with image artifacts to minimise spurious fits by automatic source fitting algorithms. With the new techniques, an automatically generated, objective catalogue can be made to a 10 mJy cutoff. Catalogues can be made to a 5 mJy cutoff provided that special care is taken and certain artifacts are avoided.
Circular Polarisation in AGN
Authors: Macquart Jean-Pierre
Published: September 2002

We discuss the constraints that recent observations place on circular polarisation in AGN. In many sources the circular polarisation is variable on short timescales, indicating that it originates in compact regions of the sources. The best prospects for gleaning further information about circular polarisation are high resolution VLBI and scintillation ‘imaging’ which probe source structure on milliarcsecond and microarcsecond scales respectively.
Ubiquitous Column Density Variability in Seyfert 2 Galaxies
Authors: Risaliti G. , Elvis M. , Nicastro F.
Published: September 2002

We present a study of X-ray column density variability in Seyfert 2 galaxies. We show that variations in NH are observed in almost all the objects with multiple hard X-ray observations. Variation timescales (as short as a few months in several cases) are not in agreement with the standard scenario of a parsec-scale toroidal absorber. We propose that the X-ray absorber in Seyfert galaxies is located much nearer to the centre than previously assumed, on the broad line region scale. An extension of the model by M. Elvis (2000) can explain the observed variability. We also show preliminary results of NH variability search inside single X-ray observations, which suggest that variations can occur on timescales of a few 104 s.