bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance of tobacco to pandemic blue mould Peronospora hyoscyami de Bary syn P. tabacina Adam): a historical overview
Authors: Lea H. W.
Published: September 2002

Summary. The pandemic of
Peronospora hyoscyami de Bary (syn.
P. tabacina Adam) introduced into Britain from Australia
in 1957 swept across Europe, North Africa, the Middle East and the former
Soviet Union in the early 1960s causing catastrophic losses of tobacco crops.
Nicotiana debneyi Domin. is the major source of
resistance to this pathogen in Australia and Europe.
A blue mould resistant version of USA cultivar Hicks (designated Resistant
Hicks) was bred by H. W. Lea. This cultivar, with resistance from
N. debneyi was widely used in Europe from 1962 as a
parent with local varieties. From 1965 Bel 61 lines bred by the United States
Department of Agriculture, also with resistance from
N. debneyi were phased in as a source of resistance in
some countries. The cultivar Resistant Hicks was selected for resistance in
growing seasons with few cloudy days, and its high resistance in Australia has
been stable for over 40 years; the cultivar Dynes mostly grown in Australia
has the Resistant Hicks source of resistance. The high resistance to
Peronospora possessed by cultivars developed from the
Bel 61 lines has been stable for more than 20 years in Europe; the Bel lines
were selected under shade conditions.
Nicotiana debneyi has resistance to
Peronospora hyoscyami on 8 chromosomes; there is
evidence that both American and Australian resistant cultivars derive some
resistance from Nicotiana tabacum L. Both the cultivar
Resistant Hicks and Bel 61 lines possess only part of the full resistance
available from N. debneyi; further progress may be
possible by hybridising these 2 lines and incorporating resistance from other
resistant Australian species.
Carob agroforestry industry: an assessment of its potential for the low - medium rainfall Murray Valley region
Authors: Race D. , Curtis A. , Booth W.
Published: September 2002

This paper reports the key findings of a study examining the potential
viability of a carob agroforestry industry in the low rainfall Murray Valley
region. The carob fruit, typically produced on female and hermaphrodite trees
older than 6 years, is valued for a range of products derived from the seed
and pod. From the seeds, the endosperm is extracted for a galactomannan, which
forms an edible gum (termed ‘carob bean gum’ or ‘locust bean
gum’) and has become a valuable natural food additive. Carob powder,
made by grinding the roasted pod, is used for the human food industry (with
cocoa products and syrups). Ripe pods also have potential as a high energy
stockfeed. The gum is used extensively in Australia as a thickening or binding
agent, particularly for canned pet food products, with current imports valued
at A$10 million/year. The current Australian demand for ‘pet
food’ and ‘technical’ grade gum is estimated at 1200
t/year, with a further 200 t/year of the higher quality
‘food’ grade gum. Assuming a modern plant was built in Australia,
the current Australian demand for carob gum could be met with about 2250 t of
carob seed (seed value at $1600/t). This equates to 5405 ha of
trees (at 104 trees/ha) with medium rainfall and low technology management
(yielding 40 kg pods/tree); or 1080 ha of trees (at 208 trees/ha) with
supplementary irrigation and fertilising (yielding 100 kg pods/tree). As
such, carob could be a commercial tree crop for landholders in the Murray
Valley region. This could be through the sale of seeds and pods, or as a
supplement to livestock feeding. Economic analyses were undertaken to assess
the relative viability of commercial returns when trees had access to adequate
water through medium rainfall or irrigation, and growers had access to both
the carob gum and powder markets. Commercial opportunities for carob growers
within Australia vary considerably depending on establishment and maintenance
costs, yields and access to markets.
An improved distribution system for chaffy seeded grasses
Authors: Kelly P. J. , Wiedemann H. T.
Published: September 2002

Lack of seeding equipment that will spread chaffy seed uniformly has impeded
the improvement of pastures in Australia. A semicircular seedbox with a
pickerwheel and auger agitator (SPAA) developed in Texas, USA was tested with
three Australian grasses and compared with the Australian revolving drum
seeder. The metering units were tested for change in discharge rates as the
seedbox emptied. Modifications in the original SPAA device improved
performance. Modifications included a change in the shape of the pickerwheel
and the addition of a small post at the base of the seedbox just ahead of the
pickerwheel. A pillar protruding from the top of the seedbox was also tested
and found to have minimal effect on performance. At pickerwheel speeds of 10
and 30 rpm, the modified SPAA device experienced a 16 and 14% decrease
in discharge rate as Cenchrus ciliaris L. cv. Biloela
(buffel grass) seed was metered from 140 to 20% of seedbox capacity. In
a comparable test, the revolving drum seeder experienced an 7-fold increase in
discharge rate. Bothriochloa insculpta cv. Hatch
(creeping bluegrass) and Danthonia richardsonii cv.
Taranna (wallaby grass) seed were successfully distributed by the improved
SPAA system. Based on these data, the improved SPAA metering device can
distribute chaffy seeded grasses evenly, providing a means to sow these
grasses effectively in pastoral areas of Australia.
Performance of temperate perennial pastures in the Australian subtropics 1. Yield, persistence and pasture quality
Authors: Lowe K. F. , Bowdler T. M. , Casey N. D. , Moss R. J.
Published: September 2002

Summary. Irrigated, pure stands of perennial ryegrass
(Lolium perenne cv. Yatsyn), prairie grass
(Bromus willdenodii cv. Matua) and tall fescue
(Festuca arundinacea cv. AU Triumph) were compared with
Italian ryegrass (L. multiflorum cv. Concord) under
grazing in the subtropics of south-east Queensland.
Pastures were fertilised with 50 kg nitrogen/ha . month as urea and annual
dressings of 20 kg phosphorus/ha and 50 kg potassium/ha (as
superphosphate and muriate of potash, respectively). There were 4 pasture
treatments grazed by multiparous Holstein-Friesian cows at 3 cows/ha in a
1-week-on, 3-weeks-off rotation with 2 replicates and 3 cows/treatment
block. Feed on offer was measured weekly and pasture quality, at the mid point
of each of the 4 seasons. Detailed measurements on plant and tiller dynamics
were recorded on fixed quadrats within the grazing areas from November to May
in the second and third years.
Yield of pasture on offer was greatest with prairie grass and the difference
was most marked in spring and early summer. Yield of fescue was generally
higher than that from the other 3 grasses in the autumn. In the second and
third summers, the grass weed component in the 2 ryegrass, and to a lesser
extent the prairie grass, pastures was greater than the sown grass component.
Fescue generally produced forage lower in quality than the other 3 grasses
although the differences were small in summer. The forage quality of Italian
ryegrass was higher than perennial ryegrass in most seasons and for most
attributes measured. Generally prairie grass had similar quality forage to the
ryegrasses but at times it was as low as fescue.
Fescue was the most persistent grass; it maintained a frequency of occurrence
of 88, 56 and 71% in the first, second and third autumn periods,
respectively, compared with 36, 37 and 21% for perennial ryegrass. To
achieve these persistence figures, perennial ryegrass needed over-sowing in
each autumn. Plant density and tiller numbers per plant fell in all grasses
from November to May but the fall was significantly less in fescue than in
other grasses.
It was concluded that all 3 temperate perennial grasses demonstrated traits
which were useful for subtropical dairy pastures. Fescue was the most
persistent and the only grass which could sustain grazing in autumn. The
performance of Italian ryegrass was as good as that of perennial ryegrass in
the first year but fell substantially in the second and third years as the
level of summer grass invasion suppressed the existing population and made
oversowing increasingly less effective. Prairie grass produced the highest dry
matter on offer under grazing, its forage quality was generally similar to
that of the ryegrasses and it regenerated from self-sown seed.
Changes in soil physical properties after one pass of a sugarcane haulout unit
Authors: Braunack M. V. , Peatey T. C.
Published: September 2002

Summary. Field trials were established at different
locations within the Herbert River area near Ingham in North Queensland to
assess the ratooning ability and yield of sugarcane after a wet harvest.
Treatments consisted of harvesting under dry conditions and then applying 50
mm of irrigation, followed by no traffic (control), traffic of a haulout unit
directly over the harvested row (traffic treatment), and traffic as above with
the application of further irrigation to maintain wet soil conditions (traffic
+ water treatment). Undisturbed soil cores were collected from the row
before harvest and after treatment imposition to assess the change in soil
physical properties due to traffic. Soil cone resistance was also measured.
Soil physical properties changed significantly after traffic with increases in
soil bulk density and soil cone resistance and decreases in saturated
hydraulic conductivity. The greatest change occurred in the top 20 cm of the
profile.
Yield at one site was significantly reduced after traffic and the effect was
enhanced in the presence of water after traffic. It is suggested that to
maintain good soil conditions in the row all traffic should be restricted to
the central part of the inter-row. One way to achieve this is to match crop
row spacing with equipment track widths.
Utilisation of white clover silage fed alone or with maize silage by lactating dairy cows
Authors: Auldist D. E. , Atkinson K. L. , Dellow D. W. , Silvapulle M. J. , McDowell G. H.
Published: September 2002

Six lactating dairy cows in mid lactation were fed either white clover silage
or a mixture of white clover and maize silages (70 : 30, dry matter basis).
Milk yields (about 20 L/day) and compositions were similar when cows were
fed either diet. Although the mixed diet was less digestible and provided less
energy and crude protein than white clover, rumen fermentation may have been
improved relative to that when white clover silage was fed alone. Flow rates
of fluid from the rumen were faster, pH values for rumen liquor were higher
and concentrations of ammonia in rumen liquor were lower when cows were fed
the mixed diet than white clover silage. Concentrations of total volatile
fatty acids and the proportions of the major volatile fatty acids in rumen
liquor were similar for both diets. The efficiency of utilisation of dietary
nitrogen for liveweight gain and milk production also appeared to be similar
for both diets. Plasma concentrations of key metabolites were consistent with
the cows being well nourished when fed both diets. Overall, it was evident
that white clover silage may be used effectively in combination with lower
quality maize silage to meet the nutrient requirements of cows with reasonably
high yields of milk during mid lactation.
The effect of nitrogen fertiliser on yield, nitrogen and mineral elements in Australian brown rice
Authors: Batten G. D. , Marr K. M. , Lewin L. G.
Published: September 2002

Summary. The average yield of rice crops grown by the
2300 producers in southern Australia has ranged from 6.5 to 9.4 t/ha over
the last 5 years. Average yields in the northern Murrumbidgee Irrigation Area
have exceeded 10 t/ha in several of these years with individual producers
attaining yields greater than 12 t/ha. Further increases in yield are
expected with new genotypes, such as Namaga released in 1997. These high
yielding crops require access to large amounts of nitrogen (and other
elements) from the soil and fertilisers. Inputs of other nutrients are
relatively minor and limited to phosphorus (P), sulfur (S) and zinc (Zn).
In the current study, we evaluate the relations between yield increase due to
nitrogen (N) fertiliser applications, and the rate of removal of elements by
medium and long-grain genotypes. Some significant differences were found
between genotypes in the concentration and accumulation of some minerals. In
the 1993–94 experiment, the long-grain genotype Langi yielded higher and
had higher mineral concentrations than Pelde, the lower-yielding genotype it
replaced. However, no consistent relationships emerged between genotype, yield
and mineral concentration or accumulation. Nitrogen applications caused
significant increases in yield, grain nitrogen and some mineral
concentrations. In the 1992–93 and 1993–94 experiments, 125 kg and
100 kg nitrogen fertiliser increased yield by 63% and 71% (from
6.8 to 11.1 t/ha and from 5.9 to 10.1 t/ha), respectively. The same N
application rates increased the nitrogen concentration in the grain from 12.9
g/kg to 14.5 g/kg in 1992–93, and from 11.4 g/kg to 12.6
g/kg in 1993–94. Grain S was significantly increased in
1992–93 from 1.04 to 1.21 g/kg, and from 0.82 to 0.94 g/kg in
1993–94. The concentrations of grain Mn also increased significantly
with N application in the 1993–94 season. Total accumulation of all
minerals (except B and Na in 1992–1993 and Cu in 1993–1994)
increased with N application. Yield increase, driven by N fertiliser, was the
major influence on increased export of N, S, P, K, Mg, Ca, Fe, Mn and Zn from
the soil.
Nitrogen efficiency of wheat cultivars in a Mediterranean environment
Authors: Anderson W. K. , Hoyle F. C.
Published: September 2002

Summary. Experiments were conducted at 3 sites in
Western Australia in 1993 using 33 wheat cultivars and crossbreds. Two rates
of applied nitrogen fertiliser (0 and 40 kg/ha of nitrogen) were used to
screen the lines for efficiency of nitrogen uptake, grain yield and grain
protein production per unit of nitrogen applied, and nitrogen translocation to
the grain. This information can be useful in determining nitrogen fertiliser
strategies for wheat cultivars in the field. Nitrogen uptake in the plant tops
was measured during the season and in the grain and straw at maturity.
Grain yield, grain protein and nitrogen efficiency parameters were not
markedly different between grain quality grades which are largely based on
grain hardness. Yield efficient lines (high net yield increase per unit of
applied nitrogen) were characterised by greater net uptake and net utilisation
efficiencies but had similar yields and grain protein percentages as yield
inefficient lines. Protein efficient lines (high net grain protein increase
per unit of applied nitrogen) also had greater uptake efficiencies but lower
utilisation efficiencies than protein inefficient lines.
No lines were both yield and protein efficient suggesting that lines either
use fertiliser nitrogen preferentially in yield production or in production of
protein. The results indicate that in nitrogen-responsive situations it will
be more profitable to use yield-efficient lines. Further investigation is
needed to examine the suggestion that where soil nitrogen levels are higher
(and yield responses to nitrogen are less) a greater economic return may come
from using protein efficient lines.
Some wheat lines had a high ability to recover fertiliser nitrogen applied to
the crop. Others had a high ability to take up soil nitrogen. It is postulated
that these differences may be due to differences in root systems. Some mid-
and long-season lines that had high concentrations of nitrogen in the tops at
anthesis metabolised that nitrogen poorly into grain yield or protein. This
suggests that nitrogen efficiency may be partly related to maturity relative
to length of growing season.
Effects of season and time since defoliation on the nutritive characteristics of three irrigated perennial pasture species in northern Victoria 2. Macro-minerals
Authors: Stockdale C. R.
Published: September 2002

During 1993–94, the nutritive characteristics of white clover
(Trifolium repens cv. Haifa), ryegrass
(Lolium perenne cv. Ellet) and paspalum
(Paspalum dilatatum) were examined at weekly intervals
on 4 occasions. On each occasion, they were initially defoliated with a drum
mower and allowed to regrow for up to 9 weeks; dates of the 4 initial harvests
were 24 September, 26 November, 28 January and 25 March. The objective of the
part of a larger study that is reported here was to examine changes in
macro-minerals of the 3 species as they regrew after defoliation, in order to
start providing information for informed decisions on the need for
supplemental minerals in northern Victorian dairy systems.
The ranges in mineral elements recorded in this study were
0.16–0.43% for phosphorus, 1.18–3.41% for potassium,
0.26–1.49% for calcium, 0.20–0.54% for magnesium,
0.05–0.44% for sodium, 0.79–2.02% for chlorine and
0.15–0.37% for sulfur. A major reason for the large ranges was
due to variations between the 3 species. White clover was richer in a number
of minerals than were the grasses, particularly calcium, potassium and
magnesium, although phosphorus was also generally higher. Perennial ryegrass
had high sodium concentrations, which were probably related to high
watertables, with the associated propensity for salinity problems, that are
endemic in irrigated northern Victoria. It is suggested that, on the basis of
the pasture on offer, phosphorus is the major mineral that can potentially
limit milk production by grazing dairy cows in this environment, although
possible deficiencies were also demonstrated for calcium, sodium and sulfur.
Where a mineral has its highest concentration in the leaves, lax grazing
management or the use of short pastures should result in higher concentrations
in the pasture eaten than that on offer. Leaves were not always the richest
source of a mineral although this was almost always the case for all minerals
in ryegrass leaves. In white clover, phosphorus, calcium, magnesium and sulfur
were more concentrated in the leaves than in the stem. In paspalum, calcium,
magnesium and sulfur were more concentrated in the leaves. White clover stems
had higher concentrations of potassium and chlorine than leaves, while with
paspalum this applied to sodium and chlorine. It was concluded that the
species composition of a pasture will have a large impact on the supply of
minerals for grazing dairy cows, although the leaf : stem ratio, as determined
by time since the last defoliation, will also have a role in determining whole
plant composition.
A grower survey of rotations used in the New South Wales cotton industry
Authors: Cooper J. L.
Published: September 2002

Summary. Cotton growers in the Macquarie, Namoi and
Gwydir Valleys of New South Wales were surveyed in 1992 to determine what
crops are grown in rotation with cotton, how frequently rotation crops are
used, and what influences the grower’s choice of rotation system. A
total of 155 properties were surveyed, covering 100, 49 and 58% of
irrigated cotton produced in the Macquarie, Namoi and Gwydir Valleys,
respectively.
Although a large part of the 1992–93 cotton crop (61% by area)
did not follow a rotation crop, there was widespread interest in rotations and
70% of properties had used rotations. Wheat was by far the most widely
grown rotation crop, but there was considerable interest in other crops,
especially legumes. The perceived benefits from rotation crops reported by
most growers were better soil structure, less disease in following cotton, and
more soil organic matter. However, when asked why they preferred certain
rotation crops, these factors did not rate highly with growers. Crops that
were easy to grow and gave the best financial returns possessed the main
features sought in a rotation crop. The greatest problem in growing rotation
crops was a lack of irrigation water. It is not surprising that this problem
ranked highly because when the survey was conducted, the Namoi and Gwydir
Valleys had water allocations of 15 and 0%, respectively. Not having
suitable equipment to sow rotation crops was also a problem for 17% of
growers, but 10% encountered no problems.
The survey also investigated the use of permanent beds and retained hills.
These practices have benefits for soil structure, and are almost essential for
rotation crops which need to be sown as soon as the cotton is harvested. Over
80% of growers using rotations had adopted some form of permanent beds
or retained hills. The benefit which ranked highest was a reduction in costs,
followed by less soil compaction. Some growers (44%) who used permanent
beds or retained hills had no problems, but handling the trash and keeping the
rows straight were of concern to others.
Effect of preharvest bagging and of embryo abortion on calcium levels in ‘Kensington Pride’ mango fruit
Authors: Hofman P. J. , Joyce D. C. , Beasley D. R.
Published: September 2002

Bagging mango fruit during their development on the tree can reduce insect and
disease damage. However, it is also possible that bagging can interfere with
transpiration and associated calcium accumulation. Low calcium concentrations
have been correlated with poor mango fruit quality. This study was conducted
to evaluate the influence of bagging at various stages of fruit development on
calcium concentration and postharvest quality of ‘Kensington
Pride’ mangoes. Fruits were bagged at 41, 25 or 9 days before harvest.
No statistically significant differences in either skin or flesh calcium
concentration were found between the bagged (plastic or paper) and unbagged
fruits. Postharvest weight loss was enhanced and shelf life reduced in the
‘plastic bagged’ fruits. In an ancillary study, calcium
concentrations in ‘Kensington Pride’ nubbins (seedless fruit) were
compared with those in seeded fruit, since it has been shown with apple fruit
that greater seededness is positively correlated with increased flesh calcium
concentrations. Conversely, however, calcium concentrations in the flesh of
mango nubbins were found to be significantly higher (0.80 mg/g dry weight)
than those in seeded fruit (0.58 mg/g dry weight) of similar size.
Implications for the conservation of genetic diversity in mohair goats from a comparison of a relic island population with breeds farmed in Australia
Authors: Balasingham T. G. , Robinson N. A. , McGregor B. A.
Published: September 2002

The genetic relationships between an abandoned population of mohair-style,
fibre-producing goats from the remote semi-arid Faure Island, Western
Australia and 3 modern breeds of Angora goats (Australian, southern African
and Texan) were investigated. Faure Island goats originated from stock
introduced in the 1890s, reputedly from South Africa. Farmed Faure goats were
abandoned on the island about 1918, but their fine mohair fleece has since
generated commercial interest within the Australian mohair industry. Nineteen
microsatellite loci were used to compare Nei’s genetic distance between
and variation within the breeds. Faure Island goats are more similar to
southern African and Texan Angoras than to Australian Angoras. Genetic
variability was lower in Australian Angoras than in Faure Island, southern
African and Texan Angoras (lowest proportion of polymorphic loci, mean
heterozygosity and mean number of alleles). Current Faure Island mohair-style
goats are more closely related to modern southern African Angora goats than to
traditional Australian Angora goats, while the reduced variability in the
latter may have resulted from inbreeding. These results have implications for
the genetic improvement of fibre-producing goats and for the conservation of
genetic material from island populations of goats.
Identification of pollen donors for the sweet cherry cultivars ‘Stella’ and ‘Summit’ by isozyme analysis
Authors: Brant B. , Granger A. R. , Witherspoon J. , Collins G. G.
Published: September 2002

Pollinisers of the sweet cherry cultivars ‘Stella’ and
‘Summit’ were determined by analysing isozymes of
glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase
(6-PGD), glucose phosphate isomerase (GPI), isocitrate dehydrogenase (IDH),
shikimate dehydrogenase (SKDH), fructose-1,6-diphosphatase (FDP), and
glutamate oxaloacetate transaminase (GOT) in their embryos. Possible
polliniser cultivars were selected on the basis of similar full bloom dates
and orchard position in regard to Stella or Summit. Examination of the ratios
for the segregation of isozymes showed that Summit was predominantly
pollinated by Stella, and Stella by Van. In the same orchard, but in a
different season, the main polliniser for Stella was found to be Venus, and
29% of Stella embryos resulted from selfing. Thus the effectiveness of
cherry pollinisers depends on overlapping flowering dates, which can vary from
year to year, and, for a self-fertile cultivar in a mixed block,
cross-pollination predominates over selfing.
Impact of cereal aphids on wheat yields in southern New South Wales, Australia
Authors: Milne W. M. , Delves R. I.
Published: September 2002

The effect of naturally occurring aphid infestations on yield was studied
using sprayed and unsprayed plots in commercial wheat crops at a number of
sites in southern New South Wales, Australia. In 1990, wheat was planted in
April or early May following early autumn rains. Aphids were first found in
the crops 4 weeks after the wheat was sown. Numbers were generally low and
only at 1 site was there a significant effect on yield. In 1991, sowing was
delayed by prolonged dry weather during autumn. Most crops were planted in
late May and aphids started to appear only in mid July. There was no
significant effect of aphids on yield but most crops were badly affected by
drought. In 1991, labelled plants at some sites were used to study the impact
of varying levels of aphid infestation on yield. There was a significant
negative correlation between the number of aphids and yield per plant at 1
site. In both years, aphid numbers peaked in August or September.
Rhopalosiphum padi was virtually the only aphid species
found.
Leaf samples were collected from 3 sites in 1990 and from all sites in 1991
and tested for barley yellow dwarf virus. The incidence of this virus was very
high in 1990 but negligible in 1991. The striking difference in the incidence
of barley yellow dwarf virus in the 2 years was most likely the result of
later sowing times and delayed arrival of aphids in crops in 1991. Aphids may
have a considerable impact on yield in early-sown wheat through transmission
of barley yellow dwarf virus.
The nutritive characteristics of herbage consumed by grazing dairy cows affect milk yield responses obtained from concentrate supplementation
Authors: Stockdale C. R.
Published: September 2002

The results of 7 experiments, conducted during 1994–95 (year 1) and
1995–96 (year 2) at the Kyabram Dairy Centre in northern Victoria, were
collated to test the hypothesis that nutritive characteristics of the herbage
consumed by dairy cows will affect responses to concentrates. In 6
experiments, lactating Friesian cows grazing irrigated perennial pastures were
either unsupplemented or were offered 5 kg DM/cow.day of a high energy
concentrate (pellets comprised of 75% barley and 25% wheat); in
the other experiment, cows received 0 and 3 kg DM/cow.day. Four
experiments, each of 5 weeks duration, were completed during year 1, and 3
experiments of 4 weeks duration were conducted during year 2.
The mean metabolisable energy concentration of the herbage consumed in each
experiment varied with season, being highest in spring (10.1–11.3
MJ/kg DM), and lowest from summer to early autumn (8.3–9.0 MJ/kg
DM). It is suggested that milk responses attributed to feeding high energy
supplements were influenced by characteristics of the herbage eaten in
conjunction with the supplement. The highest marginal responses to concentrate
supplementation occurred in summer and early autumn when pastures, which were
dominated by paspalum and other poor quality species, were low in energy.
Responses at that time (≥1.0 kg milk per kg DM of concentrates) were
greater than in spring (≤0.6 kg milk/kg DM). A significant negative
relationship existed between marginal returns of fat-corrected milk and
metabolisable energy concentration of the herbage consumed
(100R2 = 80.6) and several
published data sets provided support for this result. Possible reasons for
this outcome, including variations in substitution between experiments,
confounding with stage of lactation, variable partitioning of nutrients and
imbalances in dietary crude protein and neutral detergent fibre, were
examined. Of these explanations, fibre insufficiency in spring appeared the
most probable. The possibility that the lower marginal returns in spring are
associated with fibre insufficiency requires further investigation.
High phosphorus supply increases persistence and growth of white clover in grazed dairy pastures during dry summer conditions
Authors: Singh D. K. , Gourley C. J. P. , Sale P. W. G. , Hasthorpe C.
Published: September 2002

Measurements of pasture appearance, white clover leaf and stolon mass, stolon
water potential, and percentage clover cover in the sward were made for grazed
dairy pastures at Ellinbank, West Gippsland, Victoria, during the hot, dry
month of February 1997. The perennial ryegrass–white clover-based
pastures were in rotationally grazed paddocks from a large farmlet experiment
and had received different levels of phosphorus fertiliser (0 or 280 kg
P/ha over an 18-month period), and were being grazed with 2 or 3
cows/ha for the no-phosphorus, or 3 or 4 cows for the high-phosphorus
paddocks. Further measurements of white clover composition in the pasture
swards were made in April, following autumn rain.
There were marked differences in white clover (i.e. more yellow, flaccid and
desiccated plants with fewer leaves) and pasture appearance (higher frequency
of patchy, weedy, poorly utilised areas) in the no-phosphorus, compared with
the high-phosphorus treated pastures with the same stocking rate of 3
cows/ha. Also, the high-phosphorus paddocks had a greater white clover
percentage than the low-phosphorus paddocks in February with mean percentages
of 13.8 and 7.8% respectively. Following rains in March and April, the
mean percentage clover cover in high-phosphorus paddocks had increased
substantially by 30 April 1997 to 30.6% whereas there was a small
improvement in mean clover content in the low-phosphorus paddocks
(12.3%). The white clover plants in the high-phosphorus paddocks had
heavier stolons, larger leaves and, for the medium stocking rate (3
cows/ha), they appeared to have more leaves per cm of stolon. The findings
support previous studies which have highlighted how high-phosphorus
application rates can improve the performance of repeatedly defoliated white
clover plants during dry periods.
Effects of plant residue, soil characteristics, cotton cultivars and other crops on fusarium wilt of cotton in Australia
Authors: Wang B. , Dale M. L. , Kochman J. K. , Obst N. R.
Published: September 2002

The incidence and severity of fusarium wilt of cotton in glasshouse trials
increased when levels of plant residue in the soil were increased by the
incorporation of whole cotton plants (6-week-old seedlings dried out for a
further 6 weeks) into the soil. In non-residue-supplemented potting mix,
disease incidence was <50%, but ranged from 74 to >90% in
residue-supplemented potting mix. The disease was significantly affected by
soil microflora and soil type, but not affected by soil pH in the range
4.0–8.5. Although the same amount of inoculum was added to both
autoclaved and untreated soils, the disease was less severe in autoclaved
soils than in untreated soils regardless of soil type. Among the 4 clay soils
investigated, the disease was less severe in a grey sandy clay and a brown
heavy clay than in a dark grey heavy clay. Compared with the soils collected
at the end of the 1995–96 growing season, the disease became more severe
in the soil of plots planted to the most susceptible cotton cultivar Siokra
1-4, but less severe in the soil of plots planted to the less susceptible
cotton cultivar DP90 at the end of the 1996–97 growing season. However,
no significant differences were observed in the soil of plots planted to
cotton cultivar Siokra L22, sorghum, maize or soybean.
Distribution of pest nematodes on sugarcane in south Queensland and relationship to soil texture, cultivar, crop age and region
Authors: Blair B. L. , Stirling G. R. , Whittle P. J. L.
Published: September 2002

Summary. Five plant–parasitic nematode species
were found to be widespread on sugarcane crops surveyed in south Queensland,
namely Pratylenchus zeae,
Meloidogyne javanica,
Paratrichodorus minor,
Helicotylenchus dihystera and
Tylenchorhynchus annulatus. Apart from
Meloidogyne, high nematode populations were found in
most soil types, suggesting more extensive crop losses could be occurring than
previously estimated. The most important pests were
P. zeae and M. javanica, as they
were often found at high densities and their pathogenicity on sugarcane is
established.
Mean densities for most nematode genera did not differ significantly between
sugarcane cultivars, except that fewer Pratylenchus were
associated with cultivar CP51-21 than other cultivars surveyed. The density of
Pratylenchus in roots was significantly higher in plant
crops than in ratoon crops, whereas the density of
Paratrichodorus was highest in first and second ratoons.
Sedimentation in canola oil: a review
Authors: Hermann L. , Mailer R. , Robards K.
Published: September 2002

Summary. Sediment formation or cloudiness in canola oil
presents a problem for the industry which is currently solved by
winterisation. Various techniques have been used to examine the chemical and
physical properties of the sediment. Knowledge of the physical properties are
due largely to investigations using differential scanning calorimetry.
Chemical composition has been determined by high resolution chromatographic
methods particularly gas chromatography following preliminary separation of
the sediment from the oil and fractionation. Major components of the sediment
are wax esters with lesser amounts of triacylglycerols, hydrocarbons, free
fatty acids and alcohols. Nevertheless, full characterisation of the sediment
is yet to be achieved although the full potential of developments such as
softer ionisation techniques for mass spectrometric detection in high
performance liquid chromatography have not been exploited. The process of
sediment formation is discussed in relation to nucleation of the oil and
crystal growth. On this basis, factors determining sedimentation behaviour in
a particular sample are probably kinetic and influenced by trace components of
the oil. The fundamental question to be answered in future work is the
relative role of environment and genetics in regulating susceptibility to
sedimentation.
Effects of ethephon on fruit yield, colour and pungency of cayenne and paprika peppers
Authors: Krajayklang M. , Klieber A. , Wills R. B. H. , Dry P. R.
Published: September 2002

Summary. ‘PS72285’ paprika pepper and
‘Caysan SPS705’ cayenne chilli pepper
(Capsicum annuum L.) were treated with ethephon
[(2-chloroethyl) phosphonic acid] with the aim of synchronising
maturation for once-only machine harvesting. Ethephon solutions of 0, 1000,
3000 or 5000 µL/L were applied once as foliar applications to
pot-grown plants in a shadehouse at the Waite Campus, Adelaide. The effects of
ethephon on red fruit yield, colour intensity, pungency, abscission and
defoliation were determined. Ethephon did accelerate fruit maturation of both
cultivars by increasing the percentage of red marketable fruit for chillies
and decreasing the percentage of green paprika fruit. The intensity of
extractable red colour in chilli fruit was increased by 16% for 1000
µL ethephon/L, while pungency improved by 46 and 48% for 1000
and 3000 µL ethephon/L respectively. However, red marketable fruit
yields measured as fresh and dry weight decreased in chillies due to a large
number of abscised fruit. Paprika quality and yield were unaffected. Ethephon
also induced defoliation and fruit skin damage. Thus, this study found little
benefit from using ethephon as a chemical ripening agent.
Effect of high rates of potassium chloride fertiliser on banana leaf conductance, plant growth, nutrient concentration and root death under contrasting watering regimes
Authors: Vimpany I. A. , Johns G. G.
Published: September 2002

Weak root systems, which predispose banana plants with a bunch to topple, are
common in the Australian subtropical banana industry. Many banana growers
consider the problem could be associated with the use of potassium chloride
(KCl) fertiliser under dry soil conditions. We assessed the effect of high
rates of KCl on banana leaf abaxial conductance
(gab), plant growth including root
weights, and whole plant nutrient concentration under a range of watering
regimes using banana plants growing in troughs of soil in a glasshouse. The
trial factorially combined watering after 15 (W1), 30
(W2), 60 (W3) and 120
(W4) mm evaporation from nearby bins with 4 rates of
KCl—78 (T1), 376 (T2), 617
(T3) and 796 (T4)
g/m2.
At the end of the trial exchangeable potassium on the T4
treatment was 5.8 cmol(+)/kg with 31% of this in the soil
solution. A substantial proportion of exchangeable calcium, magnesium and
sodium were also displaced into the soil solution. Banana leaf abaxial
conductance peaked at 2–2.5 cm/s on the T1
W1 treatment combination, but decreased as soil matric
potential decreased or KCl rate increased. The linear relationship for effect
of KCl rate on gab indicated that
gab was reduced by an average of
80% on the T4 treatment across a wide range of
matric potentials. Increasing KCl and withholding irrigation generally had
similar effects on the concentration of nutrient elements in the plant. The
high concentration of KCl in the soil did not appear to interfere with plant
uptake of calcium and magnesium.
Plant size was reduced 42% on the T4 treatment,
but at harvest most plant components were reduced more by infrequent watering
than by the highest KCl rate.
Dead root weight as a percentage of total root weight ranged from
<30% for combinations of T1 or
T2 with W1 or
W2 to >50% for other treatment combinations.
It was concluded that the interaction of dry soil conditions and reasonable
fertiliser application rates was unlikely to contribute greatly to the death
of banana roots in the field.
Mobility and persistence of three sulfonylurea herbicides in alkaline cropping soils of south-eastern Australia
Authors: Black I. D. , Pederson R. N. , Flynn A. , Moerkerk M. , Dyson C. B. , Kookana R. , Wilhelm N.
Published: September 2002

Biologically active residues of the herbicides metsulfuron-methyl,
chlorsulfuron and triasulfuron were estimated with field pea bioassays in soil
samples to 80 cm depth from 4 field trials in south-eastern Australia situated
on neutral to highly alkaline soil. Residues were both mobile and persistent
at low levels. Leaching occurred beyond the lowest sampling depth during the
winter–spring growing season. Metsulfuron-methyl was the most mobile of
the 3 herbicides. Plant-back experiments involving susceptible crop and
pasture species on 2 of the sites showed that the rates of decline of these
residues in the sampling zone were slower than might be inferred from label
plant-back recommendations in 1 of 2 seasons.
Full-fat canola seed meal as a protein source for weaner and grower - finisher pig
Authors: Brand T. S. , van der Merwe J. P. , Brandt D. A.
Published: September 2002

Summary. Full-fat canola seed
(Brassica napus cv. Oscar) (260 g/kg crude protein
and 410 g/kg ether extract) was evaluated as an alternative protein source
in diets fed to weaner and grower–finisher pigs. Four diets for weaner
pigs were formulated on an iso-nutrient (about 198.9 g/kg crude protein,
15.2 g/kg lysine, 8.3 g/kg methionine and cystine and 2.4 g/kg
tryptophan on a dry matter basis) and iso-energy basis (16.2 MJ/kg dry
matter digestible energy) to substitute full-fat soybean with increasing
levels of full-fat canola seed meal (0, 8, 16 and 24%). Similarly, 4
diets for grower–finisher pigs were formulated on an iso-energy and
iso-nutrient basis (about 14.9 MJ/kg dry matter digestible energy, 178
g/kg crude protein, 10 g/kg lysine, 6.8 g/kg methionine and
cystine and 2.2 g/kg tryptophan on a dry matter basis), where soybean
oilcake meal was similarly substituted. Weaner pigs (n
= 80) were fed ad libitum from 9.6 to 26.7 kg
liveweight. Piglets were kept in groups of 4 (2 gilts and 2 castrated boars
combined at random) in cages (1.5 by 1 m) with solid floors, fitted with a
self-feeder and equipped with an automatic water nipple. Grower–finisher
pigs (n = 52), individually housed in flat
deck-type cages (1.6 by 1.0 m), fitted with a self-feeder and equipped with an
automatic water nipple, were fed ad libitum from 22.9 to
91.1 kg, whereafter pigs were slaughtered, carcass characteristics determined
and back-fat samples taken. Energy and nitrogen metabolism data were evaluated
in a digestion and metabolism trial for the 4 grower–finisher diets. No
significant difference in the intake, growth rate or feed conversion of weaner
pigs was observed. The dry matter digestibility of the grower–finisher
diet differed significantly (P<0.05) between diets
and decreased linearly by 4.5% (P<0.01; SEb
= 0.36) for each incremental increase in the canola inclusion level.
The digestible energy content of the diets was not affected. Regression
analysis revealed a linear decrease [2 g N/day
(P<0.01; SEb = 0.18)] in nitrogen
retention rate for each increment increase in canola inclusion. The inclusion
of up to 24% canola had no significant effect on feed intake,
liveweight gain or feed conversion ratio of grower–finisher pigs,
although regression analysis revealed a linear decrease of 21.7 (SEb =
5.9) g/day in growth rate with increasing canola levels. Inclusion levels
of 16% in diets for grower–finisher pigs were recommended for
maximum efficiency. The back-fat of pigs consuming diets with 16 and
24% full-fat canola in their diets had 13%
(P<0.05) higher iodine numbers than pigs that
received 0 and 8% full-fat canola in their diets. Generally, all
saturated fatty acids decreased while monounsaturated and polyunsaturated
fatty acids increased, with increasing levels of canola in the diets.
Low rates of dicarboximide seed treatment reduce brown spot in narrow-leafed lupin
Authors: Sweetingham M. W.
Published: September 2002

Field experiments at 7 sites over 3 seasons showed that the dicarboximide
fungicides iprodione and procymidone could reduce brown spot severity in lupin
seedlings when applied as a seed treatment at rates as low as 0.06 g/kg
seed. Treatment at previously recommended rates (1.0 g/kg) gave only
slightly or no improved disease control. Where either brown spot or
pleiochaeta root rot was severe, seedling death occurred and seed treatment
increased plant population, dry matter and grain yield. In some experiments
seed treatment reduced pleiochaeta root rot. In no experiment was there an
additional grain yield benefit from applying either fungicide above 0.12
g/kg seed even where disease pressure was extreme at an artificially
infected site. The direct effect of dicarboximide seed treatment appears
mainly due to reduced infection on cotyledons and to a lesser extent the first
4 true leaves. Disease reduction can be measured higher up the plant later in
the season as a result of reduced secondary infection.
Perennial grasses of Mediterranean origin offer advantages for central western Victorian sheep pasture
Authors: Anderson M. W. , Cunningham P. J. , Reed K. F. M. , Byron A.
Published: September 2002

Perennial ryegrass, tall fescue, cocksfoot and phalaris were evaluated under a
rotational grazing regime in the 600 mm rainfall region of western Victoria.
Over 4 years, seasonal dry matter production, persistence and nutritive value
were assessed. Several selected lines and commercial cultivars were compared.
Melik selection tall fescue and Sirosa phalaris significantly
(PPP
The benefits of Mediterranean genotypes of perennial grasses for improving
winter yield and plant longevity is discussed in relation to the need to
maximise pasture productivity and improve pasture longevity in environments
with a short growing season.
Broadcasting phosphate fertilisers produces higher yields of potatoes (Solanum tuberosum L.) than band-placement on coastal sands
Authors: Hegney M. A. , McPharlin I. R.
Published: September 2002

The relative effectiveness of broadcasting compared with band-placement of
phosphorus (P) fertilisers (0–480 kg P/ha) was compared using
potatoes grown on P-deficient sandy soils over 2 seasons in Western Australia
(Karrakatta sand in 1993, experiment 1; and Spearwood sand in 1996, experiment
2).
The maximum yield of potatoes when P fertiliser was broadcast and incorporated
to 20–25 cm before planting (broadcast) was 17 t/ha higher than when
P was placed in 2 bands 5 cm to the side of and below seed piece level
(banded) in experiment 1, and 13 t/ha higher in experiment 2. However,
higher rates of applied P were required to reach 99% of maximum yield
on the broadcast compared with the banded plots in both years (i.e. 174
v. 134 kg/ha in experiment 1, and 279
v. 125 kg/ha in experiment 2). Despite the lower
levels of applied P required to achieve maximum yield in the banding
treatment, banding P fertiliser for potatoes grown on Karrakatta and Spearwood
sands would result in significant economic loss.
The higher yield in the broadcast treatment corresponded with significantly
(P<0.001) higher P concentrations (about 2-fold) in
petioles of youngest fully expanded leaves from 56 to 131 days after sowing.
When tubers were 10 mm long, the petiole P concentrations corresponding with
95 and 99% of maximum yield were 1.13 and 1.28%, respectively,
for the broadcast P treatments in experiment 1, and 0.95 and 1.11% in
experiment 2. The reduced yield in the banded treatments was assumed to be due
to P fertiliser toxicity in the soil and not P toxicity in the plant tissue.
Phosphorus uptake by tubers was significantly
(P<0.001) higher (about 2-fold) when P was broadcast
rather than banded, especially at high levels of applied P. Phosphorus
recovery efficiency by tubers (P uptake by tubers/P applied, both in
kg/ha) was higher when P was broadcast rather than banded, particularly at
high levels of applied P (e.g. at 480 kg applied P/ha, recovery efficiency
was 0.07 in the broadcast treatment compared with 0.03 in the banded
treatment).
These results show that, for growers to avoid significant economic loss,
broadcast applications of P fertilisers should continue to be recommended for
potatoes grown on the low P-fixing, sandy soils of the Swan Coastal Plain.