bluuebunny/crossref_metadata_2025 huggingface dataset:
MICROTUBULE ASSEMBLY IS DIRECTLY AFFECTED BY MPP+IN VITRO
Authors: Cappelletti Graziella , Pedrotti Barbara , Maggioni Maria Grazia , Maci Rosalba
Published: September 2002

The microtubular system is emerging as a cell target in neurodegeneration evoked by the Parkinsonism‐inducing neurotoxin N‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) and its toxic metabolite N‐methyl‐4‐phenylpyridinium (MPP+). Looking for a direct effect of the neurotoxin on microtubules, we have undertaken an in vitro study by using microtubule protein purified from bovine brain. We show that MPP+, but not MPTP, modifies the initial rate and the critical concentration of assembly without affecting microtubule ultrastructure. These findings strengthen the hypothesis for the role of microtubules in the transduction of MPP+neurotoxic effect and, probably, in neuronal cell death.
Evaluation of seedling allelopathy in 453 wheat (Triticum aestivum) accessions against annual ryegrass (Lolium rigidum) by the equal-compartment-agar method
Authors: Wu H. , Pratley J. , Lemerle D. , Haig T.
Published: September 2002

Allelopathy has been receiving world-wide attention for its potential in
integrated weed management. A newly developed screening bioassay, the
‘equal-compartment-agar method’ (ECAM), was used to evaluate
seedling allelopathy against annual ryegrass in a collection of 453 wheat
accessions originating from 50 countries. Significant differences in
allelopathic potential were found in this worldwide collection, inhibiting
root growth of ryegrass from 9.7% to 90.9%. Wheat seedling
allelopathy also varied significantly with accessions from different
countries. Wheat allelopathic activity was normally distributed within the
collection, indicating the involvement of multiple genes conferring the
allelopathic trait. Of the 453 wheat accessions screened, 2 distinct groups
were identified. Condor-derivatives were more allelopathic than
Pavon-derivatives, with an average inhibition of root growth of ryegrass by
76% and 46%, respectively. Research was further extended to
investigate the near isogenic lines derived from Hartog (Pavon-derivative) and
Janz (Condor-derivative). Hartog and its backcrossed lines were less
allelopathic than Janz and its backcrossed lines, inhibiting root length of
ryegrass by 45% and 81%, respectively. These results strongly
indicate that wheat allelopathic activity might also be controlled by major
genes, depending on the particular populations. The present study demonstrates
that there is a considerable genetic variation of allelopathic activity in
wheat germplasm. It is possible to breed for cultivars with enhanced
allelopathic activity for weed suppression.
Natural crossing in cotton (Gossypium hirsutum L.)
Authors: Xanthopoulos F. P. , Kechagia U. E.
Published: September 2002

The extent of natural crossing in cotton
(Gossypium hirsutum L.) was studied in 2 experiments
conducted in Greece during 1998 and 1999, using glandless and red-leaf traits
as genetic markers. The glandless line was planted in the middle, and the
red-leaf both in the middle and the corners, of a commercial cotton field. In
the first experiment where estimation of natural crossing was based upon gland
status, the percentage ranged from 1.67% to 2.67% in adjacent
rows, dropped to 1.42% in plants 2 m apart, and declined to almost zero
after 10 m. In the second experiment, where the red-leaf marker gene was used,
the mean of natural crossing was 3.85% in adjacent rows, fell to
2.79% in plants 2 m apart, and progressively diminished to 0.31%
after 10 m. The mean natural outcrossing in different rows was almost the same
in both experiments at the middle of the field and was actually double at the
corners. Differences in the extent of natural crossing between the middle and
the corners of the field continued to be significant up to 4 m distance. In
all cases, distances greater than 10 m among cottons were sufficient to
minimise out-crossing ranges.
The influence of tagasaste (Chamaecytisus proliferus Link.) trees on the water balance of an alley cropping system on deep sand in south-western Australia
Authors: Lefroy E. C. , Stirzaker R. J. , Pate J. S.
Published: September 2002

Components of the water balance of an alley cropping system were measured to
assess the extent to which tree rows 30 m apart with access to a fresh,
perched watertable at 5 m depth were able to capture deep drainage from an
inter-cropped cereal–legume rotation. Neutron probe data showed that the
4-year-old trees, cut back to 0.6-m high at the beginning of the experiment,
depleted soil water to 2, 4, and 8 m laterally from the tree rows in their
first, second, and third years of coppice regrowth, respectively. Combining
data from soil water depletion in summer and comparisons of deuterium:
hydrogen ratios of groundwater, xylem sap of trees, and herbaceous plants, it
was shown that tagasaste trees drew on soil water for 80% of their
transpiration in the first winter and 40% in the second, while
switching to near total dependence on groundwater each summer and early
autumn. Tree water use on a whole plot basis was 170 mm in 1997 (68%
from groundwater) v. 167 mm in 1998 (73% from
groundwater). Recharge to the perched watertable was estimated to be 193 mm
under sole crop in 1998 (52% of rainfall), reducing to 32 mm when
uptake of groundwater by trees was included. The degree of complementarity
between tagasaste trees and crops in alley cropping used for water management
is quantified for 1998 by calculating the ratio of the distance over which
trees reduced drainage to zero to the distance over which they reduced crop
yield to zero. It is concluded that segregated monocultures of trees and crops
would be a more appropriate strategy than a closely integrated system such as
alley cropping in this case.
Specific and genotypic variation in the nutrient content of lupin species in soils of neutral and alkaline pH
Authors: Kerley S. J. , Shield I. F. , Huyghe C.
Published: September 2002

Evaluation of the nutritional status, dry weights, and yields of genotypes of
white lupin (Lupinus albus L.) and of the species
L. pilosus Murr. and
L. angustifolius L. were made in a field of mildly
acidic (minimum pH 5.8; air-dried soil : water ratio 1 : 2.5) to alkaline
(limed to a pH maximum of 8.4) soil at IACR-Rothamsted, UK, during the 1997
growing season. Plants were sampled for shoot biomass and nutritional content
during the season and seed yield per plant.
Lupinus pilosus was the species most tolerant of the
calcareous soil, whereas L. angustifolius was the least
tolerant. Considerable variation in tolerance was apparent between the
L. albus genotypes; the cultivar Lucyanne was comparable
with L. angustifolius, whereas the genotypes La 673,
668, and 675 were more comparable with L. pilosus.
Leaf chlorosis was shown to be an unreliable measure of calcareous soil
tolerance in the field. A genotype soil-pH interaction in the expanded leaf
number indicated that this analysis might be of use in genotype evaluations.
Nutrient concentration differences were apparent between the species and
between the L. albus genotypes. This indicated the
occurrence of possible tolerance mechanisms including the control of calcium
uptake and the partitioning of iron. Clear differences were apparent between
the three species in terms of tolerance to the calcareous soil. Within
L. albus important differences were apparent when
specific analyses were examined. However, variation between different analyses
and at different stages of growth resulted in the differences, taken as a
whole between the L. albus genotypes, not being of
sufficient magnitude to discriminate potentially tolerant from susceptible
genotypes. The complexity of calcareous soil stress and the potential
application of the analyses for physiological studies and genotype screening
are discussed.
Anatomical structure and nutritive value of lupin seed coats
Authors: Miao Z. H. , Fortune J. A. , Gallagher J.
Published: September 2002

Selection and breeding for yield and adaptation to environmental conditions
often changes a number of characteristics of crops, and may influence the
value of seed for animals. A series of experiments was conducted to evaluate
the effect of breeding and growing conditions on the structure and
degradability of lupin seed coats. Breeding has had significant influences on
both seed size and seed coat structure of lupins. For instance, cultivars of
Lupinus angustifolius released in 1987 and 1988 tended
to have smaller seeds with a thicker seed coat than those released in 1971
(P < 0.05). Selection for soft seeds has resulted in
a reduction of seed coat thickness in L. angustifolius.
Hardseeded and roughseeded lines of L. cosentinii had
thicker coats (P < 0.05) than softseeded and
smoothseeded, respectively. The main contributor to the thick seed coat of
hardseeded lines was a layer of cells known as the hourglass layer, which is
located between the outer palisade and inner parenchyma. Anatomical analysis
revealed that the soft seed coat tended to have short and round cells, whereas
the hard seed tended to have long cells in the palisade layer. Smooth seeds
had round cells in the subpalisade, but rough seeds had long cells in this
layer. Although the seed coats of lupins contained about 80% crude
fibre, with L. cosentinii and
L. pilosus having more fibre than
L. angustifolius, the fibre in lupin seed coats was
highly digestible by sheep.
Seedling vigour in wheat - sources of variation for genetic and agronomic improvement
Authors: Richards R. A. , Lukacs Z.
Published: September 2002

The early growth of wheat is slow compared with that of barley and triticale.
This is expected to limit the yield of wheat in environments where greater
seedling vigour is advantageous. To overcome the slow growth of wheat, genetic
sources of seedling vigour are required for use in breeding programs,
and/or ways to increase seedling growth by manipulating seed
characteristics. This study reports (i) new sources of
and 3 heights at cutting (cutting was done when the grass
reached 0.5, 1, and 1.5 m above the ground). The N fertiliser treatment did
not yield any significant difference in DMD, ND, or IVDMD. Height at cutting
had a significant (P < 0.05) effect on rumen DMD and
ND and their degradability characteristics for all incubation times. There was
a reduction in DMD and ND and their degradability characteristics as plant
height increased at cutting. Similarly, as height at cutting increased there
was a decline in IVDMD. There was a positive linear correlation between IVDMD
and both DMD and ND at 48, 72, 96, and 120 h (r =
0.917, 0.923, 0.921, and 0.850 for DMD; r =
0.795, 0.814, 0.787, and 0.787 for ND). Hence, further study on intake and
performance of animals is suggested to develop Napier-based diets for
smallholders.
Nodulation and symbiotic nitrogen fixation by genotypes of blackgram [Vigna mungo (L.) Hepper] as affected by fertiliser nitrogen
Authors: Singh B. , Usha K.
Published: September 2002

Intercropping with legumes and non-legumes is commonly practised in many parts
of the world to maximise productivity per unit area of land. In India,
blackgram or urd [Vigna mungo (L.) Hepper] is a
popular pulse legume component of intercropping farming systems. Often,
however, potential production is compromised, particularly in high fertiliser
input systems, because blackgram competes with the non-legume component of the
system for nitrogen in the soil.
In order to identify lines of blackgram that could obtain the majority of
their nitrogen requirements from symbiotic fixation of atmospheric nitrogen
rather than from uptake of soil nitrogen, 50 genotypes were screened for
tolerance to (applied) nitrogen in soil. The parameters used to appraise
tolerance were extent of root nodulation, the amount of nitrogen fixed,
nitrate reductase activity in roots and nodules, and nitrite content of roots
and nodules. There were 2 nitrogen treatments applied as urea,
viz. 40 (N40) and 120 (N120) kg N per ha.
There were 3 genotypes whose nitrogen-fixing effectiveness was apparently
unimpaired by applications of nitrogen to the soil. Genotype NC-59308
nodulated and fixed atmospheric nitrogen satisfactorily at both the lower and
higher levels of applied nitrogen. At N40, genotypes EC-48215 and PLU-726
formed a great abundance of large nodules effective in nitrogen fixation; even
at N120, both lines had better symbioses than the majority of the 50 blackgram
lines originally screened. These 3 genotypes are deemed worthy of further
examination for their suitability for intercropping systems. How this might be
done is discussed.
Relationships between age and biomass of individual plants and seed production in two grazed tropical legumes. 2. Validation of models
Authors: McDonald C. K. , Jones R. M.
Published: September 2002

Relationships predicting legume seed production from total legume biomass and
from age and biomass of individual legume plants in a grazing trial at CSIRO
Narayen Research Station, in south-eastern Queensland, were compared with
observed soil seed measurements over 9 years. This was part of a larger
project to develop a demographic model of tropical perennial forage legumes in
grazed pastures. Suitable data were available from
Chamaecrista rotundifolia–Cenchrus ciliaris
pastures stocked at 0.54 and 1.09 head/ha and from
Stylosanthes scabra–
C. ciliaris pastures at 1.09 head/ha.
Use of legume plant age and biomass, in conjunction with grass biomass
(C. rotundifolia) or kg legume/head
(S. scabra), to predict soil seed accounted for
87% (C. rotundifolia) and 77%
(S. scabra) of the variation in observed values, and
gave accurate and unbiased predictions. Prediction of soil seed from total
legume biomass was better correlated with observed values for
S. scabra
(r2 = 0.72) than for
C. rotundifolia(r2
= 0.63), but over-predicted values for
S. scabraand under-predicted those for
C. rotundifolia.
The results highlight that, with C. ciliaris, the grass
biomass needs to be kept below 3000 kg/ha to maintain a
C. rotundifolia population. Similarly, the results
indicate that biomass of S. scabra may need to be kept
below 400 kg/head to avoid the possibility of S. scabra dominance,
depending on the companion grass.
Application of the seed production models in assessing the agronomic
adaptation of these legumes and in predicting persistence of legumes and other
species (e.g. weeds) is discussed.
Spatial and temporal patterns in Australian wheat yield and their relationship with ENSO
Authors: Potgieter A. B. , Hammer G. L. , Butler D.
Published: September 2002

Spatial and temporal variability in wheat production in Australia is dominated
by rainfall occurrence. The length of historical production records is
inadequate, however, to analyse spatial and temporal patterns conclusively. In
this study we used modelling and simulation to identify key spatial patterns
in Australian wheat yield, identify groups of years in the historical record
in which spatial patterns were similar, and examine association of those wheat
yield year groups with indicators of the El Niño Southern Oscillation
(ENSO). A simple stress index model was trained on 19 years of Australian
Bureau of Statistics shire yield data (1975–93). The model was then used
to simulate shire yield from 1901 to 1999 for all wheat-producing shires.
Principal components analysis was used to determine the dominating spatial
relationships in wheat yield among shires. Six major components of spatial
variability were found. Five of these represented near spatially independent
zones across the Australian wheatbelt that demonstrated coherent temporal
(annual) variability in wheat yield. A second orthogonal component was
required to explain the temporal variation in New South Wales. The principal
component scores were used to identify high- and low-yielding years in each
zone. Year type groupings identified in this way were tested for association
with indicators of ENSO. Significant associations were found for all zones in
the Australian wheatbelt. Associations were as strong or stronger when ENSO
indicators preceding the wheat season (April–May phases of the Southern
Oscillation Index) were used rather than indicators based on classification
during the wheat season. Although this association suggests an obvious role
for seasonal climate forecasting in national wheat crop forecasting, the
discriminatory power of the ENSO indicators, although significant, was not
strong. By examining the historical years forming the wheat yield analog sets
within each zone, it may be possible to identify novel climate system or
ocean–atmosphere features that may be causal and, hence, most useful in
improving seasonal forecasting schemes.
Contributions of soil and crop factors to plant available soil water capacity of annual crops on Black and Grey Vertosols
Authors: Hochman Z. , Dalgliesh N. P. , Bell K.
Published: September 2002

Improved methods for field measurements of plant available soil water capacity
(PAWC) of Black and Grey Vertosols in Australia’s north-eastern grain
region were employed to characterise 83 soil–crop combinations over 7
depth intervals to 180 cm. Soil sub-order was shown to influence all
components of PAWC (means of 224 and 182 mm in Black and Grey Vertosols,
respectively) with drained upper limit (DUL), bulk density (BD), and crop
lower limits (CLL) showing clear separation between soil sub-orders and a
trend with soil depth. In addition to soil sub-order and soil depth effects,
CLL showed crop effects such that expected PAWC of various crops when adjusted
for soil sub-orders were: cotton 240 mm; wheat 233 mm; sorghum 225 mm;
fababean 209 mm; chickpea 197 mm; barley 191 mm; and mungbean 130 mm. A total
of 549 measured CLL values were used to develop a predictive model for
estimating CLL from the soil sub-order, depth, DUL, and crop by predicting a
CLL as a function of DUL and a depth-dependent variable for each
crop–soil sub-order. The model CLL = DUL *
(a + b * DUL) explained
85% of observed variation in the measured data with no significant bias
between observed and predicted data. While properly measured data would be
more reliable than estimated data, where specific site accuracy is less
critical, this model may be used to estimate PAWC with an acceptable degree of
accuracy.
Efficacy of Impact® to manage blackleg (Leptosphaeria maculans) in canola
Authors: Khangura Ravjit K. , Barbetti Martin J.
Published: September 2002

The efficacy of the fungicide Impact® (a.i. flutriafol at 250 g/L) was
tested for control of blackleg (Leptosphaeria maculans),
and for improved yield and oil content in canola
(Brassica napus) cultivars with varying levels of
blackleg resistance. Field trials were conducted in 1996 in Western Australia
at 3 locations (Merredin, Wongan Hills, Mt Barker) in paddocks containing
1–4-year-old blackleg-infested residues. The fungicide (400 mL
product/ha) was coated on a double superphosphate fertiliser and applied
at seeding. Blackleg was substantially reduced and the seed yield improved
following the application of Impact® in most treatments at all locations
except Mt Barker, where the fungicide had no effect on reducing the blackleg
severity. The percentage reduction in blackleg severity with Impact®
ranged between 18 and 59% and 1 and 43% at Merredin and Wongan
Hills, respectively, in cultivars with different levels of resistance and
exposed to infected residues of various ages. Likewise, the application of
Impact® increased the seed yield by 40–322, 186–357, and
71–426 kg/ha at Merredin, Wongan Hills, and Mt Barker, respectively,
on residue of various ages. Seed oil content was also improved following the
application of Impact® in most treatments at all locations. The
improvement in seed yield when using Impact® was variable for different
ages of the residue, and was greater under severe to moderate disease
conditions caused by exposure to more recent residues than under the milder
disease conditions resulting from older residues. In general, susceptible to
moderately resistant cultivars showed greater improvement in yield than
resistant cultivars. The rates of Impact® were further evaluated in
paddocks containing 3-year-old residue in field trials at the same 3 locations
during 1997. The fungicide was applied at 200, 400, and 800 mL product/ha.
Although blackleg severity was substantially reduced following application of
Impact® at 400 and 800 mL/ha compared with 0 and 200 mL/ha, yield
was improved only in some cultivars and at some locations.
Effect of cortisol acetate on wool quality in sheep selected for divergent staple strength
Authors: Schlink A. C. , Wynn P. C. , Lea J. M. , Briegel J. R. , Adams N. R.
Published: September 2002

These studies utilised cortisol treatment to clarify the role of stress in
reducing staple strength (SS). The first study established the impact of the
duration of exposure and nutritional status on SS, wool parameters, and
epidermal growth factor (EGF) receptors. Sheep (n
= 42) were fed at 0.75 or 1.5 times maintenance for 62 days and then
administered with 120 mg cortisol acetate/day for 0, 3, or 12 days. SS was
reduced significantly (P < 0.05) only in the group
fed below maintenance and treated with cortisol for 12 days. In the sheep fed
below maintenance, the mean SS was 31.6, 32.7, and 21.5 N/ktex for groups
treated for 0, 3, and 12 days of cortisol, respectively. Cortisol
administration in these sheep also increased the rate of fibre shedding
(P < 0.001) but did not affect their mean fibre
diameter. The shed fibres had a finer diameter than those that were not
(P < 0.001). The concentration of EGF receptors was
not affected by cortisol administration, although submaintenance feeding
(P < 0.05) significantly reduced EGF receptor
concentration. The second experiment examined whether some sheep were
predisposed to reduce SS in response to cortisol. Sheep
(n = 42) of low and high prior SS were fed to
maintain liveweight for 84 days and then administered with 0 or 120 mg
cortisol/day for 12 days. Cortisol administration significantly reduced SS
(P < 0.001) and wool growth (P
< 0.001), and increased the rate of fibre shedding (P
< 0.001) but did not affect fibre diameter. SS history did not affect the
response to cortisol administration. We conclude that cortisol reduced SS by
increasing fibre shedding, without decreasing fibre diameter. Treatment was
only effective in sheep fed at or below maintenance, and required between 3
and 12 days of exposure to cortisol. This is longer than would be observed in
many stressful situations in the field.
Establishment and characterisation of wheat genetic mapping populations
Authors: Kammholz S. J. , Campbell A. W. , Sutherland M. W. , Hollamby G. J. , Martin P. J. , Eastwood R. F. , Barclay I. , Wilson R. E. , Brennan P. S. , Sheppard J. A.
Published: September 2002

Doubled haploid populations from 5 carefully selected wheat
(Triticum aestivum L.) crosses were established in order
to produce genetic maps. The characterisation of the parental material
included pedigree analyses to define the extent of the genetic relationships
among the lines and to determine the occurrence of alien chromosome segments
that may contribute to segregation distortion. The characterisation of the
parents also defined the range of grain quality traits that could be examined
in the lines derived from each cross. Populations of up to 321 lines were
produced using wide cross-mediated doubled haploid production from
F1 plants. Assessment of the lines for heterogeneity was
carried out using readily identifiable phenotypic markers and electrophoresis
of seed storage proteins, with 2.3–11.6% of the lines being
removed from further analysis. Segregation distortion was estimated in several
populations where sufficient information from genetic markers was available.
In a Sunco/Tasman doubled haploid population, heterogeneity was detected
between the first 51 lines and the remainder of the mapping population and
this could be traced to F1 plants that were produced
from an earlier set of crosses. χ2 tests on the
mapping data available for the Cranbrook/Halberd, CD87/Katepwa, and
Sunco/Tasman doubled haploid populations revealed segregation distortion
at rates of 1.8%, 5.1%, and 12.5% respectively. Whereas
the wide-cross doubled haploid protocol does not appear responsible for the
bulk of the non-Mendelian segregation observed, several potential sources were
identified. In particular, clustering of distorted loci at specific chromosome
regions appeared to be associated with the presence of alien introgressions in
one of the parents. This was especially marked in the Sunco/Tasman
population. Providing such distortions are recognised in the models used,
these populations provide powerful tools for extensive mapping studies to
determine the genetic factors controlling grain quality traits and other wheat
characters of interest.
Mapping quantitative trait loci associated with variation in grain dormancy in Australian wheat
Authors: Mares D. J. , Mrva K.
Published: September 2002

Preharvest sprouting is a problem in many regions of the world, resulting in
downgrading of quality, substantial economic losses to wheat growers, and
difficulties for grain handling and marketing agencies. Improvements in
tolerance from the introduction of better grain dormancy at, or near,
harvest-ripeness would be expected to have a significant impact on the
incidence and severity of sprouting. Intermediate levels of dormancy in older
Australian wheats, such as Halberd, and a small number of current cultivars
could be used in the short term while more extreme dormancy is being
introgressed into locally adapted germplasm. A doubled haploid population
derived from Cranbrook (extremely non-dormant, very susceptible to sprouting)
x Halberd (intermediate dormancy, moderately tolerant to preharvest sprouting)
was grown in replicated experiments and ripe grain harvested for assessment of
dormancy, measured as a germination index. Consistent differences were
observed between the parents in both experiments. For the bulk of the progeny,
the germination index fell within a range defined by Cranbrook at the upper
and Halberd at the lower end. Significant quantitative trait loci, all
contributed by the very susceptible parent, that explained 11%,
9%, and 9% of the phenotypic variation were identified on
chromosome arms 2AL, 2DL, and 4AL, respectively. These QTLs offer the
opportunity to develop molecular markers for grain dormancy and to develop a
better understanding of the mechanisms involved in this trait.
In vitro methods as predictors of voluntary intake and digestibility of hays fed to sheep
Authors: Carro M. D. , López S. , González J. S. , Ovejero F. J. , Ranilla M. J.
Published: September 2002

Eleven sun-cured hays were used to study the suitability of different
in vitro methods to predict their voluntary dry matter
(DM) intake (VDMI; g DM/kg liveweight) and in vivo
DM digestibility (DMD; g/kg). The methods used were:
(1) gas production at different incubation times when
hays were incubated in vitro with buffered rumen fluid,
(2) DM disappearance at different incubation times with
cellulase (CEL), (3) release of sugars to the
supernatant after incubation with cellulase, and (4)
optical density of the supernatant at λ = 280 nm (as an indicator
of phenolic compounds release) after incubation with cellulase. All kinetic
data were fitted to first-order kinetics models to estimate the rate of
degradation and the potential degradability, and the average degradation rate
and effective degradability (ED) were calculated. The most accurate prediction
of VDMI was by using the average degradation rate of the CEL method in a
single regression equation, which accounted for 0.78 of the variation in
intake (residual s.d. = 1.40). When only data from grass-rich hays were
considered, the inclusion of potential degradability and rate of degradation
of the CEL method in a multiple regression equation accounted for 0.98 of the
variation in intake (residual s.d. = 0.32). The ED of the CEL method
explained 0.93 and 0.92 of the variation in the in vivo
DMD for all hays and grass-rich hays, respectively (residual s.d. =
18.1 and 21.7, respectively). The predictive ability of the different methods
is discussed and compared with that of the in situ
technique that has been previously reported.
Phosphorus efficiencies and their effects on Zn, Cu, and Mn nutrition of different barley (Hordeum vulgare) cultivars grown in sand culture
Authors: Zhu Y.-G. , Smith F. A. , Smith S. E.
Published: September 2002

A sand-culture experiment was carried out in a growth chamber to investigate
the phosphorus (P) efficiencies of 8 barley cultivars that are parents of 4
mapping populations, and the effects of P nutrition on plant uptake of zinc
(Zn), copper (Cu), and manganese (Mn). Two sources of phosphate were used,
rock phosphate (sparingly soluble) and CaHPO4 (readily
available). There were significant differences in P uptake and utilisation
efficiencies between the 8 cultivars. Among the cultivars, the
Sahara–Clipper pair is of the most interest, because these 2 cultivars
had large differences in root/shoot ratios, P allocation between root and
shoot, and P uptake/utilisation efficiencies. Higher P availability
significantly reduced plant Zn uptake and tissue concentrations in all
cultivars. Shoot Zn concentrations were found to decrease significantly with P
influx to the xylem (P < 0.01), indicating that
genotypic variations in P translocation from roots to shoots may interact with
Zn accumulation in shoots. Higher P availability reduced Cu concentrations in
shoots, probably due to a dilution effect. P availability (rock
phosphate v. CaHPO4) seemed to
affect plant uptake of Mn in some cultivars, but further study is needed to
elucidate the mechanisms involved and the practical implications of this
interaction in Mn-deficient soils.
Viruses infecting winter tomato crops in the North West Frontier Province of Pakistan
Authors: Ali A. , Hassan S.
Published: September 2002

Malakand Agency is a unique production area in the North West Frontier
Province (NWFP) of Pakistan that is frost-free and in which tomato is grown as
a winter crop. Tomato production in this area has been affected by virus-like
diseases for the last 10 years. Tomato nurseries and fields at 11 locations in
Malakand Agency were surveyed for tomato viruses during 1994–95. A total
of 1071 samples from nurseries and 5083 samples from 142 fields were tested by
indirect enzyme-linked immunosorbent assay (ELISA). In nurseries, 3 viruses,
Potato virus X (PVX),
Potato virus Y (PVY), and
Tomato mosaic virus (ToMV), were detected with an
incidence range of 9.8–22.3, 0–36.6, and 16.5–51.3%,
respectively. In the field, 5 viruses
[Cucumber mosaic virus (CMV), PVX, PVY, ToMV, and
Tomato yellow top virus (TYTV)] were frequently
found with an incidence range of 0–13.3%, 2.6–16.7%,
0.4–13.8%, 26.1–41.3%, and 1.7–11.3%,
respectively. All 5 viruses except TYTV were also detected from weed species
in tomato fields or in the nearby vicinity.
Of 12 commercial tomato varieties screened against CMV, PVX, PVY, and ToMV, 2
varieties (Florist and Forset) were resistant to 4 of the viruses including
ToMV, for which the highest incidence was recorded in nurseries and field.
These 2 varieties represent a previously undescribed and potentially useful
source of resistance to the 4 inoculated viruses.
An alternative method for assessing the value of the Southern Oscillation Index (SOI), including case studies of its value for crop management in the northern grainbelt of Australia
Authors: Robinson J. B. , Butler D. G.
Published: September 2002

Previous studies have identified extra profit that could result from selecting
management options according to particular phases of the Southern Oscillation
Index (SOI). Those studies identified optimal decisions for each phase and the
value of these decisions. However, this may have overestimated the value of
SOI-based management through a lack of data for independent evaluation. This
study compares the previous approach with a new method based on a simple
sampling technique (analogous to leave-one-out cross
validation) that estimates the range of future outcomes when independent
validation data are not available. The new method gave much-improved estimates
of the mean and variance of the value of the SOI for management. In studies
involving wheat-growing in southern Queensland, this method indicated that
management according to the April–May SOI phase yielded either small
long-term increases (in 4 of 6 cases) or decreases (in 2 of 6 cases) in
profit. There was considerable heterogeneity among phases, and the annual
variance of the outcomes was large relative to the long-term average value in
all 6 cases. Consequently, unless a strategy is applied long term (at least 10
years), there is a relatively high likelihood of higher or lower profit than
for non-strategic management. The likelihood of increased and decreased
short-term profit is approximately equal. In all 6 case studies, the long-term
average economic value of SOI-adjusted management was less than, or equal to,
the economic value of 1 mm of extra plant-available soil moisture at sowing.
Pedigree analysis of selected lines of Merino sheep. 1. Inbreeding
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). The characters subjected to selection were clean fleece weight, crimp frequency, weaning weight, and skin folds. The average inbreeding coefficients calculated from the pedigree data of the those selected lines ranged from 3.79% in the Fleece Plus line to 9.09% in the Folds Plus line, corresponding to average annual inbreeding rates of 0.211% and 0.505%, respectively. Generally, there were similar fluctuating patterns in the means of inbreeding coefficients across years, with higher variation in the early years, and different rates of inbreeding in different flocks. The only exception was the Fleece Plus flock with a trend to increased variation across years, higher fluctuations in average inbreeding coefficient in final years, and inbreeding, which was not located in the 95% confidence interval of the inbreeding in flocks simulated for an infinitesimal model. Although the Folds Plus line showed inbreeding within the 95% confidence interval of simulation inbreeding, it was located at the higher end of the confidence interval, due to natural selection. Excellent agreement was found between the simulated flocks inbreeding (6.54%) and predicted inbreeding from an adaptation of the formula of JA Woolliams, NR Wray, and R Thompson (1993) (6.44%).
The effects of liquid fertilisers derived from natural products on crop, pasture, and animal production: A review
Authors: Edmeades D. C.
Published: September 2002

The results from field trials measuring the effect of liquid fertilisers derived from organic materials on crop yields are summarised and reviewed. Trials comparing the efficacy of 26 specific products and 2 unnamed generic products were identified. Of these 28 products, 15 were derived from seaweed, 4 from fish waste, 5 were of vegetable origin, and 2 were from animal products. Cereals were the most frequently used test crop (328 recorded treatment effects) followed by root crops (227), legumes (88), pastures (59), and vegetables (52). Fifty-three other treatment effects were recorded on crops such as rape (15), peanuts (8), tobacco (6), and miscellaneous other crops (25). The effects of liquid fertilisers on animal performance were measured in 4 trials.The observed effects of these products on a wide range of crops were normally distributed about zero with an equal number of positive and negative 'responses'. The frequency of statistically significant events, both positive and negative, was consistent with probability theory, assuming that the products are ineffective. The range of observed effects are also consistent with the normal variability associated with field trial experimentation, taking into account the odd intrusion of other experimental errors. There was no evidence to support the conclusion that at least some product-types or products were effective on some crop-types, crops, or cultivars. Similarly, liquid fertilisers had no effect on animal production when applied as recommended. This conclusion, based on the field evidence, was consistent with, and could be predicted from, independent evidence showing that these products do not contain sufficient concentrations of plant nutrients, organic matter, or plant growth substances (PGSs) to elicit increases in plant growth when applied as recommended.
Analysis of genetic diversity within Australian lucerne cultivars and implications for future genetic improvement
Authors: Musial J. M. , Basford K. E. , Irwin J. A. G.
Published: September 2002

Lucerne (Medicago sativa L.) is autotetraploid, and predominantly allogamous. This complex breeding structure maximises the genetic diversity within lucerne populations making it difficult to genetically discriminate between populations. The objective of this study was to evaluate the level of random genetic diversity within and between a selection of Australian-grown lucerne cultivars, with tetraploid M. falcata included as a possible divergent control source. This diversity was evaluated using random amplified polymorphic DNA (RAPDs). Nineteen plants from each of 10 cultivars were analysed. Using 11 RAPD primers, 96 polymorphic bands were scored as present or absent across the 190 individuals. Genetic similarity estimates (GSEs) of all pair-wise comparisons were calculated from these data. Mean GSEs within cultivars ranged from 0.43 to 0.51. Cultivar Venus (0.43) had the highest level of intra-population genetic diversity and cultivar Sequel HR (0.51) had the lowest level of intra-population genetic diversity. Mean GSEs between cultivars ranged from 0.31 to 0.49, which overlapped with values obtained for within-cultivar GSE, thus not allowing separation of the cultivars. The high level of intra- and inter-population diversity that was detected is most likely due to the breeding of synthetic cultivars using parents derived from a number of diverse sources. Cultivar-specific polymorphisms were only identified in the M. falcata source, which like M. sativa, is outcrossing and autotetraploid. From a cluster analysis and a principal components analysis, it was clear that M. falcata was distinct from the other cultivars. The results indicate that the M. falcata accession tested has not been widely used in Australian lucerne breeding programs, and offers a means of introducing new genetic diversity into the lucerne gene pool. This provides a means of maximising heterozygosity, which is essential to maximising productivity in lucerne.
Grain protein and grain yield of durum wheats from south-eastern Anatolia, Turkey
Authors: Koç M , Barutçular C. , Zencirci N.
Published: September 2002

High grain protein in durum wheat
[Triticum turgidum ssp.
turgidum L. conv. Durum
(Desf.)] is one of the main goals of breeding programs. Landraces may be
very useful germplasm for achieving this goal. To examine their potential as a
source of high grain protein content, 11 genotypes, including 7 landraces,
were evaluated in 8 environments.
Environment, genotype, and the interaction of the two (G E) significantly
influenced the variation in grain yield, grain protein content, and grain
protein yield. The environmental effect was the strongest, mostly due to
differences in water supply. Grain yields of the modern genotypes were higher
than those of landraces. Yields of the modern genotypes tended to respond more
strongly to the higher yielding environments, but they varied more than the
yields of landraces. With the exception of VK.85.18, the grain protein content
of the high-yielding genotypes was almost as high as that of the best
landraces. Moreover, grain protein content of these bred genotypes tended to
respond more strongly to the higher protein environments. Differences in grain
protein yield were closely related to the differences in grain yield.
The results indicate that it is possible to improve grain protein content
without grain yield being adversely affected. The results also indicate that
potential gene sources should be compared over a number of environments before
they can be used as breeding material or as crop varieties producing high
grain protein yields.
Analysis of line x environment interactions for yield in navy beans. 3. Pattern analysis of environments over years
Authors: DeLacy I. H. , Redden R. J. , Butler D. G. , Usher T.
Published: September 2002

Yield trials of navy bean (Phaseolus vulgaris L.) lines
were grown over a diverse range of locations for 7 years in Queensland, with
changes in entries and locations in each year. The yield data were analysed
over years using 3 recently developed pattern analysis techniques for the
integration of historical, severely unbalanced data from plant breeding
programs to derive relationships among environments in the way they
discriminate among the entries grown in them. These techniques have been named
as cumulative analysis, sequential analysis, and status analysis. The
relationships among the locations for testing navy bean lines, although
sensitive to the addition of new locations, quickly stabilised. These
relationships were related to management (irrigation and row width) and
latitude (north v. central v.
Kingaroy v. southern Queensland).
Interaction between Helicoverpa armigera and Colletotrichum gloeosporioides on the tropical pasture legume Stylosanthes scabra
Authors: Wilson Peter A. , Room Peter M. , Zalucki Myron P. , Chakraborty Sukumar
Published: September 2002

Glasshouse experiments determined effects of a moth,
Helicoverpa armigera (Lepidoptera: Noctuidae), and the
anthracnose pathogen, Colletotrichum gloeosporioides
(Penz.) Penz. and Sacc., on each other when attacking the same host plant,
Stylosanthes scabra (Vog.) (Leguminosae) cv. Fitzroy.
The host was treated with both organisms in 2 ways of succession and at 2
different life stages each. Larvae of the moth preferred to feed on healthy
plants rather than plants recently infected with
C. gloeosporioides, and preferred such newly infected
plants to severely diseased ones. Adult female moths laid more eggs on healthy
and recently infected plants than on diseased plants, when given a choice of
all 3 plant types. Severity of anthracnose disease was neither promoted nor
retarded by damage to leaves caused by larvae of the moth.
The timing of nutritional restriction during reproduction influences staple strength
Authors: Robertson S. M. , Robards G. E. , Wolfe E. C.
Published: September 2002

The staple strength of wool from Merino ewes (liveweight 41 kg; condition
score 1.5) was assessed in response to a short-term nutritional restriction at
different stages of pregnancy and lactation. Single- and twin-bearing ewes
were fed to maintain maternal liveweight (control) or restricted to lose 2 kg
in maternal liveweight between Days 85 and 98, 113 and 126, or 141 and 154 of
pregnancy, or Days 169 and 182 in early lactation. Unmated control ewes were
fed to maintenance, and a group of unmated ewes was restricted between the
equivalent of Days 141 and 154 of pregnancy. All groups were maintained in
group-feeding pens from Day 8 of pregnancy to 4 weeks after weaning of lambs.
The ewes were fed lucerne hay.
Control ewes fed to maintain liveweight produced sound wool (unmated 52.7, or
single-rearing 46.0, and twin-rearing 43.0 N/ktex). Nutritional
restriction only reduced the staple strength of wool produced by unmated ewes
by 2.2 N/ktex (P > 0.05), but reduced that of
reproducing ewes by 0–26.8 N/ktex. The decline in staple strength of
reproducing ewes increased as the time of restriction during pregnancy
advanced. Restriction during lactation did not significantly
(P > 0.05) influence staple strength. The effect of
restriction appeared to be mediated via changes in diameter along fibres. The
results indicate that there is variation in the sensitivity of staple strength
to short-term nutritional restriction, with both pregnancy status and the
stage of pregnancy at which the restriction is imposed influencing the impact
on staple strength.
Genotype by environment interactions affecting grain sorghum. I. Characteristics that confound interpretation of hybrid yield
Authors: Chapman S. C. , Cooper M. , Butler D. G. , Henzell R. G.
Published: September 2002

Past sorghum hybrid trials in north-eastern Australia have detected
substantial genotype by environment (G×E) interactions for yield in
sampling a variable target population of environments (TPE) that is affected
by spatial and seasonal differences in crop water supply. Three datasets,
comprising yields of commercial and final stage experimental hybrids and
covering 9–17 years (Y) and up to 30 locations (L), were analysed to
quantify variance components for trial error, genotypic
(σ2g), and G×E
(σ2gl,
σ;2gy, and
σ2gly) interaction effects.
Whereas trial means varied 2–3-fold across seasons, a greater range was
estimated for variance components of trial error (range of 0.05–0.5), G
(0–>0.3), and G×L interaction (0.05–>1.0). There was
substantial seasonal variation in the ratio of
σ2g to
(σ2g
+σ2gl), and in two
datasets, 73% of the seasonal
σ2gl was due to poor genetic
correlations among locations. This implies that any given set of hybrids in a
random set of locations would be ranked differently from season to season.
Analysis of locations over years detected 90% of the total G×E
interaction as G×L×Y, rather than G×L or G×Y, although
this was reduced by accounting for genotype maturity. To achieve
repeatabilities of >80%, trials would need to be conducted over at
least 5 years and 20 locations per year.
The variable and unpredictable nature of much of the G×E interaction in
the region implies that broad adaptation to different water regimes is
required, unless prior knowledge of the seasonal weather can be used to choose
‘narrowly adapted’ cultivars. With current approaches, a large
sample of environments is needed to identify such hybrids, and testing across
locations and years is equally important. Alternative breeding strategies
based on classifying environment types are discussed.