bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of aluminium and calcium in the soil solution of acid soils on root elongation of Glycine max cv. Forrest
Authors: Bruce RC , Warrell LA , Edwards DG , Bell LC
Published: November 2004

In the course of three experiments, soybean (Glycerine max (L.) Merr.) cv. Forrest was grown in 21 soils (four surface soils and 17 subsoils) amended with liming materials (CaCO3 and Mg CO3) and soluble Ca salts (CaSO4.2H20 and CaCl2.2H2O). In most soils, the soluble salts increased concentrations and activities of Al species in solution to levels that restricted root growth, and MgCO3, induced a Ca limitation to root growth. Root lengths after three days were related to so11 and soil solution attributes.Suitable diagnostic indices for the prediction of Ca limitations to root growth were either Ca saturation of the effective cation exchange capacity or Ca activity ratio of the soil solution, which was defined as the ratio of the activity of Ca to the sum of the activities of Ca, Mg, Na, and K. Values corresponding to 90% relative root length (RRL) of soybean were 0.05 for the Ca activity ratio and 11% for Ca saturation. Calcium activity and Ca concentration in the soil solution and exchangeable Ca were less useful for this purpose.Soil Al saturation was not a good predictor of Al toxicity, but soil solution measurements were. The activities of Al3+ and AlOH2+ gave the best associations with RRL, and values corresponding to 90% RRL were 4 8M and 0.5 8M respectively. The results suggested that Al(OH)3� , Al(OH)2+, and AlSO4+, were not toxic species. Soil solution pH and soil pH measured in water were more sensitive indicators of root growth than soil pH measured in 0.01 M CaCl2.Using a Ca activity ratio of 0.05 and an Al3+ activity of 4 8M as diagnostic indices, none of the 20 soils in two experiments were toxic in Al, while 13 (all subsoils) were deficient in Ca. Thus the first limitation on root growth was Ca deficiency and not Al toxicity, in spite of high Al saturations and relatively low pH in these soils. However, Al toxicity could be induced by increasing the ionic strengths of soil solutions.
Effect of phosphorus deficiency in wheat on the infection of roots by Gaeumannomyces graminis var. tritici
Authors: Brennan RF
Published: November 2004

Wheat was grown in a slightly acidic grey sand at six levels of phosphorus, in the presence or absence of take-all inoculum in a glasshouse experiment. The incidence and severity of take-all was related to the phosphorus supply and the phosphorus status of wheat.Plants grown without P were more severely infected by take-all than those grown at adequate levels of phosphorus. The percentage of both nodal and seminal roots infected by take-all declined as the level of P was increased. The percentage of seminal roots infected was reduced from 35% to 13.7% by increasing the supply of phosphorus from levels severely deficient to those adequate for plant growth. Infection in nodal roots was reduced from 24% to 2.3% as the P supply increased. In both the seminal and nodal root systems, increasing the P supply decreased the length of proximal lesions (closest to seed) and increased the length of root between the crown and the proximal lesions.
The effects of flowering and leaf area on sward growth in winter of temperate pasture grasses
Authors: Kemp DR
Published: November 2004

Pasture growth rates in winter, in many regions are low, and this often sets the limit on the stocking rates possible on those pastures. This research was done to examine some of the reasons for the differences in productivity between grasses In winter. Eight perennial and two annual grasses were compared over three years in a field experiment, where mean daily air temperatures in winter averaged 5�C. Species separated into five groups. The largest yields, over winter from plots cut either in autumn or early winter, were obtained from Kangaroo Valley perennial ryegrass (Loliurn perenne) and Wimmera annual ryegrass (L. rigidurn). Their yields were significantly greater than from oats (Avena byzantina) and prairie grass (Bromus catharticus), which in turn were greater than mountain rye (Secale montanum) and Sirosa phalaris (Phularis aquatica); the next group were CPI 69358 perennial ryegrass, currie cocksfoot (Dactylis glomerata) and Australian Commercial phalaris, and least was CPI 68318 cocksfoot. Greater forage yield, within years, was obtained from grasses that switched into reproductive development early in winter rather than from a high leaf area index in swards prior to winter. Differences in yield between years were, though, related to differences in leaf area. The average sward net assimilation rates over winter were greater for ryegrass cultivars, and oats, than for the other species. Plots uncut from autumn had greater yields throughout winter but lower net assimilation rates. It was concluded that improved pasture yields in winter can be obtained by selecting or recommending grasses that commence reproductive development early. This effect would apply in most environments where temperate grasses and cereals are grown.
Corrigendum - Epidemiology of nematode infections of weaner sheep in the cereal zone of South Australia
Authors: Pullman AL , Beveridge I , Martin RR
Published: November 2004

Trichostrongyloid nematode infections of weaner sheep were investigated at the Turretfield and Minnipa Research Centres in the cereal zone of South Australia over a three-year period (1982-1985). Acquisition of nematode larvae from pasture occurred over a limited period each year, principally during the winter months, and coincided with the elimination of, or a reduction in the numbers of adult nematodes; sheep subsequently resisted challenge by infective larvae. Faecal egg counts were elevated during the summer, but declined to negligible levels during the winter months when larval challenge was at its maximum. Scouring, which was common in untreated sheep during winter at Turretfield, did not occur in regularly treated sheep, but no adverse effects were noted at Minnipa.
Digestibility of threonine from protein concentrates for growing pigs. 1. The flow of endogenous amino acids to the terminal ileum of growing pigs
Authors: Leibholz J , Mollah Y
Published: November 2004

Six pigs (25 kg initial weight) were fitted with T cannulas in the terminal ileum. Each pig was fed a nitrogen (N) free diet or one of eight diets containing increasing amounts of threonine from milk (four diets) or cottonseed meal (four diets). The flow of endogenous nitrogen from the terminal ileum was 1.1 g/kg dry matter DM intake in the pigs given the nitrogen-free diet and 0.9 g/kg DM intake when estimated by extrapolation in the pigs given the milk or cottonseed meal diet. There were no significant differences in the flow of individual endogenous amino acids from the terminal ileum when measured in pigs given a nitrogen-free diet or when extrapolated from data for pigs given diets containing milk or cottonseed meal. The flow of endogenous threonine from the terminal ileum was between 0.39 and 0.45 g/kg DM intake as estimated in pigs given diets with similar threonine intakes from cottonseed meal or milk and the nitrogen-free diet.
Effect of pre-season management and in-crop herbicdes on weed seedling numbers and triticale grain yield
Authors: Dowling PM
Published: November 2004

Six pre-season treatments which aimed to reduce seed set of annual grasses were imposed at Orange, N.S.W., during spring 1985. Five in-crop treatments (cultivation plus trifluralin, trifluralin, oryzalin plus trifluralin, chlorsulfuron, nil - all direct-drilled) were superimposed over the pre-season treatments at sowing time. Triticale was sown 8 days after application of glyphosate (0.72 kg a.i. ha-1) in May 1986. All pre-season treatments reduced potential grass seedling numbers (89-94% reduction), with the grazing treatments being less effective then the herbicide treatments. Actual grass seedling numbers (those emerging within the crop) followed a similar pattern to potential seedling numbers, but at 10-20% of the potential level. Species not targeted for pre-season management (legume spp., Polygonum aviculare, Poa annua) tended to he present in larger numbers on those pre-season treatments where reduction of the topped grasses was greater. In-crop herbicides did not consistently reduce grass weed seedling numbers further. Grass weeds were more effectively controlled by the cultivation plus trifluralin treatment. Triticale crop yield was reduced as seedling numbers of topped grasses increased. In the direct-drilled situation, it was concluded that satisfactory crop yields will be obtained only after imposition of some form of pre-season management. For longer term grass control, these treatments would need to be imposed in at least two consecutive years.
Utilization of clover diets by sheep. 1. Intake and digestion of organic matter and cell wall constituents
Authors: McLaren CE , Doyle PT
Published: November 2004

Nine mature Merino sheep received three clover diets in a randomized block design experiment. The diets were mature subterranean clover (MSC), apparent organic matter digestibility (OMD) 60%; green subterranean clover (GSC), OMD 72%; persian clover (PC), OMD 67070, and were given at 95% of measured ad libitum intake. The voluntary consumption of the MSC was lower than the intakes of the CSC and PC. Consequently, the sheep given MSC lost weight, while those receiving the more digestible diets gained weight. Associated with the different intakes in these clover diets, there there were no differences in the levels of ruminal fill, but there were differences in ruminal loads of dry matter (DM) and neutral detergent fibre (NDF) in sheep given MSC, GSC and PC, respectively. The flows of DM and OM through the abomasum were lower for MSC, and with a tendency for the fractional outflow rate of NDF of this diet to be lower (2.3 v. 2.8% h-1) when compared to the GSC and PC hays. The proportions of apparent OM (0.65-0.71), of NDF (0.71-0.82) and of ADF (0.95-140) digestion occurring in the rumen were similar for the three clover hays. The fractional digestion rates of potentially digestible NDF were higher for the more digestible clovers (c. 8.6% h-1) than for the MSC (6.5% h-1). The intake of the higher digestibility clovers may have been more related to the capacity of the sheep to use absorbed nutrients than to constraints imposed by ruminal digesta load, rate of digestion in the rumen or rate of outflow to the omasum. With the MSC the level of ruminal or dry matter load was low. In addition, the fractional rates of digestion and of outflow of cell wall constituents were or tended to be lower for this diet than for the other clovers. Intake of MSC may have been limited not only by these factors, but also by the supply of essential nutrients to the tissues or by other characteristics of the hay influencing its acceptability to sheep.
Diagnosis of sodium status in small ruminants
Authors: McSweeney CS , Cross RB , Wholohan BT , Murphy MR
Published: November 2004

Existing techniques of determining the Na status of ruminants were evaluated in goats and sheep that had widely varying intakes of Na (3-86 mmol/day) and K (20-780 mmol/day). The experiments involved the examination of relationships between Na balance, plasma aldosterone and renin, Na content of faeces and urine, and salivary Na:K ratio in these animals. The variables were measured at monthly intervals for 6 months in goats receiving low or high Na diets, and during 1 month in sheep offered a low Na and low K diet alone or supplemented with 1.5 or 3.0% K. Aldosterone was closely correlated with salivary Na, K and Na:K ratio for both goats and sheep, but there was little relationship indicated between aldosterone and the other variables, either by the raw or logarithmically transformed data. Sodium balance was poorly correlated with all variables, probably because of the unavoidable inaccuracies in measuring Na intake and output. Therefore it was assumed that aldosterone was the best indicator of Na status, since it is the major hormone regulating Na conservation. Stepwise multiple linear regression of all the data with aldosterone as the dependent variable yielded the equation: in (aldosterone) = 5.7 - 0.87 in (saliva Na:K). Coefficient of multiple determination (R2) was 0.93. In both species aldosterone levels increased markedly when salivary Na:K ratio was less than 4:l. It is concluded that the ratio of Na:K in saliva is a reliable indicator of Na status and a ratio of less than 4 is diagnostic of an incipient Na deficiency.
Nitrogen kinetics in cattle fed a mature subtropical grass hay with and without protein meal supplementation
Authors: Hennessy DW , Nolan JV
Published: November 2004

Ammonia kinetics in the rumen, and the rates of urea synthesis, excretion, and recycling to the rumen and post-ruminal digestive tract were estimated by means of tracer dilution methods in eight 12-monthold Hereford steers, all given free access to a mature, subtropical grass (Axonopus spp.) hay (7.8 g N and 5.8 MJ of metabolizable energy (ME)/kg dry matter). These estimates were made towards the end of a 45-day study, including a 12-day adjustment period, and 33 days in which four steers were supplemented with pelleted protein meal and minerals; the other four were supplemented only with minerals. After 10-20 days of supplementation (days 23-32 of the experiment), the voluntary intake of hay was 19% higher (P < 0.05) in supplemented compared with non-supplemented steers, and from days 33 to 42 was 23% (P < 0.01) higher. Therefore, during the period between days 22 and 42 of the experiment when ammonia and urea kinetics were estimated, total ME and N intakes were higher (30 v. 22 MJ/day and 71 v. 29.5 g N/day), and liveweight gain was also higher (P < 0.01) in supplemented steers (800 v. 200 � s.e.d. 88 g/day). Ammonia and volatile fatty acid concentrations in rumen fluid were higher (P < 0.05) in supplemented steers (55 v. 7 mg N/l and 93 v. 77 mmol/l respectively). The rate of synthesis of urea in the body, and the concentrations of urea in plasma and saliva, predominantly of parotid origin, were also higher (P < 0.01) in supplemented steers. Non-supplemented steers appeared to conserve nitrogen, excreting only 0.41 g urea N/day in urine, which was less than 3% of their daily urea synthesis compared with 9 g N/day or 21% of the daily urea synthesis in supplemented steers. More urea N (P < 0.01) was recycled to the digestive tract in supplemented than in non-supplemented steers, but in either case c. 60% of the total amount recycled was transferred to the rumen. A model summarizing N transactions in the body is presented for steers on the basal hay diet and when supplemented with the pelleted meal.
Forecasting wheat yields using a water budgeting model
Authors: Cordery I , Graham AG
Published: November 2004

A model has been developed to forecast soil water variations and wheat crop growth in dry land situations. The forecast of the yield to be expected if sowing occurred today is obtained by running the calibrated model for all years for which meteorological data are available. The soil water content on today's date in each year is fixed at today's observed soil water value. From each year of observed meteorological data, an estimate is made of the yield. These yield data allow construction of a frequency distribution of yield which can be used to make a probabilistic forecast. The model involves two sub-models, a water balance model and acrop development model. The two sub-models interact to provide 5-day estimates of soil water content, actual evaporation and transpiration, runoff and increments to biomass and grain yield. The water balance model takes inputs of daily rainfall and estimated potential evapotranspiration. Available energy is partitioned between evaporation and transpiration depending on leaf area index. There are two soil layers plus a surface interception and depression store. Water removal from the soil layers is dependent on root development and the location of available water. Biomass production is driven by actual transpiration and transpiration efficiency and so biomass and grain development are dependent on the timing and amount of water and energy utilization by the crop. The model was first calibrated in northern New South Wales with 13 years of research station data. With minor recalibration, it provided good estimates of observed district wheat harvests for a continuous period of 75 years. Further recalibration with 30 years of shire data from Queensland, 29 years of single farm data in southern New South Wales and with 31 years of county data from northwestern USA., indicated the model is able to accurately reproduce observed yields and has the potential to provide reliable forecasts of yield, in a range of different climates.
Varietal differences in leaf water potential, leaf net CO2 assimilation, conductivity and water use efficiency in upland rice
Authors: Dingkuhn M , De Datta SK , Dorffling K , Javellana C , Datta SKde
Published: November 2004

Twenty-eight rice (Oryza sativa L.) genotypes of different origin and habitat were grown in upland culture during the dry season in the Philippines. Irrigation was supplied by overhead sprinklers at a level which kept the crop under continuous mild water stress. Leaf net CO2 assimilation, conductivity, intercellular CO2 concentration, water potential and leaf rolling status were determined on the same leaf of all varieties between 0900 and 1200 hours during the vegetative growth stage.Leaf water potential ranged from -0.8 and -1.3 MPa, with japonica types showing the highest values, AUS types from Bangladesh, the lowest, and indica types intermediate. Leaf conductivity and leaf rolling did not differ significantly among these groups. Most cultivars showed a logarithmic relationship between net CO2 assimilation and conductivity. AUS cultivars had the lowest rates of leaf CO2assimilation, but no differences were observed between japonica and indica varieties. At a given intcercellular CO2concentration, net CO2 assimilation was lowest in AUS varieties, resulting in low water use efficiency, and possibly indicating a higher CO2 compensation point for AUS than for other rice types.
Winter feed production and grain yield in mixtures of spring and winter wheats
Authors: Davidson JL , Jones DB , Christian KR
Published: November 2004

The possibility of combining the early rapid growth of extreme spring (express) wheat cultivars with the high grain-producing ability of long-season types as a dual-purpose crop (fodder and grain) for the high-rainfall zone of E. Australia was investigated in an experiment at Canberra in 1985. Mixtures of cv. Sunset, an express wheat, and Isis, a winter wheat, in the proportions of 1:3, 1:1 and 3:1, were compared with 4 long-season and 2 short season wheat cultivars, oats and pastures (Lolium rigidum/Trifolium subterraneum with and without N fertilizer), all sown at the end of summer. Cereals and pastures were cut monthly from 3 different starting dates. Cereals were cut until their developing ears were above ground, and pastures were cut until the trial ended in Nov. In a 4th treatment, cereals were left uncut. An early start to cutting allowed all long-season wheats to be harvested several times for fodder, but in general the total amount harvested was greatest from the latest initial cutting date treatment. The greatest amount of DM harvested (9 t/ha) came from the express wheat Sunset and from Sunset/Isis mixtures, 2 t/ha more than from Isis alone. As well as producing considerably greater amounts of DM during winter, the Sunset/Isis mixtures yielded as much grain (3.4 t/ha from the latest initial cutting date treatment) as Isis alone. DM and grain yields of mixtures were stable across the range of ratios used. It was concluded that grazing of crops sown for winter feed in cool environments should be delayed as long as possible without endangering ears, thereby providing max. amounts of fodder and effectively smothering weeds. Under this regime, mixtures of express and winter wheats should provide at least as much feed as a pasture treated similarly. If cutting started early, both would be less productive, and the crop could be inferior to the pasture.
The cereal cyst nematode (Heterodera avenae) on oats. I. Identification of attributes useful in early screening for tolerance to H. avenae
Authors: Volkmar KM
Published: November 2004

Variation in morphology, development, and water relations of four oat cultivars inoculated with a range of densities of Heterodera avenae larvae was assessed during early growth to identify distinguishing traits for tolerance. Experiments were performed under glasshouse conditions on cultivars previously rated for tolerance. Cultivar differences were found in the effects of H. avenae on final leaf length, and on root and shoot mass within 20 to 30 days of planting. These differences corresponded to cultivar differences in tolerance to H, avenae at maturity. Differences between cultivars in their sensitivity to root stunting by H, avenae were also related to their final tolerance ratings. Tiller removal generally enhanced tolerance but had little effect on the overall tolerance ranking of the four cultivars examined. H. avenae infection had the least effect on the water use efficiency (WUE) of the most tolerant cultivar and the greatest effect on the least tolerant cultivar. In the absence of nematodes, intolerant cultivars used water more efficiently than did tolerant cultivars. Results suggest that oats can be screened for tolerance to H. avenae during early plant development.
Immunization against somatotropin release inhibiting factor improves digestibility of food, growth and wool production of crossbred lambs
Authors: Sun YX , Drane GL , Currey SD , Lehner ND , Gooden JM , Hoskinson RM , Wynn PC , McDowell GH
Published: November 2004

Crossbred ewe lambs [Dorset Horn X (Border Leicester X Merino)] fed chopped 1ucerne:rolled barley in the proportions 2:1 at either 36 g kg-1 liveweight (moderate intake) or 40 g kg-1 (high intake) were immunized on four occasions at intervals of 25 days with a conjugate of somatotropin release inhibiting factor (SRIF) and keyhole limpet haemocyanin (KLH). Before the fourth immunization, some of the barley was replaced with fish meal so that the diet contained 10% by weight air dry of fish meal. Antibodies against SRIF were detected in plasma from 10 out of 12 immunized lambs after the second immunization; two lambs on the high feed intake failed to produce measurable antibodies even after four immunizations. In the lambs producing antibodies, plasma concentrations of growth hormone, insulin and non-esterified fatty acids were similar to concentrations for non-immunized (control) lambs, but plasma concentrations of glucose were increased in the immunized lambs on the moderate intake. Apparent digestibilities of dry matter and nitrogen as well as nitrogen retention rates were greater for immunized than control lambs, with differences being significant for lambs on the moderate intake. Liveweight gains and growth rates over the experiment were significantly increased by immunization in lambs on the moderate intake and tended to increase for lambs on the high intake, but there were no effects of immunization on body composition. Wool growth and diameter of wool fibres increased after the second or third immunization, and in most cases the increase was significant. When fish meal was included in the diet, plasma glucose and growth rates decreased and wool fibre diameter increased in all lambs. Differences between immunized and control lambs were maintained.
An efficient method for generation of full climatological records from daily rainfall
Authors: McCaskill MR
Published: November 2004

Three methods were compared for providing data to accompany a daily rainfall record: (i) a seasonal mean calculated from smooth curves; (ii) a seasonal mean modified by rainday effects; and (iii) actual data with missing observations filled in by method (ii). Existing plant growth models developed for the Australian tropics were used to compare the three data generation methods. These models were used to predict the number of growth days (a measure of how much plant growth would be expected in a season), green days (a measure of the duration of weight gain by rangeland cattle), runoff, and germination days. Three stations were used, one each from the monsoonal tropics, the coastal dry tropics, and the coastal subtropics. Comparatively little bias was introduced from methods (i) and (ii). Differences were greater for episodic events such as runoff and germination, than for more continuous events such as growth. There were no significant effects of generation method on calculated growth days or green days. Runoff calculated from method (i) averaged 7% lower than when actual data were used, compared with only a 3% underestimate from method (ii). The number of germination days were underestimated by between 4 and 17% when method (i) was used, compared with between a 3% underestimate and a 6% overestimate with method (ii). It was concluded that method (ii) should be used in preference to the seasonal mean alone, because of the more accurate model predictions from method (ii). A stochastic weather generator would however be required where events such as frosting would be important in risk analyses.
Corrigendum - Triticum tauschii: a novel source of resistance to cereal cyst nematode (Heterodera avenae)
Authors: Eastwood RF , Lagudah ES , Appels R , Hannah M , Kollmorgen JF
Published: November 2004

Four hundred and twenty accessions of Triticum tauschii (genome DD) were assessed for resistance to cereal cyst nematode (Heterodera avenae Woll.) and 13 were found to be resistant (P = 0.05). Synthetic allohexaploid wheats produced from different Triticum turgidurn var. durum (genome AABB) lines and H. avenae resistant accessions of T tauschii maintained the level of resistance expressed in the diploids. This is the first report of resistance to H. avenae in T. tauschii, and in synthesized allohexaploid wheat. Since the resistance is in the D genome it is likely to be novel. Resistance was most common in T. tauschii ssp. eusquarrosa var. meyeri, and its derivatives which are confined to the Pahlavi region of Iran.
Consequences of selection for weaning weight in zebu, Bos taurus and zebu × Bos taurus cattle in the tropics
Authors: Burrow HM , Burrow HM , Seifert GW , Seifert GW , Hetzel DJS , Hetzel DJS
Published: November 2004

Direct and correlated responses to a single generation of divergent selection for weaning weight per day of age (WA/A) were examined in Bos taurus, zebu and zebu crossbred cattle in a tropical environment. Selection for high WW/A resulted in increased liveweights at all ages in all genotypes, with the exception of birth weight in the Bos taurus genotype. Preweaning daily gains were higher in all genotypes selected for high WW/A, but postweaning daily gains did not differ in two zebu crossbred genotypes. Overall parasite and heat resistance did not change significantly as a result of selection. However, selection within the more resistant genotype/sex populations resulted in higher tick and worm burdens, while in the more susceptible populations tick and worm loads decreased. An examination of lifetime cow fertility showed that cows with high preweaning growth reared more calves to weaning (P < 0.05), had fewer neonatal mortalities (P < 0.10) and also calved earlier (P < 0.01) than cows with low preweaning growth, leading to the conclusion that cows with high WW/A have improved lifetime fertility. Heritability of birth weight, WW/A and 18 month weight per day of age over all genotypes was estimated by parent-offspring regression to be 0.46, 0.21 and 0.22 for each of the traits respectively. The realized heritability of WW/A was 0.17 over all genotypes.
Genotypic variation in osmotic adjustment in grain sorghum. I. Development of variation in osmotic adjustment under water-limited conditions
Authors: Tangpremsri T , Fukai S , Fischer KS , Henzell RG
Published: November 2004

Development of genotypic variation in osmotic adjustment was examined in two glasshouse experiments using two sets of sorghum material. In the first experiment, 47 S2 lines extracted from a randomly mated population were used, whereas in the other, inbred parents and their 15 hybrids were compared. In both experiments, water deficit was induced in two periods, one before anthesis and the other after anthesis for most genotypes. In both experiments osmotic potential at the beginning of the first drying period was similar among genotypes and therefore osmotic potential obtained under water deficit was used for the comparison of osmotic adjustment among genotypes. In the first drying period of both experiments, when stress was milder, about 40% of the variation in osmotic adjustment was accounted for by difference in leaf water potential. When the effect of water potential was removed by covariance analysis, there was significant genotypic variation in osmotic adjustment in the second experiment, but not in the first experiment. On the other hand, in the second drying period, when stress was more severe, the effect of leaf water potential on osmotic adjustment was small. There was significant genotypic variation in osmotic adjustment in both experiments after the water potential effect was removed by covariance analysis. Osmotic adjustment in the second drying period was also negatively correlated with grain sink/source ratio (number of grains/leaf area) in the first set of materials. The comparison of osmotic adjustment among hybrids and their parents showed that, in this particular set of genotypes, the female parents were more important than the male in determining osmotic adjustment of the hybrids. The genotypic variation was associated with performance under water deficit in the field. It is concluded that there is considerable genotypic variation in osmotic adjustment in the genetic material examined. Osmotic adjustment is, however, correlated with water potential and grain sink/source balance, and hence the selection for osmotic adjustment needs to ensure that high value is not due simply to low water potential or small head size.
Effective use in livestock feeds of mouldy and weather-damaged grain containing mycotoxins—case histories and economic assessments pertaining to pig and poultry industries of Queensland
Authors: Blaney BJ , Williams KC
Published: November 2004

Mould growth in field crops or stored grain reduces starch and lipid content, with consequent increases in fibre, and an overall reduction in digestible energy; palatability is often adversely affected. If these factors are allowed for, and mycotoxin concentrations are low, there are sound economic reasons for using this cheaper grain. Mycotoxins are common in stock feed but their effects on animal productivity are usually slight because either the concentration is too low or the animal is tolerant to the toxin. In Australia, aflatoxins occur in peanut by-products and in maize and sorghum if the grain is moist when stored. Zearalenone is found in maize and in sorghum and wheat in wetter regions. Nivalenol and deoxynivalenol are found in maize and wheat but at concentrations that rarely affect pigs, with chickens and cattle being even more tolerant. Other mycotoxins including cyclopiazonic acid, T-2 toxin, cytochalasins and tenuazonic acid are produced by Australian fungi in culture but are not found to be significant grain contaminants. Extremely mouldy sorghum containing Alternaria and Fusarium mycotoxins decreased feed conversion in pigs and chickens by up to 14%. However, E moniliforme- and Diplodia maydis-infected maize produced only slight reductions in feed intake by pigs and Ustilago-infected barley produced no ill effects. Use of these grains would substantially increase profits if the grain can be purchased cheaply.
Doubled haploid production by anther culture for Australian barley breeding
Authors: Luckett DJ , Smithard RA
Published: November 2004

Agarose-solidified media containing maltose and glutamine were used to produce double-haploid lines, by anther culture, from Australian spring barley (Hordeum vulgare L.) genotypes. Three sets of F1 and two sets of F2 breeder's hybrids were used. Genotype differences were significant for the proportion of anthers responding, and the number of green and albino regenerants per 100 anthers plated. It was confirmed that the environmental conditions experienced by the donor plants (time of year, and field or glasshouse) had a large impact upon explant performance in culture. A minimum level of anther culture efficiency was achieved to allow a breeding program to produce all its inbred lines by this method. The procedure has the potential to save research costs, and deliver improved genotypes to the grower up to four years earlier than conventional methods.
Production of summer crops in northern New South Wales. I. Effects of tillage and double cropping on growth, grain and N yields of six crops
Authors: Herridge DF , Holland JF
Published: November 2004

The effects of tillage practice and double cropping on growth, yield and N economies of summer crops were examined in field experiments near Tamworth, northern New South Wales. Sorghum, sunflower, soybean, mungbean, cowpea and pigeon pea were sown into alkaline, black earth soils which contained either high (Site A, sown January 1983), moderate (Site B, sown December 1983), or low concentrations of nitrate (Site C, sown December 1984). During the previous winters, the land had been sown to wheat (double crop) or fallowed using cultivation or no-tillage practices. At Sites A and B, dry matter yields, averaged over all crops, were increased by 34 and 14% under no-tillage. Average increases in grain yields at the two sites were 22 and 11%. At Site C, tillage practice did not affect yields. Soybean showed the greatest responses to no-tillage. Increases in grain yields were 46, 15 and 18% for Sites A, B and C respectively. The least responsive legume was mungbean. Yields of sorghum were increased by 41% at Site A; responses at Sites B and C ranged between a 9% decrease and a 7% increase. With double cropping, grain yields were, on average, 18 (Site A), 81 (Site B) and 72% (Site C) of the yields in the cultivated (fallow) plots. However, when comparisons were made for the 12 month periods, i.e. wheat and summer crops v. fallow and summer crops, production was more than doubled at Site B and tripled at Site C, compared with the cultivated fallow. Significant in the responses to double cropping were the 192 (Site B) and 230 mm rainfalls (Site C) during November and December that replenished the soil profile with water to a depth of >0.75 m. Assessments of soybean N2 fixation using the ureide method indicated large effects of site and season on the proportion of plant N derived from N2 fixation (range, 0-0.83), on the amount of N2 fixed (range, 0-233 kg N ha-1) and on the N balance as a result of the cropping (range, -69 to +45 kg N ha-1).
Egg weight responses of laying hens fed different concentrations of vegetable oil and linoleic acid
Authors: Mannion PF , Neill AR , Brewster M
Published: November 2004

The relationships between dietary fat content and dietary fatty acid composition and egg weight were investigated in two strains of laying hens. Six diets were fed in which the levels of readily absorbable fatty acids, including linoleic acid, were increased by the addition of up to 32.6 g kg-1 safflower oil. Two additional diets containing olive oil provided intermediate or high levels of readily absorbable fatty acids and a low level of linoleic acid. The diets were fed from 30 to 46 weeks of age (phase 1) and again from 54 to 70 weeks of age (phase 2) after an intermediate buffer period in which a diet low in both fat and linoleic acid was fed. The diets had no significant effect on feed intake, liveweight or egg mass output, although small differences in egg number occurred. Egg weight responded to increasing levels of safflower oil in the diet but not to similar levels of olive oil. These differences cannot be attributed to dietary energy or to the intake of nutrients other than those associated with the inclusion of vegetable oil. It is concluded that the linoleic acid component of safflower oil is responsible for the observed effects on egg weight. As judged by regression analyses the egg weight response was significant in only one strain, being linear in phase 1 and curvilinear in phase 2.
Assessment for animal feed of maize kernels naturally-infected predominantly with Fusarium moniliforme and Diplodia maydis. I. Fungal isolations and changes in chemical composition
Authors: Williams KC , Blaney BJ , Dodman RL , Palmer CL
Published: November 2004

A study was made of the physical characteristics, fungal associations and the chemical composition of five batches of maize grain (designated A, B, J, M and P) damaged by ear-rot. All batches were the yellow hybrid, Dekalb XL81, except batch A which was a white variety, Dekalb DS456W. Batch A was separated by vibrating gravity grading into heavy (A-H) and light (A-L) fractions. For each batch, kernels were sorted visually into sound and mould-damaged samples to examine for any differences. The proportion of sound kernels in batches A, A-H, A-L, B, J, M and P was 874, 926, 260, 830, 854, 789 and 964 g kg-' respectively. Bulk density (r = 0.98) and 100 seed weight (r = 0.81) were highly correlated (P < 0.01) with the proportion of mould-damaged kernel in the sample. In visually sound kernels, Fusarium monilifome, Acremonium strictum and Penicillium spp. were the most prevalent fungi isolated. In visually damaged kernels, F. moniliforme was the fungus most frequently isolated other than for batch J where D. maydis was equally prevalent. Penicillium spp. and F. subglutinans were found in all batches but at low isolation frequencies. Compared to the respective sample of sound kernel, the content of crude protein and ash was increased and crude fat was decreased by the mould damage (P < 0-05); fibre, though more variable, was generally increased but gross energy was unaffected (P > 0.05). In visually sound kernels, the amounts of threonine, valine and glycine in the protein (g 16gN-1 ) decreased (P < 0.05) with increasing grain N content. In contrast, in visually mould-damaged kernels, lysine increased and histidine and cystine decreased with increasing grain N content (P < 0.05).
Assessment for animal feed of maize kernels naturally-infected predominantly with Fusarium moniliforme and Diplodia maydis. II. Nutritive value as assessed by feeding to rats and pigs
Authors: Williams KC , Blaney BJ , Young RA , Peters RT
Published: November 2004

Four batches of ear-rot damaged maize grain and a batch of reportedly sound maize were assessed by rat and pig growth assay and digestibility determination in pigs. All batches were the yellow hybrid, Dekalb XL81, except one which was a white variety, Dekalb DS456W. The fungus most frequently isolated from damaged kernels was Fusarium monilifome, with the exception of one batch where Diplodia maydis was equally prevalent. Traces of aflatoxin were detected in two samples but ochratoxin A, sterigmatocystin, zearalenone, T-2 toxin, deoxynivalenol, nivalenol, diacetoxyscirpenol and moniliformin were not detected. In the growth assays, no illness was apparent in any of the rats but scouring, vomiting and a persistent and generalized muscle tremor were observed in a number of pigs. Diets based on sound maize resulted in better (P < 0.05) growth performance of both rats and pigs than those based on mouldy maize. The apparent digestibility of the sound maize was better than each batch of mouldy yellow maize, but no better than the batch of mouldy white maize. Differences in nutritive value between the batches of maize were more closely related to the degree of fungal damage and the nature of the endosperm than to either the proximate chemical or amino acid composition of the grain. The muscle tremor observed in some pigs might have been due to undetected mycotoxins.
Genetic parameters for liveweight and ultrasonic fat depth in Australian meat and dual-purpose sheep breeds
Authors: Brash LD , Fogarty NM , Gilmour AR , Luff AF
Published: November 2004

The genetic and phenotypic variances and covariances for liveweight at 5 to 19 months of age and ultrasonic subcutaneous fat depth were estimated using REML procedures for the Border Leicester, Suffolk, Corriedale, Coopworth and Gromark breeds. The data comprised 12 923 progeny from 46 flocks, representing 590 sires, and were collected by the New South Wales Meatsheep Testing Service between 1981 and 1990. Fixed effects included in the model were management group, birth type, rearing type, age of dam and age of lamb. Each breed was analysed separately, and the larger breed data sets (Border Leicester and Suffolk) were split on age at measurement. The estimates of heritability for the various data sets ranged from 0.09 � 0.09 to 0.40 � 0- 10 for liveweight and 0.07 � 0.08 to 0.40 � 0 -07 for fat depth. There was a moderate positive genetic correlation (0 - 14 to 0.77) between liveweight and fat depth. Adjustment of fat depth for liveweight reduced this genetic correlation (-0.34 to 0.24) and had little effect on the heritability of fat depth, which then ranged from 0-06 � 0-08 to 0.44 � 0.07. Variation in estimates between the breeds is discussed. The results will be used to provide breed-specific parameters to improve the accuracy of Estimated Breeding Values produced by LAMBPLAN, Australia's national performance testing scheme for meatsheep. The mean age of sires at the birth of progeny varied from 3-2 to 3-5 years amongst the breeds, with 14% to 30% of animals sired by rams 5 years of age or older. Sire-use patterns in some breeds indicated high levels of inbreeding.
The effects of salt and boron on growth of wheat
Authors: Holloway RE , Alston AM
Published: November 2004

Wheat (Triticum aestivum L. cv. Warigal) was grown in a glasshouse in deep pots (0.125 x 0.125 x 1.2 m) containing sieved solonized brown soil (calcixerollic xerochrept) comprising 0.2 m sandy loam topsoil above 0.6 m treated calcareous sandy loam subsoil and a base layer of light clay 0.26 m thick. The subsoil was treated with a mixture of salts (0, 13, 39, 75 mmolc kg-1) and with boric acid (0, 20, 38 and 73 mg B kg-1) in factorial combination. The soil was initially watered to field capacity and water use was determined by regularly weighing the pots. The soil was allowed to dry gradually during the season, but the weights of the pots were not permitted to fall below that corresponding to 17% of the available water holding capacity of the soil. Tillering, dry weight of shoots and grain, and root length density were determined. Water-use efficiency was calculated with respect to total dry weight and grain production. Salt decreased tillering, dry matter production, grain yield, root length and water-use efficiency (total dry weight): it increased sodium and decreased boron concentrations in the plants. Boron decreased dry matter production (but not tillering), grain yield, root length and water-use efficiency (total dry weight and grain yield): it increased the concentrations of boron and decreased the concentration of sodium in the plants. At the concentrations of salt and boron used (which cover the range normally encountered in subsoils in much of Upper Eyre Peninsula), boron had more deleterious effects on wheat than did salt. Yield was depressed by salt at concentrations of sodium in the tissue commonly found in field-grown plants.
Sodium chloride and soil texture interactions in irrigated field grown sultana grapevines. II. Plant mineral content, growth and physiology
Authors: Prior LD , Grieve AM , Cullis BR
Published: November 2004

Effects of salinity on the mineral composition, growth and physiology of field-grown sultana grapevines were studied by adding NaCl solution to River Murray water. Five salt treatments, ranging between 0.37 and 3.47 dS m-l, were applied for six seasons. Petiole levels of Cl and Na were better predictors of yield than were lamina levels. There was no evidence of safe threshold salinity levels, so grapevine growers should aim to keep tissue salinity levels as low as possible, certainly below 1.5% and 0.5% for petiole Cl and Na respectively. Yield was affected not only by the salinity of the tissue in the current season, but also by tissue salinity in the preceding seasons. A model was developed which included previous tissue salinity measurements. Salt treatment reduced all growth parameters measured-pruning weight, shoot length, cane number and leaf and petiole weight. Decreases in stomatal conductance and photosynthesis were measured in the field in leaves of salinised vines, but leaf water potential was not affected. These decreases in photosynthetic rate are the probable cause of the severe yield and growth reductions in salinised vines.
Vesicular-arbuscular mycorrhiza in semi-arid pastures of south-west Queensland and their effect on growth responses to phosphorus fertilizers by grasses
Authors: Armstrong RD , Helyar KR , Christie EK
Published: November 2004

Field and controlled environment studies were undertaken to determine the seasonal variation in vesicular-arbuscular mycorrhizal (VAM) propagules under different types of vegetation in the mulga (Acacia aneura) shrublands of south-western Queensland and how inoculation with VAM affects the growth and response to phosphorus fertilizers of several grasses common to this region. A most probable number (MPN) technique was used to estimate the number of viable VAM propagules under mulga shrubland and native pasture. There was a pronounced rise in MPN at a native pasture site from June to November, peaking at 1 propagule/g soil, before declining between November and May to non detectable concentrations. In the mulga shrubland site, MPN remained very low (less than 0.2 propagules/g soil) throughout the study. Pasture species in the field were screened for VAM infection in both winter and summer. Only three of the 14 species sampled were infected with VAM in winter (June) after a long drought. In contrast, 10 of the 14 species sampled in December possessed VAM-infected roots. A pot experiment was conducted to examine the influence of VAM inoculation on growth and the response to phosphate fertilizer of several important pasture grasses in pastures derived from mulga shrublands. The treatments comprised a factorial combination of inoculation or non-inoculation with VAM, four grass species (Aristida armata, Cenchms ciliaris cv. USA, Digitaria ammophilla, and Thyridolepis mitchelliana), and four rates of P fertilizer designed to range over very deficient to non-limiting for each species. All species except D. ammophilla produced growth responses to VAM inoculation. Though C. ciliaris and T. mitchelliana responded to VAM inoculation only in soil unamended with P fertilizer, A. amata showed growth responses across all P rates examined, suggesting some factor other than P was limiting this species. The growth response of the grasses to VAM inoculation was poorly correlated with the percentage of root infected with VAM. D. ammophilla had the highest levels of root infection (32%) despite producing no growth response to VAM. In contrast, T. mitchelliana had less than 2% of the root infected with VAM. All species had thin fibrous roots with long (0.35-0.47 mm), frequent root hairs. The differential growth responses to VAM inoculation of A. armata compared with the other grasses may provide a management strategy to control Aristida ingress into pastures established from mulga shrublands.