bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of initial soil water content and application of water on urea applied to pasture
Authors: Mundy GN
Published: November 2004

A 15N study with microplots was conducted to determine the effect of initial soil water content and of water application on the recovery of 15N-labelled urea applied at 60 kg N/ha to a paspalum-dominant pasture. A second experiment with the same pasture type investigated the effects of individual urea granules on soil pH and mineral nitrogen (N) after application to a moist soil with and without follow up rain and to wet soil without follow up rain. The 15N balance showed that initial soil water content and 10 mm of simulated rainfall affected the recovery of 15N in the soil/pasture. Fertilizer recovery was lowest (79%) from dry soil (evaporation minus rainfall (ER) 50 mm) without rainfall, but when the initial soil water (ER 25 mm) was higher, the recovery of fertilizer was greater. Simulated rainfall (10 mm) after urea application to the dry soil increased urea recovery to 90%. The recovery of applied 15 N was greater than 90% following the application of the urea to saturated soil (E-R 0 mm) and was comparable to the recommended procedure of irrigation after application. In experiment 2, the initial soil water content and follow up rain (10 mm) were important factors affecting soil pH and mineral N concentrations at urea granule sites after urea was applied to soil. Urea increased soil pH of granule sites to more than 8.5 in moist soil, but with 10 mm of rain or with wet soil, pH only reached 7.6. Similar effects with soil mineral N were also measured. The effects of these changes in pH and mineral N are discussed in relation to recovery of urea applied to pasture soil.
Adaptability and virulence specificity in Australian strains of blackleg [Leptosphaeria maculans (Desm.) Ces. et De Not.] on different host genotypes of rapeseed (Brassica napus L.)
Authors: Pang ECK , Halloran GM
Published: November 2004

Five clone-lines of rapeseed (Brassica napus L.) were artificially inoculated with 24 isolates of blackleg (Leptosphaeria maculans (Desm.) Ces. et De Not.) from 12 sites around Australia to determine the proportion of virulence genes in L. maculans which interacted with genes for specific resistance in B. napus. Resistance/susceptibility was evaluated both as external lesion size (%G) and internal lesion area (%II) of individual plants of the clone-lines. Using two different regression techniques (stability analysis) involving levels of infection caused by the isolates on the clone-lines, isolates were ranked according to levels of specific virulence. There were differences in stability between isolates in their capacity to exhibit consistent virulence over the range of genotypes used. Using deviations from regression as an indicator of the proportion of genes for specific- and non-specific virulence, it was observed that a third of all isolates used possessed significant levels of specific virulence. The significance of this finding in relation to glasshouse screening programs for blackleg resistance is discussed.
Vernalization responses in narrow-leafed lupin (Lupinus angustifolius) genotypes
Authors: Landers KF
Published: November 2004

Three experiments were conducted to characterize vernalization response in 13 diverse narrowleafed lupin (Lupinus angustifolius) genotypes, and to identify the genetic basis of differences in vernalization response. The aim was to better understand how flowering time may be manipulated in lupin breeding. The genotypes consisted of breeding lines with parents of wild origin, plus selected commercial varieties. Treatments included response to different periods of vernalization and response to different sowing dates. Most of the genotypes required vernalization for flowering. There were three types of response to vernalization observed; an absolute requirement, a reduced response, in which vernalization did not appear to be essential for flowering, and no response in lines carrying the natural mutant gene Ku (Gladstones and Hill 1969). In genotypes with an absolute requirement for vernalization, the period of vernalization at 5�C required to ensure flowering varied between 2 and 4 weeks, and flowering was hastened by increasing periods of vernalization. When vernalization was marginally inadequate, abnormal inflorescences formed. An apparent thermosensitive response, in which vernalization hastened flowering but did not appear to be essential, occurred in cv. Wandoo, which carries the gene �efl�. This response could also possibly be explained not by the lack of an essential requirement for vernalization, but by an ability of the cultivar to respond to vernalization at fairly high temperatures, around 16�C. Crossing studies identified a major gene the same as or allelic to �efl� in one genotype, but no other single genes with major effect on vernalization response were detected in genotypes of wild origin.
Changing sink strengths influence translocation of phosphonate in avocado (Persea americana Mill.) trees
Authors: Whiley AW , Hargreaves PA , Pegg KG , Doogan VJ , Ruddle LJ , Saranah JB , Langdon PW
Published: November 2004

Translocation of phosphonic acid (H3PO3) in cv. Hass avocado trees was studied after trunk injection with 20% H3PO3, formulated as potassium phosphonate, at three stages of tree phenology during the growing season. Initially, translocation was solely acropetal in the xylem, and H3PO3was detected in the leaves 24 h after treatment. Several days after injection, H3PO3concentration in the bark of trunks and in roots increased, indicating basipetal phloem transport of H3PO3from leaves. The rate of accumulation and the final concentration of H3PO3in the roots were directly related to the sink strength of the shoot at the time of injection. For example, trunk injection at the beginning of spring growth flush, when renewal shoots were strong sinks, resulted in low H3PO3root concentrations (<9 8g gfw-1) which peaked about 45 days after treatment. When potassium phosphonate was injected after the transition of spring-grown shoots from sinks to sources, or at summer shoot maturity, root concentrations of H3PO3increased to >25 8g gfw-1 by 30 days after treatment. These results suggest that strategic timing of injections according to phenological events may greatly improve fungicide efficacy when targeting specific organs for protection.
The productivity of lactating dairy cows grazing white clover and supplemented with maize silage
Authors: Stockdale CR , Dellow DW
Published: November 2004

Ten grazing studies were undertaken in which lactating cows either grazed limited amounts of pure white clover (Trifolium repens cv. Haifa) alone, or were supplemented with 3.4-5.0 kg DM/cow day-1 of maize silage. Marginal returns to additional feeding were 0.58 and 1.03 kg of 4% fat-corrected milk/kg of total DM in spring/early summer (when cows were producing >20 kg milk/day) and autumn (when cows were producing <20 kg milk/day) respectively. While the responses from the lower producing cows were exceptionally good, the relativity between the two groups of cows was contrary to normal expectations; an increase in feeding should result in a greater response from the higher producing cows. The protein level in the clover diet was only slightly lower (23 v. 25%) in spring/summer than in autumn, yet this was associated with significantly (P < 0.05) lower mean rumen ammonia concentrations (114 v. 190 mg/L), indicating that rumen degradable protein may have limited the utilization of energy from maize silage in spring/summer. This is supported by higher faecal nitrogen concentrations recorded in spring/summer. Concentrations of condensed tannins in clover were also higher in spring/summer than in autumn (0.7 v. 0.2%). It is suggested that a significant proportion of the clover protein complexed with the condensed tannins occurring in the flowers present in the sward in spring/summer.
Field leaching and degradation of soil applied herbicides in a gradationally textured alkaline soil: chlorsulfuron and triasulfuron
Authors: Stork PR
Published: November 2004

A bioassay method was used to monitor changes in the leaching and degradation of chlorsulfuron and triasulfuron in a field experiment on a gradationally textured alkaline cropping soil. Following application in May 1991, it was estimated that approximately 46% of chlorsulfuron and 21% of triasulfuron were leached beyond 50 cm by late winter 1991 with 103 mm of cumulative rainfall. No leaching was detected from mid spring 1991 to early autumn 1992. During this time the sulfonylureas were rapidly degraded, with a 50% reduction in residues complete by 80 days. The degradation was increased by increasing soil temperatures and not constrained by lowering soil water contents. Leaching of the sulfonylureas took place again in the following growing season, between late autumn and mid spring 1992, where trace quantities of the herbicides moved from shallower depths to reaccumulate at higher levels, deeper in the soil profile. A part of these residues still remained within the 20-30 cm, 30-40 cm and 40-50 cm soil layers at mid spring 1992, after 344 mm of growing season rainfall. The residues were in the range 0.1 to 0.4 ng g-1 soil of chlorsulfuron and triasulfuron, for this last sampling taken approximately 18 months after the commencement of the experiment. These residue levels are known to be phytotoxic to leguminous crop and pasture species, and oilseed crop species.
Some aspects of constraint to forage consumption by ruminants
Authors: Weston RH
Published: November 2004

Various aspects of forage intake regulation are discussed with the objective of providing a basis on which assessments could be made of (i) the scope for forage intake manipulation, and (ii) priority areas for further research. A simple conceptual model of the regulation is presented which permits the linking of rumen function and energy metabolism. It takes cognizance of upper physiological limits for (i) energy disposal, (ii) the clearance of digesta organic matter from the rumen, and (iii) muscular fatigue, as well as a range of dietary and environmental constraints. The transmission to the brain of signals relating to amount of digesta in the rumen and the ruminant's energy deficit are considered to be important in the intake regulation. An alternative conceptual model which recognises the amount of energy in the circulating energy pool, rather than the energy deficit, as the origin of signals relating to energy metabolism, is also discussed. It is considered that over a range of forage qualities neither the rumen digesta load ceiling nor the capacity to use energy limit intake; in this range both the resistance of the forage organic matter to removal from the rumen and the net energy value of the forage act as constraints. A method to calculate forage intake constraint is presented, and theoretical relationships between rumen digesta load, net energy intake, energy deficit and forage intake constraint have been formulated to facilitate interpretation of data obtained in forage intake studies. Forage intake in the reproduction cycle is discussed in the context of an optimum nutritional strategy for ensuring species survival. It is considered that the intake changes at mating and immediately prior to parturition, together with the decrease in rate of nutrient storage in maternal reserve tissues in late pregnancy and the use of these tissue stores in early lactation, are consistent with such a strategy. In this context it is suggested that (i) the relevant reproduction hormones affect intake via modulation of the metabolism of the maternal tissue stores and (ii) this type of regulation and its accompanying production losses need not be necessary in those production systems permitting some control of nutrition.
Plant and animal constraints to voluntary feed intake associated with fibre characteristics and particle breakdown and passage in ruminants
Authors: Wilson JR , Kennedy PM
Published: November 2004

Effects of artificial shading to 50% sunlight of nitrogen (N) limited tropical pastures of different grass species on a high (clay loam) and low (granitic loam) fertility soil type were evaluated in a semi-arid. subtropical environment over 3 years. The hypothesis was tested that shade can stimulate shoot growth by providing a modified environment more conducive to organic matter breakdown leading to increased mineralisation and availability of soil N, and the ability of tropical grasses to take advantage of this effect was examined. Unfertilised pastures of green panic (Panicum maximum var. trichoglume), buffel (Cenchrus ciliaris). rhodes (Chloris gayana), and speargrass (Heteropogon contortus) in full sun or shaded by sarlon cloth were sampled on 9 occasions. Additional green panic plots on both soils were irrigated for the first 2 years, and all other plots were dependent on natural rainfall. Shoot and root dry matter and N yield, and soil nitrate and ammonia N, were measured. In one set of green panic plots on each soil, canopy. litter, and surface soil temperatures were monitored continuously, and soil moisture at different depths was measured fortnightly. Shade stimulated shoot dry matter yield over the 3 years by up to 37% in green panic. 22% in rhodes, and 9% in speargrass. Shade decreased buffel yield on the clay soil but had no effect on the granitic soil. Relative increases in yield of shoot N were similar to those for shoot dry matter, except for buffel on the granitic soil where N yield was increased by 39% with no increase in shoot growth. Positive shade responses occurred in all 3 years but were reduced by extreme drought in year 3, particularly on the clay soil. Irrigation gave a greater shade response on the clay but not on the granitic soil. Root mass was lower under shade than in full sun. but there was no long-term trend of progressive decrease. and the change in N yield of roots did not appear to explain the gain in shoot N of the shaded pastures. Nitrogen percentage in the youngest expanded leaf was higher in the shade than the sun leaves only after about 2 to 2 5 months of shading. Surface soil nitrate and ammonia concentrations tended to be higher under shade for most harvests. Shade lowered temperature extremes of surface soil and litter by up to 10-12�C, and improved soil water status. compared with the sun plots. Soil water data were analysed to separate effects on plant water stress and soil microbial activity. The consistent positive response of shoot N yield to shade across grass species. weeds, and soil type. the delay in it becoming evident, and its longevity all support the hypothesis that shade enhances organic matter breakdown and N cycling. Harsh surface temperatures and low soil moisture in open sun pastures appear inimical to high microbial activity. Implications for pasture management are discussed. with the caveat that the outlined benefits of artificial shade may not necessarily arise with tree canopies.
Growth of shoots and roots, and interception of radiation by wheat and lupin crops on a shallow, duplex soil in response to time of sowing
Authors: Gregory PJ , Eastham J
Published: November 2004

Crops of lupin (Lupinus angustifolius L. cv. Gungurru) and wheat (Triticum aestivum cv. Kulin or Spear) sown close to the break of the season and 3-6 weeks later were grown on a duplex soil at East Beverley, WA, over 3 seasons. The overall aim of the work was to examine the influence of time of sowing on growth and water use of the crops, and this paper reports their growth and yield. Early sowing resulted in greater shoot weight of all crops (up to 2.8 t/ha for lupin and 1.7 t/ha for wheat at maturity) and grain yield of lupin, but grain yield of wheat was increased in only 1 of the 3 seasons. The principal effect of the delayed sowing was to reduce the duration of linear growth; the rate of the initial exponential phase was slightly reduced by later sowing as was the rate of growth during the linear phase in lupin (by about 1.5 g/m2day) but not in wheat. Late sowing generally reduced both the number of pod/ears per unit area and the number of grains per pod/ear. Doubling the density of sowing in one of the seasons had no effects on the shoot weight and grain yield of lupin with early or late sowing but decreased those of wheat. Downward root growth of early-sown crops averaged 5.2 mm/day for lupin and 8.7 mm/day for wheat in the 3 seasons and ceased at about 0.8 m; time of sowing had no effect on these measures. Root weight at flowering was greater in lupin than in wheat crops, and root weight of lupin was about 0.5 of total plant weight during vegetative growth compared with 0.25-0.3 in wheat. Typically, only 5-6% of the root length of both crop species was present in the clay layer at flowering irrespective of sowing time. The proportion of radiation intercepted reached a higher maximum value for early-sown crops (about 0.75 in 1991 and 0.90 in 1992) than late-sown crops (about 0.60 in 1991 and 0.8 in 1992). The conversion coefficients of radiation to dry matter were very similar (about 1.8 g/MJ) for both species, but the greater partitioning of dry matter to roots in lupin than wheat meant that conversion coefficients for shoot dry matter were greater in wheat (1.43-1.68 g/MJ) than in lupin (0.93-1.16 g/MJ). The results demonstrate that early sowing produced larger crops of both lupin and wheat; this resulted in larger lupin yields, but yield of wheat was affected by disease and drought during grain filling.
Incidence and measurement of autumn seed softening within Medicago polymorpha L
Authors: Taylor GB
Published: November 2004

Softening of hard seeds during autumn rather than summer is a desirable characteristic for reducing seed losses in annual legumes from false breaks of season in Mediterranean environments. The incidence of this characteristic in Medicago polymorpha L. was determined in 34 lines grown at Toodyay, Western Australia, in 1993 and collected in December. Patterns of seed softening during summer and autumn 1993-94 were studied in pods placed on the soil surface in the field at Merredin, and in laboratory and glasshouse simulations at Perth. Summer seed softening was simulated in the laboratory by the removal of seeds from pods by hand, subjecting them to a diurnally fluctuating temperature of 60/15�C for 16 weeks, and testing their permeability. Residual hard seeds were subjected to 4 gradual diurnal temperature fluctuations of 35/10�C and re-tested for permeability as a measure of autumn seed softening. In the glasshouse study, pods were placed on the surface of soil in boxes, and emerged seedlings were counted after watering in March and June. Field softening in the first year ranged from 6.8 to 69.6%, but exceeded 40% in only 6 of the 34 lines. Proportions of total soft seeds present in the field in June that had softened after 1 March in the 34 lines were normally distributed, and ranged from 2.5 to 78.7%. The laboratory simulation markedly underestimated both autumn and total seed softening in 13 of the lines but effectively predicted field softening behaviour in the other 21 lines. The glasshouse technique overestimated the proportions of seeds softening in autumn in most lines and underestimated total softening in 12 of the 34 lines. A technique involving the use of a rain-out shelter is proposed for routine determination of the incidence of autumn seed softening in medic evaluation programs.
Breed differences in the fatty acid composition of subcutaneous and intramuscular lipid of early and late maturing, grain-finished cattle
Authors: Siebert BD , Deland MP , Pitchford WS
Published: November 2004

Fatty acid composition was measured in lipid extracted from adipose tissue and muscle collected at slaughter from 6 groups of crossbred cattle of about 2 years of age, grain-finished in a feedlot. The cattle ranged in biological type from late to early maturing. They were progeny of the following crosses: Charolais x (Simmental.Hereford), Simmental x (Simmental.Hereford), Charolais x (Jersey.Hereford), Hereford x Hereford, Hereford x (Jersey.Hereford), Jersey x Hereford. The fat content of muscle from the leanest late-maturing cross was 5.2% rising to 10.4% in the fattest early-maturing cross. There was no significant difference in the fatty acid composition of subcutaneous fat between the 6 crosses, but there was in the concentration of some of the fatty acids of intramuscular lipid. The latter was due on one hand to the increased deposition of neutral lipid in early-maturing animals and on the other to a higher proportion of polyunsaturated fatty acids in membrane phospholipid in late-maturing animals. The proportions of the monounsaturated fatty acids palmitoleic (C16:l) and oleic (C18:l) were higher in the early-maturing Jersey x Hereford crosses than in straight-bred Herefords or the other crosses, but only in the C16:l values was there a significant difference between breeds. There was also a significant difference between breeds in the sum of monounsaturates and the sum of polyunsaturates in intramuscular fat. The Jersey crosses had the highest level of monounsaturates and the lowest level of polyunsaturates. Intramuscular phospholipid was examined in the 2 breeds that were the most divergent in terms of intramuscular fat content, the Charolais x (Simmental.Hereford) and the Jersey x Hereford. The latter had significantly higher C16:l values and significantly lower C18:2 and polyunsaturate fatty acid values. The experiment demonstrated that breed differences occurred in fatty acid composition of muscle total lipid and phospholipid. The differences are of significance in human health and in identifying maturity breed-types of cattle.
Fatty acid profile of adipose tissue and performance of feedlot steers supplemented with dehulled cottonseed and sunflower seed meal protected from ruminal metabolism
Authors: Gulati SK , Ashes JR , Ryde I , Scott TW , Brown GH , Rich AC , Rich JC
Published: November 2004

The effect of feeding dehulled cottonseed protected from ruminal metabolism (PCS). Together with supplements of protected sunflower seed meal (PSM), on the performance and fatty acid profile of adipose tissue in feedlot steers was examined. Sixty-two Hereford cross steers, average weight 470 kg, were assigned to 4 groups and fed rations based on barley-corn silage for 150 days. The diets offered contained 10% untreated whole cottonseed +6% untreated sunflower seed meal (Group I), 10% PCS + 10% PSM (Group 11), 15% PCS + 10% PSM (Group 111), or 20% PCS + 10% PSM (Group IV). Inclusion of PCS at the level of 10, 15, and 20% together with 10% PSM resulted in an increase (P < 0.01) in dressing percentage together with an improvement in feed conversion ratio. There was a 5-8-fold increase in the proportion of linoleic acid (C18: 2) in omental, perirenal, and subcutaneous fat from cattle fed the PCS supplement. A significant reduction occurred in the proportion of oleic acid (C18: 1 cis), but the percentage of palmitic acid (C16: 0) was not affected; the proportion of stearic acid (C18 : 0) in subcutaneous fat increased with PCS supplementation.
In situ 15N labelling of lupin below-ground biomass
Authors: Russell CA , Fillery IRP
Published: November 2004

This paper describes the use of a cotton-wick method to enrich lupin plants with 15N. The method involved the insertion of a cotton thread through the stem and the submergence of the ends of the cotton thread in a solution of highly enriched 15N urea. The distribution of 15N in lupin plant components during pre-reproductive growth and pod filling. and in relation to the frequency of labelling, was determined. The recovery of applied 15N within plant tissues was close to 100% for lupins grown in solution culture, but 15N was not distributed between plant components in the proportions observed for total plant N. Stems and leaves were preferentially labelled with 15N irrespective of the phase of lupin growth when the 15N was applied. Pre-reproductive and mature lupin root biomass was depleted in 15N because of the poor assimilation of 15N within lupin nodules. More applied 15N was found in the root biomass of lupin plants that received fortnightly, compared with weekly, applications of 15N. The distribution of 15N between lupin components was reproducible when 15N-urea was wick-applied to plants of the same age. Recovery of 15N was incomplete when urea was fed to lupins grown in sand culture. Incomplete recovery of root material and loss of 15N associated with root exudates probably contributed to the lower recoveries of 15N in root material in sand compared with solution culture. The ability to manipulate the 15N solution concentration, the volume of solution fed to plants, time of application, and frequency of 15N application underscore the usefulness of the wick technique to label woody legumes with 15N.
Potential adaptation zones for temperate pasture species as constrained by climate: a knowledge-based logical modelling approach
Authors: Hill MJ
Published: November 2004

Potential adaptation zones were modelled for major temperate pasture species using climate data and knowledge-based logical rules. A GIs database was constructed using a 0.025 degree digital elevation model and the Australian Climate Surfaces to create layers of monthly mean climate data for Australia. Soil pH maps for New South Wales, Victoria, and south-eastern South Australia were digitised and added to the database. Simple models using logical operators were constructed using estimates of temperature and aridity thresholds for the main temperate pasture species. The logical models were executed using primary and derived climate layers to create raster maps of potential adaptation zones for pasture species in eastern and south-western Australia. Areas of adaptation on freehold/leasehold land were expressed relative to a potential temperate pasture adaptation zone described by the lower (arid) limit of annual legume adaptation in temperate Australia and the northern limit of lucerne adaptation. Potential adaptation within this area ranged from 66% for lucerne down to <20% for perennial ryegrass in eastern Australia, and 93% for subterranean clover down to zero for perennial ryegrass in south-western Australia. Utility of the species adaptation zones could be enhanced using soil pH maps: a zone for serradella in NSW was refined by restricting adaptation to areas of climatic suitability with low soil pH. Maps for lucerne and Mount Barker subterranean clover showed good agreement with validation data for NSW. The zones may be readily adjusted by simple changes to parameter values in the algorithms. This knowledge-based approach has potential as an aid to targeting resources for plant improvement or to provide advice for more efficient utilisation of existing commercial pasture plants.
Characterisation of the Kangaroo Valley ecotype of perennial ryegrass (Lolium perenne)
Authors: Blumenthal MJ , Prakash K , Leonforte A , Cunningham PJ , Nicol HI
Published: November 2004

A breeding program commenced in 1992 to produce perennial ryegrass (Lolium perenne) cultivars based on the Kangaroo Valley perennial ryegrass (KVPR) ecotype with improved winter and late season growth, disease resistance, and persistence. Perennial ryegrass plants (9000) were collected from 45 sites within the Kangaroo Valley and Shoalhaven flood plain in August 1992. Using principal component analysis, site differences were greatest for N percentage, Mg and Na concentration, and A1 saturation. Collections were space planted along with standard cultivars (Banks, Ellett, Embassy, Grasslands Lincoln, and Vedette) at Berry, New South Wales (34�48'S), and Timboon, Victoria (38'32'S), with 50 treatments and 10 replicates. Plants were visually scored for seasonal yield, rust incidence, greenness, leafiness, persistence, habit, and tiller density at both sites. At Berry, leaf angle, leaf width, and heading date were determined. Despite the differences in moisture, temperature, and growth indices between the 2 test sites, seasonal yield scores (mean of 100 plants) at Berry and Timboon were highly genetically correlated (r = 0.79-0.99). Standard cultivars were higher yielding with higher tiller density but with a greater rust incidence than collections (P < 0.01). Collections originating from the Shoalhaven flood plain were higher yielding with greater tiller density than plants from the Kangaroo Valley (P < 0.01), although differences were not as great as site of origin differences would suggest. Selections have been made for polycross half-sib formation, and half-sib evaluation will take place at a number of sites to determine the average general combining ability of parent selections for synthetic cultivar production.
Effectiveness of liming to minimise uptake of cadmium by wheat and barley grain grown in the field
Authors: Oliver DP , Tiller KG , Conyers MK , Slattery WJ , Alston AM , Merry RH
Published: November 2004

The effects of soil pH on cadmium (Cd) concentration in wheat and barley grain were determined from 8 field experiments in the Rutherglen (Victoria) and Wagga Wagga (New South Wales) regions of south-eastern Australia. Generally, raising soil pHc, from 4.0 to 5.0 using lime decreased Cd concentration in the grain. However, the response was variable between sites and years, with the greatest variation occurring between years. At those sites where there were statistically significant decreases in Cd concentration with increasing pH, the rate of decrease was small. The Cd concentration exceeded the maximum permissible concentration (MPC) of 0.05 mg/kg in barley grain at 3 sites and in wheat at 1 site. In some cases, raising soil pHCa, to 6.0 was not sufficient to decrease Cd concentration in grain below the MPC and raising soil pH above this value would not be considered economically viable in many areas.
Selection programs for fleece rot resistance in Merino sheep
Authors: Cottle DJ
Published: November 2004

Midside wool samples can be measured for predictive colour (PC colour, acetone extract colour after incubation), incubated colour (IYZ colour, yellowness reflectance of wool after incubation; IY colour, brightness), average fibre diameter (FD), FD variability (FDCV, coefficient of variation; FDSD, standard deviation), potassium (K) content of water extract, and pH of water extract. These characteristics were assessed for their potential as indirect selection criteria for fleece rot (FR) resistance on midside wool samples from 2095 Merino hoggets representing the progeny from 84 sires in 7 sire evaluation schemes. Indirect selection can be superior to direct selection, in terms of increasing FR resistance, when FR incidence is low. The indirect traits with the highest phenotypic correlations with hogget FR liability, calculated from a 2-category (incidence) model, were clean fleece weight (CFW), FDCV, and FD. Based on combined estimates of the heritability of the indirect trait and its genetic correlation with FR score (0-5), the traits that showed the highest relative potential (RP, the estimated gain from selecting on the indirect trait relative to the gain from direct selection at the same selection intensity) were FD, pH, FDSD, and CFW. The RP value, however, takes no account of the responses in other economic traits or the costs of selection. As FR score increased, there was a linear increase in mean CFW and FDCV and a decrease in FD. Changes in other trait means with FR score followed inconsistent pat terns. By calculating selection indices, it was shown that the use of indirect criteria in ram selection increased the response in breeding objective in a self-replacing flock by $0.01-0 15/ ewe lifetime. year (based on selecting 5% of hogget rams/year). These increases were restricted by the undesirable correlations of FR score with the main economic traits, i.e. sheep with high CFW and low FD were predicted to breed sheep more susceptible to FR. Selection programs based on CFW, FD, FDSD, and FDCV with or without FR score were the most economic single-stage selection options studied. There was a lower but positive estimated net financial benefit, after 10 years of selection, when all ram hoggets were measured for CFW, FD, FDSD, FDCV, and IYZ colour and assessed for FR score in a single-stage selection program. As expected, 2-stage selection was more cost-effective than single-stage selection. The most economic 2-stage option studied was to measure CFW, FD, FDSD, and FDCV and assess FR score on all hoggets at stage 1 then measure the best 7-10% (on Index) for IYZ colour. The best 5% of all hoggets were then selected at stage 2 for joining on the basis of an index that included CFW, FD, FDSD, FDCV, HFS, and IYZ colour.
The genetic foundation of fitness and reproduction traits in Australian pig populations. 2. Relationships between weaning to conception interval, farrowing interval, stayability, and other common reproduction and production traits.
Authors: Tholen E , Bunter KL , Hermesch S , Graser HU
Published: November 2004

Data sets from 2 large Australian piggeries were used to estimate genetic parameters for the traits weaning to conception interval (WCIi-l,i) and farrowing interval (FIi-l,i), number born alive (NBAI), average piglet birthweight (BWi), 21-day litter weight (W21i), and sow stayability (STAYli) recorded for each ith parity, as well as sow average daily gain (ADG) and backfat (BF) recorded at the end of performance test. Over parities and herds, heritabilities for each trait were in the ranges: WCI/FI, 0.0-0.10; NBA, 0.09-0.16; BW, 0.11-0.35; W21, 0.12-0.23; STAYli, 0.02-0.09; ADG, 0.35-0.37; BF, 0.36-0.45. Genetic correlations between NBAl and NBA from later parities were significantly different from 1. In addition, in 1 herd negative genetic correlations (rg = -0.04 to -0.25) were found between sow stayability traits and NBA1, but not NBA recorded in later parities. Stayability was Unfavourably correlated with ADG and BF, and favourably correlated with WCI12. However, WCI12 was unfavourably correlated genetically with BF (rg = -0.24) but uncorrelated with ADG. Antagonistic relationships also existed between NBA and BW, NBA and W21, and BW and STAY. In addition to the traditional traits currently included in pig-breeding programs (e.g. ADG, BF, and NBA), traits such as WCI, BW, and STAY should also be considered as selection criteria to minimise the detrimental effects of antagonistic genetic relationships between traits.
Effects of species, plant part, and plant age on the n-alkane concentrations in the cuticular wax of pasture plants.
Authors: Dove H , Mayes RW , Freer M
Published: November 2004

Plants of the pasture species Phalaris aquatica cv. Sirosa, Lolium perenne cv. Victorian, Trifolium repens cv. Irrigation White, T. subterraneum ssp. subterraneum cv. Mt Barker, T. subterraneum ssp. yanninicum cv. Trikkala, and Medicago sativa cv. Siriver were grown under controlled glasshouse conditions. At weekly intervals, 6 plants of each species were harvested and dissected into their component plant parts. The concentrations of n-alkanes in plant parts from all species were then estimated using gas chromatography. Results confirmed earlier studies that alkanes with odd-numbered carbon chains were predominant in cuticular wax, especially C27, C29, C31, and C33 alkanes. For the individual alkanes (225433, differences between species accounted for 85% of the total variance in alkane concentration. Calculation of similarity coefficients indicated that the greatest similarities in the pattern of alkane concentrations occurred either between plant parts within a species or between the same plant part in closely related species. Multivariate statistical analysis using canonical variates analyses indicated that despite these similarities, it would still be possible to distinguish both plant species and plant parts in mixtures of these components. In particular, an examination of hypothetical perennial ryegrass-white clover or phalaris-subterranean clover pastures demonstrated that all fractions of all species would be likely to be distinguishable. The results are discussed in relation to the use of herbage and faecal alkane concentrations in least-squares estimates of the composition of the diet of the grazing animal.
Partitions with difference conditions and Alder's conjecture
Authors: Yee Ae Ja
Published: November 2004

In 1956, Alder conjectured that the number of partitions of
n
into parts differing by at least
d
is greater than or equal to that of partitions of
n
into parts ≡ ±1 (mod
d
+ 3) for
d
≥ 4. In 1971, Andrews proved that the conjecture holds for
d
= 2

r

– 1,
r
≥ 4. We sketch a proof of the conjecture for all
d
≥ 32.
α,β hybrid peptides: A polypeptide helix with a central segment containing two consecutive β-amino acid residues
Authors: Roy Rituparna S. , Karle Isabella L. , Raghothama S. , Balaram P.
Published: November 2004

Conformational studies on the synthetic 11-aa peptide
t
-butoxycarbonyl (Boc)-Val-Ala-Phe-α-aminoisobutyric acid (Aib)-(
R
)-β
3
-homovaline (βVal)-(
S
)-β
3
-homophenylalanine (βPhe)-Aib-Val-Ala-Phe-Aib-methyl ester (OMe) (peptide 1; βVal and βPhe are β amino acids generated by homologation of the corresponding
l
-residues) establish that insertion of two consecutive β residues into a polypeptide helix can be accomplished without significant structural distortion. Crystal-structure analysis reveals a continuous helical conformation encompassing the segment of residues 2–10 of peptide 1. At the site of insertion of the ββ segment, helical hydrogen-bonded rings are expanded. A C
15
hydrogen bond for the αββ segment and two C
14
hydrogen bonds for the ααβ or βαα segments have been characterized. The following conformational angles were determined from the crystal structure for the β residues: βVal-5 (φ = –126°, θ = 76°, and ψ = –124) and βPhe-6 (φ =–88°, θ = 80°, and ψ =–118). The N terminus of the peptide is partially unfolded in crystals. The 500-MHz
1
H-NMR studies establish a continuous helix over the entire length of the peptide in CDCl
3
solution, as evidenced by diagnostic nuclear Overhauser effects. The presence of seven intramolecular hydrogen bonds is also established by using solvent dependence of NH chemical shifts.
Glyceraldehyde 3-phosphate dehydrogenase-S, a sperm-specific glycolytic enzyme, is required for sperm motility and male fertility
Authors: Miki Kiyoshi , Qu Weidong , Goulding Eugenia H. , Willis William D. , Bunch Donna O. , Strader Lillian F. , Perreault Sally D. , Eddy Edward M. , O'Brien Deborah A.
Published: November 2004

Although glycolysis is highly conserved, it is remarkable that several unique isozymes in this central metabolic pathway are found in mammalian sperm. Glyceraldehyde 3-phosphate dehydrogenase-S (GAPDS) is the product of a mouse gene expressed only during spermatogenesis and, like its human ortholog (GAPD2), is the sole GAPDH isozyme in sperm. It is tightly bound to the fibrous sheath, a cytoskeletal structure that extends most of the length of the sperm flagellum. We disruptedGapdsexpression by gene targeting to selectively block sperm glycolysis and assess its relative importance forin vivosperm function.Gapds–/–males were infertile and had profound defects in sperm motility, exhibiting sluggish movement without forward progression. Although mitochondrial oxygen consumption was unchanged, sperm fromGapds–/–mice had ATP levels that were only 10.4% of those in sperm from WT mice. These results imply that most of the energy required for sperm motility is generated by glycolysis rather than oxidative phosphorylation. Furthermore, the critical role of glycolysis in sperm and its dependence on this sperm-specific enzyme suggest that GAPDS is a potential contraceptive target, and that mutations or environmental agents that disrupt its activity could lead to male infertility.
Probabilities of spurious connections in gene networks: application to expression time series
Authors: Bickel David R.
Published: November 2004

Motivation: The reconstruction of gene networks from gene-expression microarrays is gaining popularity as methods improve and as more data become available. The reliability of such networks could be judged by the probability that a connection between genes is spurious, resulting from chance fluctuations rather than from a true biological relationship.

Results: Unlike the false discovery rate and positive false discovery rate, the decisive false discovery rate (dFDR) is exactly equal to a conditional probability without assuming independence or the randomness of hypothesis truth values. This property is useful not only in the common application to the detection of differential gene expression, but also in determining the probability of a spurious connection in a reconstructed gene network. Estimators of the dFDR can estimate each of three probabilities: (1) The probability that two genes that appear to be associated with each other lack such association. (2) The probability that a time ordering observed for two associated genes is misleading. (3) The probability that a time ordering observed for two genes is misleading, either because they are not associated or because they are associated without a lag in time. The first probability applies to both static and dynamic gene networks, and the other two only apply to dynamic gene networks.

Availability: Cross-platform software for network reconstruction, probability estimation, and plotting is free from http://www.davidbickel.com in Statomics, a suite of R functions with a Java application.

Contact:  bickel@prueba.info

Supplementary information: Color figures are available from http://www.davidbickel.com
Spatial accessibility and equity of playgrounds in Edmonton, Canada
Authors: Smoyer‐Tomic Karen E. , Hewko Jared N. , Hodgson M. John
Published: November 2004

Assessing spatial equity with respect to urban public amenity provision involves examining the association between amenity distribution and population need for amenities. Geographic Information Systems in coordination with local spatial autocorrelation, were used to investigate the association between neighbourhood accessibility to playgrounds and demographic and social need for playgrounds in Edmonton, while considering differences in playground quality throughout the city. The primary objectives of this study were to assess whether playground provision, for location and quality, in Edmonton is equitable and, more generally, to investigate the role that amenity quality plays in assessing spatial equity. The results indicate that playgrounds are equitably distributed within Edmonton, with the highest‐social‐need neighbourhoods having the greatest accessibility to playgrounds. However, once differences in playground quality are considered, there is less of an association between high‐social‐need and high‐accessibility areas. The findings suggest that greater attention be paid to differences in playground quality within Edmonton and that spatial equity researchers give greater consideration to amenity quality when evaluating spatial equity within cities.
Dimensions and dynamics of residential segregation by income in urban Canada, 1991–1996
Authors: Ross Nancy A. , Houle Christian , Dunn James R. , Aye Marcellin
Published: November 2004

This paper examines the trends in residential segregation by income (post‐transfer, pretax income) in the thirty‐nine largest Canadian urban areas between 1991 and 1996. The study is motivated by the relative lack of attention paid to residential segregation by income in the Canadian context and by conceptual arguments linking compromised life chances and increased social tensions for the populations of highly segregated cities. We investigated several dimensions of segregation using five different measures (we focus on three of these here given the correlation structure of the measures) to examine changes in segregation between 1991 and 1996, a period characterised by economic recession, cutbacks in social programs and a widening of inequality in market incomes at the national scale. Overall, income segregation increased in most urban areas across all dimensions of segregation during the time period, with particularly high degrees of segregation observed in prairie cities (Winnipeg, Saskatoon and Regina). Of the three largest metropolitan areas (Vancouver, Toronto and Montréal), Montréal was the most consistently segregated. We also find that increases in spatial separation and spatial concentration by income occurred despite the fact that at the national scale, the tax and transfer system appeared to be adequately redressing a rise in inequality in labour and market incomes (as demonstrated by the lack of change in post‐transfer national income inequality measures during a period when inequality in market and labour incomes rose sharply). This implies that the lived experience of changes in income distribution are unlikely fully captured by aspatial, national‐scale measures and that intra‐urban measures with a spatial dimension are an important indicators of inequality in Canadian society.
Composition and age of the Daohugou hymenopteran (Insecta, Hymenoptera = Vespida) assemblage from Inner Mongolia, China
Authors: Rasnitsyn Alexandr P. , Zhang Haichun
Published: November 2004

Hymenopteran fossils from Daohugou, Inner Mongolia, China are assigned to 17 families. These include, in decreasing order of importance, Ephialtitidae, Xyelidae, Siricidae, Xyelydidae, Anaxyelidae, Karatavitidae s.l., Mesoserphidae, Megalyridae and Praeaulacidae. Analysis of the taxonomic composition suggests that the assemblage is of Mid Jurassic age. The rather low abundance of Xyelidae suggests that the climate in Daohugou during the Mid Jurassic might have been thermally intermediate between that of peri‐Baikal Siberia during the Early/Mid Jurassic transition and southern Kazakhstan during the early Late Jurassic. A new family, Protosiricidae fam. nov., is established herein and the family Gigasiricidae is reduced in rank to Gigasiricinae and referred to the Siricidae.
A new species of the rhinoceros Alicornops from the Middle Miocene of the Linxia Basin, Gansu, China
Authors: Deng Tao
Published: November 2004

A new species of the genus Alicornops, A. laogouense, from Laogou in Hezheng County, Linxia Basin, Gansu, China, is described. It is mid‐sized in the subfamily Aceratheriinae, but is the largest known species of Alicornops. It represents the first discovery of the genus in Asia. The Middle Miocene fauna bearing A. laogouense is contemporaneous with the Dingjiaergou fauna of Tongxin, Ningxia, China, and its age corresponds to MN 6 in Europe. The discovery of A. laogouense in the Linxia Basin implies that Alicornops dispersed from Europe to Asia. During MN 6 times it was relatively widespread throughout Eurasia. Alicornops laogouense lived in open woodland rich in lakes and rivers.
The black layer in cephalopods from the German Muschelkalk (Triassic)
Authors: Klug Christian , Korn Dieter , Richter Ute , Urlichs Max
Published: November 2004

Thin, dark, probably phosphatic coatings were found on the dorsum in front of and sometimes behind the aperture of 50 specimens of Paraceratites and Ceratites (Ammonoidea) belonging to 14 species and subspecies and in three specimens of Germanonautilus, all from the Middle Triassic of Germany. The proportions, occurrences, position, outline, and preservation in fossil Nautiloidea and Ammonoidea (originally organic matter) of this structure support the hypothesis that it is homologous with the black layer in Recent Nautilus and Allonautilus. It is not yet possible to test whether these cephalopods show homologous styles of the development of these structures or whether the black layer can be identified in a common ancestor. In contrast to many ammonoids, Ceratites and Paraceratites, most Palaeozoic ammonoids, and some Mesozoic ammonoids probably did not have lower mandibles that were suitable for the closure of the aperture. They probably possessed a dorsally extending mantle (supracephalic mantle fold) and a hood, as in Recent Nautilus and Allonautilus, that was attached to the black layer. This interpretation is corroborated by a similar morphology of the black layer in an adult specimen of the nautilid Cenoceras from the South German Middle Jurassic and three specimens of Germanonautilus from the South German Middle Triassic (both Nautiloidea).