bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival and fecundity of wild radish (Raphanus raphanistrum L.) plants in relation to cropping, time of emergence and chemical control
Authors: Panetta FD , Gilbey DJ , D'Antuono MF
Published: November 2004

During consecutive seasons, wild radish (Raphanus raphanistrum L.) seedling emergence decreased exponentially with increasing time after the emergence of lupin crops. Initial survival of seedlings was markedly reduced by pre-emergence applications of simazine at 0.75 kg a.i. ha-1. In the absence of herbicide, however, the presence of a lupin crop did not have a negative effect upon early survival. Probabilities of reproduction of wild radish plants decreased with later emergence within treatments; no plants which emerged later than 21 days after crop emergence produced seeds. Seed production by wild radish was considerably higher when lupins were sown late. Regardless of sowing date, the application of triazine herbicides reduced the amount of seeds produced to the point where grain contamination was insignificant. However, the few plants which escaped herbicide treatment produced large numbers of seeds. Virtually no seeds were produced when additional post-emergence applications of simazine (0.375 kg a.i. ha-1) were made. It is argued that the major role of post-emergence application in this crop-weed system is to prevent reproduction by plants which escape the pre-emergence application, rather than to control late-emerging plants.
The narrow-leafed lupin (Lupinus angustifolius L.) as a nitrogen-fixing rotation crop for cereal production. III. Residual effects of lupins on subsequent cereal crops
Authors: Doyle AD , Moore KJ , Herridge DF
Published: November 2004

The effect of the narrow-leafed lupin (Lupinus angustifolius L.) on growth and production of subsequent cereal crops was studied at three sites on the acidic, N-infertile soils of the Pilliga Scrub region of northern New South Wales.Beneficial effects of lupins on dry matter production were evident in either one (Kamala, Florida A) or two subsequent crops of wheat (Florida B). In the absence of fertilizer N, wheat following lupins outyielded wheat following wheat by an average of 57%. At Florida B, the second wheat crop following lupins outyielded the wheat only plots by 35%. The response to lupins was established early in vegetative growth and was essentially maintained. Effects of lupins on grain yields, evident at all sites in the first crop, were maintained at the two Florida sites for a second crop. Increases in the absence of fertilizer-N were between 0.29 and 1.22 t ha-1 (55 and 145%) (crop 1) and as great as 0.39 t ha-1 (38%) in year 2. Barley responded similarly with increases of 127 and 47% in years 1 and 2, respectively. Amounts of fertilizer required to raise the yields of wheat following wheat to those of wheat following lupins ranged between 40 and 80 kg ha-1. Effects of lupins on protein concentration of cereal grains were inconsistent; largest effects were achieved through N fertilization. Both the incidence and severity of root diseases at Florida A were reduced in the rotation plots; the effect persisted into the third wheat crop following lupins. Disease control was not a factor in the lupin effect at Kamala. Nitrogen budgets for the unfertilized wheat-wheat and lupinwheat sequences at Kamala and Florida A indicated that lupin cropping (i) resulted in potential net gains of soil N of 128 (Kamala) and 29 kg ha-1 (Florida A), and (ii) increased N yields of the following wheat crops by 37 (Kamala) and 20 kg ha-1 (Florida A).
Pangola stunt virus infecting pangola grass and summer grass in Australia
Authors: Teakle DS , Hicks S , Harding RM , Greber RS , Milne RG
Published: November 2004

A widespread disease of pangola grass (Digitaria decumbens) and summer grass (D. ciliaris) in south-eastern Queensland was characterized by a bunched and stunted growth habit, yellow or red discolouration of the foliage, seed heads with crimped, distorted racemes, and sometimes premature plant death. Virus-like particles present in extracts of diseased plants were unstable, 50-70 nm in diameter, had a core and outer coat and were morphologically similar to particles of viruses in the genus Fijivirus, family Reoviridae. The particles were shown by immune electron microscopy to be serologically closely related to pangola stunt and maize rough dwarf viruses, but unrelated to oat sterile dwarf virus. Similar virus-like particles were observed in crystalline arrays in ultrathin sections of cells in vein enations of D. ciliaris. Extracts of diseased pangola grass and summer grass contained 10 double-stranded RNA species, which were somewhat similar in size to those reported for pangola stunt virus. A planthopper, Sogatella kolophon, which is related to the South American vector of pangola stunt virus, S. furcifera, was associated with diseased pangola grass and summer grass in the field, and was shown to be a vector. However, efforts to infect maize, a major host of maize rough dwarf virus, were unsuccessful. On the basis of these properties the Australian virus is considered to be pangola stunt virus.
Measurement of functional udder capacity in lactating Jersey cows
Authors: Davis SR , Hughson GA
Published: November 2004

Serial measurements of udder volume in 11 multiparous and 4 primiparous Jersey cows in mid-lactation were used to establish the time of cessation of milk production after a period of milk accumulation. Udder volume was determined from measurements of udder height, length and width. Functional udder capacity (defined as the litres of contained milk in the udder when milk secretion ceased) was greater in cows (15.5 � 0.8 litres) than heifers (9.3 � 0.7 litres). Expressed as hours-worth of secretion, on average, heifers possessed 25.9 � 1.5 and cows 33.6 � 2.9 hours-worth of capacity - data which indicate some potential for reduction in milking frequency without loss of production. Functional udder capacity (l.) was correlated with empty udder volume (tissue volume), and was greater in cows showing high residual milk volumes. The data show that once functional capacity is reached the shut down in milk secretion is rapid, occurring over a 2-4 h period, the rate of accumulation of secretion being constant up to this time.
Fleece rot and body strike in Merino sheep. III. Significance of fleece moisture following experimental induction of fleece rot
Authors: Raadsma HW
Published: November 2004

The relationship between fleece wetting and drying characteristics and liability of sheep to fleece rot and body strike was examined following experimental wetting. The liability of sheep to fleece rot was reflected by both wetting and drying characteristics. Wetness of the fleece was estimated gravimetrically and was found to be a simple, fast and relatively robust technique. Moisture increased from 13% in the dry fleece up to 123% at skin level in sheep exposed from 0 to 10 days' wetting. Consistent differences were reported in proximal and full staple moisture levels between sheep affected and unaffected with fleece rot or body strike. Drying characteristics of individual sheep were recorded by means of an electronic hygrometer in sheep up to 5 days after wetting. A lag phase in the drying of sheep susceptible to fleece rot or bodystrike was recorded, compared with resistant sheep. The most resistant sheep showed a slightly concave drying curve (-12.4% R.H. day-1 + 0.06% R.H. day-2) after wetting, whereas the most susceptible sheep showed a slightly convex drying curve (- 11.4% R.H. day-1 0.05% R.H. day-2). The maximum difference in fleece relative humidity between the two groups of sheep occurred between 1 and 3 days after wetting. Measurement of fleece relative humidity before wetting in the dry fleece, did not predict the liability of sheep to fleece rot and body strike.Moisture levels in the fleece during and immediately following wetting accounted for differences in fleece rot due to experimental treatments and genetic flock differences. Based on a single full-staple moisture measurement of 945 sheep, representing the progeny of 134 sires, the heritability of fleece moisture was 0.28 � 0.12 and had a genetic correlation with fleece rot incidence and severity of 0.74 � 0.24 and 0.79 � 0.19 respectively. Further work should identify fleece components which affect the wetting and drying characteristics of the fleece during the development of fleece rot.
Fate of urea nitrogen applied to irrigated wheat at heading
Authors: Smith CJ , Freney JR , Chapman SL , Galbally IE
Published: November 2004

This paper describes a field experiment designed to determine the fate of urea applied to a semi-dwarf wheat (cv. Matong) at heading. The urea (50 kg N ha-1) was broadcast onto the soil surface and washed into the soil with 22 mm of water applied by sprinkler irrigation. Ammonia (NH3) volatilization was determined by a micro-meteorological method and total nitrogen (N) loss was measured by the 15N balance technique. The effect of the fertilizer application on grain yield and protein content was also assessed.With this method of application the pH of the surface soil remained below 7.2 for the period of the study. The low pH, together with the dense wheat canopy, ensured that no NH3 was volatilized after urea addition.The 15N balance study showed that no N was lost from the plant-soil system between the time of the urea application (127 days after sowing; DAS 127) and the first flood irrigation 5 days later (DAS 132). However, between the first (DAS 132) and second flood irrigations (DAS 141) after fertilization, 12% of the applied 15N was lost, presumably by denitrification. Recoveries of labelled N in the soil plus plants were not significantly different between DAS 141 and harvest (DAS 193); the mean recovery being 84% of the applied N. Neither biomass nor grain yield was significantly increased by the application of urea, but the N concentration of the grain was increased from 2.03 to 2.46%.Applying fertilizer N at heading increased grain protein percentage of this semi-dwarf cultivar, thus allowing the option of using management to improve the marketability of the grain.
Atrazine persistence and phytotoxicity on wheat as affected by nitrogen and rotation-induced changes in soil properties
Authors: Holford ICR , Haigh BM , Ferris IG
Published: November 2004

Wheat growing in a rotation experiment on an alkaline black earth was severely damaged by atrazine residues, whereas wheat in an adjacent experiment on a slightly acid red clay, was undamaged. Atrazine at 1.8 kg a.i, ha-1 had been applied to both sites nine months before wheat sowing. Nitrogen fertilizer had also been applied as split-plot treatments to the previous crop in each rotation sequence. There were four rotations, each comprising grain sorghum with either lucerne, an annual grain legume, long fallow, or continuous cereal growing.There were significant rotation effects on soil organic matter, pH, mineral nitrogen and residual atrazine. Organic carbon was highest, and soil pH and atrazine were lowest in the lucerne rotation, while the opposite occurred in the long fallow treatment. Atrazine concentration was positively correlated with pH and negatively correlated with organic carbon. The numbers of dead plants on the black earth were positively correlated with atrazine levels, but mortality was lowered by increasing mineral nitrogen at any particular level of atrazine.Wheat yields varied from zero in two continuous cereal plots to over 3.0 t ha-1 in a long fallow plot, and were highly correlated with mineral nitrogen levels. At any level of nitrogen, however, wheat yields were depressed by increasing levels of atrazine. The very large yield response to nitrogen, whether from soil or fertilizer, resulted from its dual beneficial effect of lowering plant mortality and improving the nitrogen status of the surviving plants.These results show that in a wheat crop following atrazine-treated sorghum, significant atrazine damage may occur on soils of pH > 64, that atrazine persistence and phytotoxicity will increase as the pH increases, but that phytotoxicity will decrease as soil nitrogen fertility increases. Lucerne rotations will lower atrazine persistence by decreasing soil pH and increasing organic matter, and will lower phytotoxicity by raising soil nitrogen.
The nutrition of Leucaena leucocephala de Wit cv. Cunningham seedlings. 1. External requirements and critical concentrations in index leaves of Nirtogen, Phosphorus, Potassium, Calcium, Sulfur and Manganese
Authors: Ruaysoongnern S , Shelton HM , Edwards DG
Published: November 2004

A series of nutrient rate experiments was conducted in pots at the University of Queensland, St. Lucia, to determine the critical concentrations of N, P, K, Ca, and S for deficiency, and of Mn for toxicity, in youngest fully expanded leaves of Leucaena leucocephala cv. Cunnningham. The P, Ca and Mn experiments were conducted using both NH4NO3 and Rhizobium inoculation as the source of nitrogen, while the K experiment was studied with both NaH2PO4 and Ca(H2PO4)2 as the source of basal P. Least squares derived response functions were fitted to data from each experiment to link growth and nodulation with the critical concentrations in youngest fully expanded leaves and with the rate of nutrient application required to produce 90% of maximum yield. These were: N, 4.1% and 645 kg ha-1; P, 0.25% and 225 kg ha-' for inoculated plants, 0.2 1% and 250 kg ha-1 for N-supplied plants; K, 2.0�/0 and 35 kg ha-1 for Ca(H2PO4)2-supplied plants, 2.0% and 180 kg ha-1 for NaH2PO4-supplied plants; Ca, 0.49% and 225 kg ha-1 for inoculated plants, 0.38% and 160 kg ha-1 for N-supplied plants; S, 0.24% and 40 kg ha-1; Mn, 325 mg kg-1 and 35 kg ha-1 for inoculated plants, 325 mg kg-1 and 55 kg ha-1 for N-supplied plants.
The influence of pasture and animal factors on the consumption of pasture by grazing sheep
Authors: Birrell HA
Published: November 2004

Interrelations of animal and pasture factors to account for variance in (i) the time spent grazing (GT, H/day) and (ii) the rate of eating (IR, OM/h) in data collected over 2.5 years on Corriedale sheep (adult castrated males) grazing pasture of mixed perennial/annual species in south-western Victoria were examined by sequentially adding factors and analysing in nonlinear regression relationships. Three plant and two animal factors accounted for almost 80% of the variance (100R2) in the GT of sheep grazing on green pasture in the period from March to November (n = 176). Five factors, including a stress factor related to environmental conditions, accounted for 82.5% of the variance in IR of sheep grazing through the green pasture period from March to December (n = 192). Pasture factors associated with organic matter digestibility were also examined. Total pasture mass (H, t DM/ha) and the green proportion of the pasture (G, %DM) accounted for 74.6% of the variance in D (n = 232). The implications of these relationships for developing an understanding of the biological basis for intake control and compensatory growth of animals are discussed.
Contribution of osmotic adjustment to grain yield in Sorghum bicolor (L.) Moench under water-limited conditions. I. Water stress before anthesis
Authors: Santamaria JM , Ludlow MM , Fukai S
Published: November 2004

The contribution of osmotic adjustment to grain yield in Sorghum bicolor (L.) subjected to water stress before anthesis was studied using six entries. Three of the entries (Goldrush, E57, and DK470) were selected for high osmotic adjustment and the other three (Texas 6 1 OSR, Texas 67 1, and SC 219-9-1 9-1) for low osmotic adjustment, and divided into early, intermediate and late maturity groups. Entries were either well watered, or subjected to a 41-day period of water shortage prior to anthesis and well watered for the remainder of their growth. Entries selected for higher osmotic adjustment developed higher levels of osmotic adjustment during the pre-anthesis stress period than those selected for low osmotic adjustment in intermediate and late maturity groups, but not in the early group. However, the level of osmotic adjustment was not related to the maturity group, when water stress was imposed at the same developmental stage. Entries with high osmotic adjustment produced higher grain yields than those with low osmotic adjustment. The response varied from 15% for the mean of all maturity groups to 34% for the mean of intermediate and late groups, where there were significant differences in osmotic adjustment. The higher mean grain yield was due mainly to a larger grain number (19%). Even though entries with high osmotic adjustment bad a greater root length, soil water extraction and dry matter production during the pre-anthesis stress period, there was no significant difference in dry matter yield at physiological maturity between low and high osmotic adjustment groups. Consequently, the higher mean grain yield was related solely to a higher harvest index (27%), which was associated with a higher distribution index (25%) and a higher grain number (19%). A detailed analysis is given of the mechanisms by which osmotic adjustment contributed to grain yield in plants subjected to a pre-anthesis stress.
The effect of a blend of dietary unesterified and saturated long-chain fatty acids on the performance of dairy cows in mid-lactation
Authors: King KR , Stockdale CR , Trigg TE
Published: November 2004

This experiment studied the effects of feeding a supplement of a blend of unesterified and saturated long-chain fatty acids on the productivity of dairy cows in mid-lactation. Twenty-three cows in their fourth month of lactation were individually fed ad libitum, a mixed balanced ration based on maize silage, lucerne hay and rolled grain. Varying quantities, up to 1020 g cow-1 day-1 of the fatty acid supplement, were mixed into the ration. Yields of milk and milk products were linearly related to total long-chain fatty acid intake. Milk fat content increased linearly while milk protein content averaged 3.59 (s.d. � 0.15)%. The marginal returns from feeding 1 kg of the supplement were 3.3 kg milk, 0.33 kg fat and 0.07 kg protein. The proportions of C 10:0, C12:0 and C 14:0 fatty acids in milk were decreased, while those of C 18:0 and C18:1 were increased as the result of feeding long-chain fatty acids. The concentration of lipid in plasma was increased, but acetate and D-(3)-hydroxybutyrate levels in blood remained unchanged with increased levels of dietary long-chain fatty acid. Efficiency of milk production was increased by 11% from feeding 1 kg of the supplement. In vivo digestibilities of dry matter, neutral and acid detergent fibres, and dietary long-chain fatty acids were unaffected by supplement.
The effect of bentonite supplementation on ruminal protozoa density and wool growth in sheep either fed roughage based diets or grazing
Authors: Fenn PD , Leng RA
Published: November 2004

In penned sheep offered a mainly roughage diet, supplementation with 30, 50 or 60 g/day bentonite consistently increased the density of ruminal protozoa. The effect of 15 g/day bentonite administered via the drinking water to pregnant grazing ewes that were either normally faunated or had been defaunated for 6 months was studied. The wool growth of defaunated sheep at pasture was 25% greater (P < 0.05) than that of faunated animals. The wool growth of the latter was increased 17% (P < 0.15) by the addition of 15 g/day bentonite to their drinking water, while a similar addition of bentonite to defaunated sheep had no effect on wool growth. In this field study, supplementation with bentonite increased the population densities of protozoa free in the ruminal fluid of faunated sheep by 51% (5.6 X 105 v. 3.7 X 105, P<0.07). It is suggested that this allows a greater flow of protozoal protein from the rumen to the intestines, leading to increased wool growth in response to supplements of bentonite.
Physiological analysis of peanut cultivar response to timing and duration of drought stress
Authors: Wright GC , Hubick KT , Farquhar GD
Published: November 2004

Pod yield response of two spanish (McCubbin and Red Spanish) and two virginia (Virginia Bunch and Q18801) cultivars were compared under a range of irrigation treatments applied at different growth stages on a Xanthozem soil in a subtropical environment in south-east Queensland. Detailed growth and soil water use measurements were taken on a fully irrigated treatment and a treatment which received no rainfall after 83 days after planting (DAP). Soil water deficits occurring during the flowering to the start of pod growth phase (R/I) significantly reduced pod yields (range, 17-25%) relative to the well-watered control plots (I/I) for all cultivars. Where crops were irrigated until 83 DAP, then crop water deficits occurred throughout the pod growth phase (I/R), a significant cultivar by irrigation treatment interaction was observed for pod yield. The greatest reduction in yield occurred when severe stress occurred during the pod filling phase (Sh). Significant cultivar variation in pod yield was apparent. Differences in pod yield within this treatment were analysed in terms of a simple framework where pod yield is a function of transpired water (T), transpiration efficiency (TE) and harvest index ( H ) . Estimates of TE derived from measurements of carbon isotope discrimination in leaves indicated only small variation in TE, and suggest this trait contributed little to pod yield variation in the cultivars used in this experiment. Variation in pod yield among the four cultivars was largely a result of differences in harvest index characteristics.
Phosphorus efficiency in pasture species. VI. A comparison of Italian ryegrass, phalaris, red clover and white clover over time
Authors: Kemp PD , Blair GJ
Published: November 2004

Two problems in comparative studies of the P efficiency of pasture species are the choice of measurement to define P efficiency and the basis of comparison to use. Therefore, the degree to which the level of P supply and plant age, or time of harvest, influence a variety of measures of P efficiency was examined in four temperate pasture species grown in a soil at a range of P levels in a glass house. The four species were Italian ryegrass, phalaris, red clover, and white clover. Italian ryegrass was the most P efficient and red clover the least P efficient species in terms of the broad scale measures of P effiency, shoot yield per unit of P applied and total P uptake over the first 40 days after sowing (DAS), and shoot P concentration at 68 DAS. Nevertheless, by 68 DAS the shoot fresh weight yield of the four species was similar at both the low (5 kgP ha-1) and the high (80 kg P ha-1) P rate. The superior shoot biomass production at lower P rates over 40 DAS of Italian ryegrass and phalaris compared with red and white clovers was largely the result of a greater root weight and P uptake per plant. Early root weight was determined by the relationship between seed weight and root relative growth rate (PGR), whereas P uptake per plant was influenced by root weight and plant P demand as measured by relative P uptake rate (RPR). The understanding of such relationships was shown to be essential to the effective interpretation of broad scale measures of P efficiency. The comparative broad scale P efficiences of the four species changed over time. When Italian ryegrass and phalaris were compared on an ontogenetic basis, number of leaves per plant, shoot yield and P uptake per plant were similar. The comparison of the P efficiency of species on both an ontogenetic and temporal basis is proposed.
Genotypic variation in osmotic adjustment in grain sorghum. II. Relation with some growth attributes
Authors: Tangpremsri T , Fukai S , Fischer KS , Henzell RG
Published: November 2004

Two sets containing large numbers (23 and 47 entries) of sorghum genotypes were grown in the glasshouse to examine the effect of osmotic adjustment on water extraction, dry matter growth and grain yield. Water stress was developed in two periods, one before and one after anthesis. The results were similar in the two experiments despite a large difference in the genetic background of the plant material. Since osmotic potential did not differ significantly among genotypes before water stress was induced, osmotic potential obtained under stress was used directly to indicate the genotype's ability to adjust osmotically. Osmotic adjustment was positively associated with green leaf area retention during grain filling and to root length density at 70 cm depth. Genotypes with high osmotic adjustment used more water during the second drying period. As a result, total dry matter was well related to osmotic adjustment during grain filling, but grain yield was negatively associated with osmotic adjustment in one experiment and not significantly related in the other. When comparison was made for lines which had similar leaf water potential during early stages of growth but which differed in osmotic adjustment during grain filling, there was still a positive effect of osmotic adjustment on total dry matter. This suggests that the positive effect was not caused by large plants extracting more water during early stages of growth, but was due to the difference in line's ability to extract water during grain filling.
The effect of NaCl on the establishment and growth of balansa clover (Trifolium michelianum Savi var. balansae Boiss.)
Authors: Rogers ME , Noble CL
Published: November 2004

The effect of NaCl on the germination, seedling emergence and growth of established plants of balansa clover, Trifolium michelianum Savi var. balansae Bois. cv. Paradana was studied and compared with plants of subterranean clover T: subterraneum L. cv. Clare. Balansa and subterranean clover had similar salt tolerances at germination and seedling emergence. However balansa clover suffered from poor seedling vigour even under non-saline conditions, and this resulted in a low number of emerged seedlings over all NaCl concentrations compared with subterranean clover. Established plants of balansa clover, despite a lower initial seedling yield, were significantly more salt tolerant (P < 0.001) and had a greater survival rate over a four month period at concentrations greater than 75 mol m-3 NaCl. Shoot concentrations of chloride and sodium increased with increasing salinity in both species, however concentrations were lower in balansa clover especially at higher NaCl concentrations (75 and 100 mol m-3 NaCl). It is concluded that whilst established stands of balansa clover may be able to withstand high concentrations of NaCl, the major limitation to its establishment and production in saline irrigation areas is its poor seedling emergence and vigour.
Levels of germinable seed in topsoil and cattle faeces in legume-grass and nitrogen-fertilized pastures in south-east Queensland
Authors: Jones RM , Noguchi M , Bunch GA
Published: November 2004

Measurements were made of germinable seed of all species in the top 5 cm of soil beneath 9 paddocks in an 11-year-old pasture experiment in south-east Queensland. The experiment comprised two pasture types grazed by cattle: legume-grass (Macroptilium atropurpureum- Setaria sphacelata) pastures grazed at four stocking rates and nitrogen fertilized S. sphacelata pastures grazed at five stocking rates. Levels of germinable seed in the soil varied with pasture type and stocking rate and ranged from 6760 to 45480 seeds/m2. Seed reserves increased on the legume-grass pastures as stocking rate increased. Fifty-seven different plant species were identified from the seedlings grown from the soil seed reserve. For 11 of these species, which contributed 70% of the seed reserves, there were significant trends in relation to pasture type and/or stocking rate. The only species where seed reserves significantly decreased with increasing stocking rate were the two sown species. Cattle faeces were also collected from lightly and heavily stocked legume-grass and nitrogen-fertilized pastures in spring, summer, autumn and winter. Germinable seed contents of all species were measured. Seed content of faeces was higher in the summer and autumn than in the winter and spring samplings, and in the heavily stocked than in the lightly stocked pastures. The highest content recorded was 20.5 germinable seeds g-1 faecal dry matter. The species with the highest germinable seed content in faeces were Digitaria didactyla, Axonopus affinis and Eleusine indica, the latter being restricted to nitrogen-fertilized pastures. Seed dissemination in faeces is a factor contributing to the invasiveness of prostrate perennial grasses such as D. didactyla and A. affinis under heavy grazing.
Flood irrigation of wheat on a transitional red-brown earth. II. Effect of duration of ponding on availability of soil and fertilizer nitrogen
Authors: Humphreys E , Melhuish FM , Xi ZB , White RJG , Muirhead WA
Published: November 2004

Grain yield of wheat growing on a transitional red-brown earth was reduced by long periods of ponding during irrigation. To determine whether fertilizer N loss was a major cause of this yield decline, 15N-labelled urea was applied to microplots at the same time and rate as the crop was topdressed with urea (end of tillerfng, 100 kg N ha-1). In addition, 15N-labelled nitrate was used to assess denitrification potential during and after each irrigation. Prior to the first irrigation (19days after urea application), 76% of the urea N was immobilized in the plants (33%) and soil (43%), 15% was present as soil mineral N, and 9% was not accounted for. The majority (85%) of the urea-derived mineral N was present as ammonium in the 0-0.1 m soil layer. After the first irrigation, amounts of mineral N in the soil remained very low at 3-6 kg N ha-l in the 0-0.2 m layer, with only 5-15% of this in the nitrate form. There was no significant effect of duration of ponding on plant or soii recovery of urea N after any irrigation. Mean plant recovery increased to 52%, over the first 55 days following urea application, while soil recovery declined to 22%. Beyond this stage changes in plant and soil recoveries were negligible. Plant total N content increased throughout the season due to ongoing mineralization of native soil N; however, there was negligible net mineralization of recently immobilized 15N beyond day 55. At physiological maturity, 46% of the N acquired by the plants was derived from the fertilizer. Losses of urea N increased to 25% over the first 55 days, and appeared to be due to nitrification-denitrification. Field studies with labelled nitrate indicated that denitrification potential in the soil was high throughout the experimental period. After the final two irrigations there were some significant (P < 0.05) effects of duration of ponding on N loss from urea, with lowest losses in the sprinkler, 1 h and 12 h treatments. The data indicate that, on the transitional red-brown earth, the adverse effect of long periods of ponding on wheat yield was not due to decreased availability or uptake of fertilizer or soil N in the longer term.
Forage tree legumes. IV. Productivity of leucaena/grass mixtures
Authors: Horne PM , Blair GJ
Published: November 2004

A field experiment was conducted in a wet tropical environment (Ciawi, West Java, Indonesia) to assess the forage yields of mixtures of leucaena and grasses over a 1 year period in plots which had been established 2 years earlier. The tree legume Leucaena leucocephala cv. Cunningham (plant density 1 m x 0.5 m), cut at either 30 cm or 100 cm, was interplanted with either a short grass (Setaria sphacelata var. splendida) or a tall grass (Pennisetum purpureum). Mineral nutrients were non-limiting. Highest leaf production was in the setaria monoculture (20.8 t ha-l yr-l) and the low-cut leucaena/setaria mixture (18.5 t ha-l yr-1), with the grass dominating production (> 88%) in the latter because of the ability of setaria to gain preferential access to light penetrating between the rows of leucaena early in each growth period. Leucaena shoot production in the low-cut leucaena treatments was reduced from a mean of 8.8 t ha-1 yr-1 in the monocultures to 1.5 t ha-l yr-1 in the mixtures. For the high-cut leucaena treatments, grass leaf yields were lower from the mixtures than from the monocultures but leucaena shoot yields were only reduced from monoculture yields in the mixture with pennisetum. The mixture of setaria and high-cut leucaena produced a considerable yield of setaria leaf (6.2 t ha-1 yr-l) with no reduction in leucaena leaf yields and intercepted a significantly greater percentage of total incident light (64%) than the other three mixtures (42-42%).
Body temperatures and respiratory rates of free-ranging Merino sheep in and out of shade during summer
Authors: Johnson KG
Published: November 2004

Shade use by 20 unrestrained Merino wethers carrying 23-31 mm wool was monitored as they grazed dry pasture during summer (Ta max = 28-41 �C). During 17 24-h periods intra-abdominal (Tb) and trunk-skin (Tsk) temperatures were recorded with ambulatory data-loggers at 1 or 5 minute intervals; in 11 periods respiratory rates were also counted each hour during daylight. The four sheep that used shade least (6% of 8 h day) had mean, maximum and minimum Tb no different to those of the four sheep that used shade most (39%). Maximum and minimum Tb each day occurred 1-2 h earlier in animals inclined to stay in sun rather than shade. Tsk varied in sheep shuttling in and out of shade, but mean mid-back skin temperature was only slightly, and not significantly, higher for animals in sun than shade. Respiratory rates also were similar for animals in sun and shade. The similarity of thermal status of animals in and out of shade was unexpected. This may have arisen because animals had different rates of evaporative cooling that were not reflected in respiratory rates, or possibly different rates of heat production. Alternatively, all animals could have been effectively insulated from solar heating by their wool, though they presumably experienced some heat stimulus since all used shade at some time. Shade may be of benefit
Consequences of selection for growth and heat resistance on growth, feed conversion efficiency, commercial carcass traits and meat quality of Zebu crossbred cattle
Authors: Burrow HM , Burrow HM , Gulbransen B , Gulbransen B , Johnson SK , Johnson SK , Davis GP , Davis GP , Shorthose WR , Shorthose WR , Elliott RF , Elliott RF
Published: November 2004

Thirty-five steers and 37 heifers were grown at pasture and finished in a feedlot to meet Australian domestic market specifications, i.e. 160-200 kg carcass weight with 5-9 mm subcutaneous fat at the P8 rump site. The animals were from lines that had been selected for either high growth rate to 600 days (UPWT) or for low rectal temperature under conditions of high ambient temperatures (TEMP) and from a control line (CONT). They were slaughtered in six groups at fortnightly intervals when liveweight of individuals was estimated to satisfy market requirements. Animals from the UPWT line were heavier at all ages than animals from the TEMP and CONT lines (P< 0.05) and had higher liveweight gains at pasture (P < 0.01). There was no difference between the lines in liveweight gains in the feedlot. At the same carcass weight, UPM animals had leaner carcasses (P < 0.01) but similar levels of marbling to CONT line animals. TEMP line animals were also leaner than CONT line animals (P < 0.0l ) , but had more marbling (P<0.01). There was no significant difference between lines in feed conversion efficiency. Steers were heavier (P < 0.001) than heifers at all ages, grew faster (P < 0.001) except during the immediate post-castration period, had higher feed intakes (P < 0.05) but better feed conversion efficiencies (P < 0.05), and at the same carcass weight were leaner (P < 0-01) and had less marbling (P < 0.05). Meat colour, cooking loss, ultimate pH and meat tenderness did not differ significantly between lines or sexes. These results are discussed with reference to the use of selection for growth or heat resistance to improve growth and carcass traits of beef herds in tropical areas.
Root and shoot growth, and water and light use efficiency of barley and wheat crops grown on a shallow duplex soil in a mediterranean-type environment
Authors: Gregory PJ , Tennant D , Belford RK
Published: November 2004

Growth, interception of radiation and water use of three genotypes of barley (Beecher, O'Connor and Syrian) and one of wheat (Gutha) were measured on a duplex soil at East Beverley, W.A. All crops received 11 kg P ha-1 with the seed but no nitrogen fertilizer. Growth was initially slow until 69 days after sowing (das) with only small and inconsistent differences between crops. Thereafter, Beecher and O'Connor grew faster than Syrian and Gutha, maintained growth for longer, and at harvest weighed about 7.5 t ha-1 shoot dry matter, while Syrian and Gutha were about 5.0 t ha-1. Total root weight and length of Gutha increased until anthesis but reached their maxima at 83 das in all barley crops. Root weight as a percentage of total plant weight was about 40% during the winter decreasing to about 15% by anthesis. Root distributions of Beecher and O'Connor were similar but different from those of Syrian and Gutha; the former had up to 25% of the total root length at anthesis below 40 cm, but the latter had only about 5%. Dry matter production was linearly related to the amount of photosynthetically active radiation (PAR) intercepted, although the relations showed a break at about the time of flag leaf emergence, and efficiencies of conversion of PAR to dry matter were higher prior to this than after. Efficiencies for the barley crops were similar (about 2 g total dry weight MJ-1 before flag leaf emergence) and about 20% greater than for Gutha. Despite the large differences in dry matter production between crops, evapotranspiration (ET) was similar. For Beecher and O'Connor, evaporation E was about 40% of seasonal ET but for Syrian and Gutha it was about 50%. Values of water use efficiency (about 30 kg shoot ha-1 mm-1 for Beecher and OIConnor and 20 kg ha-1 mm-1 for Syrian and Gutha) were similar to other cereal crops and the amount of shoot dry matter per unit of water transpired for barley crops grown in W.A., U.K. and Syria was nearly constant; the value of the 'crop specific constant' was 3.0 Pa.
Yield improvement of oilseed rape (Brassica napus L.) in a low rainfall environment. II. Agronomic performance of lines selected on the basis of pre-anthesis development
Authors: Thurling N , Kaveeta R
Published: November 2004

Agronomic characteristics of two groups of early flowering Brassica napus lines and their respective parents were compared at East Beverley in the Western Australian wheatbelt. These lines had been derived through two generations of backcrossing and subsequent selfing from crosses of the B. napus cultivar Wesbrook (recurrent parent) with an early flowering B. napus line RU2 and an even earlier flowering B. campestris population Chinoli C42. Lines selected for this experiment had flowered earliest in a previous controlled environment experiment. Only RU2 and one WesbrookxRU2 line (IB72) had significantly higher yields than Wesbrook (149% and 166% respectively), and one Wesbrookxchinoli C42 line was the only line to have a significantly lower yield than Wesbrook. None of the lines had significantly higher yields than their respective non-recurrent parents. Although RU2 and IB72 flowered much earlier than Wesbrook, there was no significant relationship between flowering time and seed yield over all lines. Lines which were the earliest to commence stem elongation tended to have higher seed yields. However, of all the growth and development characters measured, the biological yield and the dry weight increment between commencement of flowering and maturity were most closely related to seed yield. RU2 and IB72 accumulated far more dry matter over the post-anthesis period than Wesbrook and all other lines except another WesbrookxRU2 line. The superior post-anthesis growth of RU2 and IB72 may simply be a manifestation of the longer period available for growth under more favourable environmental conditions or deeper roots extracting more water from a greater depth. However, since there was no relationship between flowering time and the post-anthesis dry matter increment, it seems more likely that IB72 has received genes for superior post-anthesis growth as well as those determining early flowering from RU2. Given the rapid decline in soil moisture availability during post-anthesis development in this environment, these genes may affect post-anthesis growth through determining a greater capacity for drought avoidance. The implications of these results are discussed with particular reference to the breeding of higher yielding B. napus cultivars for lower rainfall environments.
Iron deficiency depresses growth of furrow irrigated soybean and pigeon pea on vertisols of northern N.S.W
Authors: Hodgson AS , Holland JF , Rogers EF
Published: November 2004

Crops under furrow irrigation or after heavy rainfall on the alkaline, calcareous Vertisols of northern N.S.W. frequently exhibit chlorosis of young leaves after the soil is wetted, but the specific cause has not been identified previously. The quantitative effects of the syndrome on growth, physiological activity and yield are also unknown. Experiments on soybean and pigeon pea grown on a Vertisol at Breeza, N.S.W., Australia, examined the influence of applying Fe to the leaves, and Fe, Zn, N+P and lime to the soil before sowing, on leaf colour, leaf photosynthesis, crop dry matter, and yield of grain of soybean and dry matter and yield of pigeon pea. In soybean, chelated Fe applied to the soil before sowing increased the levels of active Fe (Fe2+) in leaves by up to 42% and dry matter of shoots by up to 46% early in the season. Active Fe and dry matter of shoots were linearly correlated (r2 = 0.76). Soil Fe treatments did not affect leaf photosynthesis, although addition of chelated Fe to the soil resulted in greener leaves than in the control. Foliar Fe had no significant effect on active Fe, leaf colour, or leaf photosynthesis. The 9% increase in grain yield in response to application of 20 kg Fe ha-1 to the soil was not significant. In pigeon pea, application of 20 kg Fe ha-1 to the soil increased dry matter by 140% and grain yield by 414%. Effects of lime and zinc were not significant, but N+P increased yield by 112%. The study showed that Fe deficiency is limiting the growth and/or yield of irrigated soybean and pigeon pea on the clay soils of northern N.S.W., and pointed to lime-induced iron chlorosis as a possible mechanism of damage.
The Synthesis and Testing of α-(Hydroxymethyl)pyrroles as DNA Binding Agents
Authors: Martyn Derek C. , Abell Andrew D.
Published: November 2004

The α-(hydroxymethyl)pyrroles 16a and 16b were prepared and shown to be cytotoxic against the P388 cancer cell line. Ethyl 5-hydroxymethyl-1H-pyrrole-2-carboxylate 18 was inactive, demonstrating that an α-(hydroxymethyl)pyrrole group alone is not sufficient for activity. Compound 16b has been shown to bind to DNA with reasonable affinity.
Linkage analysis of ordinal traits for pedigree data
Authors: Feng Rui , Leckman James F. , Zhang Heping
Published: November 2004

Linkage analysis is used routinely to map genes for human diseases and conditions. However, the existing linkage-analysis methods require that the diseases or conditions either be dichotomized or measured by a quantitative trait, such as blood pressure for hypertension. In the latter case, normality is generally assumed for the trait. However, many diseases and conditions, such as cancer and mental and behavioral conditions, are rated on ordinal scales. The objective of this study was to establish a framework to conduct linkage analysis for ordinal traits. We propose a latent-variable, proportional-odds logistic model that relates inheritance patterns to the distribution of the ordinal trait. We use the likelihood-ratio test for testing evidence of linkage. By means of simulation studies, we find that the power of our proposed model is substantially higher than that of the binary-trait-based linkage analysis and that our test statistic is robust with regard to certain parameter misspecifications. By using our proposed method, we performed a genome scan of the hoarding phenotype in a data set with 53 nuclear families, which were collected by the Tourette Syndrome Association International Consortium for Genetics (TSAICG). Standard linkage scans using hoarding as a dichotomous trait were also performed by usinggenehunterandallegro. Bothgenehunterandallegrofailed to reveal any marker significantly linked to the binary hoarding phenotypes. However, our method identified three markers at 4q34-35 (P= 0.0009), 5q35.2-35.3 (P= 0.0001), and 17q25 (P= 0.0005) that manifest significant allele sharing.
GC/AT-content spikes as genomic punctuation marks
Authors: Zhang Lingang , Kasif Simon , Cantor Charles R. , Broude Natalia E.
Published: November 2004

Large-scale analysis of the GC-content distribution at the gene level reveals both common features and basic differences in genomes of different groups of species. Sharp changes in GC content are detected at the transcription boundaries for all species analyzed, including human, mouse, rat, chicken, fruit fly, and worm. However, two substantially distinct groups of GC-content profiles can be recognized: warm-blooded vertebrates including human, mouse, rat, and chicken, and invertebrates including fruit fly and worm. In vertebrates, sharp positive and negative spikes of GC content are observed at the transcription start and stop sites, respectively, and there is also a progressive decrease in GC content from the 5′ untranslated region to the 3′ untranslated region along the gene. In invertebrates, the positive and negative GC-content spikes at the transcription start and stop sites are preceded by spikes of opposite value, and the highest GC content is found in the coding regions of the genes. Cross-correlation analysis indicates high frequencies of GC-content spikes at transcription start and stop sites. The strong conservation of this genomic feature seen in comparisons of the human/mouse and human/rat orthologs, and the clustering of genes with GC-content spikes on chromosomes imply a biological function. The GC-content spikes at transcription boundaries may reflect a general principle of genomic punctuation. Our analysis also provides means for identifying these GC-content spikes in individual genomic sequences.
Munc13-4 Is an Effector of Rab27a and Controls Secretion of Lysosomes in Hematopoietic Cells
Authors: Neeft Maaike , Wieffer Marnix , de Jong Arjan S. , Negroiu Gabriela , Metz Corina H.G. , van Loon Alexander , Griffith Janice , Krijgsveld Jeroen , Wulffraat Nico , Koch Henriette , Heck Albert J.R. , Brose Nils , Kleijmeer Monique , van der Sluijs Peter
Published: November 2004

Griscelli syndrome type 2 (GS2) is a genetic disorder in which patients exhibit life-threatening defects of cytotoxic T lymphocytes (CTLs) whose lytic granules fail to dock on the plasma membrane and therefore do not release their contents. The disease is caused by the absence of functional rab27a, but how rab27a controls secretion of lytic granule contents remains elusive. Mutations in Munc13-4 cause familial hemophagocytic lymphohistiocytosis subtype 3 (FHL3), a disease phenotypically related to GS2. We show that Munc13-4 is a direct partner of rab27a. The two proteins are highly expressed in CTLs and mast cells where they colocalize on secretory lysosomes. The region comprising the Munc13 homology domains is essential for the localization of Munc13-4 to secretory lysosomes. The GS2 mutant rab27aW73G strongly reduced binding to Munc13-4, whereas the FHL3 mutant Munc13-4Δ608-611 failed to bind rab27a. Overexpression of Munc13-4 enhanced degranulation of secretory lysosomes in mast cells, showing that it has a positive regulatory role in secretory lysosome fusion. We suggest that the secretion defects seen in GS2 and FHL3 have a common origin, and we propose that the rab27a/Munc13-4 complex is an essential regulator of secretory granule fusion with the plasma membrane in hematopoietic cells. Mutations in either of the two genes prevent formation of this complex and abolish secretion.