bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrigendum - The endogenous phosphorus excretion of preruminant lambs
Authors: Walker DM , Al-Ali SJ
Published: November 2004

Twenty-seven preruminant male crossbred lambs, aged 1-2 days at the start of the experiment, were used. Three lambs were sacrificed on day 1 and selected bones taken for analysis. Twenty-four lambs, in groups of three, were bottle-fed on low-phosphorus milk replacers in a 2 x 4 factorial experiment. The sole source of protein in the diets was whole beef blood, supplemented with L-isoleucine and DL-methionine, to supply either 10 or 25% of the total dietary energy as protein. At each protein level the diets were supplemented with CaCO3 to provide four ratios of Ca:P (0.5:1, 1:1, 2:1 and 10:1). The daily intake of gross energy was controlled at 880 kJ-0.73. Faeces and urine were collected separately each day and bulked during the last seven days of the experiment for the estimation of N, Ca and P. Serum Ca and P concentrations were determined at weekly intervals. The lambs were sacrificed at the end of the experimental period of 21 days and selected bones were taken for analysis. The concentrations of bone ash, Ca and P all decreased significantly when compared with values determined at the start of the experiment. The lambs given the high-protein diets showed significantly greater losses of bone ash, Ca and P, and had lower serum P, but higher serum Ca concentrations, than lambs fed on the low-protein milk replacers, irrespective of the dietary Ca:P ratios. Phosphorus excretions during the last seven days of the experiment were as follows: faecal P (day-1); low-protein group (n = 12), 3.1 � 0.5 mg kg-1; high-protein group (n = 11) , 4.1 � 0.5 mg kg-1; all lambs (n = 23), 3.6 � 0.3 mg kg-1. Urinary P (day-1): low-protein group (n = 12), 0.92 � 0.22 mg kg-1; high-protein group (n = 11) , 0.61 � 0.03 mg kg-1; all lambs (n = 23), 0.77 � 0.12 mg kg-1. Faecal and urinary P excretion was unaffected by variation in the dietary Ca:P ratio.
The use of uniformity data in the design and analysis of cotton and barley variety trials
Authors: Williams ER , Luckett DJ
Published: November 2004

The results of two uniformity trials, one in furrow-irrigated cotton, the other in barley, are presented and the yield data analysed. The two data sets, while both showing significant row and column effects, exhibited markedly different types of variation over the test area. The cotton data were more uniform and had stronger trends in columns and rows. There was a strong autocorrelation between plots in the barley data which was not evident in the cotton data. These results support the current preferences of cotton breeders for row and column designs and of barley breeders for neighbour designs when conducting variety trials in the field.
Corrigendum - Rates of passage of solutes, microbes and particulate matter through the gastro-intestinal tract of ewes fed at a constant rate throughout gestation
Authors: Faichney GJ , White GA
Published: November 2004

The rates of passage of solutes, microbes and particulate matter were measured at different stages of gestation in multiparous Corriedale ewes. The mean retention times (MRT) of each of these constituents in the rumen decreased as gestation progressed. There was an increase in the MRT of digesta distal to the stomach which was sufficient to compensate for the decrease in solute MRT in the rumen. Thus, for the whole tract, only the MRT of particulate matter decreased during gestation. There were good relationships between the rate of passage from the rumen of microbes and of particulate matter and that of water, reflecting the importance of water as the vehicle for passage from the rumen. The fractional outflow rate of the particle-associated marker 103Ru-phen was greater than the net value for microbes, but was similar to the calculated value for non-microbial, non-ammonia nitrogen. The proportion of the rumen microbial population that was free-floating declined to a minimum of 0.18 as the fractional outflow rate of water increased. A peristaltic activity index showed a tendency to decline, particularly in the duodenum, as gestation progressed.
Digestibility of threonine from protein concentrates for growing pigs. 2. The digestibility of threonine to the terminal ileum in pigs given six protein concentrates
Authors: Leibholz J , Mollah Y
Published: November 2004

Six male Landrace x Large White pigs (25 kg liveweight) were fitted with T-shape cannulae in the terminal ileum. The pigs were fed 1.2 kg dry matter per day containing 4.5 g threonine/kg of diet from continuous belt feeders. The apparent digestibility of dry matter (DM) to the terminal ileum was 0.91, 0.87, 0.85, 0.81, 0.80 and 0.75 for pigs given diets containing milk, fish meal, soybean meal, meat meal, sunflower meal and cotton seed meal respectively. The apparent digestibility of nitrogen (N) to the terminal ileum was 0.87, 0.87, 0.86, 0.86, 0.81 and 0.74 for pigs given diets containing milk, fish meal, soybean meal, sunflower meal, meat meal and cottonseed meal, respectively. The true digestibility of threonine to the terminal ileum was 0.96, 0.95, 0.90, 0.87, 0.80 and 0.66 for the diets containing milk, fish meal, sunflower meal, soybean meal, meat meal and cottonseed meal, respectively.
Utilization of clover diets by sheep. 3. Palatability of a mature subterranean clover hay
Authors: Doyle PT
Published: November 2004

Two experiments were conducted using an intra-ruminal feeding technique to investigate the possibility that voluntary intake of a mature subterranean clover hay was limited by its palatability.Intra-ruminal additions of the hay, in a form approximating the physical nature of rumen dry matter, at levels up to 40% of the amounts voluntarily consumed, did not reduce oral feed intake. The additions also had no significant effects on the digestibility of organic matter or cell wall constituents or on the fractional rates of digestion in or passage from the reticula-rumen. Importantly, the amounts of digesta dry matter, and its components, in the rumen were increased in proportion to additional feed given through the fistula.These results indicate that palatability limited the intake of the clover.
The statistical comparison of reproduction rates for groups of sheep
Authors: Brown GH
Published: November 2004

Statistical tests based on the chi-squared distribution are given for testing the homogeneity of lambing rates (the number of lambs born per ewe joined) and foetal survival rates. The inadequacy of a traditional chi-squared statistical test for testing the hypothesis of complete homogenity between groups, is pointed out, and the calculations illustrated with numerical examples. A comparison with the analysis of variance is also made.
Effects of level of intake and urea supplementation of alkali-treated straw on protozoal and bacterial nitrogen synthesis in the rumen and partition of digestion in cattle
Authors: Punia BS , Leibholz J , Faichney GJ
Published: November 2004

Six Friesian heifers (c. 300 kg) fitted with cannulas were given diets of wheat straw sprayed with NaOH (4.4 % wlw) and essential minerals either with or without urea (3% w/w). The total protozoal numbers in the rumen fluid were not significantly different between dietary trcatments (mean 6.2 X 104/ml). However, there were more holotrichs and medium-size entodiniomorph protozoa in the rumen fluid of the cattle given the HU and LU diets than the Hand L diets. Protozoal counts in the omasal fluid were 44% of those in rumen fluid. The apparent digestibilities of OM and neutral-detergent fibre (NDF) in the stomach and in the total tract were lower with high than low feed intakes. The urea supplement enhanced the digestibilities of OM and NDF in the stomach and in the total tract. The total nitrogen (N) and non-ammonia N (NAN) flowing to the omasum and to the duodenum per unit of N intake were significantly greater with the low than the high feed intakes and with urea supplementation of the diets than without urea supplementation. The proportions of total microbial N and bacterial N in omasal NAN were higher with the supplement of urea than the unsupplemented straw. The bacterial N in the NAN flowing to the omasum was lower for the high than the low intakes. Concentrations of ammonia-N and total volatile fatty acids in rumen fluid were higher for the ureasupplemented straw than the unsupplemented straw. The high level of feed intake was associated with higher water volume and solid contents in the rumen.
Increased responsiveness of short oat cultivars to early sowing, nitrogen fertilizer and seed rate
Authors: Anderson WK , McLean R
Published: November 2004

Oat cultivars of tall (West), intermediate (Mortlock) and dwarf height (Echidna) were compared for their response to sowing time, nitrogen fertilizer and seed rate. Experiments were carried out in the 500-800 mm average annual rainfall zone in Western Australia at nine sites. Cultivars were compared in experiments involving different times (3) of sowing, levels (5) of applied nitrogen and rates (5) of seed and in another experiment including all combinations of two levels of sowing time, nitrogen and seed. The optimum sowing times for the three cultivars were similar, but the yield advantage for Echidna over West was 0.63 t ha-1 for late May sowing but only 0.25 t ha-1 for sowing in late July. Yield responses to applied nitrogen were dependent on soil nitrogen status, seasonal rainfall, sowing date, cultivar and seed-rate. On average, Echidna was more responsive (0.42 t ha-1) to the initial 30 kg ha-1 of nitrogen than Mortlock (0.23 t ha-1). The optimum seed rate (where an increase of 1 kg of seed increased yield by 10 kg ha-1) was 77, 67 and 61 kg ha-1 for Echidna, Mortlock and West corresponding to 225, 185 and 160 plants m-2. The largest yielding combination of cultivar, time of sowing, nitrogen and seed rates increased yields by from 1.32 to 3.23 t ha-1 (51-220%) compared to the control or low input treatment. Biomass at heading increased linearly to about 6.5 t ha-1 with rainfall up to 200 mm. Rainfall to heading in excess of 200 mm appeared to be inefficiently used for biomass production. Grain yields also increased linearly up to about 4 t ha-1 with increasing biomass at heading and up to 6 t ha-l with the correct choice of cultivar, time of sowing, nitrogen and seed rates.
Annual species of Medicago differ greatly in their ability to nodulate on acid soils
Authors: Howieson JG , Ewing MA
Published: November 2004

It is possible that the use of annual species of Medicago may be broadened by the selection of genotypes more capable of achieving nodulation on acid soils when only low numbers of their microsymbiont, Rhizobium meliloti, are present. In this study 36 genotypes from 14 species of Medicago were examined for their ability to nodulate over a range of inoculum levels in a soil of pH 4.9 (1:5,0.01 M CaCl2). Variation both within and between species was evident. M. murex in particular, as well as M. polyrnorphu and M. soleirolii, were outstanding in their ability to achieve nodulation in the acid soils. This character should assume some priority in pasture selection programmes targeted for acid soils.
The effects of fishmeal and postruminal glucose on the intake and digestion of low-quality herbages by grazing cattle in southern Australia
Authors: Hynd PI
Published: November 2004

The intake and digestion of barley stubble and mature pasture were studied in grazing cattle given no supplement or supplements of fishmeal (800 g day-1 per rumen) or fishmeal (800 g day-1 per rumen) plus glucose (500 g day-1 per abomasum). Herbage intake was unaffected by supplements but was greater on pasture than stubble (P<0.001). While fishmeal increased ammonia levels above the basal level of 90 mg 1-1 , the flow of bacterial nitrogen was not increased. Bacterial efficiency (g bacterial nitrogen per kg dry matter apparently digested in the rumen) was 26 and 15 at pasture and stubble, respectively (P< 0.008), and was uninfluenced by supplementation with fishmeal. Similarly, the bacterial nitrogen content and the ratio of diaminopimelic acid to total nitrogen in the bacteria was unaffected by supplementation. Total non-ammonia nitrogen flow and the flow of essential amino acids from the rumen were greater at pasture than stubble (P<0.003) and were increased by fishmeal supplement (P<0.01). Plasma glucose was significantly affected by herbage type but not by supplement (P>0.05). Plasma insulin was not significantly altered by either herbage or supplement. It is concluded that large quantities of postruminal energy and protein supplements can be given to grazing cattle with no detrimental effects on herbage intake and utilization. Further work should be conducted to identify the cause of an apparent inefficiency of bacterial efficiency in cattle on low-quality stubble. It did not appear to result from a deficiency of either ammonia or branch-chain fatty acids.
The tolerance of wheat to high temperatures during reproductive growth. III. Booting to anthesis
Authors: Dawson IA , Wardlaw IF
Published: November 2004

A range of Australian and overseas wheat cultivars was grown in the naturally lighted glasshouses of the Canberra phytotron, with a standard day/night temperature regime of 18/1 3�C. Grain number per main culm ear under these standard conditions was compared with the response obtained when sets of plants were transferred to high temperature (24/19�C, or 30/25�C) over the period from flag leaf ligule to ear emergence (booting), or from ear emergence to the end of anthesis (pollination and fertilization).Some Australian lines such as Isis and Hybrid Titan were tolerant of high temperature at booting, while others such as Pinnacle and Olympic showed a marked sensitivity to high temperature at this stage. Cultivars from the Middle East and tropical areas were generally more tolerant of high temperature at booting than cultivars from regions such as North America and Europe, while the Australian lines were intermediate in their response. With the cultivar Pinnacle, it was shown that at least part of the low fertility associated with high temperature at booting was related to poor pollen development. Commencing the high temperature treatment earlier in the development of the ear and continuing this until ear emergence resulted in adaptation in the cultivar H757 from Afghanistan, which showed an increase in grain set above that of the short high temperature booting treatment. However, this contrasted with the response of the cultivar Banks when the extended high temperature treatment resulted in a further reduction, not an increase in grain set. It was shown that the presence of the rye translocation for rust resistance (1B/1R) in near isogenic lines of Condor resulted in reduced sensitivity to high temperature. This would suggest that species such as rye should be examined more closely for their sensitivity to environmental stress.Exposure to high temperature only during anthesis generally had a small effect oil grain set. Some cultivars showed an increase in grain set, whereas others showed a decrease. Part of this variation may be related to the finding that under high temperature conditions, high humidity (v.p.d. 6.7 mb) could reduce grain set. However, given the normal relation between temperature and humidity in Australia, this effect is likely to be limited to glasshouse conditions.
Effects of calcium supply on uptake of calcium and selected mineral nutrients by tropical food legumes in solution culture
Authors: Bell RW , Edwards DG , Asher CJ
Published: November 2004

Six tropical food legumes, peanut (Arachis hypogaea (L.) cv. Red Spanish), pigeonpea (Cajanus cajan (L.) Millsp. cv. Royes), guar (Cyarnopsis tetragonoloba (L.) Taub. cv. Brooks), soybean (Glycine max (L.) Merr. cv. Fitzroy), and cowpea (Vigna unguiculuta (L.) Walp. cv. Vita 4 and CPI 282 15) were grown for 20 days at six constant solution calcium concentrations (2, 12, 50, 100,500 and 2500 8M ) in flowing solution culture at pH 5.5 � 0.1, with adequate inorganic nitrogen and controlled basal nutrient concentrations. Increases in solution calcium concentration from 2 to 12 8M generally increased rates of absorption of nitrogen, phosphorus, potassium, manganese and zinc, and rates of transport of magnesium and iron to plant tops. These increases in nutrient absorption and transport rates were associated with the alleviation of severe calcium deficiency. Further increases in solution calcium concentration from 12 to 2500 8M generally had no effect on potassium absorption rate, but increased absorption rates of nitrogen (by 20-130%), and phosphorus (by 90-500%), and decreased those of manganese and zinc; it also decreased rates of transport of iron and magnesium to plant tops. With guar, rates of phosphorus absorption at <2500 8M calcium were too low to maintain adequate concentrations of phosphorus in tops for maximum growth. With the remaining legumes, rates of zinc absorption at 12 8M calcium were high enough for plants to accumulate excessive concentrations of zinc (347-479 mg kg-1) in their tops. These results are discussed in relation to the adaptation of tropical food legumes to soils with low concentrations of calcium in the soil solution and the response of legumes to calcium or lime applications.
The influence of saline drinking water on the activity of carbonic anhydrase in the shell gland of laying hens
Authors: Yoselewitz I , Balnave D
Published: November 2004

Carbonic anhydrase activity was measured in three experiments using mucosal extracts from the shell gland of laying hens given drinking water consisting of town water with or without the addition of sodium chloride (2 g/l). Hens laying eggs with normal or defective shells on both treatments were used. The specific activity of carbonic anhydrase was significantly lower in hens receiving the saline drinking water, but egg shell type had no significant effect on enzyme activity. The results indicate that a reduced activity of carbonic anhydrase in the shell gland contributes to the poor egg shell quality observed in hens receiving saline drinking water.
Temperature affects the mesocotyl and coleoptile length of grain sorghum genotypes
Authors: Radford BJ , Henzell RG
Published: November 2004

The effect of seven temperatures ranging from 15 to 45�C on the germination and seedling length (mesocotyl +coleoptile) of eight grain sorghum genotypes (QL10, QL27, B35, R9247, BTx2761, BKS4, RTx7078 and 1790E) was determined. There was significant variation in germination (25-100%) and seedling length (6-182 mm) across temperatures and among genotypes, and significant temperature X genotype interactions occurred. Emergence problems due to poor germination and inadequate seedling length are likely in certain genotypes at high (>30�C) and low (<20�C) seedbed temperatures, particularly when deep sowing is necessary to reach moist soil. The optimum temperature for coleoptile elongation was 15-20�C, while the optimum for mesocotyl elongation varied from 15-30�C. Generally, the coleoptile comprised only a small proportion of the total seedling length, but the proportion increased at high and low temperatures (range: 6-53% of seedling length). The mesocotyl lengths of five genotypes selected at ICRISAT for their long mesocotyls were not outstanding compared with a locally derived hybrid B35 X R9247, which had not been selected for long mesocotyls. It is recommended that commercial hybrids be screened for germination and seedling elongation at the temperatures that occur in the seedbed at sowing.
Differential response of wheat to retained crop stubbles. I. Effect of stubble type and degree of composition
Authors: Purvis CE
Published: November 2004

Field studies undertaken at Armidale in 1982-84 demonstrated that the principal factors determining the effect of retained stubble on the growth and yield of wheat were the species of the crop from which the stubble had been derived, the amount and distribution of rainfall and the degree of decomposition that the stubble had undergone prior to the next crop. Stubbles were phytotoxic only prior to leaching by rain or decomposition, with unweathered sorghum stubble proving more inhibitory to wheat than unweathered sunflower, field pea, wheat or oilseed rape stubble. The availability of soil nitrate had no influence on the degree of phytotoxicity of any stubble type. Decomposed crop stubbles stimulated wheat growth, with the greatest stimulation recorded in the presence of oilseed rape stubble.
Contrasting effects of rooting volume and aerial spacing on shoot morphology and reproductive performance of Lupinus angustifolius L. cv. Danja
Authors: Pigeaire A , Pate JS , Atkins CA
Published: November 2004

Dry matter production and reproductive performance of sand-cultured, pot-grown plants of Lupinus angustifolius L. cv. Danja were markedly affected by varied aerial density (19, 23, 45 and 90 plants m-2) at constant high rooting volume (4.7 l plants-') or by varied rooting volume (1.1, 2.4 and 4.7 1 plant-1) at constant low aerial density (19 plants m-2). Dry weight of roots decreased markedly with reduced aerial spacing, but not with reduced rooting volume, whereas root:shoot dry weight ratio was affected (increased) only by decreased rooting volume. Above-ground competition reduced fruit and seed number to a relatively greater extent than dry matter production, leading to highest 'reproductive' indices and harvest indices at lowest aerial density and least rooting volume. Decreased rooting volume reduced reproductive yield primarily by decreasing the number of orders of branches, while not affecting numbers of pods and seeds on inflorescences. Increased aerial density specifically reduced fruit set and seed number on all inflorescences. Number of branches in each order of inflorescence was reduced, but not the number of orders of branches. Results are discussed in relation to observed effects of inter-plant competition under field conditions, and to nutritional and hormonal hypotheses concerning reproductive performance.
Effect of solution pH, external calcium concentration, and aluminium activity on nodulation and early growth of cowpea
Authors: Alva AK , Asher CJ , Edwards DG
Published: November 2004

Effects of pH, calcium (Ca), and aluminium (Al) on the growth and nodulation of cowpea (Vigna unguiculata) were studied in large-volume, dilute nutrient solutions. Ca concentrations over the range 0.05 mM to 2.5 mM, and pH over the range 4.5 to 5.5, had no significant effect on the growth of the host plant. However, the combination of low pH and low Ca delayed nodulation and strongly depressed nodule number and nodule dry weight. At the highest Ca concentration, effects of pH on nodule number were small and not significant, and effects on nodule weight, although significant, were much smaller than at the lowest Ca concentration. It was concluded that nodulation was more sensitive to low Ca and low pH than was host plant growth. At pH 4.5 and 0.5 mM Ca, A1 delayed and depressed nodulation. An activity of 12.7 8M Al delayed nodulation by four days, and reduced nodule number and nodule dry weight drastically. At higher Al activities, nodulation was reduced to zero. The critical Al activities (10% reduction) were approx. 0.3 and 0.5 ,8M for nodule number and nodule dry weight. The dry weight of tops and roots showed a roughly linear decrease with increasing Al activity over the range 0 to 8 8M, both in inoculated plants supplied with 'starter nitrogen' and in plants supplied continuously with adequate mineral nitrogen. Critical A1 activities for growth were in the range of 4 to 8 PM. It was concluded that nodulation was much more sensitive to Al than was host plant growth. The results are discussed in relation to recent literature on the acid tolerance of cowpea.
Feed intake, nitrogen retention and liveweight of Hereford and crossbred Hereford steers offered forage diets differing in digestibility and nitrogen content
Authors: Hennessy DW , Barlow R , Williamson PJ , Murison RD , Herilhy JW
Published: November 2004

Forty-eight steers, comprising purebred British cattle (Hereford) and their crosses with Bos indicus (Brahman cross Hereford), dairy (Friesian cross Hereford) and large European (Simmental cross Hereford) sires were used to record feed intake and estimate nitrogen retention of each genotype. In the first experiment, the feed intake of steers fed on 3 forage diets (H, M and L, metabolizable energy 9.3, 8.4 and 7.0 MJ/kg DM and nitrogen 22.4, 14.9 and 5.6 g/kg DM, respectively) was recorded over 80 days, with feed digestibility and N retention estimated over two, 10-day periods, at the beginning and end of the experiment. The second experiment followed immediately on from the first with the feed intake of steers of each genotype being recorded over 14 days, when each steer was given the H-diet. Steers were then taken off pasture for 70 days and the third experiment completed in pens by recording the feed intake of all steers over 14 days when given the H-diet. Steers fed on the H-diet in experiment 1 had higher (Pless than0.01) feed intakes and N retentions than steers fed on the M- and L-diets; M-diet steers had significantly higher values than L-diets steers for both these measures. Consequently, H-diet steers were heavier (331+-3.6 kg liveweight) than M- (295+-5.1 kg) or L-diet (225+-3.6 kg, standard error) steers after adjusting for initial differences in liveweight by covariance. During experiment 1, Brahman cross steers ate 22% less (Pless than0.01) hay on the L-diet (as g organic matter (OM)/kgsup(0).sup(75) liveweight) than Friesian cross steers, and 17% less (Pless than0.05) than steers of the other genotypes. Brahman cross steers had a 12% lower intake of digestible OM than Friesian cross steers only on the M-diet in the early part of experiment 1, but not the later part. When all steers were given the same diet (H-diet) in experiments 2 and 3, feed intake did not differ between genotypes. There were differences between diets in the excretion and net retention of N by steers, and in the apparent digestibility of N, but differences were not attributed to genotype. It appears that diet was only partially responsible for differences between genotypes in liveweight recorded at grazing.
The effect of epistasis on chromosome mapping of quantitative characters in wheat. I. Time to spike emergence
Authors: Redden R
Published: November 2004

Chromosome mapping of genes affecting time to spike emergence was attempted using the complete series of donor cultivars Hope, Kenya Farmer and Marquis chromosome substitutions into recipient cultivar Chinese Spring, grown at four locations. Substitution line intercrosses and backcrosses were also grown at two dates of planting at one location. The expression of time to spike emergence involved both additive and between chromosome interaction expressions, which were both strongly affected by location. There was a trend for individual additive effects of chromosomes and for the overall between chromosome interactions in the Hope and Kenya Farmer series to decrease from the early to later winter sowing dates over the four locations. These effects were attributed to interactions between the substituted chromosomes and the background genotype of the recipient variety. A major gene effect accounted for the difference between Marquis and Chinese Spring genotypes, and for certain chromosome expressions in other series.
An analysis of yield reduction caused by stripe rust in Rongotea wheat.
Authors: Gaunt RE , Cole MJ
Published: November 2004

Natural field epidemics of stripe rust (Puccinia striiformis) were manipulated by seed treatment and foliar sprays to provide a range of disease severities and durations in several locations in three seasons. Yield in the absence of disease, disease severity and disease duration in the natural epidemics varied markedly between the three seasons. The effect of disease on yield and yield components was different in each season and there was no empirical model which consistently described the relationship between disease severity and yield reduction. Empirical models had little relation to the cause of yield reduction in specific crops and could not therefore be used for disease management purposes. The identification of action levels for management purposes based on mechanistic criteria is discussed.
Potential of Lotus germplasm for the development of salt, aluminium and manganese tolerant pasture plants
Authors: Schachtman DP , Kelman WM
Published: November 2004

As part of a search for alternative legumes adapted to unfavorable edaphic conditions in southern Australian pastures, nineteen accessions from nine Lotus species were tested for tolerance to salinity and/or acidity. Four Trifolium cultivars and two Medicago cultivars with known responses to salinity and acidity were grown as controls. Salt tolerance was assessed in sand culture with NaCl as the predominant salt. The growth of accessions within the species L. maroccanus, L. tenuis, L. angustissimus, L. corniculatus and L. subbbiflorus did not significantly decrease in 120 mol m-3 NaCl. Tolerance to acid soil conditions was assessed in nutrient solutions with aluminium and manganese at pH 4.5. L. pedunculatus cv. Grasslands Maku and an accession of the winter annual, L. purshianus, were tolerant to both aluminium and manganese. The L. corniculatus accessions were intermediate in their tolerance to acidity. The responses of the Trifolium and Medicago cultivars to aluminium, manganese and salinity were similar to known field responses.
The effect of high temperature on kernel dimensions and the type and occurrence of kernel damage in rice
Authors: Tashiro T , Wardlaw IF
Published: November 2004

Rice (Oryza sativa L. cv. Calrose) growing at 27/22�C was either transferred to day/night temperatures ranging from 24/19 to 39/34�C 7days after heading and held at these temperatures until maturity, or transferred to a temperature of 36/31�C for 8 day periods at regular intervals commencing from heading. Kernel dimensions were measured directly and the types of kernel damage at maturity were characterized by direct viewing under the light microscope of intact and sectioned kernels, or by scanning electron microscopy of the exposed surface of kernels cut transversely with a razor blade. Kernel thickness was reduced most by high temperature treatments commencing 12 days after heading, but other kernel dimensions (length and width) were most sensitive to high temperature earlier in development. Sterility and pathenocarpy were most evident when temperature treatments commenced at heading (approximately 2 days before anthesis) and were greatest at the highest temperature (39/34�C). Abortive and opaque kernels were most evident when the high temperature commenced 4 days after heading and were also most numerous at the highest temperature tested. From observations on the morphology of the kernels it appears that temperatures above 27/22�C can interfere with the early stages of cell division and development in the endosperm. Chalky endosperm tissue occurred in several forms depending on both the temperature level and the timing of the temperature treatment. White-core kernels were only evident at a temperature of 27/22�C. White-back kernels were most numerous at 36/31�C and when the high temperature treatment commenced 16 days after heading. Milky-white kernels were found in all but the lowest temperature treatment (24/19�C), with a peak at 36/31�C and this type of damage was most evident when the high temperature treatment commenced 12 days after heading. Differences in endosperm cellular morphology were observed between the different types of damage, and in accord with other published data the chalky appearance was associated with the development of numerous air spaces between loosely packed starch granules and a change in light refraction.
Adaptation of soybean (Glycine max (L.) Merrill) to the dry season of the tropics. II. Effects of genotype and environment on biomass and seed yield
Authors: Mayers JD , Lawn RJ , Byth DE
Published: November 2004

Eight soybean genotypes were sown at weekly intervals in three tropical dry season environments to examine genotypic and environmental effects on growth and seed yield per plant. In general, dry matter (DM) at maturity increased exponentially with crop duration and so was greater with later maturing genotypes and sowing dates where photothermal conditions slowed development. Across environments, thermal time provided a better description of DM accumulation than did crop duration, indicating direct effects of temperature on growth rates. Among genotypes, the relationship between seed yield and DM production was strongly linear, implying that under the wide spacings of the study, DM production was the main basis of genotypic differences in seed yield. Among environmental means, the relationship was both weaker and curvilinear, suggesting that environmental effects on vegetative growth were not necessarily reflected in seed yield. Further, where photothermal regime delayed flowering and maturity, vegetative growth was often excessive, and harvest index (HI) smaller. HI was also smaller where flowering coincided with cool night temperatures (< c. 14�C) and podset was reduced. Overall, HI was negatively correlated with crop duration. Responses are discussed in terms of the implications for soybean improvement for the tropical dry season.
Phosphorus efficiency in pasture species. V. A comparison of white clover accessions
Authors: Godwin DC , Blair GJ
Published: November 2004

Seed collections of 'naturalized' white clover (Trifolium repens L.) accessions, believed to have been derived from a Dutch 'wild white' clover introduced into the Northern Tablelands area of New South Wales were made. The collections were made from areas with low, high, and intermediate concentrations of extractable soil phosphorus. In a controlled environment pot experiment, the shoot and root growth and P uptake of each of these accessions was compared over a range of six P rates to three commercially available accessions-Ladino, Grasslands Huia, and Haifa and an accession from Algeria. Various methods of determining the efficiency of ultilization of P were examined. By all methods studied, Ladino generally was more efficient at utilizing applied P. Ladino produced a larger shoot biomass and greater length of root than other accessions, had a higher P uptake, and was more efficient in utilizing this P for the synthesis of biomass. The rankings of the clover accessions in terms of P efficiency changed according to the definition used. The study suggests that some scope exists for selection for P efficiency in clover accessions.
Grain protein responses to nitrogen applied to wheat growing on a red earth
Authors: Angus JF , Fischer RA
Published: November 2004

Dryland wheat was fertilized with ammonium nitrate or liquid urea-ammonium nitrate at the time of sowing or about 3 months later (generally at the terminal-spikelet stage) on a well-drained site near Harden on the south-west slopes of New South Wales. The experiments continued from the second to the fifth year (1981-1984) of the cropping phase of a crop-pasture rotation. The maximum agronomic efficiencies for yield in the four consecutive years were 19, 4, 23 and 25 kg grain per kg of applied nitrogen (N). The three large responses were obtained in wetter than average seasons and the small response was obtained during drought. In the last three years of the study the yield response to nitrogen at the terminal-spikelet stage was found to be close to but slightly less than that for N applied at sowing. In those years the agronomic efficiencies for the late-applied N were 0, 22 and 22. The apparent recovery of fertilizer N in the above-ground parts of the crop at maturity was up to 70% of the fertilizer applied in the year of sowing, and, after the drought during which there was little uptake of fertilizer N, up to 62% by the subsequent crop. The fertilizer efficiencies in the non-drought years were higher than generally reported in south-eastern Australia, and indicate potential for profitable delayed application of N fertilizer to wheat. Grain-protein responses were variable from year to year and are discussed against a simple theoretical background of the amount of N applied and grain-yield response.
The relationship between seedling infection types and field reactions to leaf scald in Clipper barley backcross lines
Authors: Abbott DC , Burdon JJ , Jarosz AM , Brown AHD , Muller WJ , Read BJ
Published: November 2004

Eighty-four third backcross (BC) lines of barley with different chromosomal segments of Hordeum spontaneum in a H. vulgare (cv. Clipper) background, were tested for resistance to a mixture of isolates of Rhynchosporium secalis using a seedling assay. Twelve of the lines were classed as resistant, including two which segregated for resistance. Plants tested using the seedling assay were subsequently planted in the field in Canberra and levels of disease monitored through to plant maturity. Seedling assay scores and field disease levels were closely correlated (r = 0.72, P < 0.001). Furthermore, grain yields for resistant BC-lines were 25% higher, on average, than those for susceptible lines. A separate field trial containing a selection of these lines was conducted in a scald-prone barley growing area (Wagga Wagga). The results obtained were consistent with those from the Canberra trial. The experiments demonstrate that resistances to leaf scald in H. spontaneum, first detected as seedling response types, also function to increase the resistance of barley throughout the growing season.
Agronomic studies on soybean (Glycine max (L.) Merrill) in the dry season of the tropics. III. Effect of artificial photoperiod extension on phenology, growth and seed yield
Authors: Mayers JD , Lawn RJ , Byth DE
Published: November 2004

Soybean cultivars developed for the tropical wet season performed poorly when grown in the dry season in north-west Australia. The proposition that breeding for later flowering time might enhance yields was tested by using artificial photoperiod extension (14 h day-1 for 28 days post-emergence) to delay flowering of field plots of agronomically improved genotypes. Canopy development and interception of photosynthetically active radiation (PAR), dry matter (DM) accumulation, seed yield and seed composition were examined, and compared with that from plants grown under natural photoperiods. Photoperiod extension delayed flowering an average 24 days, and maturity by an average 14.5 days, the effect being greater in the earlier-flowering genotypes. Differences among genotypes and photoperiod treatments in above-ground DM at the beginning and end of flowering were almost entirely due to the consequences of differences in phenology for cumulative PAR interception. DM at maturity was a simple linear function of crop duration (r2 = 0.95**), while seed yield exhibited an optimum-type response with DM ( R2 = 0.79**). The net consequence was that photoperiod extension increased DM production by an average 2.23 t ha-1 and seed yield by an average 0.65 t ha-1. The analyses suggested that a crop duration of c. 143-146 days would be needed to maximize seed yield under the agronomic conditions of the study, whereas the longest duration among the agronomically improved genotypes under natural photoperiod conditions was 136 days. It was concluded that breeding to constrain precocious flowering under short day conditions would be a viable strategy to improve the yield potential of soybean in the dry season.
Double-stranded RNA in Carica papaya is not associated with dieback disease and is unlikely to be of viral origin
Authors: Harding RM , Teakle DS , Dale JL
Published: November 2004

Two distinct double-stranded RNA (dsRNA) patterns, each comprising two major bands, were detected in extracts from apparently healthy Carica papaya plants. The slowest migrating band was present in both patterns and had an estimated Mr of 2.8 x 106 . The faster migrating bands had estimated Mrs 1.3 x 106 or 1.2x106. When papaw total and organellar DNA was extracted and hybridized with 32P-end labelled papaw dsRNA, the probe hybridized strongly with total and chloroplast DNA, but only very weakly with mitochondria1 and nuclear DNA.
Phosphorus efficiency in pasture species. VII. Relationships between yield and P uptake in two accessions of white clover
Authors: Blair GJ , Godwin DC
Published: November 2004

Lack of data on root growth and relationships between root parameters and P uptake are major limitations to understanding and modelling P efficiency in crop and forage plants. An experiment was conducted whereby two accessions of white clover (Trifolium repens, Chiswick and Ladino) were grown in pots in a P deficient soil fertilized with a low (P5 [kg ha-1]) or high (P40) P application rate. Plants were harvested at 10, 16, 22, 28, 34 and 40 days after transplanting and tops harvested and roots recovered from the pots. Detailed measures of root members were made at 10, 16 and 22 days and these correlated with P uptake. Dry weight of tops of accessions was the same between the two rates of P until day 28. At 40 days, the tops yield of Ladino was higher than Chiswick at P40. Root dry weight increased with increasing P application rate and time from day 16 onwards. Significant differences in root growth only occurred at the 16 and 34 day harvests at P5. Ladino tended to have a greater mean P uptake over time than did Chiswick at both P levels. P uptake was found to be positively correlated with shoot and root dry weight, root length, root number, root volume and surface area, and negatively correlated with mean root diameter and mean length per root. Root extension rate at low P in Ladino was greater than that in Chiswick, which may explain the greater P uptake by Ladino at low P at later harvests in this experiment. The changes in length, diameter and number of roots in the two accessions examined in this study, with time, in response to P, reflect some form of coordination. Chiswick tended to produce many short roots whilst Ladino fewer long roots. Only small differences in P uptake per unit root length were measured, which suggest that total root length or root extension rate is the primary determinant of total P uptake in these accessions of white clover.
Inheritance in hexaploid wheat of Septoria tritici blotch resistance and other characteristics derived from Triticum tauschii
Authors: May CE , Lagudah ES
Published: November 2004

In an attempt to find new sources of resistance to the disease septoria tritici blotch (STB) of wheat, we have evaluated a worldwide collection of the diploid species Triticum tauschii for their reaction to infection by pycnidiospores of Mycosphaerella graminicola, the pathogen causing this disease. We have also screened a selection of synthetic hexaploid wheats, produced by hybridizing T. tauschii with tetraploid wheats, as well as the first and second generations of hybrids between some of these synthetics and commercial wheats. Almost 90% of the T. tauschii accessions and two-thirds of the synthetic hexaploids were resistant to STB. In the intercrosses with susceptible commercial wheats (e.g. Egret), the STB resistance was effectively transmitted as a single dominant gene, as indicated by a 3:l ratio of resistant: susceptible plants in F2 progenies. In crosses with the STB-resistant wheat, M1696, a 15:l ratio in F2 progenies indicated that the two resistance genes were different. F2 progenies involving the wheat cultivar Teal were more ambivalent. Other genetic traits also segregated in these plants although not all showed easily distinguishable phenotypic differences. Non-beneficial characters included genes for height, hybrid necrosis, grass clump dwarfism, tenacious glumes or threshability, speltoid head shape, and dark seed colour. Other genes controlled the more neutral characters coleoptile colour, hairy glumes and glume colour. Beneficial genes include resistance to septoria tritici blotch.
Evidence for the existence of a single race of common rust caused by Puccinia melanocephala, in Australian sugar cane cultivars
Authors: Taylor PWJ
Published: November 2004

A detached-leaf method for testing for physiological races of common rust disease, caused by Puccinia melanocephala, in Australian sugar cane cultivars is described. Single-uredium isolates collected from various locations in Queensland, Australia, between 1978 and 1986 were screened. Host reaction type was specific to individual cultivars and did not vary when these cultivars were inoculated with different rust isolates. For each cultivar there was no difference in generation time for each isolate. These results suggest that there is only one physiological race present in the pathogen population in Queensland. Reported changes in the severity of common rust disease in sugarcane cultivars were caused by changes in environmental conditions rather than the development of new races of the pathogen. Rust infection fluctuated during the growth of sugar cane, with a major peak occurring at tillering and stem elongation, following moderate rainfall and temperatures between 12 and 25�C. Rust was more severe on older leaves than on younger leaves.
Changes in genomewide occupancy of core transcriptional regulators during heat stress
Authors: Zanton Sara J. , Pugh B. Franklin
Published: November 2004

Organisms respond to heat stress by reprogramming gene expression. In
Saccharomyces cerevisiae
, heat-induced genes tend to be regulated by factors that belong to the Spt-Ada-Gcn5 acetyltransferase (SAGA) transcription regulatory pathway, whereas heat-repressed genes tend to be regulated by a parallel pathway involving transcription factor IID (TFIID). Here, we examine whether heat stress affects the occupancy of representative factors of each pathway at promoter regions throughout the yeast genome. Representatives of the SAGA pathway include the TATA binding protein, Spt3, and Mot1. Representatives of the TFIID pathway include the TATA binding protein, TAF1, and Bdf1. We find that heat stress causes disassembly of the TFIID pathway at genes that are inhibited by stress. In contrast, heat induces assembly of the SAGA pathway at stress-induced genes, although many also assemble along the TFIID pathway. Other genes were found to assemble almost exclusively along the TFIID pathway. Strikingly, these genes are lowly transcribed and are generally not induced. Thus, heat stress leads to factor assembly along each pathway but with distinct transcriptional outcomes. Further investigation of these pathways reveals that Bdf1 and Mot1 negatively regulate the SAGA pathway in different ways. The findings suggest that Bdf1 blocks assembly, whereas Mot1 promotes disassembly of the transcription machinery.
Recycling Frank: Spontaneous emergence of homochirality in noncatalytic systems
Authors: Plasson Raphaël , Bersini Hugues , Commeyras Auguste
Published: November 2004

In this work, we introduce a prebiotically relevant protometabolic pattern corresponding to an engine of deracemization by using an external energy source. The spontaneous formation of a nonracemic mixture of chiral compounds can be observed in out-of-equilibrium systems via a symmetry-breaking phenomenon. This observation is possible thanks to chirally selective autocatalytic reactions (Frank's model) [Frank, F. C. (1953)
Biochim. Biophys. Acta
11, 459–463]. We show that the use of a Frank-like model in a recycled system composed of reversible chemical reactions, rather than the classical irreversible system, allows for the emergence of a synergetic autoinduction from simple reactions, without any autocatalytic or even catalytic reaction. This model is described as a theoretical framework, based on the stereoselective reactivity of preexisting chiral monomeric building blocks (polymerization, epimerization, and depolymerization) maintained out of equilibrium by a continuous energy income, via an activation reaction. It permits the self-conversion of all monomeric subunits into a single chiral configuration. Real prebiotic systems of amino acid derivatives can be described on this basis. They are shown to be able to spontaneously reach a stable nonracemic state in a few centuries. In such systems, the presence of epimerization reactions is no more destructive, but in contrast is the central driving force of the unstabilization of the racemic state.