bluuebunny/crossref_metadata_2025 huggingface dataset:
Heritabilities of small-scale and standard measures of wheat quality for early generation selection
Authors: O'Brien L , Ronalds JA
Published: November 2004

This paper compares offspring-parent heritability estimates for a number of small-scale early generation quality tests with those from standard macromeasures of wheat quality for their application to early generation selection for wheat quality. It especially reports heritability estimates for two new small-scale tests, the proportion of total flour protein insoluble in dilute acetic acid (residue protein) and the sodium dodecyl sulfate sedimentation volume. Materials utilized in this study were 21 random F3 lines and their derived F4 bulks from each of seven wheat crosses.The heritability estimates for the determination of quality by small-scale and standard macro-quality test procedures varied between crosses, and the lack or range in test values in either generation was generally not the cause of the low to zero estimates obtained.Flour milling yield and flour protein content were the only two small-scale tests to exhibit low to zero heritability estimates in some crosses, while for the standard macromeasures it was the farinograph properties, development time and dough breakdown, and the extensograph properties, extensibility and resistance to stretching.When data were pooled over crosses, medium to high heritability estimates were obtained for all of the small-scale test procedures and for all of the macromeasures except for farinograph development time and dough breakdown and extensograph extensibility.Despite the effects of genotype x environment interactions in reducing heritability, the estimates reported indicate that, where seed quantity is limiting, good average response to early generation selection can be expected using tests to estimate grain hardness, flour protein content and a measure of protein quality. When seed quantity is not limiting, good average response to early generation selection can be expected using the standard macromeasures of wheat quality.
Low effectiveness of three rock phosphates as phosphorus fertilizers and liming materials on an acid clay-loam
Authors: Yeates JS , Allen DG
Published: November 2004

The effectiveness of three finely ground rock phosphates (PRs) was compared with ordinary superphosphate (OSP) for subterranean clover growth and for increasing soil bicarbonate-extractable P levels over two successive 8-week periods on a very acid clay-loam (pH (0.01 M CaCl2) 4.3) in a glasshouse experiment. All PR sources were poorly effective compared to OSP. Maximum dry matter and P uptake of each PR source was less than that of OSP at each harvest. Relative to surface application, mixing throughout the soil reduced the effectiveness of OSP for dry matter and P uptake, but had little effect on the PR sources. Relative to OSP, the effectiveness of PR sources did not increase at the second harvest. Bicarbonate-extractable P levels for soil-incorporated Island PR plateaued below the highest rate applied. Phosphorus uptake by the herbage at harvests 1 and 2 was not well related to soil bicarbonateextractable P levels at harvest 1, and source dependency was indicated. Soil pH was markedly increased by each of PR sources at application rates within the rates required to reach maximum dry matter and P yield. Increased soil pH at high PR applications is likely to have reduced PR dissolution, and contributed to low agronomic effectiveness. Dry matter yield at both harvests was dependent on P concentration in the tops, regardless of the P source or method of P application. A higher soil buffering capacity for pH, P or Ca than was present in this soil seems necessary for sufficient PR dissolution to achieve the same agronomic effectiveness as OSP.
Cattle handling at abattoirs. I. The effects of rest and resting conditions before slaughter and of electrical stimulation of carcasses on carcass weight and muscle properties
Authors: Wythes JR , Shorthose WR , Powell VH
Published: November 2004

In three experiments, we studied the effects of duration of rest and nature of resting conditions before slaughter and of electrical stimulation, on carcass weight, bruising and muscle properties of cattle of known age. In experiment 1, 22 Droughtmaster steers (mean liveweight 284 kg) rested for 2.5 or 26.5 h following a 125 km road journey. In experiment 2, 82 Zebu crossbred cows (mean liveweight 416 kg) rested for 4 or 52 h after a 1310 km rail journey. Those rested for 52 h were allowed to rest either peacefully (P), subjected periodically to noise and disturbances (D) or mixed with unfamiliar cows (M). In experiment 3, 68 Hereford and Simmental x Hereford cows (mean liveweight 445 kg) rested for 28 h, after a 930 km road and rail journey, and during this time were subjected to resting treatments P, D or M. All cattle had access to water until slaughter, and were slaughtered at the same abattoir. All carcasses were electrically stimulated in experiment 1, but only half those in each treatment group in experiments 2 and 3. Electrical stimulation of carcasses had a much greater effect on tenderness than did resting conditions before slaughter. The LD muscles of stimulated carcasses were more tender than those of unstimulated ones. Of the 31 cattle slaughtered after a few hours' rest, only one carcass had a high pH value 24 h post mortem. The LD muscles of cattle rested for 26.5 h were more tender than those of cattle rested for 2.5 h. Resting treatment did not consistently affect mean carcass weight, pH24, time for LD muscle to cool to 20�C or cooking loss. Noise and disturbance during the resting period appeared to be more stressful than mixing (13.6 v. 4.5% carcasses with high muscle pH 24 h post mortem in experiment 3 only). Steers rested for 26.5 h had a higher mean bruise score than those rested for only 2.5 h, but there was no effect of resting time or resting conditions on bruising in cows.
Corrigendum - Nitrogen fixation activity by white clover pastures during flood irrigation cycles
Authors: Mundy GN , Jones HR , Mason WK
Published: November 2004

The effect of flood irrigation on clover nitrogen fixation (acetylene reduction activity) was investigated in unfertilized pastures and pastures fertilized with 100 kg N/ha as NH4N03. During the experiment acetylene reduction activities were monitored between successive flood irrigations. The rate of ethylene production increased with decreasing soil water content, peaking 13 days after irrigation. Measured nodule activity then declined, possibly owing to water stress. Nitrogen fertilizer reduced acetylene reduction activities to about half that of the unfertilized pastures. For most of the irrigation cycle acetylene reduction by the pasture was below the measured maximum.
Phosphorus seed coatings for pasture species. II. Comparison of effectiveness of phosphorus applied as seed coatings, drilled or broadcast, in promoting early growth of phalaris (Phalaris aquatica L.) and lucerne (Medicago sativa L.)
Authors: Scott JM , Blair GJ
Published: November 2004

The relative efficiency of phosphorus (P) seed coatings and drilled and broadcast applications of P was investigated in a glasshouse experiment conducted with phalaris (Phalaris aquatica L.) and lucerne (Medicago sativa L.) in P-deficient soil. Two P sources (monocalcium phosphate [MCP] and dicalcium phosphate [DCP]) were used at three rates in seed coatings (0, 5 and 10 kg P ha-1) or at six rates each of drilled or broadcast applications (0, 2.5, 5, 10, 20 and 40 kg P ha-1). MCP coatings severely reduced lucerne emergence and hence yield, but had little effect on phalaris emergence. No other fertilizer treatment affected emergence. The height of phalaris plants at 27 days after sowing (d.a.s.) was increased as much by seed coatings containing MCP at 5 kg P ha-1 as by drill or broadcast applications of MCP at 20 kg P ha-1. Plant height of the MCP seed coating treatments was also less variable than the other application methods, suggesting that the coatings provided more uniform access to P. Seed coatings containing DCP at 10 kg P ha-1 increased phalaris plant height more than did drilled or broadcast applications at 40 kg P ha-1, but there was no effect of any DCP treatment on lucerne growth at 27 d.a.s. The relatively large differences observed in plant height between different application methods at 27 d.a.s. diminished over time until, at 57 d.a.s., only small differences were evident. The dry matter yield and P content of both species were increased by increasing rates of MCP, but DCP had little effect at any rate. The reduced differences between the seed coating treatments and the other application methods at harvest may have been due to the limited soil volume of the pots used; further work is necessary in larger soil volumes to determine the significance of the early growth advantage conferred on phalaris by the phosphorus seed coatings, and to find ways of protecting lucerne from soluble P sources during germination.
The digestibility of grain of two cultivars of oats differing in lignin content
Authors: Rowe JB , Crosbie GB
Published: November 2004

A study was conducted to investigate the effect of differences in lignin content in the hulls of oats (Avena sativa L.) on digestion of whole grain by sheep. The in vivo organic matter digestibility of a low-lignin diet based on the cultivar Murray (8 g lignin/kg) was approximately 15% higher than a diet based on high-lignin Mortlock oats (23 g lignin/kg). The digestible energy (DE) values were 15.6 and 14.0 MJ/kg DM for the two diets respectively. The apparent digestibilities of neutral detergent fibre (NDF) and acid detergent fibre (ADF) were 0.63 and 0.57, respectively, in the case of the Murray diet, and 0.31 and 0.28 in the case of the Mortlock diet. Measurements were also made of the rate and extent of dry matter (DM) disappearance of whole grain and hulls from dacron bags suspended in the rumen of a steer for varying lengths of time. There was no significant difference in the loss of Mortlock hull dry matter from bags incubated for 24, 48 or 96 h (mean 5%), compared with Murray (low-lignin) hulls where there was an increase from 8.5% after 24 h to 29.9% disappearance at 96 h. The results are consistent with there being a major effect of hull lignin levels on the digestibility of both hulls and the whole grain and, when hull to groat ratios and hull silica levels are similar, may be the principal factor determining 'nutritional value' of oat grain.
Productivity of irrigated pastures following paraplowing and gypsum slotting of subsoil exposed by laser landforming dash a short term study
Authors: Blaikie SJ , Kelly KB , Mason WK , Martin FM
Published: November 2004

The effect of two soil amelioration techniques (paraplow and gypsum-enriched slots) on the productivity of white clover/ryegrass pasture was assessed by monitoring plant and soil water status and canopy gasexchange during an irrigation cycle. The soil was a dense clay, exposed when the topsoil was removed during laser landforming. Pasture growth on such exposed subsoils is very slow.All parameters of soil and plant water status indicated that there was some benefit from amelioration, with slots > paraplow > control. This trend was reflected in canopy photosynthesis. The photosynthetic efficiencies of canopies declined rapidly after 40 mm Class A pan evaporation less rainfall (E- R) in the control and after 50 mm E - R in the paraplowed treatments. At the end of the irrigation cycle (72 mm E - R) the efficiencies of the control and paraplow were about 20% and 50%, respectively, of the wellwatered. The efficiency of the canopy in the slot treatment remained high throughout.Without soil amelioration, pastures grown on exposed subsoil cannot maintain high levels of photosynthesis during a normal irrigation cycle in summer. More frequent irrigation or soil amelioration (or both) are required if pasture production on exposed subsoil is to be dramatically improved.
Inbreeding and heterosis in queen bees in relation to brood area and honey production
Authors: Oldroyd BP , Goodman RD
Published: November 2004

The brood area and weight gain of colonies headed by hybrid queens were compared with those headed by their inbred parentals. Although the colonies headed by hybrid queens had increased brood production, this did not lead to increased honey production. There was a significant increase in the longevity of hybrid queens compared with inbreds, and this alone may justify their use by apiarists.
The narrow-leafed lupin (Lupinus angustifolius L.) as a nitrogen-fixing rotation crop for cereal production. II. Estimates of fixation by field-grown crops
Authors: Herridge DF , Doyle AD
Published: November 2004

Experiments were commenced in 1978 to evaluate the impact of the narrow-leafed lupin (Lupinus angustifolius L.) on production of subsequent wheat crops in the N-infertile, acidic soils of the Pilliga Scrub region of northern New South Wales. There were four sites. Production of lupin dry matter (shoots, roots) ranged from 5.0 (Florida A) to 11.4 t ha-1 (Kamala), reflecting seasonal rainfall and crop management. Lupin seed yields varied between 1.29 (Florida A) and 2.03 t ha-1 (Kamala); at two of the sites, yields were greater than the yields achieved by the adjacent wheat crops. At Spring Creek, the wheat was not harvested for grain due to the extremely poor plant growth. Seasonal profiles of C2H2 reduction by each of the four lupin crops reflected growth characteristics; maximum activity coincided with rapid accumulation of dry mater. Diurnal profiles of C2H2 reduction were unaffected by plant age. Rates peaked around noon after rapidly increasing from minimum pre-dawn levels. Total N2 fixed by each of the lupin crops was estimated by comparing N Yields of the lupin and wheat crops. The various methods used resulted in almost identical estimates of N2 fixation at Kamala (215-218 kg ha-') and Spring Creek (222-228 kg ha-'). Estimates . of N2 fixed by the two Florida crops ranged from 72 to 101 (Florida A) and from 82 to 134 kg ha-' (Florida B). The data indicate that large amounts of N can be fixed by field-grown lupins, amounts well in excess of the quantities of N harvested in the seed.
Preliminary 'in vivo' measurements of protein and energy metabolism in the skin of sheep
Authors: Harris PM , Dellow DW , Sinclair BR
Published: November 2004

An arterio-venous preparation was developed which allowed infusion into, and/or sampling from, branches of the deep circumflex iliac artery and vein supplying and draining a discrete area of skin on the abdominal flank of Romney sheep.Measurements of blood flow (using dye dilution techniques), utilization or output of energy metabolites (oxygen, glucose, lactate and acetate) and amino acid metabolism were made in relation to whole body protein and energy metabolism.Measurements on the patch suggested that blood flow to the total skin was about 6% of cardiac output but that only 1-2% of whole body oxygen utilization occurred in the skin. This was partly accounted for by a significant proportion of glucose uptake (1.15 g day-1) being anaerobically oxidized to lactate (0.41 g day-1). Measurements of protein synthesis in the patch showed that between 10 and 16% of whole body protein synthesis occurs in the skin.Results from the preparation demonstrate that it is a useful procedure to study metabolism in a defined patch of skin in the intact animal.
The effect of 2-(4-2′,4′-dichlorophenoxy-phenoxy)-methyl propanoate on the uptake and utilization of zinc by wheat
Authors: Robson AD , Snowball K
Published: November 2004

The effect of the herbicide diclofop-methyl on the uptake and utilization of zinc by wheat was examined in a series of glasshouse experiments. Application of diclofop-methyl to soil induced symptoms of zinc deficiency and decreased zinc concentrations within shoots. Effects of the herbicide application in decreasing plant growth were more marked at marginal levels of zinc than at adequate levels. The application of diclofop-methyl to the soil induced zinc deficiency by decreasing the uptake of zinc from soil rather than by effects on the utilization of zinc within the plant. The application of diclofop-methyl to leaves with no contamination of the soil did not affect the zinc status of the plant. Effects of diclofopmethyl in decreasing zinc uptake did not appear to be due to effects of the herbicide on root weight or root length.In the field, diclofop-methyl is sprayed on crops with low leaf areas, hence a high proportion of the herbicide will reach the soil. It is thus likely that in field crops application of diclofop-methyl will induce zinc deficiency where the supply of zinc for the crop is marginal.
Water use and water use efficiency of old and modern wheat cultivars in a Mediterranean-type environment
Authors: Siddique KHM , Tennant D , Perry MW , Belford RK
Published: November 2004

Water use and water use efficiency of old and modern wheat cultivars and one barley cultivar were measured in a Mediterranean environment at Merredin, W.A. Water use efficiency for grain increased substantially from old to modern cultivars, with little difference among modern cultivars. Water use efficiency for dry matter was similar between cultivars. Barley had the highest water use efficiency of both grain and dry matter. Improved water use efficiency for grain in modern cultivars was associated with faster development, earlier flowering, improved canopy structure and higher harvest index. Modern cultivars used slightly less water than old cultivars. The pattern of water use was also different, with late-maturing old cultivars using more water in the pre- than the post-anthesis period. The ratio of pre- to post-anthesis water use was highest with the late-maturing, old cultivar Purple Straw (5.2:1) and lowest with early-maturing, modern cultivar Gutha (3.0:1). Soil evaporation estimates showed that modern cultivars had lower rates of soil evaporation in the early part of the growing season. This was associated with their faster leaf area development and improved light interception. About 40% of the total water use was lost by soil evaporation with very little difference between wheat cultivars. Barley had 15% less soil evaporation than wheat. Water use efficiency for grain based on transpiration (transpiration efficiency) for the four modern cultivars was 15.8 kg ha-1 mm-1, similar to other studies in comparable environments. Some further improvement in water use efficiency appears possible through improvement in crop biomass and harvest index. However, given the frequent and severe limitations of total water supply at low rainfall sites such as Merredin, there appears to be more scope for improvement in yield and water use efficiency in the medium and high rainfall areas of the wheatbelt.
Factors which affects the growth of grain legumes on a solonized brown soil. I. Genotypic responses to soil physical factors
Authors: Atwell BJ
Published: November 2004

Lupins (Lupinus angustifolius cvv. Yandee and 75A-258 and L. pilosus cv. P. 20957) and pea (Pisum sativum cv. Dundale) were grown in the field for 43 days on a solonized brown soil. Shoots of L. pilosus and peas grew most rapidly, while L. angustifolius cv. 75A-258 developed a relatively large root system. L. angustifolius cv. Yandee, a commercial lupin cultivar, was poorly adapted; shoot growth was restricted and roots ceased growing 36 days after sowing. The soil factors responsible for these widely differing responses were investigated. Once primary roots of L. angustifolius were 20-30 cm deep, root extension was slow or arrested. Indeed, primary root apices of Yandee were often necrotic in the soil below 20 cm. In contrast, roots proliferated rapidly in the surface 20 cm of the soil, particularly in 7SA-258, suggesting that factors in the deeper soil layers restricted root growth most severely. The vigorous growth of lateral roots of 75A-258 was reflected in a 2.6 fold greater total root length than for Yandee 43 days after sowing. Soil physical properties were not considered a likely explanation for these observations; soil water status and porosity were always favourable for root growth and root sections indicated that no cortical degradation, typical of O2 deficient roots, had occurred. Penetrometer resistance and root tip osmotic pressures suggested that poor root growth could not be ascribed simply to soil mechanical properties. The results suggest, by inference, that soil chemical factors could underlie the phenotypic responses observed.
Growth and subsequent fertility of cows implanted during pregnancy with trenbolone acetate and oestradiol
Authors: Hunter RA , Magner T
Published: November 2004

Under extensive grazing conditions in Australia the pregnancy status of cows is often not known. It is therefore conceivable that if anabolic steroids are administered to females, some may be pregnant. This experiment examined the consequences of such an action. Sixty-nine multiparous cows were grazed together from the sixth to eighth month of pregnancy in July until calf weaning the following May. Thirty-five were implanted in the ear with Revalor� (200 mg trenbolone acetate and 20 mg oestradiol-17G) only once at the commencement of the experiment in July. The remainder served as controls. Treated cows had significantly (P < 0.01) higher liveweight gains pre-calving (0.39 v. 0.28 kg/day) and significantly (P < 0.05) lighter calves at birth (32 v. 35 kg) than the controls. There was no effect of treatment on calf survival before or after birth, calf growth rate or cow fertility after calving.
Evidence for differences between three wheat cultivars in yield response to plant population
Authors: Anderson WK , Barclay J
Published: November 2004

Three wheat cultivars were grown at five seed levels in 15 experiments under rain-fed conditions in the central wheatbelt of Western Australia in the 1986, 1987 and 1988 seasons. Guthea (released in 1982, 87 cm tall) required less seed and fewer plants on average to achieve its maximum grain yield than either Gamenya (released in 1960, 82 cm) or Aroona (released in 1981, 73 cm). At sites where Gutha was best adapted its optimum population was 65 plants m-2, about half of the population required by the other two cultivars. At sites where Aroona was best adapted its optimum population was 110 plants m-2. Gutha produced larger ears, especially at small populations, but did not increase kernel numbers per m2 in response to increased populations as much as Aroona. It is suggested that when a new cultivar is released its optimum plant population should be assessed in the area for which it is recommended.
The response of wheat tops and roots grown in a leaching environment to rates of nitrogen added as calcium nitrate or organic residues containing 1, 2 or 6% nitrogen
Authors: Diggle AJ , Bowden JW
Published: November 2004

Wheat was grown under leaching conditions in a glasshouse in columns of a loamy sand soil to which nitrogen had been added in the form of calcium nitrate or organic materials containing 1, 2 or 6% nitrogen. All materials were added at a range of rates calculated on an elemental nitrogen basis, so that comparisons could be made between materials at the same level of nitrogen addition. The amount of mineral nitrogen in the soil profile 4 weeks after seeding increased with the addition of each of the sources except for the 1% nitrogen organic material which had no effect. Addition of calcium nitrate caused the greatest increase of mineral nitrogen, but did not result in the greatest plant growth because of less efficient nitrogen uptake associated with leaching. At 7 weeks after seeding, nitrogen stress, as indicated by the nitrogen content of the plant tops, had increased more where the 2 and 6% nitrogen organic materials were added than where calcium nitrate was added. This trend was also reflected in changes in the root to shoot ratios, and was the result of roots catching up with leaching nitrate from the calcium nitrate. In the columns treated with organic material, root profiles at 7 weeks after seeding showed enhanced growth at the surface, where mineralization of the added materials was occurring. Where calcium nitrate was added, a bulge in the root profile occurred at depth, associated with the leached nitrate.
Yield improvement in soybeans using recurrent selection
Authors: Rose JL , Butler DG , Ryley MJ
Published: November 2004

The objective of this study was to evaluate the potential of recurrent selection for improving seed yield in a soybean population. Seventeen parents, chosen for their high yield potential in the sub-tropical environments of Southern and Central Queensland were intermated using a diallel cross mating system. F1 plants were intercrossed in pairs for two more generations and then allowed to self for two generations to produce the base population. The selection criterion was the seed yield of S1 lines grown at Hermitage Research Station. The selection intensity was approximately 10%. After five cycles of recurrent selection the mean yield of the population and the mean yield of the lines selected for recombination had improved by 17% and 54% respectively, in comparison with one of the original parents, Davis. Progress from recurrent selection was evaluated using fifty randomly selected lines from the base population and from each of the first three cycles of selection. The average gain per cycle in seed yield, averaged over five sites was 128 kg ha-1 or 5.4% of the yield of the base population. Greater progress (9.8% per cycle) was measured at the testing site for selection (Hermitage Research Station) which was heavily infested with phytophthora root and stem rot than at three other sites (2.7% per cycle) which has nil or low levels of disease. Broad sense heritabilities for the base population and for cycles 1, 2 and 3 in the evaluation trial were 0.34, 0.25, 0.13 and 0.14 respectively compared with a mean heritability of 0-64 for the first five cycles of the selection experiment. Expected gain from further cycles of selection was estimated at 102 kg ha-1 per cycle for three replicates at a single site. In the evaluation trial correlated responses to selection for yield were found in a number of other traits. Days to flowering was reduced by 0.8 days/cycle while days to maturity increased by 1 day/cycle. Seed shattering score was significantly reduced from 0.98 to 0-69 while there were only minor changes in plant height, lodging and seed coat quality score. Resistance to root and stem rot and seed coat mottling, due to primarily to soybean mosaic virus, were also significantly increased. The improvement in phytophthora resistance was expected as the field used for S1 yield testing had become infested with the disease. A covariate analysis indicated that about half the improvement in seed yield at the Hermitage site was due to the correlated response of increased resistance to phytophthora root and stem rot.
Lambing performances and wool production of maiden and adult Merino ewes fed different amounts of lupin seed in mid-pregnancy
Authors: Kelly RW , Speijers EJ , Ralph IG , Newnham JP
Published: November 2004

Maiden (1.5 years old, 42 kg) and adult (4-5 years old, 55-58 kg) Merino ewes were divided into 15 groups of 30 on the basis of ovulation rate (three classes of ewe: maiden = 1, adult = 1 or 2) and fed lupin seed (91% digestible, 33% crude protein) three times per week at rates equivalent to 0, 100, 200, 300, or 400 g head-1 day-1 from day 28 to day 108 of pregnancy (17 December to 6 March). Thereafter the ewes were fed at the same rate (400-500 g head-1 day-1 of lupins, ad libitum oaten hay) until two weeks post lambing. They were grazed on two hectare plots from day 22 of pregnancy until two weeks after lambing; the plots had 1.3 tomes dry matter/ha (54% digestible, 11% crude protein) at the start of grazing. The differential feeding induced changes in liveweight and condition score during mid-pregnancy ranging across the ewe classifications from 8.4 to +5.0 kg and -1.6 to +1.3 units, respectively. In late pregnancy and lactation there were compensatory changes in the ewes, so that at 12 weeks post-lambing the difference between the animals from the mid-pregnancy feeding treatments had been reduced to less than 2 kg. There was a significant relationship (linear P < 0.001) between lamb birth weight and rate of lupin feeding during mid-pregnancy. For every 0.1 kg head-' day-' of lupins fed, lamb birth weight increased by 0.11 kg. There was no significant effect of class of ewe on this relationship. Maternal plasma glucose levels at about day 100 of pregnancy increased with rate of lupin feeding (interaction between class of ewe and feeding treatment P < 0.01). Ultrasound measurements of cotyledon diameters were greater (P < 0.001), and resistance to maternal placental blood flow less (assessed by Doppler arterial waveform analysis, interaction between class of ewe and feeding treatment P < 0.05) at about day 100 of pregnancy in ewes fed 400 g head-1 day-1 of lupins compared with unfed ewes. These findings indicated that in the unfed ewes there was a reduced nutrient supply to the fetus from reduced glucose availability, smaller placentas and less expansion of the placental vasculature. Growth of the lambs to four weeks of age increased with rate of lupin feeding in mid-pregnancy (quadratic P < 0.05), although the actual differences in weight at four weeks of age were small (<1 kg). Annual wool production from the ewes was significantly affected by the differential feeding during mid-pregnancy, with clean fleece weight (linear P < 0.01), staple length (linear P < 0.01) and strength (linear P < 0.001) increasing with increased rate of lupin feeding, and the position of break shifted from the period of pregnancy to after lambing (quadratic P < 0.01). Mean fibre diameter was not significantly affected by any treatment. It was concluded that the ewes at greatest risk from underfeeding in mid-pregnancy, in terms of lamb and wool production, were maiden ewes and adult ewes bearing twins.
Phosphorus efficiency of three cereals as related to indigenous mycorrhizal infection
Authors: Baon JB , Smith SE , Alston AM , Wheeler RD
Published: November 2004

The influence of indigenous vesicular-arbuscular mycorrhizal infection on the assessment of phosphorus (P) efficiency in wheat ( Triticum aestivum L. cv. Spear), barley (Hordeum vulgare L. cv. Galleon) and rye (Secale cereale L. cv. S.A. Commercial) was studied. P efficiency was defined in terms of uptake (mg P pot-1) or utilization (g dw mg-1 P). Experiments were set up with two soils which had low concentrations of plant available P and had been used in a previous study of P efficiency in cereals. Numbers of spores and infective propagules were significantly different in the two soils. In the soil with low propagule density, the extent of mycorrhizal infection of barley, wheat and rye increased with time. Twenty days after transplanting 3-day old seedlings, there was no difference in the percentage of root length infected (2.0%), but at 40 days, wheat (22.4%) and barley (19.3%) had significantly greater percentage of infected root than had rye (10.7%). At 30 days, wheat had a significantly higher percentage of root length infected than barley. In the soil with high propagule density, infection occurred more rapidly, so that the percentage of root length of wheat and barley infected was not significantly different at the three times of harvest. However, infection of rye significantly increased with time and was higher (31.8%) than that of barley (19.8%) at the final harvest. Mycorrhizal infection was positively correlated with efficiency of P uptake in barley, but not in wheat or rye. However, efficiency in utilization of P by barley and wheat was negatively correlated with infection. The colonization of cereals by the indigenous mycorrhizal fungi decreased with the addition of P to the soils. The results of these studies indicate the potential importance of mycorrhizal infection in assessment of P efficiency in cereals.
The nucleolus organizer regions (Nor loci) of hexaploid wheat cultivars
Authors: May CE , Appels R
Published: November 2004

We have used the techniques of molecular genetics to analyse the nucleolus organizer regions (Nor loci) of a broad range of Australian, Chinese, and other hexaploid wheats (Triticum aestivum L. em Thell.). Genomic DNA was extracted from the leaves of 260 wheat cultivars, 94 different F1 hybrids, and from more than 800 F2 plants. Samples of the DNA were digested with the restriction enzyme TaqI and electrophoretically separated in agarose gels. The DNA fragments were then transferred to DNA filters by Southern blotting and assayed with the probe pTa250.4. This probe specifically detects the intergenic spacer DNA sequences which alternate with the ribosomal-RNA (rRNA) genes in highly repeated tandem arrays within the Nor loci. Analyses of the spacer DNA restriction fragments present in P, F1 and F2 plants show that allelic variants of the Nor loci can be distinguished by the existence of different lengths of spacer DNA fragments, different combinations of different length fragments, or differing amounts of the same length fragments. Eight alleles of the Nor-B1 locus on chromosome 1B (Nor-Bla to Nor-B1h) and 20 variants of the Nor-B2 locus on chromosome 6B (Nor-B2a to Nor-B2t) have been identified. The DNA fragments present in the different alleles are expressed in a co-dominant fashion to give phenotypic F2 ratios of 1 : 2 : 1 and 1 : 2 : 1 : 2 : 4 : 2 : 1 : 2 : 1, indicating segregation at one or two loci, respectively. With two exceptions, individual alleles segregated in a 1 : 1 ratio. On the basis of the presence of different combinations of Nor-B1 and Nor-B2 alleles, the wheat cultivars investigated were divided into 53 phenotypic groups. These groups clearly reflect the germplasm used in wheat breeding programs in different countries. Hybrid wheats could also be recognized and plants with new combinations of alleles were produced.
Irrigation management of soybean (Glycine max (L.) Merrill) in a semi-arid tropical environment. III Response to saturated soil culture
Authors: Garside AL , Lawn RJ , Byth DE
Published: November 2004

The response of soybeans to saturated soil culture (SSC), achieved through continuous furrow irrigation, was evaluated in two studies in the Ord Irrigation Area in north Western Australia. In the first study, the effect of SSC on 14 genotypes was compared with conventional irrigation after every 60 mm pan evaporation (CI60), in an early wet season sowing. Averaged across genotypes, seed yields with SSC were increased by 0.74 t ha-1 or 21% above the mean yield of 3.47 t ha-1 with the CI60 treatment. Among genotypes, the advantage with SSC ranged from 2 to 49%. In the second study, the effect of SSC on growth and yield of three cultivars of different maturity was evaluated in a late wet season sowing, where crop durations were shorter than in the first study. There was a strong interaction between irrigation method and cultivar. Average seed yields of the latest maturing cultivar Durack were 10% greater with SSC, average yields of the intermediate cultivar Ross were relatively unchanged, while average yields of the earliest cultivar Buchanan were reduced by 24% with SSC. In both studies, and regardless of time of application of the SSC treatment, a transient chlorotic phase developed which tended to be more severe when SSC was applied earlier in crop growth. Where the chlorosis had dissipated by flowering, and providing crop duration was sufficient to compensate for the initial depression in shoot growth, seed yields were promoted by SSC. Taken together, the two studies indicate that substantial yield increases are possible with SSC in this environment, with the extent of the increases depending on genotype, crop duration, and the timing of application of the treatment.
Partial resistance of oats to P. coronata f.sp. avenae
Authors: Brake VM , Irwin JAG
Published: November 2004

Several oat cultivars (Avena sp.) were inoculated on the lst, 2nd and 4th leaves with race 264 of P, coronata f. sp. avenae to characterize and determine components of partial resistance (slow rusting). Panfive was the only cultivar to exhibit partial resistance. It gave a moderately susceptible reaction but expressed a lower infection efficiency, fewer and smaller uredia, and a lower spore production compared to the susceptible cultivars Algerian and Sual for all three leaf ages tested. In the field this cultivar has consistently shown partial resistance. Garry, a cultivar reported to be slow rusting but highly susceptible in the field in Queensland, expressed a significantly lower infection efficiency and uredium density than Algerian and Sual on the first leaf. Older leaves of Garry, however, did not show a significant reduction in the components of partial resistance when compared to Algerian and Sual. Results suggested that uredium density gave the best indication of partial resistance across the three leaf ages tested for Panfive. A significant difference was present between uredium densities on upper and lower surfaces of the 4th leaf only for the susceptible and partially resistant cultivars. In general, the resistance of all cultivars tended to increase with an increase in leaf age.
Further studies on losses in productivity caused by infection of annual pasture legumes with three viruses
Authors: Jones RAC
Published: November 2004

Trials were done in 1988-90 to examine the effects of infection with three non persistently aphid-transmitted viruses on the productivity of manually inoculated spaced plants of annual pasture legumes growing in plots. Alfalfa mosaic virus (AMV) decreased herbage and root production (dry weights) of three subterranean clover (Trifolium subterraneum L.) cultivars by 20-49%. Cucumber mosaic virus (CMV) decreased herbage and root production of a murex medic (Medicago murex Wild.) cultivar by 78-90% and of two burr medic (M. polymorpha L.) cultivars by 56-82%. A mild isolate of bean yellow mosaic virus (BYMV) decreased herbage and root production of a subterranean clover cultivar by 31-40%, but with a severe isolate the corresponding losses were 60-63010 in the same cultivar and 79-80% in another. The severe BYMV isolate caused losses in herbage and root production of 38-61% in two burr medic cultivars. Seed yield losses recorded due to infection of subterranean clover were 71% with AMV and 58-76% with BYMV (severe isolate); both viruses decreased seed size as well as seed yield. CMV decreased seed yield by 94% in a burr medic cultivar; it also decreased seed size.
Effects of abomasal protein and energy supply on wool growth in Merino sheep
Authors: Reis PJ , Tunks DA , Munro SG
Published: November 2004

The relative importance for wool growth of energy-yielding nutrients compared with amino acids required for incorporation into wool proteins was assessed in an experiment in which most nutrients were supplied via the abomasum. Nine nutritional treatments, providing three levels of protein (53, 99 and 145 g/day) to the intestines at three levels of energy (5.2, 7.5 and 9.7 MJ/day), were given to 12 Merino sheep during three consecutive periods of 3 weeks in a balanced lattice design. Abomasal nutrients consisted of varying proportions of casein, whole milk, glucose and glycerol. There was a large effect of protein supply on all components of wool growth, but there was no significant effect of energy. There was a significant interaction between the effects of protein and energy supply on diameter, length growth rate and volume of wool, but it was small relative to the main effect of protein. Extra energy appeared to enhance wool growth at the highest level of protein but reduce it at the lowest level of protein. The concentration of urea, cystine, methionine and other essential amino acids in plasma increased with protein level. Increasing energy supply reduced the concentration of urea and essential amino acids in plasma but not that of cystine or methionine. The experiment confirmed the major role of amino acid supply in controlling wool growth but indicated that there may be a small interaction with energy supply.
Studies on Western Australian Merino sheep. 1. Stud, strain and environmental effects on hogget performance
Authors: Lewer RP , Woolaston RR , Howe RR
Published: November 2004

A 6 year study is reported of Merino studs and strains (Peppin, Collinsville and Bungaree) in Western Australia. Wool and body traits of males and females were measured, with additional subjective traits assessed on females. The effects of strain, stud (within strain), birth year, dam age, birth rearing rank, weaning age and their interactions were estimated using least squares procedures. When tested against studs, strain differences were significant for fibre diameter (both sexes), clean wool yield and about half of the subjective traits (females) but for none of the liveweights. Stud and year effects were significant for all traits, as was their interaction for most traits. Some studs were more stable between years than others in both clean fleece weight and average fibre diameter. Of the remaining effects, birth rearing rank influenced the greatest number of traits, while dam age only affected yield in ewes and some early liveweights. Peppins produced wool 2.0-2.3 microns finer than Bungarees, but not significantly different from Collinsvilles. Peppins also had the best subjective wool scores, but had the highest wrinkle scores and scored poorly on other subjective body traits. Twin-born hoggets produced 0.05-0.15 kg less clean wool than their single-born contemporaries, and their fleeces were about 0.4 microns coarser with poorer subjective qualities. Twins were also lighter from birth (by 23%) up to 17 months (by 5%) in females. Late-born lambs had higher birth weights, but lower subsequent weights, persisting until 12 months in females.
Effect of crossbreeding on components of Hogget wool production
Authors: Pitchford WS
Published: November 2004

Australia's prime lamb industry is based on systematic three way crossbreeding. This paper examines various genetic effects on wool production, important determinants of profitability of the meat-sheep enterprise. Data from three purebred (Merino, Corriedale and Dorset Horn), six F1 and the six three-way cross lines were analysed. Direct genetic effects were important for all traits analysed. Maternal effects were generally not important. Individual heterosis was large for clean fleece weight (13%) and hogget weight (10%) and important also for fibre diameter (2%). Maternal heterosis averaged 3% for clean fleece weight, -2% for fibre diameter, and 1% for hogget weight (5% rams; -3% ewes). These results support the hypothesis that the action of individual heterosis through increased nutrient demand results in increased mature weights. Also, the effect of maternal heterosis is to increase nutrient supply resulting in increased rates of maturation.
Studies of the kinetics of in vivo labelling of proliferating wool follicle bulb cells with 5-Bromo-2′-deoxyuridine (BrdU): Intracutaneous labelling with BrdU and pharmacokinetics of free BrdU in the skin tissue of sheep
Authors: Holle SA , Harris PM
Published: November 2004

After establishing an immunocytochemical technique for the identification of BrdU labeled S-phase cells in the follicle bulb of wool fibres, the usefulness of a facilitated intracutaneous injection method for BrdU was investigated. This method enables easy and quick administration of the labelling agent and thus permits in vivo examination of cellular processes in the wool follicle bulb under field conditions. Because of very low dose rates, the local i.c. injection decreases the risk of toxic side effects of BrdU in the skin and more generally in the whole body, that accompany intravenous infusion. The accumulation of BrdU labelled cells over time in the follicle bulb was measured with immunocytochemical detection techniques. Intracutaneously injected BrdU was incorporated immediately into nuclear DNA of proliferating cells, and the labelling effect was confined to an area within 20 mm from the injection site. This allows sequential injections to be made on the same midside area of the sheep without interference of adjacent BrdU pools. Labelled S-phase nuclei accumulated in a linear fashion from 5 min to 24 h. Intradermally administered BrdU has a slow tissue clearance rate, with levels up to 10% of the initial peak still present after 24 h. The BrdU labelling effect showed detectable immunoreactivity at total injection loads as low as 5 8g. The free pool clearance rate in association with strong immunoreactivity suggests that a single intradermal injection can be regarded as comparable to a continuous labelling technique, if cell cycle parameters and growth fractions are to be determined. The method of administering BrdU intradermally opens a new perspective for cell population studies of wool follicles. It allows serial as well as concurrent estimates of cell activity to be made in the same animal, while eliminating difficulties and potentially toxic side effects associated with whole body infusion techniques.
Sources of resistance to barley yellow dwarf luteovirus in perennial ryegrass (Lolium perenne) L
Authors: Eagling DR , Villalta O , Halloran GM
Published: November 2004

Genotypes of perennial ryegrass cv. Ellett were classed as susceptible or resistant to infection with the PAV-related isolate of barley yellow dwarf luteovirus (BYDV) on the basis of dry weight yield and the presence or absence of detectable virus as measured with ELISA. In the inoculated treatments, there was a significant (P < 0.05) decrease in plant dry weight of susceptible compared to resistant genotypes, whereas in uninoculated treatments, there was no significant (P > 0.05) difference in yield between the two genotype classes. Superior plants from four cultivars of perennial ryegrass were selected from two field sites on the basis of superior winter growth and seasonal production. In glasshouse experiments, resistance to the virus was detected in these selections. The percentage of infected selections from individual cultivars varied between 18-46%, indicating that at least 50% were resistant to the virus.
Water use and productivity in sub. clover and murex medic swards. I. Dry matter production
Authors: Blumenthal MJ , Ison RL
Published: November 2004

A field experiment was established at Forbes in central-west New South Wales to investigate the hypothesis that the pattern and efficiency of water use varies between genotypes of both (Trifolium subterraneum) and murex medic (Medicago murex), and that this would affect the success of these genotypes in this environment. To test this hypothesis the productivity of two lines of M. murex (CD26 and CD53) and four cultivars of T.subterraneum (Seaton Park and Woogenellup, and two recently released cultivars, Junee and Dalkeith) were compared. Genotypes were grown both with and without irrigation and soil water was monitored for the duration of the field experiment (1987-1989). Soil water use differed little between genotypes, but when differences did occur they were related to maturity grading of the genotype with the earlier maturing cv. Dalkeith using more water without irrigation, and the later maturing cv. Junee using more water with irrigation. There was no evidence of sub. clover dry matter yield declining with time; total yield over the three years exceeded 18 000 kg/ha for all cultivars. Murex medic dry matter yields were higher than sub. clover in the year of sowing; however, dry matter yield in swards was depressed in the year following sowing and weeds contributed more to total sward yield compared to sub. clover in the third year. Both hard and soft-seeded subclover cultivars proved to be equally successful in terms of dry matter production with different cultivars performing better in different seasons and under different irrigation treatments. Sub. clover cvv. Dalkeith and Junee were able to take greater advantage of available soil water early. in autumn than the other genotypes. It was concluded that water availability is not the only factor limiting sub. clover and murex medic dry matter yield in this environment.