bluuebunny/crossref_metadata_2025 huggingface dataset:
Fleece rot and body strike in Merino sheep. II. Phenotypic and genetic variation in liability to fleece rot following experimental induction
Authors: Raadsma HW , Gilmour AR , Paxton WJ
Published: November 2005

Phenotypic and genetic variation in the susceptibility of Merino sheep to fleece rot and body strike were examined following experimental induction of fleece rot by wetting. A total of 949 Merino ewe hoggets, from 15 Merino bloodlines comprising 2 Fine-wool, 2 Medium Non-Peppin, 10 Medium Peppin and I Strong-wool flock were measured over a three-year period. Following wetting, 82.8'Yo of the hoggets developed fleece rot and 7.9% were affected with body strike. The incidence and severity of fleece rot was highest on the back, whereas body strike occurred mainly on the neck. Body strike was largely confined to the period of a flywave in the second year of the study. The low incidence of body strike reduced the reliability with which genetic variation in this trait could be estimated. Between-flock genetic variation in liability to induced fleece rot was largely strain variation (with increasing liability from Fine-wool to Medium-wool to Strong-wool strains). Variation between bloodlines within strains was not as large as those reported for the same bloodlines under natural conditions. The heritability ( � s.e.) of liability to fleece rot was 0.86 using quasi-maximum likelihood procedures, which agrees well with the heritability of fleece rot incidence (0.40 � 0.13) after transformation on to an underlying scale (0.87 � 0.29) obtained through restricted maximum likelihood (KEML). Estimates of genetic parameters obtained for these data through REML procedures were in good agreement with estimates obtained through ordinary least squares analyses. Fleece rot induction allowed screening of a large number of sheep in a relatively short period for their susceptibility to fleece rot. Further evaluation is needed to determine the role of fleece rot induction in breeding programmes aimed at reducing the susceptibility of Merino sheep to natural fleece rot and body strike.
The effect of soil compaction and fumigation on poor early growth of wheat under direct drilling
Authors: Chan KY , Mead JA , Roberts WP , Wong PTW
Published: November 2005

Poor early growth of wheat was studied in a tillage experiment at Cowra, N.S.W., in the 1986 season to determine the involvement of soil physical and biological factors in this problem. A compaction treatment to achieve bulk density and shear strength comparable with those detected in the direct-drilled soils was imposed on the conventionally cultivated soil. Soil fumigation was used to investigate the significance of biological factors in causing poor early growth. In the absence of fumigation, the dry weight per plant 98 days after sowing for the direct-drill treatments was approximately a third of the conventional treatment. The fumigation treatment was effective in completely eliminating the poor early growth observed in the direct-drilled soils. No significant reduction in shoot growth was detected as a consequence of the compaction treatment, despite a reduction in root growth to the level detected in the nil fallow. The results suggest that poor early growth was caused by micro-organisms present in the direct-drilled soils.
An autecological study of the take-all fungus (Gaeumannomyces graminis var. tritici) in Western Australia
Authors: Cotterill PJ , Sivasithamparam K
Published: November 2005

The Western Australian (W.A.) grainbelt has a mediterranean-type climate, with hot-dry summers and mild-wet winters, and this together with the old, and often nutritionally poor, sandy acidic soils has determined the nature of the agricultural system of the region. Wheat is the major crop, and take-all disease is a serious problem which is exacerbated both by the climatic and edaphic conditions and the prevailing agricultural practices.The behaviour of the inoculum of the take-all fungus (Gaeumannomyces graminis var. tritici) in W.A. is markedly different from that reported from cool-temperate regions and therefore the disease requires different control strategies. Although relationships between inoculum and disease have been studied in W.A., the potential use of inoculum status of field soil for disease prediction is limited by the lack of predictability of rainfall.
Nitrogenase activity (C2H2 reduction) in soils following wheat straw retention: effects of straw management
Authors: Roper MM , Marschke GW , Smith NA
Published: November 2005

The effects of stubble management practices on straw decomposition (C02 production) and nitrogenase activity C2H2 reduction) were examined in situ on a black earth (pH 7.4, clay content 51%)) near Gunnedah in the wheat-belt of New South Walcs. Straw treatments were: (1) mulching (bladeploughed) or surface cultivation (scarification), (2) burning and cultivation, (3) no-tillage, and (4) incorporation (disc-ploughed). In 1979, the straw was mulched on the surface in treatment 1. When moisture was applied, preliminary measurements (1 980) showed that nitrogenase activity was highest in the incorporated treatment with less in the surface mulched and no-tillage treatments respectively. There was only a small amount of activity in the burnt treatment due to some straw remaining. In a longer-term study in 1985 and 1986 straw in treatment 1 was lightly mixed near the soil surface by scarification. Following moisture application, nitrogenase activity was significantly higher in the scarified treatment than in the incorporated treatment, indicating that depth of mixing of straw with soil was important. Nitrogenase activity in the no-tillage treatment was similar to that in the incorporated treatment, and there was substantially less activity in the burnt treatment. Production of CO2 was similar in the straw-retained treatments, but significantly lower in the burnt treatment. In a series of short-term assays throughout 1985, microbial activity from January to May 1985 decreased with falling soil temperature. With the increase in temperature from July to November 1985, there was no corresponding increase in activity. Despite changes in microbial activity throughout the year, there was little change in the numbers of N2-fixing bacteria in the 14-month period from February 1985 to March 1986, indicating stability in the potential for N2 fixation. Although surface-cultivation (scarification) of straw is apparently the most favourable for free-living N2 fixation, other factors such as erosion and disease control need to be considered in deciding which straw management practice is to be adopted.
The Phakopsora pachyrhizi-Kennedia rubicunda host-pathogen association and its relation to leaf rust of Glycine spp
Authors: Burdon JJ , Lenne JM
Published: November 2005

The relationship of isolates of Phakopsora pachyrhizi found on the coastal legume Kennedia rubicunda to isolates found on Glycine spp. was determined by assessing the virulence of ten Kennedia-derived isolates on a wild line of Glycine canescens and on a commercial cultivar of G. max. These two lines are both known to be susceptible to all Glycine-derived isolates of the pathogen. Three patterns of pathogenicity were detected among the Kennedia-derived isolates with isolates being either avirulent or virulent on both host lines; or being avirulent on G. canescens and virulent on G. max.The pathogenicity of five of these Kennedia isolates of P. pachyrhizi was also tested on ten populations of K. rubicunda. The mean levels of resistance and virulence of the host populations and pathogen isolates respectively showed a considerable range. Significant interactions were detected between particular host population-pathogen isolate combinations. These results were compared with those obtained with two representative isolates of P. pachyrhizi collected on Glycine hosts.
Germination and vigour of black gram (Vigna mungo (L.) Hepper) seed from plants grown with and without boron
Authors: Bell RW , McLay L , Plaskett D , Dell B , Loneragan JF
Published: November 2005

Black gram (Vigna mungo (L.) Hepper) cv. Regur was grown to maturity in three potted soils [Badgingarra (Sl), Lancelin (S2) and Quailing (S3)] with (+B) or without (-B) added H3BO3. The subsequent germination and vigour of seeds from treated plants was tested by germinating them for 7 days with 2000 8M CaSO4 and 98M H3BO3and, for S2 and S3 only, by staining with tetrazolium. No symptoms of B deficiency were observed in plants on any soil:leaf B concentrations at early vegetative and flowering stages were above values regarded as critical for this species (7-8 mg kg-1). On S1, B depressed pod and seed dry matter (DM), weight per seed and % hard seed (14 v. 58); it enhanced % non-viable imbibed seed (18 v. 5) and abnormal seedlings (37 v. 2). On S2, -B had no effect on reproductive yield or % hard seed but increased the % abnormal seedlings (32 v. 0) and depressed the tetrazolium rating for seed vigour, and weight per seed. No effects of B were observed on seeds from plants grown on S3 soil. When considered over all replicates of all treatments, a B concentration of 6 mg kg-1 DM seed was critical for viability of imbibed seed and production of normal seedlings. The results suggest that the subsequent germination and morphology of seeds and seedlings are more sensitive to low B supply during seed production than are growth of the plant and the amount of seed produced. It is thus likely that black gram crops low in B but with no symptoms of B deficiency may produce seed with low % germination and a high % abnormality in their seedlings.
The effect of barley yellow dwarf virus on early plant growth in ryegrass (Lolium spp.)
Authors: Eagling DR , Sward RJ , Halloran GM
Published: November 2005

Measurements were made on the effect of barley yellow dwarf virus (BYDV) infection on the early growth of four commercial cultivars of ryegrass (Lolium spp.) under two different temperatures (24�C and 16�C). At 24'C, BYDV infection was associated with reduced root dry weight (30-40%) in all cultivars; the effect of infection on shoot dry weight and leaf area was variable. At 16�C, the effect of BYDV infection was variable, being associated with increases in root dry weight, shoot dry weight, and leaf area in one cultivar (Grasslands Ariki) and decreases in another (Victorian). In two other cultivars, root dry weight, shoot dry weight and leaf area were not significantly affected (P>0.05) by infection with BYDV.At 24�C, the reductions in root dry weight associated with BYDV infection were not concomitant with reductions in the root relative growth rates. Up to at least 28 days after inoculation (46-50 days after germination) reductions in root dry weight were associated with both aphid-feeding damage and virus infection. Experiments with the cultivar Victorian, showed that shoot dry weight was not significantly affected (P>0.05) by feeding with viruliferous (BYDV) or non-viruliferous aphids (Rhopalosiphum padi L.). At 16�C, changes in root and shoot dry weight were associated with changes in the root and shoot relative growth rates.
The influence of sowing method on perennial grass establishment. II. Seedbed microenvironment, germination and emergence
Authors: Bellotti WD , Blair GJ
Published: November 2005

'Demeter' tall fescue (Festuca amndinacea Schreb.) and 'Victorian' perennial ryegrass (Lolium perenne L.) were sown separately into a white clover (Trifolium repens L.) dominant pasture. Eight sowing methods were compared to assess the ability of perennial grasses to germinate and emerge from direct drill sowing methods relative to conventional seedbed and aerial sowing methods. Within direct drill treatments, two drill implements were factorially combined with three herbicide treatments. Soil temperature and moisture conditions were cold and moist, but generally adequate for emergence of temperate pasture species. In-groove soil moisture content was always greatest in the disc plus herbicide treatment. Differences in seed level soil temperatures were minor, although diurnal fluctuations were greatest in the aerial plus herbicide treatment. Emergence of ryegrass at 50 days after sowing was similar in all sowing methods (67.9-93.9% viable seed sown) except for the aerial plus herbicide and disc plus band herbicide methods (23.4 and 44.0% of viable seed sown). There was a wide range of emergence percentages for fescue at 50 days after sowing (17.8-69.2% viable seed sown) and again the aerial plus herbicide treatment was lowest. One-pass, band spraying of a paraquat.diquat plus dicamba herbicide mixture at the time of sowing impaired the germination percentage of ryegrass seeds sown with the disc drill. Apart from the aerial plus herbicide treatment, sufficient seedlings passed through the germination/emergence filter in all direct drill and cultivated seedbed treatments to provide for a productive grass-based pasture.
The influence of sowing method on perennial grass establishment. III. Survival and growth of emerged seedlings
Authors: Bellotti WD , Blair GJ
Published: November 2005

'Demeter' tall fescue (Festuca arundinacea Schreb.) and 'Victorian' perennial ryegrass (Lolium perenne L.) were sown separately into a white clover (Trifolium repens L.) dominant pasture in June 198 1. Eight sowing methods were compared to assess the survival and growth of perennial grasses sown by direct drill sowing methods relative to conventional seedbed and aerial sowing methods. Within direct drill treatments, two drill implements were factorially combined with three herbicide treatments. Sown seedling density decline was approximately linear from the maximum emerged density at 50 days after sowing to the established plant density at 250 days. Established ryegrass density ranged from 104.9 plants m-2 in the cultivated seedbed to 30.0 plants m-2 in the aerial plus herbicide method. Established plant density of fescue in the direct drill sowings was higher for the plus herbicide treatments (56.6-61.6 plants m-2) compared with the minus herbicide treatments (0-6.6 plants m-2). Seedling growth was severely reduced when seeds were direct drilled into unsprayed vegetation. Fescue seedlings in these treatments had failed to develop tillers by 250 days. The distribution of an index of individual seedling size was highly skewed towards smaller seedlings in the direct drill minus herbicide treatments indicating a high level of stress in these treatments. Competition from the unsprayed resident sward was intense and occurred at a very early stage in seedling development. Promotion of rapid early seedling growth through cultivation or herbicides enhanced survival of sown perennial grasses.
The effect of differences in intensity and frequency of defoliation on the growth of Phalaris aquatica L. and Dactylis glomerata L
Authors: Hill MJ
Published: November 2005

The response of phalaris (Phalaris aquaticu cv. Sirosa, Sirolan and Seedmaster) and cocksfoot (Dactylis glomerata cv. Currie) to 2- or 4-weekly cutting at heights of 2 or 7 cm was compared in a glasshouse experiment. Treatments were imposed over a period of 16 weeks.Dry matter production was greatest under the most lenient defoliation regime (4 week17 cm) and least under the most severe defoliation regime (2 week12 cm). Differences in harvested dry matter per tiller and leaf area per pot among cultivars increased with increasing leniency of defoliation. There were significant cultivar x cutting frequency x cutting height interactions for total winter leaf and spring stem production. Harvested dry matter from Sirosa and Sirolan was greater than that from Seedmaster under 4-weekly cutting, although differences in harvested dry matter per tiller were evident under all cutting regimes. Currie cocksfoot consistently maintained higher tiller numbers than the phalaris cultivars, but leaf, stem and leaf area production per tiller were generally ranked Sirolan > Sirosa > Seedmaster> Currie. When reproductive tillers were decapitated, Sirolan and Sirosa tended to produce more new tillers than Seedmaster under frequent cutting. More crown buds were found at the base of Sirolan tillers than on those of other phalaris cultivars, but the number of buds was reduced more on Sirolan with increasing severity of defoliation than on other cultivars. It is postulated that Sirolan and Sirosa may benefit from spelling in spring, and defoliation to a higher residual herbage mass andlor sward height than Australian-Seedmaster type.
The effect of differences in intensity and frequency of defoliation on the growth of Sirolan phalaris in the field
Authors: Hill MJ , Watson RW
Published: November 2005

A two-year old sward of Phalaris aquatica cultivar Sirolan was cut at 2-, 4-, 6- or 12-week intervals and at heights of 2 or 7 cm over two 12-week cycles from June to November 1986. Defoliation treatments were split and 100 kg ha-1 of nitrogen was applied to half the plot at the beginning of each cycle. Tiller density and dry matter production were measured throughout winter and spring of 1986, and in two 6-week regrowth periods in 1987.During winter, high cutting always gave less harvested dry matter than low cutting. In spring, the regression lines relating cutting frequency to cumulative harvested dry matter crossed over at a frequency of about 5 weeks. Below this frequency high cutting yielded more harvested dry matter than low cutting. High cutting gradually changed sward appearance in winter, resulting in better yields at later harvests. At the conclusion of spring cutting, there were more dead tillers on plots cut at 6- and 12-week intervals than on those cut every 2 or 4 weeks, while numbers of live tillers increased progressively as cutting interval rose from 2 to 12 weeks. Regrowth in autumn 1987 was much better on plots cut every 12 weeks than on other plots, primarily owing to the greater vigour of individual tillers, but also owing to higher tiller numbers. The timing of defoliation in spring appeared to be the most important factor governing crown bud production and regrowth in the following season. Spelling in spring is recommended to permit reproductive and crown bud development in Sirolan.
New records on the occurrence of beet western yellows virus in Australia, New Zealand and Mexico
Authors: Johnstone GR , Duffus JE , Guy PL
Published: November 2005

An isolate of beet western yellows virus (BWYV) from lettuce in Tasmania was propagated in shepherd's purse, purified, and used to produce an antiserum in a rabbit. The lettuce isolate and the antiserum to it reacted similarly to the Californian type isolate from radish and its antiserum in double antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISA). The Tasmanian DAS-ELISA system was used to confirm the presence of BWYV in a range of plant species from the southern mainland states of Australia, from the North Island of New Zealand and from central Mexico. Leaf tissue containing BWYV remained serologically reactive for long periods after the tissue was desiccated either by freeze-drying, air-drying or drying over silica gel. Bean leaf roll, potato leaf roll and soybean dwarf viruses were clearly distinct from BWYV and from each other in DAS-ELISA.
Response of orchard 'Washington Navel' orange, Citrus sinensis (L.) Osbeck, to saline irrigation water. I. Canopy characteristics and seasonal patterns in leaf osmotic potential, carbohydrates and ion concentrations
Authors: Lloyd J , Howie H
Published: November 2005

Effects of irrigation water salinity on tree canopy volume, leaf area, rates of leaf abscission and production, as well as seasonal patterns in leaf osmotic potential (=), starch, soluble sugars and sodium and chloride concentrations were determined for 24-year-old 'Washington Navel' orange trees (Citrus sinensis [L.] Osbeck) on sweet orange (C. sinensis) rootstock. Trees had been irrigated with water containing either 5 or 20 mol NaCl m-3 for 5 years prior to measurements.Trees irrigated with 20 mol NaCl m-3 had a greater number of vegetative flushes in spring. This occurred at the expense of flowering, as numbers of reproductive and mixed flushes were reduced by salinity. Despite a high number of vegetative buds on trees irrigated with 20 mol NaCl m-3, leaf area was still less than low salinity trees.Extensive abscission of spring flush leaves occurred from mid-summer onwards for trees irrigated with 20 mol NaCl m-3. This was not a consequence of leaf water deficit, as more negative leaf osmotic potentials resulting from increased foliar sodium and chloride concentrations resulted in maintenance of leaf turgor. Excessive concentrations of sodium and/or chloride may have been responsible for abscission observed. Some acclimation of foliage to salinity was evident.Irrespective of salinity treatment, leaf osmotic potential became more negative as the season progressed. This was partly due to increased concentrations of soluble sugars in foliage during autumn and winter. Levels of soluble sugars and starch were consistently lower in leaves on trees irrigated with high salinity water, indicating that production rather than utilization of carbohydrate may limit citrus productivity under saline conditions.
Response of orchard 'Washington Navel' orange, Citrus sinensis (L.) Osbeck, to saline irrigation water. II. Flowering, fruit set and fruit growth
Authors: Howie H , Lloyd J
Published: November 2005

Flowering, fruit set and fruit growth of 'Washington Navel' orange fruit was monitored on 24-year-old Citrus sinensis trees on Sweet orange rootstocks that had been irrigated with either 5 or 20 mol m-3 NaCl for 5 years preceding measurements.Trees irrigated with high salinity water had reduced flowering intensities and lower rates of fruit set. This resulted in final fruit numbers for trees irrigated with 20 mol m-3 being 38% those of trees irrigated with 5 mol m-3 NaCl. Final fruit numbers were quantitatively related to canopy leaf area for both salinity treatments.Despite little difference between trees in terms of leaf area/fruit number ratio, slower rates of fruit growth were initially observed on high salinity trees. This effect was not apparent during the latter stages of fruit development. Consequently, fruit on trees irrigated with 20 mol m-3 NaCl grew to the same size as fruit on trees irrigated with 5 mol m-3 NaCl, but achieved this size at a later date. Measurements of Brix/acid ratios showed that fruit on high salinity trees reached maturity standards 25 days after fruit on low salinity trees.Unimpaired growth of fruit on high salinity trees during summer and autumn occurred, despite appreciable leaf abscission, suggesting that reserve carbohydrate was utilized for growth during this period. Twigs on high salinity trees had much reduced starch content at the time of floral differentiation in winter. Twig starch content and extent of floral differentiation varied in a similar way when examined as a function of leaf abscission. This suggests that reduced flowering and fruit set in salinized citrus trees is due to low levels of reserve starch, most of which has been utilized to support fruit growth in the absence of carbohydrate production during summer and autumn.
Supplementation of rice straw with dry leucaena
Authors: Doyle PT
Published: November 2005

The effects of supplementation with three levels (5, 10 and 15% of DM offered) of dry leucaena on the voluntary intake and digestion of rice straw by sheep were studied. These effects were compared with those of a supplement of urea and sulfate. In all cases, the rice straw was supplemented with minerals.Total dry matter intake (DMI) increased linearly with the level of leucaena, but there was no affect on intake of straw. Nor did supplementation with urea and sulfate affect straw intake. Neither of these supplements affected the apparent digestibility of organic matter (OM).There were significant linear relationships between DM1 and the amounts of total digesta or DM in the reticulo-rumen (RR). The amount of non-ammonia nitrogen (NAN) in the RR also increased with the amount of leucaena offered, as did the concentration of ammonia N in rumen fluid.While the flows of digesta constituents increased linearly with the amount of leucaena in the diet, there were no significant effects of dietary treatments on the fractional outflow rates of NDF from the RR. The fractional digestion rates of NDF in the RR were also not affected by supplementation. The intake of nitrogen, the amount of crude protein apparently digested in the intestines (DCPi) and apparent nitrogen retention all increased with the amount of leucaena given. In contrast, supplementationwith urea and sulfate increased N intake, but DCPi was not increased to the same extent as with leucaena. The proportion of NAN flowing through the abomasum which was of microbial origin was lower (0.66 v. 0.73) when 15% leucaena was in the diet than with straw alone or straw plus urea and sulfate.
Aflatoxin and cyclopiazonic acid production by Queensland isolates of Aspergillus flavus and Aspergillus parasiticus
Authors: Blaney BJ , Kelly MA , Tyler AL , Connole MD
Published: November 2005

The production of aflatoxins (AFB1, AFB2, AFG1, AFG2) and cyclopiazonic acid (CPA) by 50 Queensland isolates of thc Aspergillusflavus-Aspergillus parasiticus group was examined for the purposes of chemotaxonomy and toxicology. lsolatcs were cultured on Czapek Dox agar at 28�C and examined microscopically after 5, 7 and 10 days. Conidial heads were classified as either bearing phialides only or phialidcs and metulac, while conidia were classified according to degree of roughness. Isolates were also sown onto maize meal incubated at 28�C for 28 days and assayed for aflatoxins and CPA. A. flavus types were classified as having biseriate sterigmata in 40-100% of cases and slightly to moderately rough conidia, whereas A. paraszticus types were those with 0-35% biseriate sterigmata and spikey conidia. Of the 38 isolates classed as A. flavus, 34 produced CPA (range 1-70 mg kg-1). Three isolates produced neither aflatoxins (t0.02 mg kg-1) nor CPA (< 1 mg kg-1). Seven produced CPA but no aflatoxins. The remaining 28 isolates produced AFB1 (0.02-280 mg kg-1); seven of these produced low concentrations of AFG1(0.02-0.08 mg kg-1); and only one did not produce CPA. There was no quantitative correlation between CPA and aflatoxin production by the A. fIavus isolates. Of the 12 isolates classed as A. parasiticus, none produced CPA; all produced AFB1 (4-400 mg kg-1); all produced high concentrations of AFG1 (1-400 mg kg-1). The relative prevalence of the two fungi in Queensland is discussed as a guide to the likelihood of aflatoxin and CPA contamination of different agricultural commodities.
Ultrasound guided blood sampling from fetal sheep
Authors: Newnham JP , Kelly RW , Boyne P , Reid SE
Published: November 2005

The feasibility of obtaining fetal blood samples by needle aspiration under ultrasound guidance was assessed in 32 fetal sheep from 101-1 36 days' gestation. Seventy-six attempts at blood sampling were made, of which all but two were successful. The overall fetal death rate resulting from this procedure was 9.2%. However, with increasing operator experience and with advancing gestational age, 95.5% of fetuses survived the procedure. Repeated sampling from individual fetuses had minimal effects on arterial blood gas values. Ultrasound guided blood sampling now provides an alternative to chronic catheterization as a basis for some types of research with fetal sheep.
Effects of nutrition on wool follicle cell kinetics in sheep differing in efficiency of wool production
Authors: Hynd PI
Published: November 2005

Wide phenotypic variation in fibre output per follicle was generated by selecting sheep (five South Australian strongwool Merinos, one finewool Merino and one Corriedale) on this basis, and by offering these sheep a low-protein diet for 9 weeks, followed by a high-protein diet for a further 8 weeks. Clean wool production was measured over the final 3 weeks of each period, while fibre diameter, the rate of length growth of fibres and a number of follicle characters were measured over the last 7 days of each period. The rate of division of follicle bulb cells and the total volume of the germinative region of the follicle was estimated by image-analysis of bulb sections in skin biopsy samples.With the change from the low-protein diet to the high-protein diet, the rate of clean fleece production was increased by 33% (P<0.002), reflecting an increase in fibre diameter (8%) and rate of length growth of fibres (26%); the volume of the germinative region of the average bulb increased 30% (P<0.012) and the rate of bulb cell division by 35% (P<0.004); cortical cell volume also did not change (923 8m3 v. 965 8m3; the average proportion of fibre cross-sectional area occupied by paracortical cells increased from 0.2 1 to 0.35 ( P < 0.01 0); the proportion of dividing cells entering the fibre cortex ranged from 0.25 to 0.42 (mean, 0.31) between sheep on the low-protein diet, and from 0.22 to 0.39 (mean, 0.32) when the animals were fed the high-protein ration; the effect of diet on cell distribution to fibre and inner root sheath was not significant (P<0.601).Phenotypic differences in fibre output were primarily related to differences in the rate of bulb cell division (r= 0.896, P < 0.001), but inclusion of a term for the proportion of bulb cells entering the fibre cortex, removed an additional, significant proportion of the variance. Cortical cell volume, on the other hand, was poorly related to fibre output.
The effect of Haemonchus contortus on liveweight gain and wool growth in young merino sheep
Authors: Albers GAA , Gray GD , Le Jambre LF , Piper LR , Barger IA , Barker JSF
Published: November 2005

Results of three crossover experiments on a total of 1078 Merino lambs were used to estimate the effect of a single infection of 11 000 Haernonchus contortus larvae on liveweight gain, clean wool growth and wool fineness. Estimates were obtained by direct comparison of six groups of infected and matched uninfected iambs under field conditions. Infections were terminated after 5 weeks, at which stage some mortality had occurred and haematocrits had in five out of six cases declined to less than 24%. Over an 8-9 week period, beginning at the time of infection, liveweight gains of infected lambs were reduced by on average 1.29 kg (range 0.83-1.71 kg) amounting to 38% (12-64%) of liveweight gain in uninfected controls. The detrimental effect of infection was most severe towards the end of the infection period. There was a lag phase of 3-6 weeks between larval administration and the onset of wool growth depression. The reduction of wool growth persisted for at least 14 weeks after termination of infection. The size of this reduction was very variable. Over a 4 month post-infection period, reductions ranged from 11 to 97 g clean wool (mean 46 g) or 1.4 to 157% (mean 6.8%) of clean wool grown by uninfected lambs. Estimates of reduction of fibre diameter over the same period ranged from 0.39 to 0.79 8m (mean 0.57 8m).
Genetic evaluation of production traits between and within flocks of Merino sheep. I. Hogget fleece weights, body weight and wool quality
Authors: Mortimer SI , Atkins KD
Published: November 2005

Wool production traits were measured on Merino hogget ewes in an unselected multiple-bloodline flock over a 7-year period at Trangie Agricultural Research Centre, N.S.W. The traits measured were greasy fleece weight (GFW), skirted fleece weight (SKFW), yield (Y), clean fleece weight (CFW), fibre diameter (FD), body weight (BWT) and staple length (SL). These measurements were used to examine genetic differences between and within flocks of Merino sheep, and to estimate heritability of and genetic and phenotypic correlations among these traits. Significant strain, flock within strain and flock effects were present for all traits. Interactions between these effects and year were non-significant. Within-flock genetic variance was always larger than between-flock within strain genetic variance for each trait. The influence of environmental effects on these traits was also examined. The environmental effects of birth-rearing type, age at observation and age of dam together accounted for about 7-10% of the total within-flock variation in fleece weights and body weight.After adjusting for significant environmental effects, paternal half-sib heritability estimates were 0.29 �. 0.06 for GFW, 0.22 � 0.05 for SKFW, 0.35 � 0.05 for Y, 0.30 �0.06 for CFW, 0.48 �0.07 for FD, 0.34 �. 0.06 for BWT and 0.44 �0.07 for SL. Estimates for genetic and phenotypic correlations were in agreement with published estimates except for the genetic correlation between CFW and FD (0.40 �. 0.11), and the genetic correlations involving BWT, which were essentially zero. The implications of the results of this study for the genetic improvement of Merino sheep for wool production are discussed.
Yield improvement and associated characteristics of some Australian spring wheat cultivars introduced between 1860 and 1982
Authors: Perry MW , D'Antuono MF
Published: November 2005

Twenty-eight Australian wheat (Triticum aestivum L. em. Thell.) cultivars representing a series from the 1860s to 1982, were grown in 20 field trials over four years in the wheatbelt of Western Australia. The cultivars included introductions and selections made before 1900, plus important cultivars bred or grown in Western Australia up to 1982. Five of the latter group were from crosses including semidwarf cultivars as parents. Grain yields were measured on all trials, and six trials were also sampled for biomass and yield components.Based on the regression of mean grain yield versus the number of years elapsed since 1884, yields have increased from 1022 kg ha-1 in 1884 to 1588 kg ha-1 in 1982. This represents a rate of increase of 5.8 kg ha-1 year-1 or 0.57% per year. Regression of cultivar yield on site mean yield gave values of b, the slope of the regression, from 0.66 to 1.24, and these were higher for modern than for old cultivars.In six trials sampled for yield components, above-ground biomass appeared to have increased slightly when comparing early selections and their derivatives with later cultivars, but over 80% of the overall increase in grain yield was due to increase in harvest index. Grains per car and grains m-2 were strongly and positively correlated with grain yield, but there were weak negative correlations between 1000-grain weight and yield, and between 1000 grain weight and years since 1884. Cultivars with a semi-dwarf background had equal biomass, but higher yield, harvest index, ear number m-2 and grains ear-2 than modern tall cultivars. The results show that genetic improvement has substantially increased yield potential in this environment and that this has been achieved through substantial increases in grain number m-2 associated with an improvement in harvest index.
Growth, development and light interception of old and modern wheat cultivars in a Mediterranean-type environment
Authors: Siddique KHM , Belford RK , Perry MW , Tennant D
Published: November 2005

A field experiment was conducted at Merredin in the eastern wheat belt of Western Australia, comparing 10 wheat cultivars representing old and modern wheats. The aim of the study was to identify any morphological and physiological characters associated with higher grain yield of modern wheat cultivars.The modern cultivars reached double ridge, terminal spikelet, anthesis and maturity earlier than the old cultivars, but modern cultivars had a longer duration between double ridge and terminal spikelet stage. The number of leaves on the main stem generally decreased from old, Purple Straw (14) to modern cultivars like Kulin (8). The modern cultivars had a shorter phyllochron interval than the old cultivars. The old cultivars also produced more tillers per plant (7.3) and had a lower percentage (35%) of ear bearing tillers, as compared with 3.9 and 51% for modern cultivars.The green area index and ground cover was higher in old than modern cultivars. However, the efficiency of conversion of photosynthetically active radiation to dry matter was slightly greater for modern cultivars. Although dry matter at final harvest was similar between cultivars, there was a trend for higher dry matter production with modern cultivars. The post-anthesis green area duration was longer with modern cultivars and grain yield increased with increase in post-anthesis green area duration.Grain yield and HI increased consistently from old to modern cultivars. The most recent cultivar Kulin had the highest yield and second highest harvest index, which were 63% and 48% respectively higher than the oldest cultivar, Purple Straw. Increases in grain yield in the modern cultivars were associated with increased grains spikelet-1 and grains ear-1. Mean grain weight showed a slight reduction with modern cultivars. The results are discussed in relation to future improvement in yield.
Using a penetrometer to predict the effects of soil compaction on the growth and yield of wheat on uniform, sandy soils
Authors: Henderson CWL
Published: November 2005

The relationships between soil penetration resistance and the growth and yield of wheat were examined for a range of tillage and compaction experiments conducted on earthy sands near Geraldton, W.A. Overall, a single index of penetration resistance explained around 50% of the growth and yield variation, across sites and seasons. Equations using this index showed good potential for predicting the impact of various tillage and traffic practices on wheat yield.
Effects of timing and placement of urea on aerial-sown semi-dwarf rice in south-east Australia
Authors: Heenan DP , Bacon PE
Published: November 2005

Three field experiments over two seasons and on two soil types studied the effects of placement and time of nitrogen fertilizer (N) application on yield and N uptake of aerial-sown semi-dwarf rice. Grain yield and apparent N fertilizer recovery were greatest when fertilizer was drilled into the soil, with no significant difference between 3 cm and 7 cm depth. Placement onto wet soil resulted in significantly lower grain yield and total N uptake than placement onto dry soil or incorporation into the soil. Reducing the time of application before flooding from 15 days to 1 day significantly improved the efficiency of fertilizer use. Delaying the time of application from before flooding to soon after flooding produced much lower grain yield and agronomic efficiency. Further delaying the application time from soon after flooding to around mid-tillering increased the yield response and agronomic efficiency. The results demonstrated that urea should be drilled into the soil as soon as possible before flooding rather than broadcasting onto the soil surface before flooding or into the floodwater after flooding.
Emergence of lupins from a hard setting soil compared with peas, wheat and medic
Authors: White PF , Robson AD
Published: November 2005

The formation of a hard crust on a soil can severely decrease seedling emergence. The magnitude of the effect depends on a number of characteristics of the seed and seedling.The emergence of two species of lupin was compared with that of peas, wheat and medics. Seeds were sown into a sandy-clay loam where a hard crust was allowed to develop and where crust formation was reduced by the application of CaSO4.Emergence of seedlings with an epigeal pattern of emergence was reduced by crust formation. Emergence of Lupinus angustifolius and medics was severely reduced by crust formation, whereas emergence of the larger seeded L. albus was only slightly affected. In contrast to the epigeal seedlings, emergence of peas and wheat was unaffected by crust formation. Sowing lupins deeper exacerbated the problem.Seed size and pattern of emergence appeared to be the major factors determining the success of establishment of these species.
Comparisons of perennial ryegrass (Lolium perenne L.) accessions grown as turfs (lawns)
Authors: Rogers ME , Lush WM
Published: November 2005

Accessions of Victorian perennial ryegrass (Lolium perenne L.) grown as turfs were inferior to or no better than European and North American ryegrasses developed specifically for turf. This applied to all aspects of their growth, except those of germination (which was faster, especially at temperatures around 12�C), thatch accumulation (which was less), and in their possession of an entophytic fungus, Acremonium loliae, which in the longer term could be associated with greater persistence. At the seedling stage, Victorian and turf ryegrasses produced similar dry weights, but the Victorian ryegrasses had fewer, larger leaves and tillers. Victorian ryegrass turf swards had lower tiller densities and standing dry weights, yet produced more clippings. The total production of Victorian ryegrass turfs was less than that of the turf ryegrasses. There were no differences in the seasonality of growth. In spring, flowering heads were more common in Victorian ryegrass turfs and the leaves of these turfs also shred more when mown. During the first year of turf growth, differential selection occurred in favour of plants that were prostrate, had shorter leaf sheaths, were later flowering, and that contained endophyte. The direction of selection confirmed the functional significance of observed differences between pasture and turf ryegrasses.
Effects of temperature and salinity on the germination of Puccinellia ciliata (Bor) cv. Menemen
Authors: Myers BA , Couper DI
Published: November 2005

Puccinecia ciliata is a salt-tolerant, winter-growing grass. The responses of germination of P. ciliata to salinity and temperature were investigated. With a day/night temperature regime of 25/15�C, the final germination percentage of P. ciliata in distilled water was 54%, and was not significantly affected by salinities up to 87 mol m NaCl (osmotic potential, =, -0.4 MPa), but decreased to 5.2% in 260 mol m-3 NaCl (=, -1.2 MPa). The n at which the final germination percentage was reduced by 5O0/n of that in distilled water was about -0.5 MPa, which was similar to that of Lolium perenne. However, for L. perenne, the final germination percentage decreased more rapidly with increasing salinity and from a higher value in distilled water (97%) compared with P. ciliata. Germination of P. ciliata was completely inhibited at constant 33�C and was low (<20%) where day temperature was 30�C and night temperature was greater than or equal to 17�C. Maximum germination was observed where day and night temperatures were between 17 and 24�C, but were not equal. The rate of germination decreased with increasing salinity and was maximal at temperatures between 17�C and 24�C. The reduction in the final germination percentage in NaCl solution was apparently an osmotic effect since the final germination percentage in iso-osmotic solutions of mannitol, polyethylene glycol, NaCl, KC1 and KNO3 were similar. P. ciliala and L. perenne were more salt sensitive during germination than during early seedling growth; for 35-day-old seedlings, shoot dry weight was reduced by 50% of that of the nonsaline treatment when irrigated with solution with = of -0.75 MPa for L. perenne and - 1.25 MPa for P. ciliala.
The influence of weather on the quality of tropical legume pasture during the dry season in northern Australia. III. Effects of digestibility and chemical composition
Authors: McCown RL , Wall BH
Published: November 2005

In the semi-arid tropics, accumulated shed leaf of certain pasture legumes can provide highly nutritious feed for cattle in the dry season. Previous papers in this series have dealt with the fungal spoilage of leaf of Caribbean stylo in response to dew and unseasonal rainfall and the threat to acceptability by cattle. This paper focuses on the effects of varying degrees of moulding and leaching on dry matter digestibility of leaf of this legume. Uniform leaf material of high digestibility was exposed at six locations during the dry season and samples retrieved at 4-weekly intervals. From initial values of 75%. in vitro digestibility dropped to as low as 50%. Degree of moulding, as indicated by a quantitative index of discoloration, accounted for about 80�/o of loss. Moulding was much more important than leaching. This latter finding in the winter-dry tropics contrasts with previous findings in the summer-dry Mediterranean climate.
Classification of the Australian collection of the legume Macrotyloma
Authors: Blumenthal MJ , O'Rourke PK , Hilder TB , Williams RJ
Published: November 2005

The existing Australian collection of Macrotyloma africanum (13 accessions), M. axillare (28) and M. daltonii (12) were grown in and adjacent to a glasshouse in two experiments. The objective was to describe and classify the collection on the basis of morphologic and agronomic attributes, and examine the affinities between accessions and provenance. Seven morphologic-agronomic groups were identified, and together with another agronomic group, form the basis for future field evaluation of the species. Unusual accessions were identified. The perennial and annual species each appeared to have different strategies to avoid environmental stress. Consequences for field evaluation are discussed.
Effects of applied sulfur on glucosinolate and oil concentrations in the seeds of rape (Brassica napus L.) and turnip rape (Brassica rapa L. var. silvestris (Lam.) Briggs)
Authors: Mailer RJ
Published: November 2005

The effect of sulfur availability on glucosinolate concentration in seed meal of glasshouse grown Brassica nupus cv. Wesbrook and Brassica rapa cv. Runyip was studied. In addition, field trials were evaluated to determine the degree of variability of glucosinolate concentrations in the seed and of sulfur in the plants of rapeseed grown at a number of sites throughout New South Wales.Glucosinolate concentration in seeds grown in the glasshouse increased (P < 0.01) in both cultivars with increasing sulfur application, ranging from an average of 5 8mol at 4 8g g-1 to 55 8mol at 100 8g g-1 sulfur. Bunyip containcd significantly higher concentrations (Pt0-01) than Wesbrook. Increased rates of sulfur application resulted in increased (P < 0.01) seed oil concentrations (from 28.7 to 37.6%), yield (3.1-27.1 g) and 1000-grain weights (2.1-2.9 g). Field trials showed site (P < 0.01) and cultivar (P<0.01) variation in glucosinolate levels. However, sulfur did not appear to be an independently limiting factor in field-grown plants.
Factors limiting the intake of feed by sheep. 15. Voluntary feed consumption and digestion in lambs fed chopped roughage diets varying in quality
Authors: Weston RH
Published: November 2005

Feed intake and digestion transactions for diets based on wheaten straw and mature ryegrass diets, both supplemented to provide additional essential nutrients, were compared with those for lucerne hay and high quality forage oats diets in lambs weighing c. 24 kg. The data obtained and comparable published data were used to examine relationships between a range of variables. Decrease in roughage quality, as evidenced by decrease in digestible organic matter (OM) intake, was accompanied by increase in (i) times spent eating, ruminating and chewing rumination boluses, (ii) the quantities of digesta or digesta OM in the reticula-rumen and omasum. It was not associated with increase in the large particle content of rumen or omasum digesta. Over the range of diets, close direct relations were demonstrated between (i) ruminating time and the amount of digesta in the reticulo-rumen, (ii) the amounts of digesta in the reticulo-rumen and omasum, (iii) the OM concentrations in rumen and reticulum digesta, (iv) the OM concentrations in reticulum and omasum digesta, (v) the OM concentration of reticulum digesta and of digesta flowing to the omasum, and (vi) the increase in OM concentration from reticulum to omasum digesta and OM concentration of reticulum digesta. Reticulum digesta were of finer texture than rumen digesta, and the bulk density of digesta particle fractions varied between diets, and sometimes between rumen and large intestine digesta. With a straw-based diet, relative to lucerne hay, small particles ( <600 �m sieve) were cleared more slowly from the reticula-rumen, associated with a larger reticulo-rumen particle pool. The data are discussed in relation to (i) the flow of digesta through the alimentary tract and (ii) the regulation of roughage intake. They were considered to be consistent with a concept that energy metabolism and digesta load in the reticulo-rumen interact in the regulation of roughage intake.