bluuebunny/crossref_metadata_2025 huggingface dataset:
Early generation selection for milling quality in five bread wheat crosses
Authors: O'Brien L , Mares DJ , Ellison FW
Published: November 2004

A milling quality assessment protocol using a 10 g seed sample was developed. Its ability to discriminate between wheats differing in milling quality and its application to early generation selection were evaluated. The procedure reliably and accurately discriminated between the varieties Sunco, Hartog and Sunelg for the flour parameters yellow pigment content, Kent-Jones colour grade and yield. The procedure was applied to progeny of F2 single plant selections from five bread wheat crosses, and heritabilities and simulated response to selection measured in the F3 generation. Medium to high heritabilities were obtained for yellow pigment content and colour grade, while those for flour yield were generally lower and varied considerably between crosses. Results of simulated selection versus values for control varieties indicated that the protocol would result in positive response to selection for milling quality. The outcome for some crosses, however, was influenced by the comparatively high values for the control varieties, whereas the use of a lesser standard gave improved response to selection. The best simulated selection results were obtained from the Suneca/Sunfield cross in which values for both parents exceeded those of the standard (Hartog). However, there was no transgressive segregation for improved milling quality in any cross. Phenotypic correlations between milling parameters and grain yield were generally non-significant indicating that the sequence of trait selection (i.e. grain yield or milling quality) would have minimal influence on the other attribute. The data indicate that response to selection for milling quality would result from application of this protocol to the early generations of a wheat breeding program.
Row spacing fails to modify soil evaporation and grain yield in spring wheat in a dry Mediterranean environment
Authors: Yunusa IAM , Belford RK , Tennant D , Sedgley RH
Published: November 2004

The loss of moisture by evaporation from soil under crop canopies (Esc) has been recognized as a major cause of poor water use efficiency (WUE), and hence poor grain yield, in crops grown in environments with limited rainfall. Agronomic approaches to restrain Esc aim to reduce the transmission of solar radiation to the soil beneath the crop by improving ground cover by the crop canopy. However, the sparse canopies produced in these environments have a limited effect on evaporation during the energy dependent first stage (Es1); much of the evaporation is independent of energy at the soilsurface (Es2), and therefore less sensitive to the influence of the crop canopy. Manipulating plant arrangement, primarily by changing row spacing, may provide a simple approach for improving ground cover and restraining E,, without changing GAI, and thus improving WUE and grain yield. To explore the potential benefit of variable row spacing on Esc and grain yield in the dry (300 mm) Mediterranean environment of the eastern wheatbelt of Western Australia, spring wheat was grown in 0.09, 0.18, 0.27 and 0.36 m row spacings on coarse textured and fine textured soil types at Merredin in 1989. Esc was determined with an empirical model and measured with microlysimeters. Row spacing had no significant effect on the development of green area index (GAI), dry matter (DM) accumulation and evapotranspiration (ET) throughout the season. However, in mid-season, the proportion of ground covered by the canopy was higher and transmission of solar radiation was reduced in the 0.09 m row spacing compared with the 0.36 m row spacing. These effects did not restrain E,,, which was similar in all treatments. Esc was not restrained even when the plant density was doubled in the 0.09 m row spacing treatment. Esc during the season averaged 88 mm across all row spacings on both soils; this accounted for 56% and 48% of the mean seasonal ET on the coarse textured and fine textured soils respectively. Consequently, neither water use efficiency nor grain yield were affected by variation in row spacing; water use efficiency averaged 25 kg DM ha-1 mm-1 on both soil types. For dry Mediterranean environments of Western Australia, it was concluded on the basis of these results, and yield data from other row spacing trials in the same districts, that there are no significant yield benefits to be obtained by reducing the row spacing from the current spacing of 0.18 m.
Temperature affects germination, mesocotyl length and coleoptile length of oats genotypes
Authors: Radford BJ , Key AJ
Published: November 2004

Seedlings of 16 oats genotypes (Algerian, Amby, Bulban, Cluan, Culgoa, Echidna, MA5030, Minhafer, Moore, Mortlock, Panorama 5, Riel, Saia, Stout, West and 81Ab1063) were allowed to elongate in darkness at six constant temperatures (10, 15, 20, 25, 30 and 35�C) to determine the effect of temperature on final mesocotyl and coleoptile length. The optimum temperature for maximum mesocotyl+coleoptile length (potential maximum sowing depth) was 15�C. Potential sowing depth at 10 to 25�C was always large (113 to 252 mm) but there was a decline with increase in temperature above 20�C. The decline was due to reduced coleoptile length rather than reduced mesocotyl length. Temperaturexgenotype interactions were significant (P < 0.01) but all cultivars showed a similar general trend in response to temperature. Shoots, but not necessarily the primary roots, failed to emerge from the seeds of any genotype at a constant temperature of 35�C. When the temperature was subsequently reduced to 20�C, however, shoot emergence took place. Poor field emergence of early sowings may be related to such temporary cessation of the germination process at high temperatures. Reduced seedling elongation at high temperature may also be involved. The wide variation at 30�C in germination percentage (8 to 100%) and seedling elongation (55 to 126 mm) suggested a genetic solution to the problem of poor emergence at moderately high soil temperatures. Germination and seedling elongation at 30�C were postively correlated. There were no significant (P > 0.05) correlations between mature plant height or seed weight with mesocotyl length, coleoptile length or potential maximum sowing depth.
Genotypic variation in growth and seed yield of soybean (Glycine max (L.) Merr.) in saturated soil culture
Authors: Hartley RA , Lawn RJ , Byth DE
Published: November 2004

Studies were conducted over several years at field sites in south east Queensland to evaluate the response of diverse soybean genotypes to saturated soil culture (SSC), relative to that in conventional irrigation (CI). In an initial study at Dalby, 56 accessions from 12 countries were tested, and all exhibited the ability to acclimate to, and grow in SSC. The chance occurrence of residual picloram herbicide on the site confounded interpretation of differential genotypic responses, but highlighted the potential vulnerability of the SSC system to chemical residues in the surface soil. In more detailed studies with representative subsets of lines at Lawes, there was large genotypic variation in relative responsiveness (RR, defined as {[Response in SSC-Response in CI]/Response in CI}) of yield to SSC, with seed yields reduced by up to 52%, enhanced by up to 37%, or unchanged, depending on genotype and agronomic management. Genotypic variation in RR was generally consistent across seasons, and was variously associated with genotypic differences in phenology when grown under CI. In general, the most positively responsive genotypes were those that started flowering late enough for the plants to have already acclimated to SSC, and that then flowered for a longer duration. Negatively responsive genotypes were those in which the pre-flowering period was sufficiently short for flowering to have commenced before acclimation was complete, i.e. where the acclimation phase intruded into reproductive ontogeny. Very late genotypes were also less responsive, perhaps because of greater lodging under the very favourable growth conditions provided by SSC. The studies indicated the potential for predicting responsiveness to SSC from knowledge of genotypic responses under conventional irrigation.
The use of a benomyl-resistant mutant to demonstrate latency of Colletotrichum gloeosporioides in avocado fruit
Authors: Coates LM , Irwin JAG , Muirhead IF
Published: November 2004

A benomyl-resistant mutant of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc., generated by irradiating a wild-type isolate of the fungus with ultraviolet light, was used as a marker organism to demonstrate latency under field conditions. This mutant could be easily distinguished from wild-type isolates of C. gloeosporioides on the basis of growth rates on benomyl-amended media, and was as virulent in avocado fruit as wild-type isolates. Through the use of this mutant in field inoculations of avocado fruit, it was possible to demonstrate conclusively the existence, for the first time, of latency in the life cycle of C. gloeosporioides in this host. It was also shown that the fungus was able to remain latent for periods of at least 6 months.
Potential for biological control of Phytophthora rootrot of chickpea by antagonistic root-associated bacteria
Authors: Myatt PM , Dart PJ , Hayward AC
Published: November 2004

Over 1000 bacteria were isolated from rhizospheres of chickpea (Cicer arietinum L.) and evaluated for their potential as biological control agents of Phytophthora megasperma f. sp. medicaginis root rot of chickpea in vitro. Following in vitro plate assays for fungal antagonism, initial pot assay results showed 31 isolates with the ability to limit or delay chickpea seedling disease in a pasteurized soil. The most promising isolates were identified as Pseudomonas cepacia (seven strains) and P. fluorescens (two strains). No relationship was observed between biological control activity of the bacteria and the soils, chickpea cultivars or the methods used in their isolation.
Variation in yield potential and salt tolerance of selected cultivars and natural populations of Trifolium repens L
Authors: Rogers ME , Noble CL , Nicolas ME , Halloran GM
Published: November 2004

The effects of NaCl (0-60 mol m-3) on growth rates, dry matter production, leaf expansion, photosynthesis and tissue ion concentrations were evaluated in 10, widely sourced cultivars and five natural populations of Trifolium repens. Shoot dry matter in all cultivars was significantly reduced at NaCl concentrations greater than 20 mol m-3. The rate of yield decline was greater in those cultivars which had the highest yield under non-saline conditions. In all cultivars, shoot concentrations of Na and Cl increased significantly with increasing external NaCl concentrations, but the response of individual cultivars differed. Differences in the capacity to control the uptake and distribution of Na and Cl into the shoot were related to differences in salt tolerance. Four cultivars (Haifa, Irrigation, Ladino and Tamar), representing extremes in relative salt tolerance, were studied in detail. There were no significant differences in root growth or in the concentrations of Na and Cl in the roots between these cultivars when grown at 0 to 60 mol m-3 NaCl. Rates of leaf expansion and petiole elongation were significantly reduced by NaCl in Ladino and Tamar, which had lower salt tolerance, but were not reduced greatly in Haifa and Irrigation, the two cultivars with higher tolerance. Individual leaf photosynthesis rates were not sensitive to NaCl and did not differ between cultivars. There were no significant differences in shoot yields or in shoot ion concentrations between five populations of T. repens, collected from the Mediterranean Region, and the control cultivar Haifa, although two populations (9028 and 9494) produced more dry matter at 60 mol m-3 NaCl. The plant-to-plant variation for all measured characters was large within both populations and cultivars. This study showed that genotypes which have greater salt tolerance or greater yield potential under non-saline conditions can be selected in order to maximize the yield of T. repens under moderately saline conditions.
Effect of saline water combined with restricted irrigation on peach tree growth and water use
Authors: Boland AM , Mitchell PD , Jerie PH
Published: November 2004

TThe effect of four levels of saline irrigation (ECi of 0.1 dS m-l, 0.25 dS m-l, 0.5 dS m-l and 1-0 dS m-l) in conjunction with restricted irrigation volumes was studied in drainage lysimeters over 2 years on peach trees (Prunus persica, L. Batsch), 3-years-old in Year 1. Strong negative linear responses to saline irrigation were measured for growth and final fruit size in Year 2. Leaf chloride increased over time and with treatment levels, reaching a maximum of 3.0% for the 1.0 dS m-l treatment at harvest in Year 2. Root weighted soil Na and Cl levels increased with increasing irrigation salinity. Both Na and C1 levels in fruit and wood were increased by saline irrigation. Photosynthesis was reduced at the high ECi level consistent with decreased conductance and likely C1 toxicity. Saline irrigation reduced tree water use (TWU). Leaf chloride was determined to be a good indicator of salinity level and expected yield reduction. The need for leaching and modification of current Regulated Deficit Irrigation (RDI) management is proposed.
Regulation of muscle protein metabolism in sheep and lambs: nutritional, endocrine and genetic aspects
Authors: Oddy VH
Published: November 2004

Muscle protein accretion, as with the body in general, increases with feed intake. Protein balance across hind limb muscles occurs at energy intakes less than energy balance in the animal as a whole. There is considerable between-sheep variation in muscle protein accretion, and in the relative rates of protein synthesis and degradation, which are in part due to inherent differences in growth potential. Lambs selected for high weight at weaning deposit proportionately more nitrogen in the body than those selected for low weight at weaning. Inherently faster growing lambs have lower rates of protein breakdown in muscle and whole body than those which exhibit slower growth. Differences in sensitivity to insulin and plasma concentration of insulin-like growth factor-1 (IGF-1) indicate that the inherent differences in growth are associated with differences in responsiveness of muscle to hormones, and possible direct effects of IGF-1. Arteriovenous difference methodology, and isotope dilution, have been important tools in improving our understanding of the regulation of muscle protein metabolism.
Fleece growth in Australian cashmere goats. IV. The role of prolactin in the initiation and cessation of cashmere growth
Authors: Kloren WRL , Norton BW
Published: November 2004

An experiment was designed to investigate the effect of prolactin (Prl) on the initiation and maintenance of cashmere growth. Intra-muscular injections of bromocryptine (0.5 mg/kg) three times per week were used to suppress Prl secretion from August to December or from January to June in two groups of three male and three female goats. Bromocryptine effectively suppressed Prl concentrations to below 10 ng/mL for the duration of the treatments. Initiation of cashmere growth goats injected in July to December occurred in January after high post-treatment levels of Prl began to decline. Cashmere growth of male control goats was considered unrepresentative of normal cashmere growth, but initiation in female control goats occurred in December. Bromocryptine treatment from January to June had no effect on active cashmere growth. but inhibited cashmere growth not already initiated. Bromocryptine injections had no effect on serum T4 concentrations. The results are discussed in relation to the role of Prl in the initiation, maintenance and cessation of cashmere growth. It was concluded that either natural or induced peaks of Prl concentrations were associated with the initiation (falling concentrations) and possibly also with the cessation of cashmere growth (rising concentrations).
The use of zymogram and anastomosis techniques to follow the expansion and demise of two coalescing bare patches caused by Rhizoctonia solani AG-8
Authors: MacNish GC , McLernon CK , Wood DA
Published: November 2004

Pectic zymogram characterization and anastomosis techniques were used to study the distribution of strains of R. solani AG-8 in a large rhizoctonia bare patch. Undisturbed soil cores were removed on nine occasions during the period 1988 to 1992. Identification of the isolates of R. solani from wheat seedlings grown in the cores demonstrated that the patch was a coalescence of two patches, each colonized by isolates of R. solani AG-8 representing different zymogram groups (ZG1-1 and ZG1-5). The demarcation between the two patches remained unchanged while both patches were active. Between the 1989 and 1990 seasons, the pathogen in half of the ZG1-5 patch died, or was reduced to such low levels that it was difficult to detect. In the remainder of the ZG1-5 patch, the pathogen died or was reduced to undetectable levels between the 1990-91 seasons. The ZG1-1 patch was evident at the beginning of the 1991 growing season and the pathogen could be isolated; however, by the end of the season the pathogen could not be isolated. In all these instances the demise of the patch was associated with the disappearance of field symptoms and an inability to isolate the pathogen and therefore the apparent death of the fungus in the soil.
Irrigation frequency and nitrogen fertilizers modify cotton yield at Emerald, central Queensland
Authors: Ockerby SE , Lyons DJ , Keefer GD , Blamey FPC , Yule DF
Published: November 2004

Four irrigation frequencies and six nitrogen (N) fertilizer rates (0-300 kg ha-1) were applied to cotton (Gossypium hirsutum L.) grown on three Vertisols in the Emerald Irrigation Area, central Queensland. The purpose was to describe lint production responses to the plant available water before irrigation and N fertilizer, in terms of the crop N content and the efficiency of crop N use for lint production. Lint yield was greatest when the plant available water before irrigation was 50-80010 of the plant available water capacity (PAWC) of each soil. The rate of N fertilizer for maximum yield varied with plant available water and soil type. Plant available water before irrigation >60% and <37% PAWC, and rain after irrigation reduced the crop N content at the time of maximum leaf area index. Relative yield generally responded to 130 kg crop N ha-', although the range from 101 to 141 kg crop N ha-1 reflected differences in the maximum yield of each treatment. If the crop N was <130 kg ha-1, yield was mostly determined by the crop N content, whereas if the crop N content was >130 kg ha-1, yield and the efficiency of crop N use for lint production was determined by the plant available water before irrigation and soil type. Nitrogen fertilizer strategies to achieve the maximum yield of cotton (var. Deltapine 61) should focus on obtaining 130 kg crop N ha-1. This crop N content produced maximum yields for a range of plant available water contents before irrigation, and for three soil types.
Genetic evaluation of production traits between and within flocks of Merino sheep. II. Component traits of the Hogget fleece
Authors: Mortimer SI , Atkins KD
Published: November 2004

Components of the fleece and wool quality traits were measured or assessed 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 recorded were face cover score (FC), leg cover score (LC), neck fold score (NF), body fold score (BF), wax content (W), suint content (S), vegetable matter content (VM), dust penetration (D), follicle density (N) and follicle ratio (RA). Genetic differences within and between flocks of Merino sheep were examined for the traits, and estimates of heritability and within-flock genetic and phenotypic correlations and between-flock genetic correlations among the traits were obtained. Genetic and phenotypic correlations were also estimated between these traits and the major wool production traits: greasy fleece weight (GFW), clean fleece weight (CFW), fibre diameter (FD), body weight (BWT) and staple length (SL). Significant strain. flock within strain and flock effects were wresent for all traits. The influence of environmental effects (birth-rearing type, age at measurement and age of dam) on the traits was estimated, with the birth-rearing type being significant and the largest effect for most traits. Paternal half-sib heritability estimates were 0.44� 0.06 for FC, 0.35� 0.06 for LC, 0.24�0.05 for NF, 0.23�0.05 for BF, 0.38�0.07 for W, 0.42�0.07 for S, 0.06�0.04 for VM, 0.22�0.06 for D, 0.20� 0.07 for N and 0.21�0.07 for RA. Estimates of within-flock phenotypic and genetic correlations were in broad agreement with available published estimates. The implications of the results for Merino breeding programs are discussed.
Effect of sward height during late pregnancy on intake and performance of continuously stocked June- and August-lambing ewes
Authors: Morris ST , Parker WJ , Blair HT , McCutcheon SN
Published: November 2004

Herbage organic matter intake (OMI), grazing behaviour and ewe and lamb production were measured during the last 4 weeks of pregnancy in 2-year-old and mixed-age Border LeicesterxRomney ewes due to lamb in June (winter) or August (spring). The intake of herbage (averaged across lambing date groups) was 1.4�0.1, 1.71�0.1, 1.7�0.1 and 1.9 9�0.1 kg OM ewe-1 day-1 (mean � s.e.m., P < 0.01) for ewes continuously stocked on 10-year-old ryegrass (L. perenne) and white clover (T. repens) pastures maintained at sward surface heights (SSH) of 2.0, 4.0, 6.0 and 8.0 cm respectively. Ewes that were in a good body condition score achieved their required daily intake of energy at a SSH of 2.0 cm. Relative to ewes on the 8.0 cm SSH treatment, those on the 2.0, 4.0 and 6.0 cm SSH treatments attempted to increase intake by increasing grazing duration rather than biting rate. Ewe liveweight, condition score, midside wool growth rate and mean fibre diameter were not affected by sward surface height in either lambing group. There was no within season effect of SSH on lamb birthweight, but lambs born in June were lighter than lambs born in August (4.4k0.2 v. 5.3�0.2 kg, P < 0.001). This trial has shown that, at the same SSH, June-lambing pregnant ewes achieve a similar daily herbage intake to that of August-lambing ewes. A target SSH of 2.0 cm during the last month of pregnancy was shown to be appropriate for both August- and June-lambing ewes in good condition. However, for August-lambing ewes in poor condition, a SSH of 2.0 cm at this stage of pregnancy would be detrimental to overall production, particularly in terms of ewe liveweight loss.
Preharvest sprouting tolerance in three triticale biotypes
Authors: Trethowan RM , Pfeiffer WH , Pena RJ , Abdalla OS
Published: November 2004

Preharvest sprouting is a major constraint to the utilization of triticale for human consumption in regions where moist, humid conditions prevail during harvest. To examine variation for different components of preharvest sprouting tolerance (PST), trials were conducted over six environments in Mexico. Seed dormancy, bract related chemical and mechanical inhibitory effects and falling number (FN) were measured in primary and secondary triticales and their wheat and rye progenitors. Seed dormancy contributed 78% to PST with significant variation among and within triticale biotypes and progenitor species for bract water soluble inhibitors, bract mechanical barriers and FN. Bract chemical inhibition was higher when soil moisture was non-limiting in moisture-stress/non-stress experiments, suggesting the presence of inhibitors other than abscisic acid. In combination, tolerance components enhanced PST. Substituted triticales [2D(2R)] showed higher seed dormancy and bract related tolerances compared with other triticale biotypes and displayed PST equivalent to wheat. The higher PST in wheat could be attributed to higher FN levels. Components of PST evident in the wheat and rye progenitors were suppressed by wheat/rye genomic interactions in primary triticales. The selection of triticales with high stable FN will be an important first step in the development of PST cultivars, by providing the building block upon which seed dormancy and other related factors can be introduced.
Effects of lupin on soil properties and wheat production
Authors: Chan KY , Heenan DP
Published: November 2004

Effect of lupin on wheat production and soil properties was evaluated on a red earth, at Wagga Wagga, N.S.W. Soil physical and chemical properties as well as soil surface aggregate stability, soil water distribution and extraction by wheat crops from a 10-year-old wheat/lupin (WL) rotation were compared with those of continuous wheat (WW), with (WW+N) and without (WW-N) nitrogen fertilizer application. Averaged wheat yield over the 1989-1990 period was 4.17, 2.95 and 3.06 t ha-1 respectively for WL, WW-N and WW+N. Despite the higher yield, important changes in soil properties have been detected in the soil under wheat/lupin rotation when compared with that under continuous wheat. The major effect was surface soil acidification and an associated loss of cations. Ten years of WL, compared with WW-N resulted in 0.2 unit reduction in pH (4 -35 v. 4.55) in 0.10-0.15 m with corresponding increases in extractable A1 and losses in exchangeable Ca2+ (17% as present in WW-N) and Mg+2 (12%). In the continuous wheat, annual application of 100 kg N ha-1 as urea resulted in much greater acidification (by 0.48 pH unit from 4.63 to 4.15 at 0.05-0.10 m) and larger losses in Ca2+ (up to 40%) and Mg2+ (up to 52%) in the top 0.2 m. Ten years of WL rotation reduced K+ by 10% in the top 0.2 m layer compared with both of the continuous wheat rotations, presumably due to higher export of K in lupin grains. Inclusion of lupin in the rotation also resulted in differences in the quality of soil organic matter. Despite similar total soil organic carbon content to WW-N, in the top 0.1 m, soil organic matter under WL had lower C/N ratio and higher polysaccharide content. Lower macroaggregate stability was found under WL compared to WW-N, but this did not result in lower soil water storage over the summer fallow during the two seasons of measurement. However, the wheat crop under WW utilized less stored subsoil water than that under WL, even under conditions of moisture stress.
The predictive value of parental, F1 and early generation hill-plot testing for yield among rapidly advanced hexaploid triticales
Authors: Trethowan RM , Darvey NL
Published: November 2004

Rapid generation turnover techniques were used to identify parental, single cross or backcross populations with yield potential in triticale. Both complete (complete rye genome) and substituted (2D/2R substitution) triticale karyotypes were crossed. Temperature and light controlled greenhouses, immature seed germination, embryo culture and off season nurseries were used to advance three generations in 11 months. Due to seed limitations in the early generations, hill-plots were used to measure total dry matter, grain yield and harvest index. Mid-parent, F2 and F3 hill-plot yield was equivalent to or better than dry matter and harvest index for the prediction of F4 hill-plot yield. Both hill-plot yield (r = 0.54) and dry matter (r = 0-51) were significantly correlated (P < 0.01) with large plot grain yield at the same site in the same year. The best predictors of F4 hill-plot yield were mid-parent, F2 and F3 mean hill-plot yield with phenotypic correlations of 0- 26� 0.17, 0.3510 -03 and 0.44� 0.06 respectively. The F1 (r = -0.02�0.12) provided no association with F4 hill-plot yield, reflecting the high average heterosis for yield (22%) observed in this material. Mid-parent, F2, F3 and F4 dry matter and yield means were significantly lower in inter-karyotypic crosses than intra-karyotypic crosses; however, the relationship between generations appeared to be independent of karyotype. A response to visual selection of individual spikes from hill-plots was obtained at two sites for dry matter and grain yield.
An evaluation of barley accessions for adaptation to the cereal growing regions of Western Australia, based on time to ear emergence
Authors: Young KJ , Elliott GA
Published: November 2004

Ear emergence was measured on a wide range of barley accessions for a number of sowing dates in contrasting environments of the Western Australian cereal-growing regions to determine suitable types for (i) early sowing in the low (<400 mm per annum) regions and (ii) barley production in the high rainfall (>450 mm per annum) regions. Accessions were classified into nine groups via cluster analysis using the time to ear emergence at four sites and a range of sowing dates. Australian cultivars were members of the three groups with the shortest mean time to ear emergence, and, on the basis of an optimum time to ear emergence at each site, were shown to be well adapted to a wide range of sowing times and sites. Members of only one other group showed an acceptable level of adaptation across sites and sowing dates, members of the other five groups being suited to early or very early sowings in the high rainfall region only.
Occurrence of bean yellow mosaic virus in subterranean clover pastures and perennial native legumes
Authors: McKirdy SJ , Coutts BA , Jones RAC
Published: November 2004

In 1990, infection with bean yellow mosaic virus (BYMV) was widespread in subterranean clover (Trifolium subterraneum) pastures in the south-west of Western Australia. When 100 leaves were sampled at random per pasture, the virus was detected by ELISA in 23 of 87 pastures and incidences of infection ranged from 1 to 64%. BYMV was present in all seven districts surveyed, but highest incidences of infection occurred in the Busselton district. In smaller surveys in 1989 and 1992, incidences of infection in pastures were higher than in 1990, and ranged up to 90%. In 1992, when petals from 1703 samples of 59 species of perennial native legumes from 117 sites were tested by ELISA, only 1% were found infected with BYMV. The infected samples came from 5/7 districts surveyed. Species found infected were Kennedia prostrata, K. coccinea, Hovea elliptica and H. pungens. Representative isolates of BYMV from subterranean clover and native legumes did not infect white clover systemically confirming that clover yellow vein virus (CYVV) was not involved. It was concluded that BYMV infection was present in many subterranean clover pastures, but normally at low incidences, except in epidemic years such as 1992. Also, perennial native legumes are unlikely to act as major reservoirs for reinfection of annual pastures each year. In areas of Australia with Mediterranean climates where perennial pastures are absent, persistence of the virus over summer is therefore by some other method than infection of perennials.
The use of a sequential batch testing procedure and ELISA to determine the incidence of five viruses in Victorian cut-flower Sim carnations
Authors: Rodoni BC , Hepworth G , Richardson C , Moran JR
Published: November 2004

A sequential batch testing procedure was used in conjunction with ELISA to estimate levels of virus incidence in Victorian cut-flower 'Sim' carnations. The industry was surveyed for five viruses, namely; carnation mottle virus (CarMV), carnation etched ring virus (CERV), carnation vein mottle virus (CarVMV), carnation latent virus (CarLV) and carnation ringspot virus (CarRSV). CarMV was the most prevalent virus (9.9%), and lower levels of CERV (0 2%), CarVMV (0.1%) and CarLV (0.1%) were detected. CarRSV was not detected in any of the samples tested. Levels of CarMV were lower than in a previous survey in 1985, suggesting that the Plant Improvement Program which has been in operation in Victoria has been instrumental in reducing the incidence of this virus. Growers who purchased cuttings from specialist propagators had lower levels of virus than propagators who implemented little or no quality control. Growers who introduced pathogen-tested cuttings at regular intervals also had lower levels of virus infection.
Effect of basal and side-dressed phosphorus on the achene yield and pyrethrins concentration in the achenes of pyrethrum (Tanacetum cinerariifolium) and on soil and plant phosphorus
Authors: Salardini AA , Chapman KSR , Holloway RJ
Published: November 2004

Field experiments were conducted for two years on a krasnozem at Devonport and on an alluvial soil at Ouse in Tasmania to investigate the effect of basal and side-dressed phosphorus (P) on the yield (achene yield) and pyrethrins (Py) concentration in dry achenes, on tissue P concentrations of pyrethrum and on soil Colwell P (Pc). At both sites, 0, 50, 100, 200 and 300 kg P ha-1 was band-placed at planting (basal P) in May 1990. In September 1991, plots were subdivided and 0, 75, 150 and 200 kg P ha-1 was side-dressed. Application of up to 100 kg basal P ha-' increased achene and Py yield by > 50% in the 1990 crop at both sites. Residual P from the 1990 application tended to reduce the 1991 achene yield, Py concentration and Py yield at both sites (P = 0.09). Side-dressing of P in spring 1991 did not influenced the achene and Py yield at either site. The maximum of combined 1990 and 1991 achene and Py yield was attained with 50 kg P ha-1 and no side-dressed P. Top-soil Pc in 1990 was highly correlated with rates of both basal and side-dressed P, achene yield and P concentration in plant tissues. The concentration of P in shoots, apical tissues and youngest fully expanded leaves of the 1990 crop was highly correlated with the rate of basal P and achene yield. The apical tissues were more suitable for diagnostic work because of the ease and speed of sampling.
Metallothionein and trace element metabolism in sheep tissues in response to high and sustained zinc dosages. 2. Expression of metallothionein m-RNA
Authors: Lee J , Treloar BP , Grace ND
Published: November 2004

Increased dietary zinc (Zn) influences metallothionein (MT) expression in sheep, which in turn effects changes in the regulation of both Zn and copper (Cu) tissue uptake. Romney wether sheep were given ZnO on a regular basis, as required in protocols for the treatment of facial eczema, at either 12 g ZnO fortnight-1 or 12 g ZnO week-1, and the effect of Zn on MT-Ia and -II mRNA expression in liver, kidney, duodenal, muscle and skin tissue was compared with those of untreated animals. Tissue concentrations of Cu, iron (Fe), manganese (Mn) and Zn were determined by plasma emission spectrometry. Metallothionein-Ia and -II mRNA concentrations were 4 to 9-fold greater in the liver and kidney of dosed sheep compared with untreated animals, but not higher in duodenal, mucscle or skin tissue. Zinc concentrations increased in all tissues, except skin, and were strongly correlated with MT expression. Copper uptake into tissues was not inhibited and it was concluded that this was because duodenum tissue MT mRNA expression was not greatly affected. Relationships between MT-mRNA, MT in liver, and Zn and Cu tissue concentrations are presented and discussed.
Effects of depilatory doses of epidermal growth factor on subsequent fertility, pregnancy rate and lambing performance in Merino ewes
Authors: Brown BW , Stockwell PR , Panaretto BA
Published: November 2004

In the present study on Merino ewes, murine epidermal growth factor (mEGF) and genetically engineered methionine epidermal growth factor (met-EGF), given at depilatory dose rates (120 8g mEGF/kg body weight (n = 82) and 250 8g met-EGF/kg body weight (n = 100) respectively), were assessed for effects on fertility, pregnancy rate and lambing performance. Following EGF injection, the ewes were fitted with a net retention system to hold the fleece on the animals for 5 weeks, at the end of which time the wool was harvested from the EGF-treated ewes by hand and was shorn conventionally from non EGF-treated controls (n = 100). All ewes were then joined to raddled-harnessed entire rams (2%) for 6 weeks. The dates of raddle markings recorded during the teaser period and during joining to entire rams revealed that the majority (97%) of control ewes were in oestrus at expected times during the joining period, whilst significantly (P < 0.001) fewer ewes in the mEGF (75%) and the met-EGF (65%) treated groups exhibited oestrus at the expected time. The majority of the ewes that were delayed in onset of oestrus were at the mid to late luteal stages of the oestrous cycle at the time of EGF treatment. There was no material difference between the three groups in the number of ewes returning to service during the joining period, or in the number of empty ewes. The three groups were also similar in the proportions of ewes bearing single or twin lambs, in the overall lambing percentage (controls 108010, mEGF 109%, et-EGF 107%) and survival of lambs to weaning. No abnormalities were found in any of the lambs. It appears that an interval of 5 weeks between dosing and joining is sufficient time for EGF-treated ewes to resume normal cyclicity and fertility.
Nature of resistance in Cucumis melo cvs to papaya ringspot virus type W
Authors: Gibb KS , Padovan AC , Herrington ME
Published: November 2004

Comparative studies were made of the reactions of a 'resistant' (Cinco), a susceptible (Planters Jumbo) and a Cinco x Planters Jumbo (Cinbo) cultivar of muskmelon to papaya ringspot virus-watermelon strain (PRSV-W). Neither Cinbo nor Cinco supported levels of virus that were detectable by biotin-ELISA, but PRSV-W was detected in individual cells of the three cultivars. In inoculated leaves of Planters Jumbo most cells were infected, but in both Cinbo and Cinco only 3-7% of cells were infected. When cotyledons of Cinbo were inoculated, mild systemic symptoms were observed, but plants remained symptomless when true leaves were inoculated. Virus was recovered from both cotyledon - inoculated Cinbo grown at 25 or 40�C and true leaf-inoculated Cinbo, but only when the latter were grown at 25�C. There was no difference in the percentage of infected cells in these leaves despite the differences in symptom expression. Cinco was highly resistant and only occasionally showed mild systemic symptoms on cotyledon-inoculated plants grown at 25�C. Unlike those of Cinbo, leaves with symptoms were not infective, but there was no difference in the percentage of infected cells in these leaves compared to those in Cinbo. For both Cinbo and Cinco, several lines of evidence are presented that suggest PRSV-W is restricted to a few cells throughout the plant.
Corrigendum - Genotypic variation for stolon and other morphological attributes of white clover (Trifolium repens L.). Populations and their influence on herbage yield in the summer rainfall region of New South Wales
Authors: Jahufer MZZ , Cooper M , Brien LA
Published: November 2004

A random sample of 60 germplasm accessions from the Australian white clover germplasm collection was characterized in the field at Glen Innes, N.S.W. Genotypic variation for stolon and other morphological attributes was measured in one season. Herbage yield was evaluated over seven seasons to quantify the magnitude of accession-by-season interaction. There were significant (P < 0.01) differences among accessions, seasons, and accession-by-season interactions for herbage yield. Classification was used to group the accessions on their seasonal herbage yield. A summer active group, a winter active group and a group showing autumn activity for herbage yield were identified. There was significant (P < 0.01) variation among accessions for all plant attributes measured and their accession mean repeatability was moderate to high. There were strong genotypic correlations among the morphological attributes. Five of the morphological attributes (stolon density, stolon branching, plant spread, plant height, stolon thickness and leaf length) expressed a strong genotypic correlation with average herbage yield over seven seasons. The genotypic variation estimated for herbage production and plant attributes signifies the potential of the collection to be used as a source of variation for the genetic improvement of productivity and perenniality of white clover for Australian environments.
Management of Lolium perenne/Trifolium repens pastures in the subtropics. II. Effect of summer defoliation, irrigation duration, seedbed preparation and pasture type
Authors: Fulkerson WJ , Slack K
Published: November 2004

This study on the north coast of New South Wales, Australia, evaluated the effect of irrigation and defoliation management over summer, pasture type and seedbed preparation on production and survival of a perennial ryegrass pasture over an 18-month period from sowing. In a relatively dry summer, irrigation sufficient only to keep plants growing, increased production of ryegrass plus clover from 2826 to 5515 and 3210 to 5396 kg DM/ha in summer and the subsequent autumn/winter, respectively, and increased survival of ryegrass plants by 34%. The more summer active Olwen white clover/NZA895 perennial ryegrass combination had a 16% higher production in summer, but a 11% lower production in winter than a Haifa/Yatsyn sward. The difference in production was entirely due to the clover component of the pasture. DM yield in the first growing season for the ryegrass/white clover pasture was equivalent to applying 20 kg N/ha/month to a pure ryegrass sward. In the subsequent summer/autumn/winter, the yield of pure ryegrass pasture was well below the ryegrass/white clover swards at any rate of N application. There was no difference between survival of NZA895 and Yatsyn ryegrass or incursion of summer grass into their respective plots. Plots defoliated over summer at 6 cm, as opposed to 12 cm, stubble height yielded 54% more edible DM and resulted in a 65% higher ryegrass plant survival rate. There was no effect on summer grass incursion. Multiple cultivations appear to be the key to appropriate seedbed preparation, with this treatment achieving the highest ryegrass survival rate, lowest summer grass incursion and highest DM yields.
Cadmium concentrations in kidneys of sheep and cattle in Western Australia. 1. Regional distribution
Authors: Morcombe PW , Petterson DS , Masters HG , Ross PJ , Edwards JR
Published: November 2004

A sample of 4973 kidneys from sheep stratified by age and shire of origin within the Agricultural Region of Western Australia, was analysed for cadmium (Cd) content during the period August 1989 to April 1991. The geometric mean Cd concentration in the kidney of hogget ewes was 0.9 mg/kg, in 4-tooth ewes 1.47 mg/kg and in adult ewes 3.34 mg/kg on a wet weight basis. The mean Cd concentrations of either ewe or hogget flocks from different Divisions of the Agricultural Region did not differ from each other. The annual increase in Cd concentration of kidney from hogget sheep was estimated to be 0-65 mg/kg. The rate of accumulation of Cd in kidney from cattle and sheep grazing the same properties was similar. Kidneys from a sample of 354 adult cattle from the Kimberley Region and 483 aged sheep from the Pastoral Region, both areas of unimproved rangelands, had geometric mean Cd concentrations of 0.15 mg/kg and 0-31 mg/kg respectively. A higher Cd concentration in flocks from the divisions adjacent to the Agricultural Region may have resulted from the establishment of some volunteer species of winter annual pastures in the rangeland.
Distribution in Australia and host plant specificity of Phomopsis emicis, a stem blight pathogen of Emex australis
Authors: Shivas RG , Lewis JC , Groves RH
Published: November 2004

The stem blight pathogen, Phomopsis emicis, is widespread on Emex australis throughout those regions of southern Australia with a Mediterranean climate. Host specificity tests showed that P. emicis was able to cause leaf lesions or stem collapse on five closely related species, E. australis, E. spinosa, Rumex alcockii, R. dumosus and R. pulcher, in the Polygonaceae. Two of these species, R. alcockii and R. dumosus, are native to Australia and the others are introduced weeds. P. emicis was able to colonize the wounded or senescent tissue of several other plant species, thereby demonstrating its facultative saprophytic ability. There was evidence that P. emicis was able to survive as an endophyte in Muehlenbeckia adpressa and Polygonum aviculare.
Colonization of a South Australian grassland by invading Mediterranean annual and perennial pasture species
Authors: Cocks PS
Published: November 2004

Spatial variation in the composition of the soil seed bank was studied in a 5 ha area of pasture in South Australia dominated by naturalized annuals originating from the Mediterranean basin. The results were analysed with regression, cluster and principal component analysis. A total of 34 species was collected, including 17 grasses, seven legumes, eight broad-leaved species and two rushes. The total size of the seed bank was over 200 seeds dm-2, equivalent to about 450 kg ha-1 Although the site was nearly flat, elevation affected the distribution of all species, probably because of its effect on drainage in winter. Five legumes (Tbifilium clusii, T. ornithopioides, T. dubium, T. glomeratum and T. subterraneum) dominated the seed bank, but the dominant species changed with elevation above the zone of winter-waterlogging. Of the grasses Serrafalcus hordeaceus and Vulpia spp. were present at well drained sites, while Lolium perenne and Hordeum geniculatum were found at low sites, with Holcus lanatus intermediate. Seeds of legumes were more frequent at sites where soil nitrogen and phosphorus were low, and seeds of grasses where they were high. The results are compared with those obtained from perennial species in north Europe, and the implications for pasture deterioration and improvement in Australia are discussed. It is concluded that genetic diversity is likely to be important in the successful invasion of pasture by Mediterranean annuals. The presence of several naturalized legumes in niches incompletely occupied by subterranean clover suggests that germplasm is available to increase the legume component of many annual pastures
Microbial fermentation of cereal grains in vitro
Authors: Opatpatanakit Y , Kellaway RC , Lean IJ , Annison G , Kirby A
Published: November 2004

The stoichiometry of fermentation was investigated in vitro with wheat and maize grains. Gas production proved to be an accurate index of VFA production and change in pH. Gas and total VFA production from wheat were strongly correlated with starch disappearance. On a stoichiometric basis, 66% of gas and 64% of VFAs produced from wheat were accounted for by starch fermentation. With maize only 18% of gas and 23% of VFAs produced were accounted for by starch disappearance. There were significant differences between grain species in rates of gas production (P < 0.001), being ranked in the order wheat > triticale, oats > barley > maize > rice, sorghum. Effects of varieties and growing sites on gas production were significant with wheat, oats, maize and sorghum. With barley, only varietal effects were significant (P < 0.001). With maize and sorghum, there were significant variety by site interactions.