bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of extended (4-12 years) burial on seed softening in subterranean clover and annual medics
Authors: Taylor GB , Ewing MA
Published: March 2005

The effect of burial of seeds of 3 cultivars of subterranean clover (Trifolium subterraneum) and 1 cultivar each of burr medic (Medicago polymorpha) and barrel medic (M. truncatula) that had experienced 1 summer at the soil surface was continued from 4 to up to 12 years. Seeds were situated at 2, 6 and 10 cm depth, as well as at the soil surface. Numbers of residual seeds were determined after each sampling occasion, the timing of which was varied between cultivars and depths of burial according to the progress of seed softening. The marked reduction in the rate of seed softening in all 3 clover cultivars with increasing depth of burial established during the first 4 years of the experiment was maintained. After 12 years, 37% of the Nungarin clover seeds that had been buried at 10 cm were still present as hard seeds. All residual hard seeds germinated readily after nicking with a razor blade. Seeds of both medic cultivars, that were slower to soften than the clovers at the soil surface, continued to show little effect of burial at 2 cm, or of burial to 6 cm in the case of Cyprus barrel medic. Species differences in response to seed burial are explained in terms of the effects of soil temperatures on the 2-stage seed softening process. The absence of an effect of shallow burial on the softening of medic seeds appears to be attributable to a lower optimum temperature for the first stage of seed softening than is the case for subterranean clover. Unfavourable temperatures for the final stage of seed softening can result in the accumulation of latent soft seeds, particularly in subterranean clover. These latent soft seeds will soften during the first summer/autumn after their return to close to the soil surface as a consequence of tillage. Whereas increased seed longevity as a consequence of burial in crop years can be advantageous in terms of legume persistence, particularly of clover, it can also be distinctly disadvantageous when it comes to cultivar replacement.
Perennial legumes for the high rainfall zone of eastern Australia. 1. Evaluation in single rows and selection of Caucasian clover (Trifolium ambiguum M. Bieb.)
Authors: Hill MJ , Mulcahy C , Rapp GG
Published: March 2005

A range of perennial legume species, including Trifolium ambiguum, T medium, Astragalus cicer, Coronilla varia, Lotus corniculatus, L. pedunculatus, and Lespedeza cuneata, were evaluated in glasshouse and field trials in 1989-92 at Armidale, New South Wales. Hexaploid germplasm of T. ambiguum was subjected to selection for increased seedling vigour, early biomass production and profuse flowering in glasshouse screening and spaced plant field nurseries. On an acid, solodic soil, T. ambiguum and T. medium grew modestly, Lotus spp. grew vigorously initially, but died out within 3 years, A. cicer and C. varia failed to persist beyond 1 year, but isolated plants of Lespedeza cuneata thrived. On an acid, freedraining, red-basalt soil, all accessions grew vigorously until early 1991. During the succeeding drought, Lotus sp. died out, A. cicer thinned out on the acid soil, but T. ambiguum, T medium, and C. varia remained persistent and productive. A large nursery of A. cicer accessions on the same soil limed to 5 t/ha before planting remained vigorous to the present. Superior hexaploid material of T ambiguum selected from spaced plants, originated chiefly from CPI 43909 and the ARS-2678 germplasm collection from Utah, USA.
Effect of time of application of MCPA and bromoxynil in relation to flowering on subterranean clover seed yield and quality
Authors: Dear BS , Sandral GA , Pratley JE , Coombes NE
Published: March 2005

The importance of stage of phenological development and cultivar maturity ranking in influencing the seed yield response of subterranean clover (Trifolium subterraneum L.) to broadleaf herbicides was examined in a field study in southern New South Wales. The herbicides, bromoxynil (200 g a.i./L) at 1.4 L/ha and MCPA (500 g a.i./L) at 1.0 Wha, were applied 6 (TI) and 3 weeks (T2) before flowering, and at 5% flowering (T3) to 7 cultivars ranging from early to late flowering. The stage of phenological development at herbicide application, the maturity ranking of the cultivar and the herbicide applied, all influenced seed set. Application of bromoxynil at T1 did not reduce seed yield of any cultivar but increased seed yield of 4 cultivars by up to 30%. MCPA applied at the same time reduced seed yield in 1 cultivar by 26% and increased yields in 4 others by up to 57%. Application of bromoxynil at T3 caused reductions in seed yield in 3 of the 7 cultivars. MCPA applied at this time was more damaging than bromoxynil with all cultivars showing large seed yield reductions ranging from 22 to 64%. Despite large reductions in herbage yield as a result of some herbicide treatments, there was only a low correlation (r = 0.3, P<0.01) between herbage yield at full flower and seed yield. Our findings suggest that the reduction in herbage yield and change in canopy structure as a result of the early application of herbicides stimulated seed production. Seed number was the primary yield component responsible for the change in seed yield with a high correlation (r = 0.86, P<0.01) between these 2 parameters. Seed size was relatively insensitive to herbicide treatment but varied markedly with cultivar. Germination percentage of seed produced by swards treated with bromoxynil was unaffected, even when applied at T3, whereas MCPA lowered germination percentage of almost all cultivars if applied within 3 weeks of the commencement of flowering. The maturity ranking of the cultivars was highly negatively correlated with percentage seed yield loss (r = -0.80, P<0.01) when either herbicide was applied at T3, the seed yield of the early flowering cultivars being most depressed by the herbicides. Length of recovery period between herbicide application and flowering was shown to be very important in influencing seed yield, the effect being modified by both herbicide and cultivar maturity.
Wounding can improve efficacy of Colletotrichum orbiculare as a mycoherbicide for Bathurst burr
Authors: Klein TA , Auld BA
Published: March 2005

Colletotrichum orbiculare offers potential as a mycoherbicide for control of Bathurst burr (Xanthium spinosum) but infection is restricted where there are limited periods of free moisture on plant surfaces. Wounding of plants ruptures cells and releases moisture and/or nutrients which may enhance infection. Wound sites may also offer easier access to the fungus. In 7 field trials over 2 seasons at 4 sites, plants were wounded by mowing or harrowing before application of C. orbiculare at several spore dose rates. Harrowing plus spores caused a significantly (P<0.05) higher mortality than spores alone in 3 out of 5 experiments. This effect of wounding did not occur for all spore dose rates applied in individual experiments. In experiment 6, 2.5 x 1011 spores/ha following harrowing were equally as effective in causing plant death as 5 x 1011 spores/ha without harrowing. Mowing of plants was associated with increased (P<0.05) mortality in 2 out o f 3 experiments. Thus, wounding can increase the efficacy of C. orbiculare but further study is required to ellucidate the mechanism. The procedure may allow a reduction in quantities of mycoherbicide necessary for weed control.
Effect of time of tiller emergence and nitrogen fertiliser on seed yield components of Digitaria eriantha cv. Premier
Authors: Ramirez L , Hacker JB
Published: March 2005

The effect of fertiliser nitrogen (N) and season (spring or autumn seed harvests) on tiller appearance, development and survival, and seed production in D. eriantha was investigated in a trial in south-east Queensland. In both spring and autumn, rate of tillering was maximal within the first week after cutting and declined rapidly thereafter, regardless of the level of applied N. Rate of tillering was greater in spring than in autumn. Tiller survival decreased as tiller emergence was delayed, and with increasing levels of applied N. At seed harvest, early-emerged tillers were consistently taller, heavier, thicker, and more fertile than late-emerged tillers, and they contributed most of the inflorescences. Fertility of all tillers was increased by application of N, particularly in spring. Seed yield, percentage seed set, and 1000-seed weight were larger in early-emerged tillers, which also bore the biggest inflorescences with the most spikelets per inflorescence, although spikelet number per unit raceme length was lower than on inflorescences borne on late-formed tillers. In general, the effect of N on seed yield components (inflorescence size, 1000-seed weight and seed set) was not significant. Early-emerged tillers contributed more than 70% of the total seed yield in both seasons.
Identifying suitable grass species for saline areas
Authors: Rogers ME , Noble CL , Pederick RJ
Published: March 2005

The salt tolerance of 20 lines of perennial grasses, including both native Australian and introduced species, was evaluated in 3 separate experiments over 0-180 mol Na Cl/m3 in the greenhouse, with the aim of identifying material that may be grown productively in saline areas in Australia, particularly the Murray- Darling Basin. Lolium perenne cv. Victorian, a species that is recognised as having a moderate level of salt tolerance, was included in all experiments as a reference species. In relative terms (as defined by the rate of the decline in dry matter production under saline conditions), only 5 species or cultivars (Psathyrostachys juncea cvv. Mankota, Tetracan and Vinall, Pascopyrum smithii cv. Walsh and Thinopyrum elongatum cv. Tyrell) were more salt tolerant than L. perenne cv. Victorian. However, several species including the native species Enteropogon acicularis and Themeda triandra, and the introduced species Eragrostis curvula cv. Consol and Thinopyrum elongatum, produced more dry matter than L. perenne over NaCl concentrations ranging from 0 to 180 mol/m3. The salt tolerance of Danthonia richardsonii was very similar to that of L. perenne. It was concluded that Psathyrostachys juncea, Pascopyrum smithii, Enteropogon acicularis and D. richardsonii, may offer potential as salt-tolerant germplasm, however, further field studies are recommended in order to fully assess the response of this material to saline soil conditions.
Long-season wheats extend sowing opportunities in the central wheat belt of Western Australia
Authors: Anderson WK , Heinrich A , Abbotts R
Published: March 2005

Wheat cultivars and crossbreds with different maturities were tested at a range of sowing times from 1989 to 1991 at 13 sites in the central wheat belt of Western Australia. The aim was to determine if long-season cultivars would allow sowing before mid May, the earliest period estimated by previous studies. Rainfall in the growing season ranged from 176 to 330 mm. Long season cultivars showed the potential to extend the sowing season from early May into late April without loss of yield. Mid-season cultivars reached their maximum yields from sowings in May and short-season cultivars yielded most from late May and early June sowings. The optimum flowering period for the study area over the 3 years was 2-22 September, a period similar to earlier estimates made using only short- and midseason cultivars. It was concluded that, despite considerable variability from year to year both within and between sites, the optimum flowering period did not vary greatly on average and was not greatly affected by the use of long-season cultivars. Sowing after the optimum time resulted in slightly increased grain protein percentages but losses in the value of grain yield would have more than offset increases in the value of grain protein. At the nitrogen rates used in the experiments (80 kg/ha), grain proteins over 11.5% [the minimum for the Australian Hard (AH) grade] were only achieved on average for the long-season AH cultivar Blade at sowing times later than its optimum for yield. The Australian Standard White cultivars, however, mostly achieved 10% protein, an acceptable minimum for that grade, from sowings made at their optimum time. Hectolitre weights fell below the delivery standard of 74 kg/hL in only 3 grain samples. These were all from short-season cultivars sown before their optimum time. Fifteen grain samples from 4 sites contained small grain sievings (2-mm slotted screen) above the delivery standard. Eleven of these samples came from cultivars sown outside their optimum sowing times.
Effect of waterlogging on the severity of disease caused by Mycosphaerella pinodes in peas (Pisum sativum L.)
Authors: McDonald GK , Dean G
Published: March 2005

The effect of waterlogging on the severity of disease caused by Mycosphaerella pinodes infection in field pea was measured in 2 experiments in the glasshouse. Disease significantly reduced root and shoot growth in both experiments. In a comparison of 2 cultivars with different sensitivities to waterlogging, the severity of disease was lower in the cultivar which was less sensitive to short-term waterlogging. Flooding the roots of plants after infection increased the visual symptoms of disease, but if plants were inoculated with the pathogen after flooding commenced, disease severity was reduced by waterlogging. Inoculation before waterlogging significantly reduced plant dry matter, but there was no reduction in plant growth by disease when inoculation occurred after waterlogging commenced. The results suggest that waterlogging of peas already infected with Mycosphaerella pinodes may result in more severe infection and greater reductions in plant growth, and cultivars more sensitive to waterlogging damage may also suffer greater losses from disease.
Seed production and seedling emergence of Giant Parramatta grass on the north coast of New South Wales
Authors: Andrews TS , Whalley RDB , Jones CE
Published: March 2005

Inputs and losses from Giant Parramatta grass [GPG, Sporobolus indicus (L.) R. Br. var. major (Buse) Baaijens] soil seed banks were quantified on the North Coast of New South Wales. Monthly potential seed production and actual seed fall was estimated at Valla during 1991-92. Total potential production was >668 000 seeds/m2 for the season, while seed fall was >146000 seeds/m2. Seed fall >10000 seeds/m2.month was recorded from January until May, with further seed falls recorded in June and July. The impact of seed production on seed banks was assessed by estimating seed banks in the seed production quadrats before and after seed fall. Seed banks in 4 of the 6 sites decreased in year 2, although seed numbers at 1 damp site increased markedly. Defoliation from mid-December until February, April or June prevented seed production, reducing seed banks by 34% over 7 months. Seed banks in undefoliated plots increased by 3300 seeds/m2, although seed fall was estimated at >114 000 seeds/m2. Emergence of GPG seedlings from artificially established and naturally occurring, persistent seed banks was recorded for 3 years from bare and vegetated treatment plots. Sown seeds showed high levels of innate dormancy and only 4% of seeds emerged when sown immediately after collection. Longer storage of seeds after collection resulted in more seedlings emerging. Estimates of persistent seed banks ranged from 1650 to about 21260 seeds/m2. Most seedlings emerged in spring or autumn and this was correlated with rainfall but not with ambient temperatures. Rates of seed bank decline in both bare and vegetated treatment plots was estimated by fitting exponential decay curves to seed bank estimates. Assuming no further seed inputs, it was estimated that it would take about 3 and 5 years, respectively, for seed banks to decline to 150 seeds/m2 in bare and vegetated treatments.
Nitrogen and potassium nutrition of Australian waxflowers grown in siliceous sands. 2. Effect on leaf colour, vase life, and soil pH and conductance
Authors: Maier NA , Barth GE , Bartetzko MN , Cecil JS , Chvyl WL
Published: March 2005

The effects of nitrogen (N) and potassium (K) on leaf colour, vase life of flowering stems, and soil pH and electrical conductivity (conductance) were investigated for Australian waxflowers. Experiments were conducted on commercial plantings of Chamelaucium uncinatum cvv. Alba and Purple Pride, and a Chamelaucium hybrid (C. floriferum x C. uncinatum) known locally as Walpole wax, at 3 sites in South Australia. Nitrogen (as NH4NO3) and K (as K2SO4) were applied at rates up to 160 g N/plant and 80 g K/plant over several side dressings during the growing season. Application of N significantly (P<0.05) increased leaf colour ratings for the cv. Alba and Walpole wax. At the higher N rates leaves were dark green. Differences between years were small compared with the effect of applied N. The N x year interaction, and the effect of applied K, were not significant (P>0.05) at any site. For cv. Alba, application of N significantly increased vase life by 5 days in 1992 and 3 days in 1993. For Walpole wax, the effect of N was not consistent between years. Each year, the vase life of flowering stems from cv. Alba were consistently greater compared with stems from Walpole wax. Application of K did not significantly (P>0.05) effect vase life at any site. Annual applications of 80 or 160 g N/plant, as ammonium nitrate, significantly decreased soil pH by 0.3-1.4 units after 2-3 years, whereas application of K, as potassium sulfate, did not affect soil pH. The effect of applied N on soil conductance, although significant, was not consistent between sites. For example, at site 1, increasing the rate of applied N from 0 to 80 g N/plant increased conductance from 0.04 to 0.08 mS/cm in 1992. However, in 1993 it decreased from 0.04 to 0.02 mS/cm. The low conductance values (0.02-0.09 mS/cm) in the 0-60 cm soils, show that fertiliser salts did not accumulate over the course of the study to concentrations which adversely affect plant growth and yield. We conclude that N stress was a significant factor in the occurrence of poor leaf colour, and may be a major factor in the occurrence of defoliation during the flowering period. Optimising N nutrition improved leaf colour, vase life and, depending on the rate, did not significantly increase soil acidity or conductance after 2-3 years.
Vase life characteristics of selected Grevillea
Authors: Joyce DC , Beal P , Shorter AJ
Published: March 2005

Grevillea is a large genus containing many species, forms and hybrids bearing inflorescences with desirable cut flower characteristics. Nineteen different Grevillea spp. and forms (7), and 39 hybrids (including 11 repeat collections) were assessed for vase life. Longevity varied 3-fold, from 3 days for G. wickhamii to 9 days for a G. whiteana accession. Species with comparatively long vase lives included G. pteridifolia, G. sessilis and G. whiteana. These genotypes may be useful for cut flower production and/or in breeding programs aimed at producing new cut flower Grevillea.
Effects of equilibrium relative humidity on in vitro growth of Botrytis cinerea and Alternaria alternata
Authors: Alam S , Joyce D , Wearing A
Published: March 2005

Mycelial growth in vitro of 2 fungal pathogens responsible for postharvest loss of horticulture produce, Botrytis cinerea and Alternaria alternata, was related to equilibrium relative humidity (e.r.h) at ambient temperature (20�C) using solutes to adjust the 'osmotic water potential' of the growth medium. Colony diameter growth of B. cinerea and A. alternata on solid medium (1/2 potato dextrose agar) was initially stimulated slightly when the e.r.h. was decreased from 99.7 (unamended medium) to 99.3% (-0.4 to -1.0 MPa). Thereafter, colony diameter growth continually decreased as a function of reducing e.r.h. over the range 99.3-94.3% e.r.h. (-1.0 to -8.0 MPa). Similar trends were recorded with both pathogens for their dry matter growth in liquid medium (Oxoid Czapek Dox) as a function of osmotic potential. Initial stimulation of dry matter growth at -1.0 MPa (equivalent to 99.3% e.r.h.) was not evident in liquid medium. Fungal growth data suggest that postharvest mycelial growth of Botrytis cinerea and Alternaria alternata on wounds, senescing tissue or secretions such as cell sap or nectar could be restricted through control of e.r.h. in packages of horticulture produce.
The use of lasalocid in long-term feeding of Friesian steers
Authors: McMeniman NP , Elliott R , Hogden A
Published: March 2005

Seventy-two Friesian calves with a mean (� s.e.) liveweight of 130.6 � 3.82 kg were divided into 8 groups which were then allocated to 2 dietary treatments, a grain-based feedlot diet (Cont) and the same diet with lasalocid added at the rate of 22 g/t (Las). After 127 days (period 1) of feeding, 2 of the groups in the Cont treatment were changed to the Las treatment (Cont -> Las) and 2 on the Las treatment were changed to the Cont treatment (Las -> Cont). The animals were slaughtered after a further 168 days of feeding (period 2). Liveweight gain of the Las group (1.39 kg/steer.day) was superior to that of the Cont group (1.28 kg/steer.day) in period 1. In period 2, liveweight gain in the Las and Las -> Cont groups was superior to that of the Cont -> Las group. Food conversion ratio in the Las group was lower than in the Cont group during period 1 but there were no differences between treatments in period 2. The slaughter data showed that the Friesian steers produced acceptable carcasses in terms of carcass weight and fat depth. The study showed that Friesian steers can be successfully grown to slaughter weight on high grain diets and that long-term lasalocid supplementation results in improved liveweight gain and feed conversion efficiency.
Predicting resistance and managing susceptibility to cyromazine in the Australian sheep blowfly Lucilia cuprina
Authors: Yen YL , Batterham P , Gelder B , McKenzie JA
Published: March 2005

Four cyromazine-resistant variants of Lucilia cuprina were selected after ethyl methanesulfonate mutagenesis and screening above the concentration of cyromazine lethal to susceptibles. Resistance is controlled by a single gene in each variant. Two resistance loci have been identified, one (Cyr 4) closely linked to the marker 'reduced eyes' on chromosome IV, the other (Cyr 5) closely linked to the 'stubby bristles' marker on chromosome V. Concentration-mortality line analysis shows resistance ratios are low (1.5-3x). One variant [Cyr 4(2)] is viable as a homozygote, the others are lethal [Cyr 4(1)] or, at best subvital [Cyr 5(1) and Cyr 5(2)]. Competition experiments between resistant heterozygotes and susceptibles show that resistance to cyromazine is selected for over a limited range of concentrations. The capacity of laboratory studies to predict likely resistance mechanisms before they evolve in the field is discussed. The use of genetic, toxicological and relative fitness data arising from these studies to devise the most effective strategies of insecticide usage while minimising the evolution of resistance is emphasised.
Measurement of cashmere yield and mean fibre diameter using the optical fibre diameter analyser
Authors: Peterson AD , Gherardi SG
Published: March 2005

A new technique was developed to measure the yield and mean fibre diameter of cashmere. The fibre diameter distribution of 2-mm snippets measured by the Optical Fibre Diameter Analyser (OFDA) was used to calculate cashmere yield of a goat fleece without dehairing. The total volume of fibres <35 and >35 �m was then calculated from the diameter distribution, and from this it was possible to predict the cashmere yield of 6 standards ranging from 10 to 60% yield (r2 = 0.98, n = 30). In addition, the Shirley Analyser was compared with the OFDA technique for measuring cashmere yield (r2 = 0.59, n = 110). OFDA estimates of cashmere yield were on average 10% higher (standard deviation � 7%) than those of the Shirley Analyser, indicating poor agreement between the 2 techniques. This is likely to be due to the Shirley Analyser and OFDA estimates of cashmere yield being affected by different fibre properties of the fleeces. There was good agreement between the Fibre Diameter Analyser (FDA) and the OFDA for measuring mean fibre diameter (MFD) of dehaired cashmere samples (r2 = 0.97, n = 108). There was also a good agreement in estimates of cashmere MFD between whole fleece and dehaired cashmere samples measured by the OFDA (r2 = 0.97, n = 77). Calculation of cashmere yield and down MFD by the OFDA has shown it to be accurate for measuring standard samples, and as precise as the Shirley Analyser. Therefore, the use of the OFDA is a potential low cost alternative to rank the value of cashmere goats for breeding.
Association of high and low molecular weight glutenin subunits with dough strength in durum wheats (Triticum turgidum ssp. turgidum L. conv. durum (Desf.)) in southern Australia
Authors: Liu CY , Rathjen AJ
Published: March 2005

A large set of durum wheat lines (79 including 8 advanced Australian breeding lines) randomly collected from 11 countries and 11 bread wheat cultivars were grown in replicated trials at 2 field locations to compare yield and gluten quality. Gluten strength, as measured by the sodium dodecyl sulfate (SDS)-sedimentation (SDSS) test, varied considerably among the durum lines and was associated with the presence of specific glutenins. Unlike some previous reports, the present study showed that durum wheat cultivars having the high molecular weight (HMW) glutenin subunits coded by Glu-B1 genes such as 13 + 16 and 7 + 8 were highly correlated with improved dough strength, which was consistent with the effect of HMW glutenin subunits on dough quality in bread wheat. Cultivars having the low molecular weight (LMW) glutenin allele LMW-2 (or gliadin band r-45) generally gave stronger gluten than lines with allele LMW-1, as reported by earlier workers. The LMW pattern LMW-IIt gave the strongest glutenin. The combined better alleles at Glu-B1 (coded bands 13 + 16, 7 + 8 v. 6 + 8, 20) and Glu-3 (patterns LMW- II, LMW-IIt v. LMW-I) showed linear cumulative effects for dough strength. All the durum lines studied had lower SDSS values than the bread wheat controls (45.8 v. 76.2 mL), though durum wheats tended to possess higher grain protein concentrations (14.0 v. 11.9%) and gave lower grain yield than bread wheat. The Australian advanced lines had higher yield and better dough strength than durums from other countries except those from CIMMYT. The Australian lines also had 1-1.5% higher protein concentration and equal or better grain yield than the bread wheat, suggesting that these lines had potential for commercial use.
Effect of sowing depth and water potential on seedling emergence of Lupinus species
Authors: Wilson CE , Thurling N
Published: March 2005

Large differences in responses of germination and seedling emergence to water potential and sowing depth were detected among Lupinus species varying substantially in seed size. Seeds of 7 species (L. pilosus, L. atlanticus, L. albus, L. cosentinii, L. luteus, L. angustifolius and L. hispanicus) germinated rapidly in moist sand (-0.05 MPa). Germination of all these species was reduced when seeds were raised in sand in which water potential was increased from -1.0 to -0.5 MPa at 4 days after sowing, and then to -0.2 MPa at 18 days after sowing. Percentage germination after 20 days was much higher in small-seeded species (L. hispanicus, L. angustifolius, L. luteus) than in large-seeded species (L. albus, L. atlarzticus, L. pilosus). Germination responses were related to rate of water uptake by seeds from sand at 0.5 MPa. Seedling emergence of pre-germinated seeds sown at different depths in moist (-0.05 MPa) and dry (-0.3 MPa) sand varied greatly among 6 species. An increase in sowing depth from 4 to 8 cm retarded seedling emergence to a greater extent than a decrease in water in L. piosus, L. luteus, L. cosentinii and L. atlanticus. L. angustifolius seedling emergence was less affected by variation in sowing depth and water potential than other species, although a decrease in water potential had a relatively large effect on seedling emergence from 4 cm. A decrease in water potential also decreased seedling emergence of L. albus more than deeper sowing. Seedling emergence responses of 4 species (L. angustifolius, L. luteus, L. albus, L. atlanticus) were compared in an experiment where dry seeds were sown in dry sand (-0.3 MPa) at different distances above a moist sand (-0.05 MPa) zone in specially constructed trays. Small-seeded species (L. angustifolius and L. luteus) emerged most rapidly from the shallowest sowing (3 cm below the surface, 9 cm above the moist zone), whereas the large-seeded species L. albus and L. atlanticus emerged most rapidly from sowings at intermediate depths (6 and 9 cm). L. albus and L. angustifolius seedlings emerged far more rapidly when sown on the surface of the moist sand (12 cm) than did L. luteus and L. atlanticus, and were far more tolerant of variation in sowing depth. The implications of these findings are discussed with particular reference to improving lupin crop establishment following early dry sowing in the West Australian wheatbelt.
Critical plant and seed concentrations of phosphorus and zinc for predicting response of faba beans (Vicia faba)
Authors: Lewis DC , Hawthorne WA
Published: March 2005

Faba beans (Vicia faba cv. Fiord) were grown in 1 glasshouse and 3 field experiments to calibrate the critical concentrations of phosphorus (P) and zinc (Zn) in selected plant tissues for vegetative and grain yields. In the field experiments, responses in grain yield to soil-applied P were between 0.5 and 0.8 t/ha (20-25%) at sites with extractable Colwell soil P concentrations of 20 and 23 mg/kg. Similarly, grain yields were increased by 0.6-1.2 t/ha (20-30%) from the application of either soil-applied or foliar Zn. These field responses to Zn only occurred if P fertiliser was applied at sowing. Maximum yields were obtained by either applying about 2 kg Zn/ha to the soil at sowing, or 500 g Zn/ha as a foliar spray, 8 weeks after sowing. In field experiments, critical P concentrations in the youngest open leaf during vegetative growth for prediction of maximum grain yield in the field, remained constant over a 10-week growing period. A critical nutrient range of 0.40-0.41% is proposed. However, critical concentrations of P in whole top for maximum grain yield, declined from 0.40 to 0.27% over the same growing period. For bean seed collected at harvest, a critical concentration of 0.36% P for maximum grain yield was derived. Critical concentrations of Zn during vegetative growth for prediction of maximum grain yield, derived in both glasshouse and field experiments, were very similar in youngest open leaf and whole top, and no significant decline with plant age was observed; a critical nutrient range of 19-24 mg/kg is proposed. For seed collected at harvest, a critical nutrient range for diagnosis of Zn deficiency of 13-15 mg/kg is suggested.
Conditioning with hot air reduces heat damage caused to 'Kensington' mango (Mangifera indica Linn.) by hot water disinfestation treatment
Authors: Jacobi KK , Wong LS , Giles JE
Published: March 2005

Hot water treatment (HWT) offers a cost-effective method for fruit fly disinfestation but may cause injury to 'Kensington' mango (Mangifera indica Linn.). Conditioning fruit with hot air before disinfestation may alleviate these injuries. Fruit from 2 major production regions in Queensland were subjected to conditioning treatments with hot air (38-40�C) for 0, 4,8, 12, and 16 h before HWT (fruit core temperature of 45�C held for 30 min). Injuries to fruit not conditioned before HWT included accentuated lenticel spotting, external and internal cavities, and a starchy layer beneath the skin. Fruit conditioned for 8 or 12 h before HWT had minimal injuries. Conditioning with hot air before HWT has the potential to minimise and/or eliminate heat injuries associated with hot water disinfestation treatment. Further testing, particularly on a commercial scale, will be required to optimise these conditioning treatments for use by the Australian mango industry.
Evaluation of the Western Australian queen bee breeding program
Authors: Manning R
Published: March 2005

Agriculture Western Australia's former Queen Bee Breeding Program (QBBP) was successful in significantly raising the productivity of honey bee colonies for those beekeepers who regularly purchased queen bees from the program. The increased productivity was measured through honey production. Over 2 nectar flows, colonies headed by queens purchased from the breeding program (group 2) showed a 35% increase in honey production over unselected colonies (group 1-not purchased from the QBBP). Over individual nectar flows, colonies headed by queens purchased from the breeding program showed a 22% increase in honey production from a Eucalyptus calophylla nectar flow, and for a second protracted winter nectar flow from coastal heath they also produced 46% more honey than unselected queen bees. Honey production (kg/colony.day) from Eucalyptus calophylla was 0.95 and 1.13 kg for groups 1 and 2, respectively. Honey production from the coastal heath was 0.27 and 0.4 kg/colony.day for groups 1 and 2, respectively. Results were projected for 1 year and scaled up to represent a commercial apiary of 400 colonies. According to estimates from the data, group 2 beekeepers should have benefited from the QBBP by being able to produce 24 t of honey from their apiaries, valued in excess of $A32 000, more than group 1 beekeepers.
Differences in the properties of a red earth after ten years of wheat-lupin and wheat-subterranean clover rotations
Authors: Chan KY , Heenan DP
Published: March 2005

2 different rotations, wheat-lupin (WL) and wheat-subterranean clover (WC) were compared under 2 different tillage systems, direct-drilled (DD) and conventional tillage (CT) at a 10-year-old experimental site in Wagga Wagga, New South Wales. Significant differences in soil organic carbon concentration between the 2 rotations were found only under the DD systems; soil under WC rotation had a significantly higher organic carbon in the top 0.05 m than the WL soil. No such difference was detected under CT. Under both tillage systems, WC soil had lower pH (by 0.32 unit), with accompanying lower exchangeable magnesium but higher extractable aluminium than the WL soil in the top 0.05 m. Despite similar earthworm population and surface macroporosity, there was evidence suggesting that, under direct drilling, 10 years of WC rotation had reduced the subsoil water storage after summer fallow and reduced the effective rooting depth of wheat when compared with the WL rotation. These had not resulted in difference in wheat yield between the rotations even though a smaller average grain size was found under WC rotation in the 1990 season.
Applications of the herbicide sethoxydim increase wheat yield in the absence of weeds
Authors: Black ID , Dyson CB , Fischle AR
Published: March 2005

In 11 experiments over 6 seasons the herbicide sethoxydim was applied to Machete, Spear and Blade wheat cultivars in the absence or near absence of weeds (10 sites) or where the weeds were controlled by selective herbicides (1 site), in the cropping area north of Adelaide, South Australia. The rates applied included 9-47 g a.i./ha at the 2-3 leaf growth stage and 9-74 g a.i./ha at early tillering. Except for the very long growing season of 1992, there was a highly significant positive linear correlation between the number of degree days in the growing season at each experimental site and relative mean yield increase of these sethoxydim treatments. Yield increases ranged from nil in growing seasons of about 1000 degree days to 32% in a growing season of 1480 degree days, with a median of 8% over the experiments.
Nitrate accumulation under pea cropping and the effects of crop establishment methods: a sustainability issue
Authors: Evans J , Fettell NA , O'Connor GE
Published: March 2005

Grain legume-cereal rotations are unsustainable on acid soils because they promote acidification of surface soil through nitrate leaching. Two field experiments were conducted on red, clay-loams in the cropping zone of central western New South Wales to determine whether soil mineral N concentrations during crop growth are higher under pea than barley, and whether the nitrate concentration under pea crops can be decreased by ammending soil with cereal straw before sowing.Significantly higher mineral N, particularly nitrate, was found under pea than under barley, as early as 6 weeks following autumn sowing, and also in spring. The pea effect represented an increase of up to 23 kg N/ha of mineral N (0-30 cm). It is proposed that the source of higher nitrate concentration under pea may be residual soil nitrate not utilised by pea, or nitrate derived from the mineralisation of pea roots or exudate. The increase in soil nitrate during pea growth contributes to greater postharvest soil mineral N and higher wheat yields after pea, but also increases the risk of soil acidification. Soil ammendment with cereal straw was partially effective in reducing nitrate concentration under pea, but a more effective treatment is required.
Growth and seed yield of vetches (Vicia spp.) in south-western Australia
Authors: Siddique KHM , Loss SP
Published: March 2005

The growth and seed yield of 5 vetch (Vicia) cultivars representing Vicia sativa, V. benghalensis and V. villosa were compared at 8 sites over 2 years in south-western Australia. The vetches showed considerable potential as grain and forage legume crops in the low to medium rainfall areas of the Western Australian cereal belt. Cultivars of V. sativa showed the most potential in terms of dry matter and seed yield, and on average across sites and seasons both Languedoc and Blanchefleur produced over 2.5 t/ha of dry matter at flowering: Machine-harvested seed yields were over 1.6 t/ha. Cultivars of V. benghalensis and V. villosa produced considerably less dry matter at flowering and had lower harvest index (0.14-0.42) and seed yield < 4 t/ha) when compared with the V. sativa cultivars, possibly due to their poor growth rates and delayed phenology. Early Purple, an early flowering and maturing selection from the V. benghalensis cultivar Popany, showed improved adaptation and seed yield at many low rainfall sites. Nevertheless, Languedoc, Blanchefleur and Early Popany are all considered late flowering (up to 126 days) compared with grain legumes adapted to this environment, and further improvement in vetch species could be achieved by selecting for more rapid development. Both soft-seededness and non-shattering pods should also be high priorities for vetch selection and/or breeding programs. It is concluded that vetch species may have a role in farming systems in Western Australia for the production of fodder, hay, grain or green manure while providing the other rotational benefits of legumes on fine-textured neutral to alkaline and shallow duplex soils where narrow-leafed lupin is poorly adapted.
A method to identify lupin species tolerant of alkaline soils
Authors: Tang C , Adams H , Longnecker NE , Robson AD
Published: March 2005

Narrow-leafed lupins (Lupinus angustifolius L.) grow poorly on alkaline soils. In contrast, L. pilosus Murr. and L. atlanticus Glad. grow well on such soils. This study aimed to develop a solution culture method to screen lupin species for their ability to grow well on alkaline soils. Sixteen lupin genotypes from 6 species, including introduced cultivars and wild types, were grown in high pH solutions with varying concentrations of buffers and bicarbonate. Relative taproot elongation, shoot growth and iron chlorosis were compared with iron chlorosis, relative shoot growth and seed yield for the same genotypes on an alkaline soil in the field. The results suggested that root elongation rate at pH 7 in solution buffered with a mixture of 1 mmol MES/L and 1 mmol TESL (plus 10 mmol CaCl2/L), and shoot weight at 5 mmol bicarbonate/L at pH 8.7 are good indicators of tolerance to an alkaline soil among the lupin species.
Influence of gibberellin treatment on flowering and fruiting patterns in mango
Authors: Turnbull CGN , Anderson KL , Winston EC
Published: March 2005

The potential for using gibberellins (GAS) to modify time of flowering and fruit maturity in mango was investigated. Winter spraying of mango trees grown in the coastal subtropics of Queensland (latitude 27OS) with gibberellin A3 (GA3) or GA4 solutions caused a delay in flowering time of up to 4 weeks, depending on cultivar (Kensington Pride, Glenn, Early Gold) and concentration (50-200 mg/L). There was also a general reduction in number of panicles, particularly at higher GA concentrations. Similar experiments with GA3 on cvv. Kensington Pride and Keitt in tropical North Queensland (latitude 17�S) did not show any effect either on time or extent of flowering. Fruit yield was highly correlated with the proportion of terminal buds that flowered. Consequently, GA treatments caused significant yield reductions in cv. Kensington Pride, especially at 200 mg/L where only 23% of terminal buds flowered. Fruit size was inversely related to yield, and yield was influenced by tree size. Delayed flowering also resulted in later fruit maturation, by up to 2 weeks. With Early Gold, late-flowering panicles retained 3 times more fruit than those which flowered early, which was possibly related to differences in night temperatures before or at anthesis. Delays in flowering time, which lead to somewhat lesser delays in fruit maturation, can be achieved with suitable GA treatments, but concentration and timing of application are critical if flowering and, hence, yields are not to be reduced. The potential use of this treatment in commercial mango orchards is discussed in relation to extending the fruit production season.
Controlling rootstock sprouts of Agonis flexuosa, (Willd.) Sweet at ambient and elevated CO2 by multiple applications of low concentration NAA
Authors: Grant WJR , Loveys BR
Published: March 2005

A method for grafting variegated scion material to green leafed Agonis flexuosa (Willd.) Sweet stock was developed to overcome the difficulty of striking cuttings. However sprouting of both seedling and cutting-grown A. flexuosa rootstocks was a significant problem. Microwedge grafting of actively growing leafy scions and stocks in fog at 32/22�C gave 90-100% success and scion bud activity was stimulated within 2 weeks. Weekly or fortnightly spray applications of 100 mg NAA/L (napthaleneacetic acid), starting at the time of grafting, gave effective sprout control whereas a single pre-graft spray of 200 mg NAAL was not effective. CO2 enrichment of the fog environment was investigated as a means of enhancing scion growth. CO2 at 80 kPa increased scion dry weight (DW), leaf and branch numbers, but had no effect on rootstock sprout or stem DW or sprout numbers. Optimum NAA concentrations for rootstock sprout suppression under elevated CO2 with fog, were 50-100 mg/L, which were not deleterious to scion shoot length, when sprayed on the stock portion only. Stock sprout numbers, scion leaf and branch numbers were negatively correlated with NAA concentration. Sprout growth at 100 mg NAA/L was about 5% of control sprout growth. Concentrations >200 mg NAA/L caused leaf tip necrosis and excess stem callusing. Scion growth was inversely related to the degree of resprouting in control treatments.
Evaluation of Australian commercial honey bees for hygienic behaviour, a critical character for tolerance to chalkbrood
Authors: Oldroyd BP
Published: March 2005

Chalkbrood of honey bees (Apis mellifera) is caused by Ascosphaera apis, and is new to Australia. As yet, no treatment or prophylaxis is available for this disease. The best prospects for control are likely to come from the use of 'hygienic' bees, those with a strong genetic tendency to uncap and remove dead pupae, together with good beekeeping practice. Ten strains of Australian commercial honey bee were evaluated for hygienic behaviour. Dead pupae were inserted into the colonies and checked after 3, 5 and 7 days for the number of pupae removed. Most colonies (80%) were non-hygienic and hence likely to be susceptible to chalkbrood. However, 2 strains provided good overall performance in the test and comprised 1 or 2 colonies that were highly hygienic. Colonies were evaluated 3 times, and the good performance of these colonies was repeatable across trials. These data suggest that hygienic behavioural morphs exist in Australia's commercial bee strains, and it is unnecessary to obtain breeding stock from overseas for this reason alone. Selective breeding, with relatively simple techniques which can be used by beekeepers and queen breeders, should produce suitable genotypes.
Grazing a saltbush (Atriplex-Maireana) stand by Merino wethers to fill the autumn feed-gap experienced in the Western Australian wheat belt
Authors: Morcombe PW , Young GE , Boase KA
Published: March 2005

Three-year-old Merino wethers were grazed at 4 stocking densities (15, 20, 25 and 30 sheep/ha) in 3 consecutive autumns on saltbush forage. About 50% of edible material was leaf [70% digestible dry matter (DDM), 8.9% crude protein (CP)] and 50% was small stems <5 mm diameter (40% DDM and 4.5% CP). In 1992, 9-month-old wethers also grazed the saltbush stand at 30 sheep/ha. Liveweight initially increased by 1-3 kg during the first 14 days of grazing, then declined at 60-100 g/day until the diminishing forage reserves became critical, by which time the stand had provided for about 450 grazing-days/ha. The performance of the 9-month-old wethers was comparable with the 3-year-old sheep at equivalent grazing pressure. In 1992, the tensile strength of wool staples from the 3-year-old sheep grazed at the higher density of 30 sheep/ha, 17.2 N/ktex, was weaker (P<0.05) than staples from sheep grazed at 15 and 20 sheep/ha, 27.1 N/ktex, and 25 sheep/ha, 24.9 N/ktex. Saltbush plantations can be used to provide a feed source which could partly fill the 'autumn feed-gap' for <9-month-old dry sheep. Grazing at <20 sheep/ha, removal of sheep from the saltbush before the mean liveweight declines below that at the start of grazing, and provision of a reliable supply of water will avoid low staple strength wool. More productive stands of saltbush, grown together with winter-active plant species, are needed to improve the economic viability of this grazing resource.
Sublethal exposure to corynetoxins affects production of grazing sheep
Authors: Davies SC , White CL , Williams IH , Allen JG , Croker KP
Published: March 2005

This paper reports the production losses resulting from treating sheep with sublethal doses of corynetoxins, the causal agent of annual ryegrass toxicity. Merino ewes were given 3 levels of corynetoxins twice weekly for 11 weeks from 26 days before the start of joining to day 51 of pregnancy, giving a cumulative dose of 0 , 0.4 or 0.8 mg/kg liveweight. The effect on ovulation, pregnancy, lamb birth weight, lamb survival and weaning weight were measured along with the liveweight and wool growth of the ewes. Corynetoxin treatment depressed (P<0.005) the activity of uridine diphospho-N-acetylglucosamine: dolichol-phosphate N-acetylglucosamine-1-phosphate transferase and liver damage was detected in ewes on the high toxin treatment (P<0.05). Ewe liveweight was unaffected by treatment but wool growth and wool fibre diameter were reduced by 10 and 7%, respectively (P<0.05). Corynetoxin treatment appeared to increase ovulation (P<0.05) and, as there was no effect on conception and embryo survival, this resulted in a 30-35% increase in the number of lambs weaned. Lamb birth weight and survival were not affected by treatment but weaning weight of the low toxin group was depressed (P<0.05). While reproduction was not adversely affected, the sheep in this trial were exposed to extremely low levels of corynetoxins which did not accumulate to levels capable of causing detectable liver damage until 23 days after joining. Even at these levels of intake, well below those required to show clinical signs (3-5 mg/kg liveweight), wool growth was reduced, suggesting that sheep grazed on mildly toxic pasture experience wool production losses in the absence of signs of the clinical disease.