bluuebunny/crossref_metadata_2025 huggingface dataset:
Recombinant growth hormone in growing lambs: effects on growth, body and carcass characteristics, hormones and metabolites
Authors: Zainur AS , Tassell R , Kellaway RC , McDowell GH , Dodemaide WR , Kirby AC
Published: November 2005

Forty-eight crossbred wethers [Dorset Horn X (Border Leicester X Merino)] were injected subcutaneously each day for 42 to 133 days with recombinant bovine growth hormone (rebGH) at doses of either 0,50,150 or 250 pg rebGH kg-1 liveweight day-1 from 22 kg liveweight (LW) until slaughter at either 34, 42 or 50 kg LW. The lambs were fed ad libitum pellets consisting of (g kg-1 as fed) 850 lucerne, 100 barley and 50 cotton seed meal.Injections of rebGH exerted anabolic effects which were dose dependent. Overall, there were linear increases (P<0.001) in liveweight gain (LWG), total non-carcase weight, weights of heart, liver, skin, reticula-rumen, loin eye area, carcase crude protein, non-carcase crude protein, carcase ash and noncarcase ash, as well as plasma concentrations of insulin and glucose (P<0.01). There were linear decreases (P< 0.001) in feed conversion ratio, carcase weight, tissue depth (GR) and subcutaneous fat depth at the 12th rib, carcase fat and non-carcase fat as well as plasma urea. Significant interactions of dose rate with liveweight groups indicated that overall, the effects were larger in sheep grown to 50 kg than to 34 kg LW, or occurred only in the former in respect of weights of carcase, heart, liver and reticula-rumen. The same was true for depth of tissue, depth of subcutaneous fat and loin eye area at the 12th rib and also carcase and non-carcase weights of CP, fat and ash.
Variation in goat fibre protein
Authors: Tucker DJ , Hudson AHF , Laudani A , Marshall RC , Rivett DE
Published: November 2005

The proteins from a range of cashmere, mohair, angoratcashmere crossbred and wool fibre samples were extracted at pH 8 with 8 M urea containing dithiothreitol, and were then radiolabelled by S-carboxymethylation using iodo(2-14C) acetate. The proteins from each sample were examined by two dimensional polyacrylamide gel electrophoresis in which the separation in the first dimension was according to charge at pH 8.9 and in the second dimension according to apparent molecular weight in the presence of sodium dodecyl sulfate. After electrophoresis the proteins were detected by fluorography. Protein differences in keratin samples from some individual goats existed, although the overall protein patterns were similar. None of the differences were consistent with any one goat fibre type. The protein patterns obtained for fibre samples from individual cashmere goats showed some differences when compared to those found for commercial blends from the same country of origin, indicating that blending can mask any animal-to-animal variation. While the electrophoretic technique does not unequivocally distinguish between cashmere, mohair and angora/cashmere crossbred fibres it does differentiate between wool and goat fibres.
Biological activity of 2,4-D esters on rubber vine (Cryptostegia grandiflora): dependence on vapour pressure and molecular weight and isomerism of the alcohol substituent
Authors: Harvey GJ
Published: November 2005

The relationship between molecular structure and biological efficacy was investigated for 16 esters of 2,4-D [(2,4-dich1orophenoxy)acetic acid] on rubber vine (Cryptostegia grandiflora). These included the normal (n) or straight-chain esters from C-1 (methyl) to C-8 (octyl), the n-decyl, n-dodecyl, isobutyl, amyl (iso-pentyl), 2-ethylhexyl (iso-octyl), and the methoxy-, ethoxy-, and butoxyethyl esters. For the normal series esters, biological efficacy was found to be a function of both the molecular weight and the vapour pressure of the esters. This relationship was linear for the higher molecular weight, low volatile esters, biological efficacy decreasing with increasing molecular weight and the accompanying decrease in vapour pressure of the esters. The low molecular weight, volatile esters were more active than the higher molecular weight, low volatile esters, and increases in the vapour pressure of these low molecular weight, volatile esters were sufficient to account for the deviation from linearity of those esters. When all esters are considered, the same relationships hold but the branched-chain (iso) and chemically substituted (alkoxy alcohol) esters are less effective than the corresponding normal esters. Possible reasons for these results are discussed.
The effect on American foulbrood of standard oxytetracycline hydrochloride treatments for the control of European foulbrood of honeybees (Apis mellifera)
Authors: Oldroyd BP , Goodman RD , Hornitzky MAZ , Chandler D
Published: November 2005

Twenty honeybee colonies were treated with various oxytetracycline hydrochloride (OTC) preparations at the time of inoculation with Bacillus larvae spores or after American foulbrood (AFB) disease signs had developed.Treatment with 1 g OTC, at the time of inoculation delayed the development of AFB disease signs in four hives for periods between 2 months and 1 year. One colony so treated did not contract the disease.Colonies with a light AFB infection treated with 1 g of OTC recovered from the disease in 3-4 weeks, but AFB disease signs reappeared in three of five colonies the following season. Colonies with a well-established infection showed complete recovery from AFB disease signs after various OTC treatments. However, nearly all of these colonies developed AFB disease signs in the following season.B. larvae was cultured from adult bee samples from colonies that were AFB disease-free at the time of sampling but subsequently developed disease signs, and from colonies that were AFB disease-free at the time of sampling but did not subsequently develop disease signs.The results show that recommended treatments for European foulbrood (EFB) effectively mask AFB disease, making it likely that beekeepers treating EFB also suppress signs of AFB disease if it is present. As it is common practice in Australia to treat EFB prophylactically with OTC, an escalation of AFB in Australian hives is anticipated.
Project STAG: an experimental study in agroforestry
Authors: Cameron DM , Rance SJ , Jones RM , Charles-Edwards DA , Barnes A
Published: November 2005

An agroforestry study to identify problems in the development of stable silvopastoral systems in a subtropical environment was run over 4.6 years.Eucalyptusgrandis was planted in a Nelder fan design with tree stand densities ranging from 42 to 3580 stems ha-1 into a Seturia-dominated pasture. Growth of trees improved with increasing stand density until competition for water and light outweighed the benefits of mutual protection. For most parameters measured, there was a change in magnitude with time away from the centre of the wheel like ripples in a pond. At 1.5 years the maximum above-ground individual tree biomass was at a stocking of 3580 stems ha-1 . At 2,2.5,3,3.5 and 4.6 years the maxima were at 1140,595,305, 158 and 82 stems ha-1 respectively. Trees interacted with each other, even at low stand densities.Pasture production also showed a ripple effect, being little affected by the trees at age 0.5 years, but was substantially reduced after 1.5 years at stand densities over 1000 stems ha-1. By age 3.5 years, pasture production was reduced at stand densities over 300 stems ha-1. At this age and stocking, tree growth, taper, crown dimensions and health were also optimal.Trees and pasture can be successfully grown together to provide substantial production from each. A thinning regime would be required to maintain an optimum balance between the two components of this agroforestry system.
Some effects of temperature regime during grain filling on wheat quality
Authors: Randall PJ , Moss HJ
Published: November 2005

Dough quality from grain samples from the Interstate Wheat Variety Trials for 3 cultivars at Wongan Hills and Narrabri in 6 seasons and 4 cultivars at Narrabri, Wagga Wagga and Dooen in 4 seasons was studied in relation to av. daily min. and max. temp. from anthesis to harvest. In greenhouse experiments, wheat cv. Olympic, Hartog and Skua seedlings were raised at day/night temp. of 21/16degreesC and then transferred to 33/28degrees at 14 or 32 d after anthesis. Air temp. influenced wheat baking quality, particularly dough strength, loaf score and volume in both field and greenhouse trials. Dough strength increased with av. daily temp. up to 30degrees and tended to decrease at higher temp. Field data indicated that protein concn was most dependent on max. temp. The cultivars differed in inherent dough strengths but for all cultivars dough strength increased with protein concn, and a strong positive correlation with max. temp. was observed. In the greenhouse, high temp. increased grain moisture loss and shortened the time to maturity. Grain from the higher temp. regime was smaller and the dough particularly resistant to deformation. Loaf volume was very similar for all 3 cultivars but for other quality characteristics responses differed between cultivars.
The effects of fumigation, rotation with lupins, and nitrogen application on plant growth and common root rot of wheat at Geraldton, Western Australia
Authors: Wilson JM , Hamblin J
Published: November 2005

The effects of soil fumigation (98% methyl bromide + 2% chloropicrin at 580 kg/ha) and N fertilizer (0, 12.5, 25, 50 or 100 kg N/ha) were examined in field trials on continuous wheat and wheat in rotation with lupins on the Geraldton sandplain. Fumigation increased grain yields at N fertilizer levels more or =25 kg/ha and was associated with reduced incidence and severity of common root rot (Bipolaris sorokiniana)[Cochliobolus sativus]. Grain yield was not significantly affected by rotation. Fumigation increased soil ammonium levels and decreased soil nitrate levels. Rotation of wheat and lupins increased mid-season growth at all levels of applied N but only increased grain yield where no N was applied.
Variation among somaclonal progenies from three species of Stylosanthes
Authors: Godwin ID , Cameron DF , Gordon GH
Published: November 2005

Plants were regenerated from leaf-derived callus cultures of the diploid species Stylosanthes guianensis (four genotypes), and the tetraploid species S. scabra (four genotypes), and S. hamata (one genotype). No morphological variation was observed in the 97 regenerated plants (SC1) of S. scabra, but 23 of the 104 SC1 plants of S. hamata were sterile dwarfs. In a field experiment with 42 SC2 families of S. scabra, four were low yielding and five segregated for late flowering. Dwarfs were again found in SC2 families of S. hamata, and both high and low yielding families were observed. Glasshouse inoculations with various pathogenic races of Colletotrichum gloeosporioides were performed to assess the reactions of 276 S. guianensis, 56 S. scabra and 62 S. hamata SC2 families. A major gene mutation from dominant to recessive appeared to confer increased susceptibility in S. hamata SC2 families. Eight of twelve tetraploid S. guianensis cv. Graham families exhibited partial resistance to Type B race 3 anthracnose. Two S. scabra cv. Fitzroy families segregated for reaction to Type A race 1 anthracnose. Selfed progenies (SC3 generation) of two of the three partially resistant SC2 individuals maintained their partial resistance, indicating stable inheritance. Segregation data suggested that changes in minor genes caused this variation.
Improving the tolerance of Phalaris aquatica L. to soil acidity by introgression of genes from P. arundinacea L
Authors: Oram RN , Ridley AM , Hill MJ , Hunter J , Hedges DA , Standen RL , Bennison L
Published: November 2005

A comparison was made of the growth on acid and non-acid soils near Canberra of 66 lines in Phalaris aquatica, in seven other Phalaris species which can be crossed with P. aquatica and in seven allopolyploid or backcross hybrids involving P. aquatica. The yield of tops by mid-spring on the strongly acid site was only 20% of that on the mildly acid site. Some variation was apparent among the 38 P. aquatica accessions and cultivars, but some P. arundinacea accessions and hybrids were less inhibited by acidity than any P. aquatica line. Fifty plants from the first or second backcross of four P. aquatica X P. arundinacea hybrids to P. aquatica were selected for their capability of producing a large root system in a nutrient solution containing 10 mg aluminium per L at pH 4.1. On acid soils near Bendigo, Seymour, Benalla and Canberra, offsets of seven of these backcross plants were rated as growing significantly larger at the end of the first growing season than plants of Sirosa, Sirolan and Uneta phalaris, Porto and Currie cocksfoot, Demeter and Melik tall fescue and of Victorian and Brumby perennial ryegrass. However, two of the backcross genotypes appeared to be significantly smaller than the phalaris and cocksfoot controls. Thus, factors in addition to excess aluminium appear to affect the growth of phalaris in these soils, but some backcross genotypes tolerate these adverse conditions. Four of the productive, acid-tolerant genotypes survived the first summer, regenerated vigorously in the following autumn, were palatable to sheep in test grazings over two summers at Armidale, N.S.W., and also were fertile and retained some of the ripe seed in their panicles. Therefore, it seems probable that phalaris cultivars for acid soils in south-eastern Australia can be selected from later generations of the backcross population.
Factors contributing to reduced productivity of subterranean clover (Trifolium subterraneum L.) pastures on acidic soils
Authors: Hochman Z , Osborne GJ , Taylor PA , Cullis B
Published: November 2005

In a field study on four sites, soil acidity, root rot (Phytophthora clandestina), and soil phosphorus were identified as causes of 'subterranean clover decline'. Liming increased herbage and seed production at four sites, with a tendency for lime to increase herbage yields in autumn (22%) and winter (15%) but not in spring. The presence of ryegrass with clover increased total herbage yields, and reduced clover seed production, but there was no interaction with liming. Losses caused by root rot associated with P. clandestina were quantified for the first time in New South Wales. Root rot reduced survival of seedlings as well as herbage production in autumn and/or winter at three of the four sites. In the presence of the disease, lime did not improve root health or seedling survival. On two sites with high aluminium saturation of exchangeable cations (> 17%) and high phosphorus sorption index values, subterranean clover growth responded to high levels of P fertilizer. On one site, where lime increased the soil pH to above 5.5, the P sorption index was temporarily increased, and this was associated with a temporary adverse effect on herbage yields. Some possible mechanisms underlying the seasonality of lime responses are proposed and the practical implications of our findings are discussed.
Tree pasture interactions at a range of tree densities in an agroforestry experiment. I. Rooting patterns
Authors: Eastham J , Rose CW
Published: November 2005

The effects of tree density on the distribution of tree and pasture roots under an agroforestry experiment were investigated. Trees were planted in a Nelder fan design, and three planting densities of 2150,304 and 82 stems per hectare were chosen for this study. Proximity to trees and increase in tree density reduced pasture root growth, with lowest concentrations of pasture roots occurring under the highest tree density. Tree root systems were deeper and denser at high tree densities, although total length and mass of roots produced per tree decreased with increasing tree density. Tree root:shoot ratios increased as tree density decreased owing to greater root production at low tree densities.
Tree/pasture interactions at a range of tree densities in an agroforestry experiment. III. Water uptake in relation to soil hydraulic conductivity and rooting patterns
Authors: Eastham J , Rose CW , Cameron DM , Rance SJ , Talsma T , Charles-Edwards DA
Published: November 2005

Eucalyptus grandis was planted in a Nelder fan design in November 1983 into a previously established pasture dominated by Setaria sphacelata cv. Kazungula, at the CSIRO Sanford Pasture Research Station, Queensland, Australia. Nine concentric rings of 18 trees were planted at radii of 4.4-61.6 m, giving a range of tree densities which decreased from 3580 to 42 stems/ha. Tree transpiration was studied at three tree densities (2150, 304 and 82 stems/ha, representing high, medium and low densities) over a 'drought' period of approximately 1 yr (Nov. 1985-Sep. 1986) and related to rooting patterns and soil hydraulic properties. Over the range of soil water contents studied, the ratio of tree transpiration rate to equilibrium evaporation rate (T/Esub(eq)) decreased linearly with decreasing mean soil water content at each tree density. To investigate the effects of soil hydraulic conductivity and root length density on the total transpirational flux, overall soil conductances (Ksub(s)) were calculated, with soil conductance in each horizon weighted according to the length of root in that horizon. At each tree density, decreases in the ratio T/Esub(eq) were related to decreases in ln Ksub(s) measured at 1.2 m from the stem. A more rapid decrease in T/Esub(eq) with decrease in water content observed at the low tree density was attributed to a greater decrease in Ksub(s) as mean water contents decreased. The greater decrease in Ksub(s) at low tree densities was associated with a larger proportion of water extracted and a higher proportion of total root length in surface soil horizons, which showed a greater decrease in hydraulic conductivity than subsoil horizons for the same decrease in water content.
Use of wool growth response to estimate escape of protein supplements from the rumen
Authors: Neutze SA
Published: November 2005

Wool growth response to formaldehyde-treated (HCHO) casein was used as an index of protein escaping degradation in the rumen. Merino wethers, 3 years old and weighing 41-49 kg, were given a basal diet of oat husks and urea, supplemented with HCHO-treated casein or 1 of 10 protein supplements. All sheep were given DL-methionine 2.4 g. Wool growth indices (%) were casein 10, linseed oilmeal 82, sunflower oilmeal 84, groundnut oilmeal 68, fish meal 113, lupins 83, peas 29, cottonseed meal 83, soyabean meal 73, HCHO-sunflower oilmeal 83 and HCHO-casein 100%. It was concluded that the technique was not sensitive enough to estimate loss of protein from the rumen with accuracy.
The derivation of economic values in breeding programs for Australian Merino sheep with changing wool prices and flock production averages
Authors: Cottle DJ
Published: November 2005

The impact of fluctuating wool prices on setting economic values (EVs) in selection indices, e.g. WOOLPLAN, are studied by modelling genetic change in a flock following index selection, Operating under different wool price regimes. Because future price changes are difficult to predict, there is no guaranteed, optimal method of determining EVs. One possibility is the use of a moving regression of the last five years' wool prices (in real terms), rather than setting the index once, or every five years, or every year, based on current prices. The ratio (R) of clean wool price to micron premium is more important than actual prices. It is suggested that the default EVs used currently in WOOLPLAN are appropriate for strong wool Merino flocks. The choice and implications of EVs in other situations are discussed.
Skin and abdominal temperatures recorded by data loggers attached to Merino sheep voluntarily staying out of shade
Authors: Sherwin CM , Johnson KG
Published: November 2005

To investigate individual differences in thermal status of sheep during voluntary shading, a method of recording body temperatures was developed using data loggers attached to free-ranging animals. During summer, recordings were made of body temperatures of Merino wethers grazing irrigated pasture. Despite shade being readily accessible, the sheep voluntarily stayed in the sun throughout the day. Twenty, 24-h records of intra-abdominal temperature and 12 of concurrent skin temperature were obtained. Both core and skin temperatures exhibited diurnal rhythms influenced by ambient conditions. Short-term fluctuations without obvious cause also occurred in both body temperatures. Skin temperatures of the dorsal surface were considerably higher than previously reported. Core temperatures of sheep voluntarily staying in the sun were not hyperthermic. The maximum 24-h range in intra-abdominal temperature (i.e. 1.9�C) does not support previous data (Bligh and Harthoorn 1965) that indicated sheep might be more thermostable than other mammalian species. The effective heat load and thermal displacement were apparently insufficient to cause the sheep to seek shade in competition with other factors influencing their behaviour.
Physiological attributes associated with drought resistance of wheat cultivars in a Mediterranean environment
Authors: Blum A , Pnuel Y
Published: November 2005

Twelve spring wheat (Triticum aestivum L.) cultivars were planted in 16 trials which received seasonal rainfall (including irrigation) ranging from 230 to 755 mm year-l. Under low rainfall conditions, drought stress occurred during the period of stem elongation when the ears grew. Grain filling was largely free of stress. Variation in precipitation explained 75% of the variation in mean yield among trials, and the main yield component responsible for yield reduction at low precipitation was ear number, as affected by tiller survival rate. The larger-yielding cultivars sustained a higher kernel number per ear in compensation for the reduced number of ears under stress. The yield stability of cultivars under low precipitation was defined by both the joint linear regression method and by the linear regression of yield on precipitation, both of which gave very similar predictions. The magnitude of the intercept of the latter regression was taken as indicator of drought resistance in terms of yield. The variations among cultivars in this intercept was well explained by corresponding variations in osmotic adjustment, heat tolerance and canopy temperature. Grain filling from stem reserve mobilization was not important in this respect, evidently because grain filling was not subjected to drought stress in these trials. Early-heading cultivars had a relative yield advantage only when precipitation were less than about 300 mm and grain yield was less than about 350 g m-2. Both early heading and heat tolerance were positively correlated with osmotic adjustment across cultivars. It was therefore concluded that the main physiological attribute associated with yield stability under conditions of drought stress during the period of ear growth was the capacity for osmotic adjustment, which apparently allowed sustained ear growth under drought stress.
Yield advantage of two semi-dwarf compared with two tall wheats depends on sowing time
Authors: Anderson WK , Smith WR
Published: November 2005

Slow adoption by farmers in Western Australia of new wheat cultivars led us to propose that their grain yield advantage over the old cultivars may not be evident under the traditional agronomic practices used in the State. The experiments, including both tall (rht) and semi-dwarf (Rht) commercial cultivars, were sown from early to mid-May, up to early July at five locations each year in the central wheatbelt of southwestern Australia in 1986, 1987 and 1988. Semi-dwarf outyielded tall cultivars more when sown in May (0.65 t ha-l) than in early June (0.35 t ha-1) and did not outyield them at later sowings. It is postulated that the yield advantage of the semidwarfs is dependent on early sowing. The yield advantage of the semi-dwarfs was related to greater ear and kernel numbers. The relative reduction in kernel size with later sowing was greater in the semi-dwarfs than in the tall cultivars. The semi-dwarfs had larger harvest indices at the May sowings but the talk equalled or exceeded them at the sowings in June. We concluded that the semi-dwarfs used in our experiments were more sensitive to the stresses associated with later sowing in this environment than the tall cultivars. The optimum flowering period for the study area over the three seasons was 7 to 29 September. However, there was considerable variation from season to season, and we concluded that an adequate definition of the optimum flowering period should be based on time-of-sowing experiments over a range of seasons.
The effect of stripe rust on the quality of Australian wheat varieties
Authors: O'Brien L , Brown JS , Panozzo JF , Archer MJ
Published: November 2005

The effect of stripe rust on the processing quality of Australian wheat varieties was examined over a four year period. Each year in field experiments, stripe rust was allowed to develop naturally on one half of each plot block while the other was kept disease free using three weekly applications of fungicide. Changes in grain quality were observed with susceptible varieties when subjected to an epiphytotic of the disease. Stripe rust caused kernels to be shrivelled, which resulted in reduced test weight and flour milling yield and increased grain protein content. Dough properties were also affected. Dough development time was shorter, mixing tolerance deteriorated and extensograph maximum resistance was lower for susceptible varieties affected by the disease.
The influence of temperature on the accumulation and distribution of manganese in two cultivars of soybean (Glycine max [L.] Merr.)
Authors: Heenan DP , Campbell LC
Published: November 2005

Accumulation and distribution of manganese in soybeans (Glycine max [L.] Merr. cvv. Lee and Bragg) grown over a range of manganese concentrations from 0 to 275 8m in solution culture were studied at four day-night temperatures ranging from 20-15�C to 33-28�C in growth cabinets. High levels of solution manganese (275 8m ) produced symptoms of manganese toxicity and reduced yields of both varieties with the symptoms and yield reductions being more severe on Bragg than Lee. Increasing the day-night temperatures from 20-15�C to 33-28�C increased the ability of both cultivars to tolerate high concentrations of manganese in solution but there was no indication of any effect of temperature on the differential tolerance of the two cultivars. At high managanese concentrations in solution, high temperatures increased the rate of absorption by roots and total plant uptake of manganese, but there was no effect on the concentration of manganese in the plant tops. Total leaf concentration increased markedly while stem concentration were reduced at high temperatures. Young leaves contained lower concentrations of manganese than older leaves at all temperatures. While the concentration of manganese in the youngest expanding leaf decreased slightly as temperatures were raised from 20-15�C to 28-25�C, there was no significant difference in concentrations at 20-15�C and 33-28�C. These results suggest that the increased tolerance of soybeans to high manganese supply was not due to growth dilution in young tissues.
Effect of leaf nitrogen and water regime on the photosynthetic capacity of kenaf (Hibiscus cannabinus L.) under field conditions
Authors: Muchow RC
Published: November 2005

To understand the influence of nitrogen (N) supply on the productivity of kenaf (Hibiscus cannabinus L.), the dependence of photosynthetic capacity, measured as light-saturated leaf CO2 assimilation rate (CA) and crop radiation use efficiency (RUE), on specific leaf nitrogen (SLN) was examined under well-watered conditions in the field. Photosynthetic capacity increased hyperbolically with SLN and was most responsive at SLN values less than c. 1.5 g m-2. The relationship reached a plateau at a maximum CA of 37 8mol m-2 s-1 and a maximum RUE of 1.5 g MJ-1 Increasing N application from 0 to 24 g N m-2 increased both RUE and SLN. Where ample N was applied, RUE and SLN were higher in those plots which previously experienced water deficit than in those that were always fully irrigated. The stimulation in growth following alleviation of water deficit was directly associated with the increase in SLN during water deficit. SLN varied according to differences in N uptake, the proportion of N allocated to leaves and the leaf area index. In particular, N application had much less effect on SLN and consequently RUE, than on N uptake, due to lower N partitioning to leaves and higher LAI where a high rate of N was applied. The importance of quantitative information on the relationship between photosynthetic capacity and SLN, in order to predict crop performance under varying environmental conditions, is discussed.
Vegetative compatibility groups within Australian populations of Fusarium oxysporum f.sp. cubense, the cause of Fusarium wilt of bananas
Authors: Brake VM , Pegg KG , Irwin JAG , Langdon PW
Published: November 2005

Wilt of bananas (Musa spp.), caused by Fusarium oxysporum Schlect. f. sp. cubense(E. F. Smith) Snyd. &Hans. (FOC), has a long history in subtropical Queensland, where it has destroyed many plantations of cv. Lady finger. Cavendish (AAA) clones are now being attacked in subtropical Queensland. Vegetative compatibility was used to subdivide Australian populations of FOC. One hundred and fortyeight isolates were placed in six vegetative compatibility groups (VCGs). VCG was correlated with virulence on specific cultivars in the field. All putative race 1 isolates belonged to VCGs 0124 and 0125 and with one exception, isolates in this group were recovered only from cultivars susceptible to race 1. Evidence is presented which suggests that wilt in Cavendish cultivars in Queensland is due to the previous widespread distribution of Cavendish competent strains (VCGS 0120,0129) in plantings of Lady finger, which is the major Australian race 1 susceptible cultivar.
Correlation of growth of the root and shoot systems of white clover after a period of water shortage and/or defoliation
Authors: Blaikie SJ , Mason WK
Published: November 2005

Relationships were established between growth in root and shoot systems of white clover under conditions of stress such as soil water deficit and defoliation that typically occur in the field. Vegetative clones of white clover (Trifolium repens cv. Haifa) were grown in pots in a greenhouse for 6 weeks. The growth and development of the shoot and root systems were followed by destructive harvests at the outset and after 2, 3, 4, 5 and 6 weeks. Treatments comprised: A) plants well watered with nutrient solution; B) restricted watering; C) well watered but defoliated after harvest three and allowed to regrow and D) restricted watering and defoliated. At the outset, all plants were of similar size (< 1.0 g DM), but by the end of the experiment, plant size ranged from 23.0 g DM in treatment A to 3.1 g DM in D. For plants in the ideal treatment (A), there were strong linear correlations between the measured root and shoot parameters that were evident at all harvests. For plants growing in the stress treatments (B-D), these correlations were initially disrupted but were almost fully restored by the end of the experiment. In white clover, the growth and morphological development of roots and shoots are highly correlated. If this balance is disturbed, white clover responds to rapidly re-establish the original coordination. If these same relationships exist in field soils, then higher shoot yields will only be possible if the growth of more roots is encouraged.
Variability in habit, flowering and seed production within the Kangaroo Valley cultivar of Lolium perenne when grown in a range of environments
Authors: Shah SG , Pearson CJ , Read JW
Published: November 2005

Diversity of flowering and seed production characteristics were measured within and between seven populations of Kangaroo Valley perennial ryegrass. The hypothesis that these characteristics would not change when grown in diverse environments was tested. The average time from seedling emergence to spike emergence was similar for each of three biotypes that represented early, intermediate and late flowering populations. This occurred in spite of variation in this character of 54 to 72 days between plants within each of these biotypes. When data from all seven populations were combined, they formed a normal distribution with respect to time of flowering. Distinctive components of seed production were found for the different populations. Early flowering populations had higher seed yields and more but shorter spikes than late flowering populations. Wide variation in habit occurred within populations but there was a high correlation between erect habit and early flowering. Spikes of erect plants emerged 27 days earlier than prostrate plants. The seed formation characteristics of an early flowering population were unaltered when grown for three generations in diverse environments. The spike emergence and anthesis times for each of the seven populations were not changed when grown in new environments. We conclude that seed production of Kangaroo Valley ryegrass in environments similar to those described in these experiments will not significantly alter the population characteristic. For changes in the character of the population to occur, the new environment would have to be so severe to (a) restrict growth and select out a proportion of the progeny or (b) cause a change in the time of seed harvest.
Dynamics of flower and pod production in annual medics (Medicago spp.). I. spaced plants
Authors: Cocks PS
Published: November 2005

Two experiments were conducted in Syria to examine flower production in annual medics. Flowers and pods of seven species were monitored throughout the flowering period in Experiment 1 and the relationships among 13 flowering attributes were investigated for 16 species in Experiment 2. Between 34% (M. rigidula) and 8 1% (M. minima) of flowers survived to maturity in Experiment 1 and between 27% (M. blancheana) and 93% (M. radiata) survived in Experiment 2. Flower and pod production and flower survival in most species increased until about node 7 and decreased thereafter. Seed size was greatest in pods produced before nodes 2-7; the seed in late-produced pods was only 50% as heavy as early-produced seeds. Seed number per pod was almost constant, indicating that ovule abortion was rare. Cluster and regression analysis suggested that greater flower retention was associated with low number of seeds per plants, small seeds, and small pods, and the data support the hypothesis that flower survival is determined by the potential mass of pods (pod mass by flower number) at each raceme. The ecological and agronomic significance of flower shedding and seed size is discussed, and it is suggested that more attention should be paid to the characteristics of successful ecotypes in a given area, when selecting cultivars for that area.
Dynamics of flower and pod production in annual medics. (Medicago spp.). II. In swards at low and high density
Authors: Cocks PS
Published: November 2005

Seven accessions of five annual medic species were grown in swards at low and high densities at Tel Hadya in north Syria. Flower shedding, seed size, and other components of seed yield were compared with data collected from spaced plants. Seed yield of the seven accessions, ranging from zero to 800 kg ha-1, was correlated with flowering time at high density but not at low density. Early flowering accessions of Medicago polymorpha and M. truncatula produced more seed at high density than at low density, but a late-flowering accession of M noeana failed to produce seed at high density. Flower shedding was greatest in dense swards and least in spaced plants. Shedding of the various accessions ranged from 70% to M. polymorpha at low density to 96% in M. rigidula and 100% in M. noeana at high density. Some accessions shed flowers uniformly from all nodes, but in other accessions late-produced flowers were more likely to be shed. The flower shedding observed here was less than found in many other legumes, but more than has been observed in subterranean clover. It seems unlikely that seed yield can be increased by selecting for increased flower retention, but it may be possible to increase seed numbers at the expense of seed size; this may be useful in pasturebased farming systems.
The effect of solution pH and external calcium concentration on the early growth and nodulation of several annual Medicago species
Authors: Ewing MA , Robson AD
Published: November 2005

The study tested the hypothesis that annual medic species which nodulate well in acid soils in the field (M. murex Willd. and M. polymorpha L.) will nodulate better in acid solutions with low calcium concentrations than annual medics which nodulate poorly in acid soils (M, truncatula Gaertn.). Effects of pH (5.5 and 6.5) and calcium concentration (0.2, 0.5, 1 and 2 mM) on the early growth and nodulation of three annual medic species (M. truncatula, M. polymorpha and M. murex) were investigated. Increasing pH or calcium concentration did not increase plant growth for any of the species. However, nodulation was generally depressed by low pH for all species. Increasing calcium concentration in solution increased nodulation in all species. Effects of low pH and low calcium concentration in decreasing nodule number were much greater for M. truncatula than for M. polymorpha and M. murex. At pH 5.5, M. truncatula failed to nodulate at any calcium concentration, whereas a large proportion of M. murex plants nodulated at 1 mM calcium and some M. polymorpha plants nodulated at 2 mM calcium. At pH 6.5, M. polymorpha required 1 mM calcium in solution for maximum nodule number, and M. murex only 0.5 mM calcium, whereas nodule number for M. truncatula increased up to 2 mM calcium, the highest concentration used. The results provide the basis for a simple screening system to distinguish differences among annual medics in nodulation tolerance to acidity. The maintenance of ranking among species with respect to nodulation over a wide range of stresses induced by combinations of low pH and calcium concentration suggest that screening using a single stress combining these two components would be adequate. Nodulation differences between species can be simply and effectively assessed using a scoring system combining number size and location of nodules.
Factors affecting diet selection by sheep. V. Observed and predicted preference ranking for six cultivars of subterranean clover
Authors: Colebrook WF , Black JL , Purser DB , Collins WJ , Rossiter RC
Published: November 2005

Samples from six cultivars of subterranean clover (Trifolium subterraneum) were harvested at two stages of maturity (vegetative and senescent) and one cultivar (Dinninup) at two additional stages. The samples were freeze dried to 90% dry matter, cut to 25 mm length and offered in pairs to trained sheep to determine their preference rankings. Within each stage of maturity, each cultivar was compared with every other cultivar. The vegetative clovers showed only a small (non significant) range in mean per cent preference (57-41), but the senescent material showed a much larger range (87-20). Preference for a forage was determined as the intake of that forage expressed as a per cent of the total intake of both forages on offer. Preference ranking changed with maturity and did not appear to be related to either oestrogenicity or length of growing season of the clovers in the vegetative stage. However, with the senescent material, clovers with a long growing season tended to have higher preference rankings (except for Dinninup). The 'palatability' of each cultivar of senescent herbage was quantified by comparing it in separate tests with a standard hay cut to several lengths. The preference ranking of the six cultivars predicted from this comparison with the standard hay was in close agreement with the observed rankings from the two-way preference tests. The agreement between the predicted and the observed rankings indicated that the method of establishing preference for forages relative to a standard hay (cut to several lengths) could be used to predict preference ranking between forages without performing a direct comparison. Seventeen of eighteen individual comparisons showed good agreement between predicted and observed preference. Preference ranking within the cultivar Dinninup decreased with maturity, and its ranking relative to the other clovers decreased markedly in the senescent stage comparisons. 'Palatability' and preference ranking may have major implications in the establishment and persistence of pastures, as well as influencing diet selection and subsequent nutrient intake by grazing animals.
Evaluation of controlled release devices for administration of chromium sesquioxide using fistulated grazing sheep. 1. Variation in marker concentration in faeces
Authors: Furnival EP , Corbett JL , Inskip MW
Published: November 2005

A group of 10 sheep grazed as a single flock; five were dosed with chromium sesquioxide (Cr2O3) using an experimental controlled release device, and five were dosed twice a day with gelatin capsules. Total faecal output was collected from each sheep over a period of 13 days, and in addition, a sample was taken twice daily from the rectum (grab sample). In a second experiment total faeces were collected every 2 h for 24 h. Total faecal output was compared with estimates of faecal output calculated from the quantity of Cr2O3 in the dose, and the concentrations in representative samples and in grab samples of faeces. An examination was made of the biases in the estimates from these two types of samples for the controlled release devices and for the gelatin capsules. Use of the controlled release devices significantly reduced circadian variation in the Cr2O3concentration in faeces, compared with twice daily dosing with gelatin capsules. Consequently variability was lower and biases in estimates of faecal output were relatively small. Once daily grab sampling from sheep with controlled release devices produced more reliable estimates of faecal output than twice daily sampling from sheep with gelatin capsules.
Evaluation of controlled release devices for administration of chromium sesquioxide using fistulated grazing sheep. 2. Variation in rate of release from the device
Authors: Furnival EP , Ellis KJ , Pickering FS
Published: November 2005

Merino sheep fitted with rumen cannulae and varying in liveweight, grazed Phalaris aquatica pastures with high and low dry matter mass. One or more controlled release devices were tethered inside the rumen and attached to its cannula. The position of the plunger within the controlled release device was recorded every 2 or 3 days for periods of up to 19 days, and the mean rate of plunger movement was calculated. Faecal output and flow of rumen digesta were measured concurrently in two experiments. Rate of plunger movement was measured in 152 devices and found to be substantially constant over time, but significant differences in mean rate of plunger movement were observed between formulation type, between sheep and between pastures varying in herbage mass. Coefficients of variation between sheep ranged from � 6 to �14%, and differences between pasture means ranged from 1 to 14%. Some of this variation was associated statistically with faecal output; assuming a linear relationship, a change in dry matter output of 100 g/day was associated with a change in plunger rate of 0.05 mm/day or about 6% of the mean rate. Liquid flow through the rumen was the rumen variable which had the highest statistical correlation with the rate of plunger movement.
The influence of protein quality on the effect of flavomycin on wool growth, liveweight change and rumen fermentation in sheep
Authors: Murray PJ , Rowe JB , Aitchison EM
Published: November 2005

The feed additive flavomycin, a glycolipid antibiotic, was evaluated for its potential to improve wool growth in sheep fed two pelleted diets: one based on lucerne chaff and lupin grain and the other on wheat chaff and fishmeal. Seventy-eight weaner ewes, approximately 20 months of age and mean weight of 32 kg (s.e. � 0.3), were placed in individual pens and fed the pelleted diets at a level equivalent to 3.5% of the mean liveweight of the group. The experiment consisted of an initial period (8 weeks) during which all animals received their respective diets with no flavomycin, followed by an experimental period (9 weeks) during which the animals received their diets with flavomycin. Flavomycin was included at three different rates (l0, 20 and 40 ppm) in both diets (nine sheep/level) during the experimental period and twelve sheep were fed each of the unmedicated diets (no flavomycin). Feed intakes were measured daily and animals weighed weekly. Wool growth was measured for the initial and experimental periods by clipping a mid-side patch of about 100 cm2. In sheep fed the lucernellupin based diet, flavomycin increased liveweight gain ( P < 0.05) at 20 ppm but had no effect on wool production, whereas in those fed the hay/fishmeal diet, there was a linear decrease in liveweight gain (P < 0.001) (161, 151, 142, 130 g day-1) and a dose related increase in clean wool production (P<0.01) (12.9, 14.5, 15.2, 15.3 g m-2 day-1) with increasing rates of flavomycin (0, 10, 20, 40 ppm respectively). There was no significant effect of flavomycin on fibre diameter in the sheep fed either diet. The inclusion of flavomycin in both diets significantly increased the molar proportions of propionate in the rumen fluid and in sheep on the hay/fishmeal pellet it reduced the concentration of rumen ammonia. The time animals took to eat their ration was increased with the inclusion of flavomycin in the hay/fishmeal diet.
Genotype, sowing date and plant spacing influence on high-yielding irrigated wheat in southern New South Wales. I. Phasic development, canopy growth and spike production
Authors: Stapper M , Fischer RA
Published: November 2005

Sowing date, sowing rate and row spacing effects were studied on high input crops at Griffith, N.S.W., between 1983 and 1985 using 25 bread wheats (Triticum aestivum L.) and 3 triticales (X Triticosecale Wittmack). The aim was to identify improved management practices and genotypes through a better understanding of development and growth of irrigated wheat grown under high-yielding conditions. The genotypes were chosen to represent a wide range in genetic background, maturity and stature. Growing period durations were between 208 days and 100 days for early April and mid-August sowings, respectively, with differences in anthesis dates within sowing dates of up to 45 days. Genotypes were classified into six major maturity groups. There was no maturity type that could flower close to 1 October from a wide range of sowing dates since anthesis was delayed by 0.3 to 0.5 days per 1-day delay in sowing. Increased daylength sensitivity tended to delay anthesis relative to the timing of floral initiation and terminal spikelet formation. The end of tillering was generally associated with the attainment of 50-60% light interception rather than a given development stage of the inflorescence. Spike density was not closely related to maximum tiller number but depended on genotype, environment and plant density. Leaf appearance rate was influenced by environment and genotype, but was independent of spike development. For a given final leaf number, internode elongation started at a later leaf number for later sowing dates, resulting in reductions in both node number and height. Crop height decreased by up to 5 cm per 1-week delay in anthesis date. The period of full light interception decreased from 133 days to 43 days between April and August sowings, respectively. The timing of reproductive development determined the green area duration, but the initial development and size of the canopy was less affected by it, because of adjustments in number and type of tillers, and size and thickness of leaves. The development and maintenance of an adequate canopy was not restricted by earliness, shortness or low sowing rates (50 kg seed/ha) for April-July sowing dates.