bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of dyebanding for measuring wool production and fleece tip wear in rugged and unrugged sheep
Authors: Wheeler JL , Hedges DA , Mulcahy C
Published: November 2004

Forty fine-wool Merinos grazed sown pastures and 40 grazed on weedy unimproved areas for 2 years. The sheep were dyebanded at intervals, and the weight of wool lost from the fleece tip was estimated from sequentially harvested sets of staples. Half the sheep in each group were fitted with woven polyethylene coats. In year 1, an estimated 4.2% of wool grown was lost from the fleece tip of unrugged sheep and 7.0% in year 2; losses from rugged sheep were 1.2 and 1.8 respectively. However, rugging had no effect on the quantity of clean scoured wool harvested each year, as rugged sheep grew slightly but consistently less wool than the controls. Rugging increased the percentage of clean scoured wool obtained from fleeces in the poor environment by 6 percentage points, but did not affect it on good pastures. Little difference in processing attributes was found in wool from rugged and unrugged sheep when assessed in bulk for commercial processing, although rugged wool was valued at 9% higher in one year. The length between bands on staples retained on the sheep for 32 weeks was shorter than between corresponding bands on adjacent staples that were removed from the sheep and stored for 32 weeks. The reduction was 13–22% on unrugged and 3–14% on rugged sheep. Attempts to use length or fibre diameter measurements to predict the weight of wool grown were unsuccessful. Theoretical considerations in the technique of dyebanding are discussed, and details of a recommended procedure are presented as an appendix.
The description and analysis of wool growth
Authors: Nagorcka BN
Published: November 2004

Analyses of experimental estimates of the wool growth rate as a function of intake have previously been based on time-independent equations and linear regression with ordinary least squares. Some of these results are reanalysed with the assumption that the sheep is a dynamic system; hence a time-dependent description of wool growth is proposed. A recursive least squares technique has been used, and the results demonstrate that there is a 3½ week lag between intake and wool growth. Time-independent descriptions have not taken account of this and have led to the misconception that efficiency is a function of body weight change.
Variation in the reaction of Stylosanthes guianensis lines to radiation frosts in controlled environments
Authors: Cameron DF , Ludlow MM
Published: November 2004

The reaction of six lines of S. guianensis to radiation frosts was studied in controlled environments. At frost temperatures of –6.1° and –4.6°C (measured at 2.5 cm height) plant survival in the three fine-stem stylo (FSS) lines was superior to that in the three robust (R) lines, in agreement with field observations. Leaf damage was severe on all lines in frosts where leaf temperatures were –2.4° or lower. In frosts with leaf temperatures of –0.8° and –1.3°, leaf damage ranged from 0 to 37% and the FSS lines showed slightly less leaf damage than the R lines. Exposure to a hardening regime of low temperature and short days did not decrease the leaf damage to either an FSS or an R line, but substantially improved plant survival in the FSS line. Three small F2 populations of crosses between FSS and R lines showed good survival after severe frosts, with values approaching those of the FSS parents. Plant survival after severe frosts of both parents and F2 populations was negatively related to the height above the soil surface of the lowest buds. Because temperature in radiation frosts increases as the soil surface is approached, development of buds at or below the soil surface appears to represent an effective adaptation for frost avoidance. Direct selection for height of the lowest bud is suggested as an efficient procedure for developing lines able to survive severe frosting in the field.
Water requirements of avocado in Israel. II.* Influence on yield, fruit growth and oil content
Authors: Lahav E , Kalmar D
Published: November 2004

The effect of four different irrigation intervals, 7, 14, 21 and 28 days, on the avocado tree was tested during the years 1968–1974 in the northern coastal plain of Israel. The respective average annual water applications were 8890, 7450, 6680 and 5940 m3/ha. The cultivars Ettinger, Fuerte and Hass were tested in five replications in randomized blocks. After 6 years no significant reduction in yield was observed with Ettinger or Fuerte trees irrigated once in 21 or 28 days. With the Hass cultivar the 28-day interval gave lower yields than with the three other intervals tested. Shortening of irrigation intervals increased the growth rate and size of individual fruits, which may be of economic importance for cv. Hass, where overproduction leads to small fruits unsuitable for export. Shortening of irrigation intervals tended to increase the oil percentage of the fruit, which may advance the harvest date. In view of the equal yields obtained and the predominance of cv. Hass in avocado plantations, it was concluded that the 21-day interval was the optimum irrigation frequency under the experimental conditions.

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*Part I, Aust. J. Agric. Res., 28: 859 (1977).
Fertility of ewes treated with prostaglandin F2α and artificially inseminated at predetermined intervals thereafter
Authors: Fukui Y , Roberts EM
Published: November 2004

An experiment was conducted to investigate the fertility rate in ewes inseminated with either fresh undiluted or frozen-thawed ram semen, without the use of vasectomized rams, at the first synchronized oestrus after a single intramuscular injection of 16 mg prostaglandin F2α (PGF2α). It was also investigated whether two injections of PGF2α at an interval of 12 days would improve the degree of synchronization of oestrus and the subsequent fertility. The degree of synchronized oestrus with two injections was similar to that with a single injection (72%v. 74% respectively). Inseminations at 46 and 54 hr or at 70 and 78 hr after treatment showed fertility comparable with that from those inseminations at oestrus detected by vasectomized rams (50% v. 45% for fresh undiluted semen and 22% v. 25% for frozen-thawed semen respectively). Inseminations at 70 and 78 hr after treatment showed a much higher fertility rate for both fresh undiluted (62% v. 39% respectively) and frozen-thawed semen (39% v. 9% respectively) than inseminations at 46 and 54 hr. Two injections of PGF2α resulted in similar fertility rates in control ewes following insemination with either fresh undiluted semen (50%) or frozen-thawed semen (22%).
Nutritional status and intake regulation in sheep. VIII.* Relationships between voluntary intake of herbage by sheep and the protein/energy ratio in the digestion products
Authors: Egan AR
Published: November 2004

In data from two separate experiments in which the same herbage diets were fed to sheep, a relationship was observed between the protein/energy ratio in digestion products and the level of voluntary feed intake: I = 0.16P—0.16 (SEb = 0.015; r2 = 0.85), where I is the voluntary intake of digestible energy (DE) (MJ/W0.75), P the protein digested in the intestine (g/MJ DE) and W the body weight (kg). When supplementary casein was infused into the duodenum of sheep fed on 15 basal diets, intake changes were greatest (up to 15% increase) with six roughage diets, in which estimated truly digestible protein contributed 5.5 g digested protein (DP) per MJ DE (about 10% of DE as protein) or less. No responses were observed with two other roughages in the same range or with seven roughages for which the estimated truly digestible protein contributed more than 6 g per MJ DE (about 13% of DE as protein). The change in voluntary intake was not found to be simply linked to the protein input, in that a consistent overall estimated protein/energy ratio in digestion products was not established as voluntary intake changed in response to protein infusion. The estimated resultant protein/energy ratios established were always high (7.4–9.4 g DP/MJ DE) relative to those observed on the basal diets (3.4–8.4 g DP/MJ DE). In a further experiment with a wheat hay–straw diet, voluntary intake was measured during periods of infusion of acetic acid per rumen, and/or protein (casein) infusion per duodenum. Energy infusion and protein infusion could be shown qualitatively to have opposed effects on oral intake. However, oral intake adjustments did not appear to act to preserve or re-establish any specific Protein/energy ratio in the total nutrients absorbed. The observations are discussed in relation to factors controlling energy intake, and the effect of protein inadequacy upon level of energy intake in the sheep.

*Part VII, Aust. J. Agric. Res., 23: 247 (1972).
Effects of Pseudopeziza leaf spot disease on growth and yield in lucerne
Authors: Morgan WC , Parbery DG
Published: November 2004

Growth analysis of lucerne plants infected with Pseudopeziza medicaginis compared with growth analysis of healthy plants showed that, while infection caused a general decrease in relative growth rate and leaf area ratio and affected the relative proportions of leaf, stem and root, there was no overall change in the growth pattern during the experimental period (7 weeks). In addition to retarding the net assimilation rate in leaves and roots, infection did slow down the rate of increase of net assimilation rate in leaves as well as its rate of decrease in roots. Infection delayed and possibly reduced flowering. Glasshouse, phytotron and field trials showed that infection with P. medicaginis can reduce dry matter production in lucerne by over 40%. It was shown that, in the absence of fresh infections, the influence of a single period of infection can have a considerable long-term effect.
Studies of the Australian Illawarra Shorthorn breed of dairy cattle. I. Breed structure
Authors: Herron ND , Pattie WA
Published: November 2004

The structure of the pedigree Australian Illawarra Shorthorn breed in Australia was analysed by using registration data from the Society's Herd Books. The breed may be divided into three broad levels, namely, Breeders' Herds, Multipliers' Herds and Grade (unregistered) Herds. Of the registered herds, 32% are Breeders' Herds and the remainder are Multipliers' Herds. These are each subdivided into four strata depending on their importance as a source of breeding material, and on their registration practices respectively. Of major importance is the highest stratum of the breed. It comprised only 13.6% of all herds, but accounted for 40.5% of male and 24.8% of female registrations. There is a high ratio of females to males registered of 5.9, which indicates considerable selective registration of males. The degree of this selective registration generally increases at the lower strata, ranging from 3.6 at the top of the structure to 8.7 toward the bottom of the structure. Of all new herds initiated from 1931 to 1971, 44% survived less than 5 years. These short-lived herds averaged only 3.3 female registrations per year, but herd size increased as longevity increased. These points highlight the instability of new, small studs, and indicate that few herds are big enough, or exist for long enough, to contribute significantly to breed improvement. It is not likely that there is much genetic variation between herds. Bulls from major breeders' herds are used widely throughout the breed, while 68% of sires and 24% of dams are bred in herds other than the one in which they were used.
Carcass beef yield as a basis for carcass evaluation and marketing
Authors: Charles DD
Published: November 2004

The carcass yield of prescribed proportions of muscle and dissectible fat, described as 'carcass beef ', was studied in 49 steers of four breeds. Carcass beef consisting of 80% muscle, 20% fat and also of 75% muscle, 25% fat was predicted from fat thickness (FT), liveweight, carcass weight and dressing percentage. Carcass beef as a percentage of carcass weight was usefully estimated from FT (± 3%) but not from the other parameters. Carcass beef percentages and the corresponding FT measurements up to 15 mm were tabulated for the four breeds. There was no significant difference between the Herefords, Angus and Charolais X. Yield was less in the Friesians at a common FT, but a smaller FT was required to obtain a yield from carcasses of that breed. Carcass beef as a percentage of carcass weight, where the carcass beef composition is of specified proportions of muscle and dissectible fat, is proposed as a basis for the evaluation and marketing of carcasses.
Pasture degeneration. I. Effect on total and seasonal pasture production
Authors: Cook SJ , Lazenby A , Blair GJ
Published: November 2004

The cessation of superphosphate dressings to a perennial ryegrass-white clover pasture which had received more than 1300 kg superphosphate per hectare resulted in pasture degeneration. Within 2½ years of the last superphosphate dressing, the sown species comprised less than 15% of the harvested forage, compared with 53% in the forage from plots receiving 500 kg superphosphate per hectare per year. Only where superphosphate was applied at either 250 or 500 kg per hectare per year did the ryegrass persist. As perennial ryegrass was the only species to contribute to pasture production in winter, this botanical degeneration significantly reduced winter production. The phosphate-deficient pastures were invaded by summer-growing native grasses such as red grass, which, although contributing substantially to summer production, made little or no growth in the 6 months April to September inclusive.
Differential tolerance to manganese in introduced and bred lines of Macroptilium atropurpureum
Authors: Hutton EM , Williams WT , Andrew CS
Published: November 2004

A number of lines of Macroptilium atropurpureum, including cv. Siratro, were grown in two experiments at different manganese levels in sand culture. In one experiment 40 ppm manganese was used in conjunction with nitrogen either in inorganic form or as Rhizobium; in the other, two levels of excess manganese (30 and 45 ppm) were used with rhizobial nitrogen at a lower pH. Dry matter yields for tops, roots and nodules were recorded, and the plant material analysed for nitrogen, phosphorus, calcium and manganese. Dry matter yields of tops were reduced, and the ratio of root to total dry matter yield increased, by both Rhizobium and excess manganese. Tops, but not roots or nodules, showed considerable differences in manganese tolerance between lines. Excess manganese caused small but significant changes in concentrations of other minerals. Regressions of rhizobial on inorganic nitrogen showed that at the levels used excess manganese does not impair rhizobial efficiency. Numerical analyses suggested that manganese tolerance operates at three levels; more vigorous lines usually remain so in the presence of manganese, some lines appear to be able to resist the uptake of excess manganese, and for any given level of manganese concentration within the plant, some lines appear more sensitive than others. The results show that growth evaluation studies can be carried out equally well with rhizobial or inorganic nitrogen sources, and they suggest that it should be possible to improve the tolerance of M. atropurpureum lines by selection and/or breeding.
Seasonal relations between animal gain, pasture production and stocking rate on two tropical grass-legume pastures
Authors: Edye LA , Williams WT , Winter WH
Published: November 2004

The relationship between stocking rate and liveweight change per animal was examined over a period of 3 years for two continuously grazed pastures, one of Brachiaria and the other consisting of guinea grass with Endeavour stylo and Siratro. On an annual basis there was no significant effect of stocking rate over the last 2 years, but on a seasonal basis there were highly significant effects in all seasons. In the dry seasons, animal gain rose as the stocking rate fell, but in the last two wet seasons gains fell with the lower stocking rates. On an annual basis the two effects cancelled out. Response surfaces for gain versus pasture yield and stocking rate were curvilinear (quadratic) during the wet season and linear during the dry. Optimum stocking rates (for maximum gain per hectare) were determined for the wet and dry seasons; the rate was greatly affected by the yield of green material during the dry season but less so during the wet. The possible causes of this reversed wetseason effect are discussed.
Accumulation and distribution of mineral elements in the annual lupins Lupinus albus L. and Lupinus angustifolius L
Authors: Hocking PJ , Pate JS
Published: November 2004

The mineral nutrition of L. albus and L. angustifolius was studied under nutrient-sufficient conditions in sand culture. Mineral accumulation by both species was closely synchronized with dry matter accumulation. Fruits acquired major proportions of the nitrogen, phosphorus, potassium, magnesium and zinc of both species. Leaflets were major sites of accumulation of calcium, iron and manganese; stem and petioles accumulated substantial amounts of potassium, phosphorus, magnesium, copper and sodium. Intensities of intake of calcium, magnesium and iron by roots of L. angustifolius were higher than in L. albus. The situation was reversed for sodium. Cotyledon reserves of nitrogen, phosphorus, potassium and zinc were mobilized to seedling parts with 85–97% efficiency, other elements much less effectively. During fruiting, vegetative parts of the shoot showed net losses of 60–80% of their nitrogen, phosphorus and potassium, 20–50% of their magnesium, iron, zinc, manganese and copper, and less than 15% of their calcium and sodium. Mobilization from vegetative structures was generally more efficient in L. albus than in L. angustifolius. Leaflets showed higher mobilization efficiencies than stem and petioles. Post-anthesis mobilization furnished the equivalent of 23–59% of the fruit's intake of nitrogen, phosphorus, potassium, magnesium and manganese, 10–25% of the zinc, calcium, iron and copper, and 2% or less of the sodium. Nitrogen, phosphorus and potassium attained higher concentrations in fruits than in mature, non-reproductive parts; less mobile elements (calcium, sodium, iron and manganese) showed the opposite effect. Concentrations of sodium and manganese were especially low in fruits of L. angustifolius compared with L. albus.
Lucerne transient streak and lucerne latent, two new viruses of lucerne
Authors: Blackstock JMcK
Published: November 2004

A previously undescribed virus, lucerne transient streak virus (LTSV), and two isolates of lucerne latent virus (LLV) were sap-transmitted from symptomless lucerne to Chenopodiurn quinoa and to herbaceous species of several families. Only LTSV could be mechanically transmitted to lucerne. LTSV was purified by clarifying C. quinoa leaf extracts with n-butanol, followed by differential and sucrose density gradient centrifugation. Isometric particles 27 ± 1 nm in diameter sedimented as a single component with a S20,w value of 114 S. An antiserum prepared against LTSV did not react with either isolate of LLV. LTSV was not seed-transmitted. LTSV reduced the dry matter yield of lucerne during one growing season by 18 % in the field and by 12% in a glasshouse. Various attempts to purify the two isolates of LLV were unsuccessful, but a few isometric particles 24–28 nm in diameter were observed in some preparations. One isolate of LLV was transmitted in 8% of lucerne seed and 9% of C. quinoa seed from infected plants. The viruses did not react against antisera to 23 other viruses and were not soil- or aphid-borne.
The distribution of cotton looper (Anomis flava Fabr.) larvae and larval damage on cotton and its relationship to the photosynthetic potential of cotton leaves at the attack sites
Authors: Bishop AL , Blood PRB , Day RE , Evenson JP
Published: November 2004

Data are given for the distribution of larvae and larval damage of the cotton looper, Anomis flava Fabr., during periods of natural attack on cotton in the south-east Queensland region. A distinct distributional pattern developed in which larvae and major damage to leaves were centrally located on both the horizontal and vertical axes of the plant. The distribution and damage potential of the larval population was subsequently greatly modified by a nucleopolyhedrosis virus epizootic disease commonly recorded in cotton looper populations in the region. Major damage was caused to leaves 14–21 days old which were approximately midway through their photosynthetic capacity range and continuing to decline in photosynthetic importance. The data are considered relative to the inclusion of loopers in a complete pest management program currently being developed for cotton in the south-east Queensland region.
Factors affecting pre-weaning growth and weaning conformation of Angus cattle
Authors: Barlow R , Dettmann EB , Williams LG
Published: November 2004

Weaning weight (ww) and conformation score (cs) records from Angus calves in five New South Wales herds were analysed by least-squares procedures to assess the nature and magnitude of variation. Herd, year, age of dam and sex were considered as main effects. Covariates included in the models were weaning age (WA) for ww and average daily gain (ADG), and both WA and ww for cs. Male calves (steers and bulls) were 16.6 kg heavier at weaning than female calves. Dams that were 5-8 years of age weaned calves that were 30.1 kg, 15.4 kg and 6.7 kg heavier than 2-, 3- and 4-year-old dams respectively. When ww was not included as a covariate in the model, age of dam effects on cs reflected those on ww, and there was little difference in cs between males and females. When adjusted for differences in ww, males had poorer cs than females, and calves from 3-year-old dams, and from dams over 8 years old, had poorer cs than those from dams of all other ages. Partial regressions of ww and ADG on WA, and of cs on ww, varied considerably between herd/year/sex subgroups.
Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. II.* The dynamics of resistance in previously unexposed and exposed cattle
Authors: Wagland BM
Published: November 2004

The dynamics of host resistance to Boophilus microplus was investigated in previously unexposed and exposed Brahmans, and in previously unexposed Shorthorn cattle. The animals were infested each day with 1000 larvae, and the development of resistance was monitored by counting the number of female ticks which engorged. The previously unexposed cattle showed an initial period of susceptibility (phase I) which was followed by a period in which most animals developed degrees of resistance (phase II), and which stabilized in some animals (phase III). The duration of phase I was shorter in Brahmans, and they developed higher levels of resistance (phase III). In contrast, previously cxposed Brahmans manifested phase III levels of resistance immediately on infestation. The results provide further evidence that resistance to B. microplus in Brahmans, as well as in European breeds, is acquired rather than innate.

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*Part I, Aust. J. Agric. Res., 26: 1073 (1975).
Senescence, digestibility and carbohydrate content of buffel grass and green panic leaves in swards
Authors: Wilson JR , Mannetje L't
Published: November 2004

Seasonal changes in the rate of production, senescence and change in dry matter digestibility (DMD), cell wall content (CWC) and non-structural carbohydrate content (TNC) of leaves of buffel grass and green panic were followed over a period of 2 years in grazed swards in a dry, subtropical environment in southern Queensland. The swards were buffel grass sown alone with (buffel plus-nitrogen) and without (buffel minus-nitrogen) nitrogen fertilizer, buffel grass/Siratro mixture and green paniclsiratro mixture. New, fully expanded leaves developed at the rate of c. one every 9–10 days in summer, 11 days in spring and 14–20 days in autumn. The overall rate of senescence of these leaves was fastest during the summer growing season and slowest during the cooler, drier conditions of autumn. Leaves in the buffel plus-nitrogen and buffel/Siratro swards senesced more rapidly than those on the buffel minus-nitrogen treatment. Leaf senescence was particularly accelerated by frost in the dry season and by intermittent periods of water stress during otherwise good moisture conditions in the growing season. The DMD of recently developed leaves was generally higher in spring than in summer and autumn, and CWC showed the reverse trend. The decline in DMD of leaves as they aged was considerably higher in spring and summer (c. 0.5 unit/day) than in autumn (0.1–0.3 unit/day); these changes were proportionately greater than expected from the increase in CWC. Frosts caused a precipitous decline in DMD. Leaves of buffel plus-nitrogen were 2–4 units higher in DMD than buffel minus-nitrogen leaves when young, but the former leaves declined in DMD more rapidly as they aged; the DMD of leaves from the buffel—Siratro swards was intermediate. The level of TNC was highest, up to c. 12%, in spring (largely due to an increase in starch) and lowest in late summer-autumn (c. 8%). Diurnal variation in TNC was small (2 percentage units from 0600 to 1800 hours) and did not affect the estimation of DMD.
Seed dormancy of Emex australis and E. spinosa
Authors: Hagon MW , Simmons DM
Published: November 2004

Seed dormancy in Emex australis and E. spinosa was investigated by the application of light, gibberellic acid (GA3) or kinetin (KT) and by scarification of the fruits. Results from these experiments suggested that dormancy was controlled by the balance between promotive hormones and inhibitors and that a semipermeable barrier prevented leaching of inhibitors and/or uptake of exogenously applied GA3 or KT, and/or restricted oxygen diffusion. Storage of seed at alternating temperatures in the laboratory or the field reduced the level of dormancy, the reduction being more rapid for E. australis than for E. spinosa. The degree of dormancy also varied between populations within E. australis. Burial of non-dormant seeds of E. australis did not induce secondary dormancy even though dormancy was enforced by burial at a temperature regime of 25/20°C. Partly dormant (light-requiring) seeds of E. spinosa attained a degree of secondary dormancy following burial for 4 weeks at 25/20° and 9/9°. The results are discussed with reference to cultural control practices.
Seasonal and diurnal variation of nitrogenase activity (acetylene reduction) in barrel medic (Medicago truncatula Gaertn.) grown in pots
Authors: Ruegg JJ , Alston AM
Published: November 2004

Seasonal and diurnal variation of nitrogenase activity in Medicago truncatula Gaertn. was measured by means of the acetylene reduction assay on plants grown in pots. In a glasshouse set at 20°C, the seasonal pattern of acetylene reduction (AR) activity was closely correlated with dry weight and photosynthetic area. Short-term fluctuations in AR activity were mainly associated with irradiance. Measurements made of the diurnal variation of AR activity showed that rates of AR at noon were 10–60% (average 33%) higher than the mean daily rates. Effects of defoliation and shading gave further evidence for the importance of light and recent photosynthate for nitrogen fixation in root nodules of legumes. Values for acetylene reduction integrated over time were highly correlated with the total amount of nitrogen in the plant. The molar ratio of acetylene reduced to nitrogen accumulated by the plants at the end of the experiment was 1.2 : 1. The significance of this value is discussed. Multiple use of the same plant material to study the time course of nitrogen fixation by the AR assay was found to be feasible under certain conditions.
Milk replacers containing isolated soybean protein for preruminant lambs: influence of experimental design on estimates of requirements for supplementary methionine
Authors: Phillips DD , Walker DM
Published: November 2004

Preruminant male crossbred lambs, aged 2–5 days at the start of the experiment, were used in two experiments with low protein milk replacers (0.10 of total energy as protein) containing isolated soybean protein as the sole source of protein. Experiment 1. Groups of three lambs were given the soybean diet supplemented with DL-methionine (seven levels) in increasing (experiment la) or decreasing amounts (experiment 1b). Dietary periods were each of 3 days. Estimates of minimum intakes of methionine plus cystine, coincident with maximum animal response, based on a 1 day nitrogen balance or on plasma urea nitrogen concentrations, indicated that there was a carry-over effect when methionine was given in decreasing amounts. Experiment 2. An 8 x 8 change-over design was used to minimize carry-over effects. Each lamb was given each diet (seven levels of methionine) for 4 days, in such an order that in the final design each diet was preceded once by every other diet. No carry-over effects were observed. It was concluded that the change-over design could be used to estimate amino acid requirements with fewer animals and with shorter dietary periods than in the conventional balance experiment.
Mimosine, administered orally, and two related compounds of chemical defleecing agents for sheep
Authors: Reis PJ , Tunks DA , Downes AM
Published: November 2004

Oral doses of mimosine (ranging from 400 to 800 mg/kg body weight) were given to 71 sheep, either as two successive daily doses (10 sheep) or as a single dose (61 sheep). The effectiveness of these treatments for defleecing was assessed and in some sheep measurements were made of the concentration of mimosine in plasma after dosing, and of the rate of wool growth before and after dosing. In addition, the effectiveness as defleecing agents of two related compounds (an analogue of mimosine, 'isomimosine', and a metabolite, 3,4-dihydroxypyridine (DHP)) was assessed. Two successive daily doses of mimosine (300 mg/kg/day) allowed all sheep to be defleeced. With sheep consuming a daily ration of 600 g, a single oral dose of mimosine (400 mg/kg) was sufficient to allow defleecing of most sheep; when the daily ration was 1200 g, a dose of 600 mg/kg was required to allow defleecing of most sheep. The effectiveness of oral doses for defleecing could be explained by the absorption of mimosine over a period in excess of 24 hr. Concentrations of mimosine in plasma were usually above 100 µmoles/l 24 hr after an effective dose. Failure to achieve complete cessation of fibre growth occurred occasionally, irrespective of dose level, and two sheep died after dosing. Fasting prior to dosing appeared to obviate the effects of previous high nutrition, but increased the risk of toxic effects. Fasting resulted in exceptionally high concentrations of mimosine in plasma (200–300 µmoles/l) 1 and 2 days after dosing. Both fibre diameter and mass of wool grown were increased in the early regrowth after dosing with mimosine. 'Isomimosine' had a similar potency to mimosine for stopping fibre growth in sheep, whether given as an intravenous infusion or as a single oral dose. DHP, given as an intravenous infusion, was ineffective as a defleecing agent.
Factors determining the optimum hardness of wheat
Authors: Moss HJ
Published: November 2004

The maximum desirable grain hardness is related to protein level and to the end product. Three methods of measuring the hardness of wheat are considered, and their dependence on other grain characteristics is shown to vary according to cultivar. Particle size index provides the best estimate of starch damage, and pearling resistance the best discrimination between cultivars. The pattern of site and seasonal effects shown by one hardness test is different from that shown by another.
Spread of bunchy top disease in established banana plantations
Authors: Allen RN
Published: November 2004

The spread of bunchy top disease by the banana aphid was studied in two established banana plantations, in the presence and absence of roguing operations for disease control. The probability P of a new infection occurring x metres from an estimated source of inoculum was described by a special case of Pearson's gamma probability functionPx = exp( – x / x) ÷ x,

where the mean distance between all of 178 new infections and their estimated sources of inoculum was x = 17.2 m, irrespective of roguing. All except two of the new infections occurred within five standard deviations (5x = 86 m) of the source as predicted, with nearly two-thirds within 20 m. The results were confirmed by successfully predicting the number of new infections that were encountered within 10 m of sources of inoculum in five other banana plantations. The results are discussed in relation to quarantine measures aimed at limiting the spread of disease in established plantations.
Antimethanogenic drugs and Heliotropium europaeum poisoning in penned sheep
Authors: Lanigan GW , Payne AL , Peterson JE
Published: November 2004

Most sheep fed for prolonged periods on a ration containing 50% dried Heliotropium europaeum developed some of the clinical manifestations seen in field cases of pyrrolizidine alkaloidosis. Histologically demonstrated liver damage in the laboratory animals was comparatively mild, but the marked decline in their bromosulphophthalein (BSP) clearance rates indicated severe depletion of liver functional capacity. In sheep fed on H. europaeum for 13-week periods separated by 18-week rests, simultaneous oral administration of iodoform (16 mg twice daily) led to an increase from 33 to 55 weeks in the time required for death of half the susceptible sheep. Iodoform at levels of 32 mg and above twice daily proved hepatotoxic when given orally for several months. All susceptible sheep not given iodoform died following two periods of H. europaeum feeding, whereas three such periods were needed for iodoform-treated animals. It is concluded that iodoform prophylaxis may be a useful protective measure in the field for sheep exposed to H. europaeum grazing during a single season. Up to 20% of the sheep used survived ingestion of H. europaeum for the full experimental term; some of them sustained little or no decline in BSP clearance rate. This finding indicates that there are prospects for development of a pyrrolizidine-tolerant strain of sheep by selective breeding. Chloral hydrate proved unsatisfactory as a replacement for iodoform.
Selection against sprouting damage in wheat. II.* Harvest ripeness, grain maturity and germinability
Authors: Gordon IL , Balaam LN , Derera NF
Published: November 2004

Examination of grain development in two white-grained (non-dormant) and two red-grained (varying dormancy) wheat genotypes has clarified concepts of maturity with respect to grain dehydration, harvest ripeness, embryo maturity, base α-amylase activity and dry weight growth. Each maturity trait had a different pattern of development. The net level of grain maturity at harvest ripeness depended on the relative progress of the maturation traits at the time at which harvest ripeness was defined. Harvest ripeness is defined as the first attainment of 12½% moisture during primary dehydration of the grain, this being closely related to fitness for harvest. The effects of adopting other definitions of harvest ripeness (at 17½% and 20% grain moisture) are discussed. Significant differences amongst genotypes in development patterns, temporal placement, and harvest ripeness level were found in each maturity trait, and the differences were not parallel across traits. Differences in maturation did not coincide with differences in putative dormancy or grain colour. Results indicated that grain maturation was a multi-faceted process, with flexible synchronizations amongst maturation traits at any point in time, such as at harvest ripeness. Germination tests or a-amylase assays on progeny grain samples, at some time after harvest ripeness, measure differences in maturity as well as putative differences in dormancy. Interpretation only in terms of dormancy could be misleading. Adjustment for immaturity is discussed.

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*Part I, Aust. J. Agric. Res., 28: 583 (1977).
The effect of some environmental conditions on seed development and hard-seededness in subterranean clover (Trifolium subterraneum L.)
Authors: Taylor GB , Palmer MJ
Published: November 2004

Subterranean clover (cv. Daliak) was grown in boxes with provision for unrestricted lateral growth. At the commencement of flowering, plants were allocated to three day/night temperature regimes of 12/7°, 18/13° and 24/19°C in controlled-temperature glasshouses and well watered until maturity (unstressed). In two additional treatments at 18/13°, plants were either subjected to intermittent moisture stress throughout the flowering period (stressed) or well watered for the first 6 weeks of flowering and then allowed to dry out (droughted). Increasing temperature resulted in more rapid inflorescence production, seed development and earlier plant maturation. The overall mean seed size was lower at 24/19° than at the other two temperatures. The stressed and droughted treatments produced fewer and smaller seeds than the corresponding unstressed treatment. There was a small effect of temperature on the degree of hard-seededness as determined from the mean softening time of seed subjected to daily alternating temperatures of 60/15°. Softening time was not significantly affected by watering treatments. There were small differences in softening time due to the position of the burr on the lateral, with a slight trend for seeds from the first-formed burrs to soften more rapidly. Most of the variation in softening time between seeds was due to variation within burrs. The sequence of seed softening within burrs was related to seed size, the larger seeds generally softening first, but no single regression could be used to describe this relationship for different burr positions or treatments. The absence of major treatment effects on the degree of hard-seededness indicates that varying the length of the seed development period does not necessarily result in differences in hard-seededness, as has been suggested from field experiments.
Histological studies of resistance to soybean rust, Phakopsora pachyrhizi Syd
Authors: McLean RJ
Published: November 2004

Histological comparisons were made of susceptible, resistant, and immune responses of soybean to infection by rust, Phakopsora pachyrhizi, at intervals after inoculation. In the susceptible host there was extensive hyphal growth and vigorously sporulating uredia developed. The immune hosts showed no macroscopic symptoms of infection, but at the microscopic level exhibited a hypersensitive response which was limited to a few cells. In the resistant host the hypersensitive response was not as limited, fungal development and associated host cell necrosis were more extensive, and symptoms of infection were visible macroscopically.
Rhizobium screening of Stylosanthes species for effectiveness in nitrogen fixation
Authors: Date RA , Norris DO
Published: November 2004

The Rhizobium strain specificity and effectiveness in nitrogen fixation of 336 accessions of the genus Stylosanthes were determined in glasshouse screening trials. In preliminary screening, against a wide-spectrum strain CB756, 224 accessions were effective (> 50% dry weight of nitrogen control). Sixty-two of these were evaluated subsequently against a spectrum of 22 strains of Rhizobium selected on the basis of host and geographic origins. Thirty-three were effective with 10 or more strains. Seventy-two accessions that were ineffectively nodulated in preliminary tests were also screened against the 22 strains. Fifty-four of these were effective with one or more strains of Rhizobium. A minimum spanning tree (MST) analysis was used to examine the interrelationships between, and the distribution of, accessions according to their effectiveness response (ER) to the 22 strains of Rhizobium. Accessions were classified into six groups, also according to their effectiveness response, by the program MULTBET. Groups I–IV were nodulated effectively by a large number of strains (mean 9.4) and groups V and VI by a limited number of strains (mean 1.3). Significant and wide-ranging Stylosanthes accession x strain of Rhizobium interactions for effectiveness in nitrogen fixation were observed, particularly in S. guianensis and S. hamata. Various reclassifications were made by MULTBET on a reduced number of strains which were selected on the basis of discriminatory powers between groups (eident values), contribution to the classification (Cramér measures) and intuitively on the basis of level of effectiveness specificity and soil pH adaption. Classifications based on Cramér measures gave least (9%) non-conforming accessions, but intuitively selected strains the widest range of effective associations. The majority of non-conforming accessions were found in effectiveness response groups ER-III and ER-IV and were mostly S. guianensis from M–A groups 2 and 14 andS. hamata M–A 28. For future screening programs strains CB 82, CB 159, CB 530, CB 756, CB 1408 and CB 2126 will be used as diagnostic strains for classification of accessions by effectiveness response, and strains CB 82, CB 1650 and CB 2126 as 'key strains' for provision of inocula for experimental purposes.Classification of strains of Rhizobium into six groups was obtained by a MULTCLAS analysis of the data matrix. A principal coordinates analysis suggested distinct clustering of strains on the basis of host specificity for effective nodulation. These corresponded very closely to the six classificatory groups.
The effects of copper and nitrogen supply on the distribution of copper in dissected wheat grains
Authors: Hill J , Robson AD , Loneragan JF
Published: November 2004

The distribution of copper between the embryo and the endosperm was studied in the grain of two wheat cultivars (Gamenya and Petit Rojo) grown at marginal and sufficient copper and two levels of nitrogen. Copper concentration in whole grain increased markedly with copper level but differed little with nitrogen level. The dry weight and copper content of the embryo expressed as a proportion of the whole grain varied little among treatments, so that copper concentration in the embryo responded to treatment in a similar way to copper concentration in the whole grain. Copper concentrations in the embryo were at least 2.5 times as high as in the endosperm or whole grain at all levels of copper and nitrogen. It is suggested that where copper deficiency decreases grain number without decreasing the weight of individual grains the copper concentration in the mature whole grain, or in the embryo, is not causally related to grain development, and may be a poor indicator of the potential response of grain yield to copper application.
Genetic control of the pre-anthesis development of spring rape (Brassica napus L.). I. Diallel analysis of variation in the field
Authors: Thurling N , Das LDV
Published: November 2004

A l0 x 10 complete diallel cross of spring rape cultivars was sown at three different times in the field to obtain basic information on the genetic control of pre-anthesis development. Analyses of variance of the diallel cross data indicated that both duration of the vegetative phase and leaf number at initiation were highly heritable in all sowings although dominance effects were also significant. No significant reciprocal differences were detected. Variance v. covariance (Vr–Wr) graphs for duration of the vegetative phase indicated that neither gene interaction nor correlated gene distribution was important. The order of parents along the regression line varied greatly between sowings. Late-flowering parents were found to possess a much higher frequency of recessive genes in the April and September sowings than in the June sowing when temperatures during early development were generally lower. It is suggested that this variation in the disposition of parents in the Vr–Wr graphs may reflect differences in genes for vernalization requirement which are expressed most strongly under higher temperatures. In the case of number of leaves formed prior to initiation, the slope of the regression line deviated significantly from unity in the first and second sowings, but the magnitude of this deviation declined with successive delays in sowing. Gene interaction and/or correlated gene distributions were apparently significant under certain conditions. The order of parents along the regression line also varied with sowing date, but not in as regular a manner as with duration of the vegetative phase. Differences in duration of the vegetative phase and leaf number between the Japanese cultivar Isuzu and all other parents in the September sowing appeared to be determined by one gene, or at most a small number of major genes.
The distribution of benomyl-tolerant Sclerotinia fructicola (Wint.) Rehm. in stone fruit orchards in New South Wales and comparative studies with susceptible isolates
Authors: Penrose LJ , Davis KC , Koffmann W
Published: November 2004

Tolerance of Sclerotinia fructicola (Wint.) Rehm, to benzimidazole fungicides was first recorded in New South Wales in 1976 and has since been confirmed on 11 orchards, all in the Orange and Bathurst districts. Crops affected include peach, nectarine, cherry and plum. The distribution of benomyl-tolerant strains was mapped in two orchards and found to be present in scattered groups of trees, rather than throughout the block. Distribution of tolerant strains was not uniform within trees, and in most cases both tolerant and susceptible strains were present in the same tree. Tolerance was found to be stable after three transfers of the fungus in fruit and after 33 transfers over 2 years in culture. The fungus persisted over the winter in mummified nectarine fruit and was still present in an orchard 18 months after the application of benzimidazole fungicides ceased. The tolerant strain was as pathogenic to peach fruit as the susceptible strain and competed successfully when peach fruits were inoculated with mixtures of spores from susceptible and tolerant strains. There were no significant differences between groups of tolerant isolates and susceptible isolates in growth, sporulation and germination percentage in vitro. It is suggested that since no competitive disadvantage was associated with tolerance, tolerant strains will exist in high numbers in orchards for a considerable period of time.