bluuebunny/crossref_metadata_2025 huggingface dataset:
Glutathione peroxidase and selenium in sheep. II.* The relationship between glutathione peroxidase and selenium-responsive unthriftiness in Merino lambs
Authors: Paynter DI , Anderson JW , McDonald JW
Published: November 2004

Low erythrocyte activities of the selenium-containing enzyme glutathione peroxidase were found in Merino lambs in an area of the Strathbogie Ranges in central Victoria where selenium-responsive conditions have previously been reported. Body weight gain trials conducted over 10 properties in the above area demonstrated that the severity of selenium-responsive unthriftiness was significantly correlated with the erythrocyte glutathione peroxidase activity (r = – 0.95, P <: 0.001). Positive body weight responses to selenium treatment were only observed in lambs with erythrocyte glutathione peroxidase activities less than 30 U/g Hb prior to selenium treatment. These findings indicate that measurement of erythrocyte glutathione peroxidase activity provides a convenient index of the selenium status in sheep.

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*Part I, Aust. J. Agric. Res., 30: 695 (1979).
The sensitivity of hexaploid and octoploid triticales and their parent species to copper deficiency
Authors: Graham RD , Pearce DT
Published: November 2004

The tolerance of two triticales to soil of low copper status was determined in deep pots in a glasshouse experiment, and compared with the tolerance of their wheat and rye parent types. Both tetraploid and hexaploid wheats were extremely sensitive to copper deficiency, producing no grain without copper added to the soil. In contrast, rye and the hexaploid triticale were completely tolerant of the copper-deficient soil, producing as much grain without added copper as at the highest rate of copper supply. The octoploid triticale produced about 60% of maximum grain yield in the unamended soil, a performance intermediate between its rye and hexaploid-wheat parents. The cause of grain failure in the wheats was pollen sterility induced by copper deficiency, and this was related to low uptake of copper into the shoot and heads of wheat from the unamended soil. The pattern of uptake of zinc was quite different from that of copper in these plants, which suggests that a specific uptake mechanism for copper exists in rye which is genetically controlled and transferable to triticale, its hybrid with wheat. The copper efficiency so conferred on triticale would appear to be adequate for most field situations where copper deficiency exists.
Drought resistance in spring wheat cultivars. II.* Effects on plant water relations
Authors: Fischer RA , Sanchez M
Published: November 2004

We studied cultivar and drought effects on the water relations of a large set of cultivars of bread wheat (Triticum aestivum L.), durum wheat (T. turgidum), triticale (X Tritosecale Wittmack) and barley (Hordeum vulgare L.), grown in field plots in north-western Mexico in the presence and absence of simulated late drought. Leaf water potential (Ψ) and osmotic potential (π), and leaf permeability (LP) to viscous air flow were measured between 1000 and 1600 hours on many dates; leaf turgor potential (p) was calculated. Drought caused associated reductions in Ψ, π and LP. Cultivar effects on these variables were usually significant on given dates, and reasonably consistent between dates and drought intensities in the case of Ψ, but less so for π and LP. There were consistent positive phenotypic correlations between Ψ and LP, and Ψ and anthesis date, and a negative correlation between Ψ and stature in the absence of drought. The relationship of LP to Ψ for different cultivars differed significantly: in particular, tall bread wheats had lower LP than dwarf cultivars at high values of Ψ, whereas at low Ψ they had higher LP than the dwarf cultivars. There was general osmotic adjustment, and a tendency for the relationship of p to Ψ to vary between cultivars. Irrespective of statistical significance, the effects of cultivar were generally small relative to those of drought intensity.
Agronomic studies on Vigna spp. in south-eastern Queensland. I. Phenological response of cultivars to sowing date
Authors: Lawn RJ
Published: November 2004

Phenological development of 16 cultivars from four Vigna species (V. radiata, green gram; V. mungo, black gram; V. angularis, adzuki bean; V. umbellata, rice bean) was studied over a range of 17 weekly sowing dates at Lawes in south-eastern Queensland. Cultivar and sowing date effects on phenology were large. In all cultivars, the rate of development during pre-flowering was associated negatively with mean day length and positively with mean maximum and/or mean minimum temperature. Cultivars differed in sensitivity to both photoperiod and temperature. Genetic lateness of flowering among cultivars was associated positively with increasing sensitivity to day length and negatively with the latitude of cultivar source. In the grams, early-flowering cultivars showed response to maximum temperatures, while the later-flowering lines responded to minimum temperatures. Rate of development in all four species during the reproductive phase was largely independent of cultivar and sowing date, per se, but rather appeared to depend on the day length and temperature regimes prevailing subsequent to the onset of flowering. The reproductive period in all species was shortest for those cultivar x sowing date combinations which commenced flowering in early autumn. Where flowering occurred in midsummer, i.e. for early sowings and for early cultivars, the reproductive period was extended as a consequence of prolonged flowering in response to the longer prevailing day lengths. As the date of flowering was delayed into mid or late autumn, the reproductive phase was extended owing to slower pod maturation rates in response to cooler prevailing temperatures. The implications of these responses on adaptation and agronomic utilization of these species are discussed.
Lysine and methionine supplements in diets for laying pullets
Authors: McDonald MW
Published: November 2004

In two experiments the effects of supplementary methionine (0.10%) and lysine (0.08% in experiment 1 and 0.10% in experiment 2) on the performance of three strains of laying pullets were examined. In both experiments small but significant responses to methionine were observed, in egg weight and daily egg mass in experiment 1 and in daily weight gain in experiment 2. In both experiments large and significant increases in rate of lay and egg weight resulted from addition of lysine. It was concluded that lysine was a major limiting amino acid in the diets used. In the second experiment a high protein (18.1%) diet produced significantly higher peak production, rate of lay and egg weight than a low protein (14.3%) diet. It was concluded that a difference in lysine content of the diets was primarily responsible for the differences. Significant strain x methionine and strain x lysine interactions were observed. Lysine requirements, however, could be predicted in the second experiment by the regression equation: Total lysine required (mg/day) = 0.086 W + 8.71G + 11.17E where body weight (W), daily weight gain (G) and egg mass (E) are expressed in grams. Predicted lysine requirements based on this regression are compared with predictions based on published multiple regression equations.
Mulches, microclimate, topsoil and the establishment of vegetative cover on a dispersible soil
Authors: Reynolds KC , Lang RD
Published: November 2004

Stabilization by vegetation of dispersible subsoil batters which cannot be adequately topsoiled has generally proven unsuccessful. Straw and bitumen mulches were used alone and combined to aid the establishment of pasture grasses and legumes on batters composed of dispersible subsoil, which were covered with either 5 cm or 10 cm of topsoil, or were not topsoiled. The mulches consistently increased plant density, vegetative ground cover, and plant production. However, percentage ground cover at the end of the first season was only 10–26%, unless 10 cm of topsoil was added first. With 10 cm of topsoil, the only treatments to provide sufficient ground cover to control erosion after a year's growth were bitumen–straw and straw. Cover was determined by individual plant growth rather than plant density. Field implications are discussed.
Rickettsia-like and mycoplasma-like organisms associated with two yellows-type diseases of strawberries in Queensland
Authors: Greber RS , Gowanlock DH
Published: November 2004

Two yellows-type diseases occur in Queensland strawberries. Affected plants show purple or bronze pigmentation of older leaves, followed by the production of small chlorotic leaves. Flower production is inhibited, and some affected plants die. Thin-section electron microscopy showed that there were two diseases, one associated with rickettsia-like organisms (RLO) and the other with mycoplasma-like organisms (MLO), both of which were found only in sieve tubes. The MLO disease caused flower abortion but not green petals, and was not transmitted by Orosius argentatus (Evans), the tomato big bud vector. The RLO disease produced more bronze pigmentation and the young leaf chlorosis was interveinal rather than marginal. This organism was sensitive to penicillin, and soil drenches of 1 mg/ml every 5 days for 7 weeks caused complete remission of symptoms. No organisms were seen in thin sections of leaves after treatment. Although these RLO morphologically resembled those associated with rugose leaf curl (RLC) disease of legumes, experiments with the RLC vector Austroagallia torrida Evans indicated that they were probably distinct.
Carcass characteristics of heavyweight crossbred lambs. II.* Carcass composition and partitioning of fat
Authors: Thompson JM , Atkins KD , Gilmour AR
Published: November 2004

Half-carcasses of 108 wether and ewe lambs from six genotypes, slaughtered at 34, 44 and 54 kg liveweight, were dissected into subcutaneous fat, intermuscular fat, muscle, bone and connective tissue. The six genotypes were the progeny of Dorset Horn and Border Leicester rams mated to Merino, Corriedale and Border Leicester x Merino first-cross ewes. As carcass weight increased, the proportion of subcutaneous and intermuscular fat increased (b > 1 ; P < 0.05) and the proportion of muscle and bone decreased (b < 1; P < 0.05). Lambs sired by Border Leicester rams had more subcutaneous fat (12.7%), more intermuscular fat (7.6%) and more bone (5.7%) than lambs sired by Dorset Horn rams at the same carcass weight (P< 0.05). Similarly, lambs sired by Dorset Horn rams had more muscle (7.2%) than lambs sired by Border Leicester rams at the same carcass weight (P < 0.05). Breed of dam had no effect on carcass composition. Wether lambs had a greater proportion of bone (5.7%) than ewe lambs at the same carcass weight (P < 0.05). The breed of sire effect and the lack of a breed of dam effect on carcass composition, in conjunction with estimated mature weights for the breeds, suggest possible differences between sire and dam breeds in the partitioning of fat between the carcass and non-carcass depots.

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*Part I, Aust. J. Agric. Res., 30: 1197 (1979).
Seedling and adult plant resistance to blackleg (Leptosphaeria maculans (Desm.) Ces. et de Not.) in spring rape (Brassica napus L.)
Authors: Cargeeg LA , Thurling N
Published: November 2004

In a glasshouse test with a large number of lines derived by self-pollination of rape plants (Brassica napus L.) randomly selected from each or four spring cultivars, considerable variation in the responses of seedlings to blackleg infection (causal organism Leptosphaeria maculans (Desm.) Ces. et de Not.) was observed between and within cultivars. Although the mean disease scores of lines within each cultivar ranged between the extremes of susceptibility and resistance, a much higher frequency of resistant lines were detected in the cultivar Nosovsky than in Ceska and Zollerngold. The lines used in this initial test provided a basis for developing a susceptible and resistant line from each cultivar, and these were tested together with six other lines previously rated as being resistant in the field, under both glasshouse and field conditions. Responses to seedling infection in four different glasshouse environments showed only three field-selected lines (Wesreo, Mutu and R46) to have adequate seedling resistance. All glasshouse-selected lines were susceptible in these glasshouse tests, and the resistant selections were In all cases slightly more susceptible than the corresponding susceptible selections. In the field test, the field-selected lines as a group were clearly more resistant than any of the glasshouse-selected lines except the Nosovsky resistant selection line. The Ceska and Zollerngold resistant selections, although susceptible in comparison with the field selections, were more resistant than the corresponding susceptible selections. Considerable variation in the mean disease scores of individual plants obtained at maturity was observed within all lines except the two Tower glasshouse selections. The frequency of resistant plants was fairly high in all field-selected lines except 73N22-1 and very low in all glasshouse-selected lines except the Nosovsky resistant selection. Coefficients of correlation between disease scores at maturity in the field and scores of young plants in each of four different glasshouse environments were significant for all but one environment. The highest correlation was observed in the case of the procedure involving a single inoculation 10 days after sowing and growth of seedlings under a daily temperature regime of 25/20�C. The five lines ranked most resistant in this test were also the five most resistant lines in the field.
Seed cobalt in Lupinus angustifolius
Authors: Robson AD , Mead GR
Published: November 2004

The concentration of cobalt in seeds of Lupinus angustifolius varied widely from 6 ng/g to 730 ng/g. High concentrations of cobalt were associated with high concentrations in cotyledons and embryo with much lower concentrations in the seed coat. The effect of the cobalt content of seeds on the response of two cultivars of L. angustifolius to cobalt application was examined in a glasshouse trial. Plants of the Unicrop cultivar grown from seed with a cobalt concentration of 730 ng/g did not respond to cobalt application. By contrast plants grown from seed with a much lower cobalt concentration (10 ng/g) responded markedly. In the Uniharvest cultivar increasing the seed cobalt concentration from 6 to 27 ng/g by cobalt application to the seed crop as a soil dressing did not reduce the extent of a very marked response to cobalt application.
Response of seedlings of three citrus-rootstock cultivars to salinity
Authors: Mobayen RG , Milthorpe FL
Published: November 2004

Responses of seedlings of Trifoliata, Cleopatra mandarin and the Iranian mandarm Bakraie to concentrations of sodium ions over the range 2.6-152.6 mol m-3 were measured in sand culture. The major differences were in rates of leaf senescence; these and leaf expansion rates indicated that the cultivars increased in tolerance in the order: Trifoliata < Cleopatra < Bakraie. Although growth and net assimilation rates were related to the sodium ion concentration over the entire range explored, differences between cultivars could not be distinguished. Sodium concentrations in leaves were linearly related to concentrations in the external solution and increased with time; they, together with phosphorus, calcium and magnesium but not potassium, were higher in Bakraie than in Cleopatra. It is suggested that leaf abscission and leaf expansion rates provide useful indices for screening cultivar seedlings for salinity tolerance; leaf analyses may be less satisfactory.
Effects of duration of grazed lucerne on long-term yields and nitrogen uptake of subsequent wheat
Authors: Holford ICR
Published: November 2004

The long-term effects of varying durations of lucerne Icy, extended fallowing, and continuous wheat growing on the growth, yield, and nitrogen uptake of subsequent wheat crops were determined on two contrasting soils in northern New South Wales. Durations of lucerne ley were 3+, 2+ and 1+ years on a black earth and 5+, 3+ and 1+ years on a red-brown earth. With the exception of the first wheat crop, wheat production for several years following lucerne exceeded that following extended fallow or continuous wheat growing, whether measured as vegetative yield at anthesis, grain yield, nitrogen uptake, or grain protein. The beneficial effects of lucerne on vegetative yield, nitrogen uptake, and grain protein reached a maximum in the second crop after lucerne, and the effects of 2+ or more years of lucerne remained significant for the next five crops on the black earth and the next two crops on the red-brown earth. Grain yields fluctuated widely with season, the magnitude of the lucerne effect being much more dependent on rainfall, but the duration of the effect was similar for grain and vegetative parameters. The shorter duration of the lucerne effect on the red-brown earth appeared to be associated with its more freely draining nature and consequent loss of accumulated nitrogen. The optimum duration of lucerne for maintaining nitrogen-dependent wheat yields was 3+ years on both soil types. It eliminated the need for nitrogen fertilizer for the following five wheat crops on the black earth and three wheat crops on the red-brown earth. Extended fallowing also had a beneficial effect on all parameters, particularly in the first and second crops after the fallow ended. Its effect was generally significantly smaller than the lucerne effect except in the first crop after fallow.
The effect of white clover mosaic virus on nodulation of white clover (Trifolium repens L. cv. Ladino)
Authors: Guy P , Gibbs A , Harrower K
Published: November 2004

White clover mosaic virus infection of Ladino clover seedlings resulted in decreased plant weight and a 71 % decrease in the number of nodules per plant without the decrease in nodule size which is usually observed when legumes are virus-infected. Nodule numbers decreased both on plants nodulated with an effective strain and on those with an ineffective strain of Rhizobium.
Classification of wheat areas and prediction of yields in north-western New South Wales by repetitive Landsat data
Authors: Dawbin KW , Evans JC , Duggin MJ , Leggett EK
Published: November 2004

Radiance data collected by Landsat were used to derive wheat production forecasts. Radiance data at three stages of wheat growth in 1976 for the Tamworth region of the New South Wales wheat-belt were analysed by multivariate statistical methods to discriminate between paddocks that had been sown with wheat and those that had not, and to relate radiance to wheat yield. A discriminant function was derived that classified the paddocks, and a regression equation was derived to predict yields of wheat paddocks. Although data were not available for the green vegetative phases of growth, intrinsic testing of classification and yield prediction indicated high accuracy, although extrinsic testing indicated that they were less accurate. Assuming that data are available in future seasons at the vegetative stages, Landsat has a great potential for improving wheat forecasts in Australia.
The effect of irrigation and nitrogen on the yield and composition of peppermint oil (Mentha piperita L.)
Authors: Clark RJ , Menary RC
Published: November 2004

Peppermint was harvested twice during the growing season. Harvest 1 was conducted on 16 February 1979, and the subsequent regrowth was harvested on 25 April 1979. High peppermint oil yields were associated with high rates of nitrogen fertilizer (100, 200 and 300 kg nitrogen/ha), and high levels of irrigation (50 mm per week) throughout the last half of the growing season. The composition of oil extracted from herb at the commercial harvest date was not significantly affected by either nitrogen or irrigation treatments. The oil yield from regrowth within the same growing season was significantly affected by irrigation and nitrogen treatments applied prior to the first harvest. When 300 kg nitrogen/ha and 50 mm of irrigation weekly (during the last half of the growing season) were applied, the oil yields from regrowth approached the commercial yield obtained from one harvest. Oil from regrowth contained high levels of menthol, menthyl acetate, menthofuran and limonene, and low levels of menthone and cineole. The possibility of obtaining two commercial harvests of peppermint per season, under southern Tasmanian conditions, is discussed
Associated growth of wheat and annual ryegrass. 2. Effect of varying the time of ryegrass germination in stands of wheat
Authors: Rerkasem K , Stern WR , Goodchild NA
Published: November 2004

In a field experiment, wheat cv. Gamenya and annual ryegrass cv. Wimmera were sown in four proportions, 80W : 20R, 60W : 40R, 40W : 60R, 20W : 80R, at a total density of 300 plants m-2 and in which a high level of nitrogen fertilizer application was maintained. Ryegrass was sown 17 days before, simultaneously with, and 17 days after wheat. At the simultaneous sowing there were also pure cultures of wheat and ryegrass; pure culture data for ryegrass corresponding to all the germination treatments were obtained in a supplementary experiment. All treatments were harvested on five occasions. Observations were made on tiller numbers, yield of dry matter, seed numbers and the yield components of wheat. There were marked effects of early and simultaneous sowing of ryegrass and of proportions; the results also showed interactions between the later sowings and proportions. In all treatments wheat tiller numbers rose to a maximum and declined to about half after about 100 days. A similar rise and fall was observed in the early and simultaneous germination of ryegrass, but not in the late one. In ryegrass, tiller numbers were much greater than in wheat, and the rate of decline was not as marked. In the late germination treatment ryegrass development and growth were seriously depressed. With respect to wheat, seed yield and ear numbers per unit area in the early and simultaneous sowings were less, while ears and grains per plant were greater in the presence of ryegrass than in pure culture. In ryegrass, seed production was highest in the early and least in the late treatments and was depressed as the proportion of wheat was increased; even in the treatment with the lowest proportion of ryegrass, seed numbers of ryegrass remained high. Relative reproductive rates showed a consistent pattern with time of sowing and with proportion, and the results suggest that control of ryegrass seed numbers cannot be achieved by manipulating planting treatments but requires positive intervention. Relative crowding coefficients (k) calculated from the data suggest that wheat was the stronger competitor. The results are discussed in terms of the competitive effects between species and the likelihood that wheat has the greater competitive ability. As in the previous study, it was noted that effects of competition were discernible at 28 days.
Analysis of the regrowth of a tropical grass/legume sward subjected to different frequencies and intensities of defoliation
Authors: Ludlow MM , Charles-Edwards DA
Published: November 2004

Dry weight, leaf area, light interception and canopy photosynthesis were measured during 3- or 5-week regrowth periods of Setaria anceps/Desmodium intortum swards cut to 7.5 or 15 cm. Dry matter production during the experiment and over the growing season increased with cutting height and with interval between defoliations, but the proportion of grass to legume was unaffected. These effects of defoliation on dry matter production were similar to those estimated for integrated canopy photosynthesis from measured light interception and calculated leaf photosynthetic characteristics. Height and frequency of defoliation had no effect on canopy extinction coefficient for light, nor on the leaf photosynthetic characteristics, except for the first 1-2 weeks after defoliation when leaf photosynthetic rates appeared to be depressed. The main effects of height and frequency of defoliation on dry matter production were through their effects on leaf area index and light interception.
Water use, growth and yield of wheat in a subtropical environment
Authors: Angus JF , Nix HA , Russell JS , Kruizinga JE
Published: November 2004

Wheat crops in southern Queensland grown on two different clay soils were studied in terms of growth, development, water economy, and uptake of nitrogen and phosphorus in a season when growing season rainfall was only 50 mm. No significant grain yield response to either nitrogen or phosphorus was detected, although growth response in the vegetative phase was apparent. Mean grain yields on the two soils were 254 and 277 g m-2. These are underestimates of yield potential because of losses due to a mouse plague. Mean yield inside metal mouse exclosures was 303 g m-2. On the higher-yielding site the water use determined from augered soil samples was 192 mm, comprising 50 mm of rain during the 139 days of crop growth and 142 mm of soil water conserved during the preceding summer. The pattern of water extraction was sequential removal of the stored water, starting from the soil surface and extending to a depth below 90 cm. Soil water potential after flowering reached well below - 15 bars. The water use efficiency for grain production was 1.58 g m-2 mm-1 of evapotranspiration, which is higher than most other reports for wheat crops found in the literature. A partial explanation for this high value is that most of the soil water (est. 86%) was transpired by the crop with only a minor proportion (14 %) lost by bare soil evaporation. In addition, the crop appeared to become progressively more adapted to water stress from early in the life cycle, and this stress resulted in slow extraction of subsoil water held at low potentials and therefore in conservation of soil water until the grain-filling phase. The results are discussed by comparing them with those of a crop grown mostly on current rainfall.
Genetic control of resistance to Kabatiella caulivora in Trifolium subterraneum subspecies yanninicum I. Diallel analysis of variation in disease development parameters
Authors: Beale PE , Thurling N
Published: November 2004

A l0 x 10 complete diallel cross of Trifolium subterraneum subspecies yanninicum genotypes was evaluated for resistance to Kabatiella cauliuoua as F2 swards. Analysis of variance of the diallel cross data indicated that variation in 10 October disease score, total disease development (TDD), rate of disease development (Rate) and time to 50% of maximum disease rating (Delay) were heritable. Coefficients of regression of Wr on Vr were significantly greater than zero but not significantly different from a value of 1 for all four disease parameters. Although this evidence is not conclusive, it does suggest that gene interactions are relatively unimportant. Most non-additive gene action could be attributed to dominance effects and, in terms of both 10 October disease score and total disease development (TDD), a high proportion of alleles conferring resistance were dominant. No clear relationship between phenotype and relative proportions of dominant and recessive alleles was evident for either Rate or Delay. Estimates of dominance variance components were, with the exception of Delay, substantially greater than the additive genetic component. Values of F were positive for all parameters and, except for Delay, values of v(H1/D) were greater than 1, which indicated that dominant alleles are more frequent than recessive alleles among the parents and that dominance is complete at those loci exhibiting dominance. Heritabilities (broad and narrow sense) were substantially greater for TDD and 10 October disease score than for Rate and Delay. The implications of these results are discussed in relation to the development of efficient breeding strategies.
Population growth of Brevipalpus lewisi McGregor (Acarina: Tenuipalpidae) on grapevines
Authors: Buchanan GA , Bengston M , Exley EM
Published: November 2004

In the Mildura district of Victoria, Brevipalpus lewisi McGregor is responsible for 'bunch mite' symptoms on grapevines. Age-specific life and fecundity tables, compiled in the laboratory, showed that B. lewisi is capable of positive population growth over a range of temperatures at relative humidity levels commonly encountered in the field. The maximum value of rm obtained in the laboratory was 0.04/day, at 28�C and 35 % relative humidity. A field study of the seasonal abundance and intra-vine distribution of B. lewisi showed that populations increased about 60-fold during a season. The rate of population increase during summer was similar to laboratory estimates of population growth potential. Although the mites were present solely at the base of canes early in the season, later all green parts of the plant became infested. Predation and loss associated with leaf fall reduced the numbers of mites overwintering. Populations were further reduced by removal of mites during pruning.
A synoptic approach for crop loss assessment used to study wheat. V. Crop growth and yield
Authors: Stynes BA , Veitch LG , Wallace HR
Published: November 2004

As part of a general study of factors that affect wheat crops on Yorke Peninsula, S.A., growing and mature wheat plants were described in terms of morphological parameters and concentrations of elements in the tops. The measurements were taken 3 and 8 weeks after emergence of the crops, at anthesis and at maturity. The analyses of the morphological variables showed consistent patterns of variation in that, firstly, plants varied widely in their overall size, and secondly, that plants differed in the relative sizes of their tops and roots except at 8 weeks and at anthesis when the seminal root systems did not relate to the remainder of the plant. These two patterns of variation accounted for major portions of the variability, on average 88 % at 3 weeks, 95 % at 8 weeks and 88 % at anthesis, when the seminal root system was separated off in the latter two groups. The seminal root system and the element concentrations at 8 weeks and at anthesis were far less coherent sets of data. The results of these analyses provide the basis of the decisions concerning the information to go into the subsequent regression analyses for growth and yield of wheat.
Corrigendum - A synoptic approach for crop loss assessment used to study wheat. V. Crop growth and yield
Authors: Stynes BA , Veitch LG , Wallace HR
Published: November 2004

As part of a general study of factors that affect wheat crops on Yorke Peninsula, S.A., growing and mature wheat plants were described in terms of morphological parameters and concentrations of elements in the tops. The measurements were taken 3 and 8 weeks after emergence of the crops, at anthesis and at maturity. The analyses of the morphological variables showed consistent patterns of variation in that, firstly, plants varied widely in their overall size, and secondly, that plants differed in the relative sizes of their tops and roots except at 8 weeks and at anthesis when the seminal root systems did not relate to the remainder of the plant. These two patterns of variation accounted for major portions of the variability, on average 88 % at 3 weeks, 95 % at 8 weeks and 88 % at anthesis, when the seminal root system was separated off in the latter two groups. The seminal root system and the element concentrations at 8 weeks and at anthesis were far less coherent sets of data. The results of these analyses provide the basis of the decisions concerning the information to go into the subsequent regression analyses for growth and yield of wheat.
Determination of the location and number of test environments for a wheat cultivar evaluation program
Authors: Brennan PS , Byth DE , Drake DW , Lacy IHDe , Butler DG
Published: November 2004

Pattern analysis procedures were used to delineate groups of test environments which elicited similar relative yield performance patterns in sets of wheat cultivars. In each of four years there was a tendency for environments from particular regions to be grouped. However, the composition of these groups varied across years. The relative values for the variance component estimates from data for two subsequent years tended to support the conclusions suggested from the pattern analysis. A phased yield evaluation system is suggested. It is derived from a consideration of the lack of consistency of similarity of cultivar response patterns across regions and the need to evaluate large populations in early generations. This system would tend to maximize discrimination among cultivars on the form of their cultivar x environment response patterns.
Copper nutrition of subterranean clover (Trifolium subterraneum L. cv. Seaton Park). II. Effects of copper supply on distribution of copper and the diagnosis of copper deficiency by plant analysis
Authors: Reuter DJ , Robson AD , Loneragan JF , Tranthim-Fryer DJ
Published: November 2004

The effect of copper supply upon the distribution of copper within Seaton Park subterranean clover was examined from early vegetative growth to plant maturity in one glasshouse experiment, and in a second experiment was assessed at early flowering. The copper content of old leaf blades of copper-adequate plants decreased progressively with senescence of the blades. Copper deficiency delayed senescence and export of copper from the older blades so that both the relative and net changes were substantially smaller than for blades of copper-adequate plants. However, copper concentrations in senesced old leaf blades still reflected copper supply. At full senescence these blades contained appreciable quantities and concentrations of copper which contrasted with the low levels found in senesced leaves of wheat and peanuts in previous studies. Copper concentration in whole plant tops was not satisfactory for diagnosing copper deficiency, since the critical concentration decreased with plant age and during late vegetative development 'Piper-Steenbjerg' curvature developed in the relationship between copper concentration and yield. It is possible that the curvature resulted partly from unusually high concentrations of copper in the old petioles of severely deficient plants. Analysis of copper in young leaf blades provided a sensitive means of diagnosing copper deficiency in subterranean clover. The estimated critical concentration for these blades (3 �g/g for maximum growth) did not change with plant age, at least until early flowering. In early growth, the copper concentration of young leaf blades may be used to forecast impending copper deficiency.
The distribution in soil and plant of 35S from sheep excreta
Authors: Kennedy AP , Till AR
Published: November 2004

The utilization of 35S from labelled sheep excreta, applied to pasture swards, was studied in two experiments lasting 384 and 217 days respectively. The possible losses due to volatilization were examined in another experiment. The percentages of sulfur in plant material that were derived from urine and faeces were as high as 94% and 57% respectively. Above-ground plant material took up to 20% of the radioactivity applied in urine and 16 % of that applied in faeces. It was calculated that the excreta from 20 sheep ha-' could provide 20% of the sulfur requirement of the above-ground plant material. The uptake by plants of labelled sulfur from excreta occurred in the surface soil, not from the 'available' soil sulfur present in the 0-5 cm depth. The recovery of radioactivity dropped rapidly, especially when 35S was applied in urine. After 384 days, less than 40 % of the radioactivity applied could be accounted for. The loss of radioactivity from the application site was not due to volatilization, but to a combination of lateral spread and leaching.
Some factors which affect the liveweight change and wool growth of adult Corriedale wethers grazed at various stocking rates on perennial pasture in southern Victoria.
Authors: Birrell HA
Published: November 2004

Monthly observations were taken on a number of animal and pasture characteristics during a 24-year study with adult Corriedale wethers which were grazed at 10, 15, 20 and 25 sheep ha-1. The seasonal patterns in all the observed parameters varied with the stocking rate. The more notable were the fluctuations in digestible organic matter intake (DOMI) which increased with stocking rate in summer (10 and 25 sheep ha-1 having 426 and 818 g DOMI d-1 respectively) and decreased in winter (655 and 448 g DOMI d-1). Both liveweight and wool growth rate (WGR) declined during autumn and increased in the spring at the two high stocking rates but not at the two low stocking rates. The herbage present and its relative growth rate both influenced the amount of herbage voluntarily eaten when the pasture was green. When the dry matter of herbage was < 1.5 t ha-1, the amount of herbage eaten increased as the yield and relative growth rates > 0.05 g g-1 d-1 increased. Sixty-two per cent of the variance in DOMI was accounted for. An exponential function fitted the overall data when relative growth rates were <0.05 g g-1 d-1. DOMI asymptoted at 740 g d-1 when herbage yields exceeded 2.0 t ha-1 (R2 = 0.70). Liveweight loss was very rapid in autumn at high stocking rates despite a high DOMI (c. 650g d-1). This was found, by using multiple regression analysis, to be associated with shearing stress, poor quality feed and long grazing times. In spring, on better quality feed, a long grazing time was associated with an enhanced liveweight response. A multiple regression analysis accounted for 73 % of the variance in WGR. The expression suggested that WGR increased and had a slightly curvilinear relationship with DOMI, was positively related to digestibility and negatively related to the daily time spent grazing. Wool growth slowed concurrently with liveweight losses, the magnitude of the decrease depending upon DOMI.
The voluntary intake, digestibility and retention time by cattle and sheep of stem and leaf fractions of a tropical legume (Lablab purpureus)
Authors: Hendricksen RE , Poppi DP , Minson DJ
Published: November 2004

Hay made from the tropical forage legume Lablab purpureus was chopped and separated into leaf and stem fractions by using a gravity separator. Each diet was fed to four cattle and six sheep fitted with rumen fistulae to measure the digestibilities of the dry matter (DM), organic matter (OM) and neutral detergent fibre (NDF), and the retention times of DM, OM and NDF in the rumeno-reticulum (rumen) and the rumen volume. Mean voluntary intake of the DM in the leaf fraction was 79 % higher by cattle and 61 % higher by sheep than the stem fraction, and this appeared to be associated with the shorter time it was retained in the rumen. Both leaf and stem DM were digested to a similar extent by cattle. Sheep digested the leaf fraction to the same extent as cattle. However, the DM digestibility of the stem eaten by sheep was 0,061 lower than that of the leaf fraction (P < 0.05). Cattle retained the DM, OM and NDF in all diets for longer periods in the rumen than did sheep. This difference led to a 48% higher voluntary intake (g(kg body d-1) by sheep. The proportion of large particles that disappeared within the rumen was lower (P < 0.01) for cattle (0.968) than for sheep (0.994). The large particles of the leaf and stem fraction were retained for the same mean time by sheep (5.7 and 5.6 h), which was shorter (P < 0.01) than the corresponding times for cattle (13.8 and 21.6 h). The rate of disappearance of large particles in the rumen appeared to be only a minor factor causing the longer retention time of stem fractions in the rumen. The concentrations of volatile fatty acids and ammonia in the rumen were higher for leaf than stem fractions with no differences between cattle and sheep. The proportion of acetic acid for cattle (0.75) was higher (P < 0.05) than that for sheep (0.69) while the corresponding propionic acid proportions were lower (P < 0.01) in cattle (0.14) compared with sheep (0.19). These differences were associated with a higher passage rate constant for water flowing from the rumen and a higher digestion rate constant in sheep. It was concluded that both cattle and sheep ate more of the leaf than the stem fraction of the legume Lablab purpureus and that the higher intake of leaf was associated with the shorter time that it was retained in the rumen and was not due to differences in digestibility. Cattle had a smaller relative voluntary intake of legume than sheep, a difference that was associated with the longer time that digesta was retained in the rumen.
Cultivar differences in nitrogen translocation in wheat
Authors: Halloran GM
Published: November 2004

The translocation efficiency of plant nitrogen to the grain was examined in six lines of bread wheat (Tvtticum aestivum L.) under four levels of soil nitrogen (48, 556, 810 and 1065 ppm). Translocation efficiency, both within the primary tiller and within the whole plant, was significantly different between cultivars; the within-tiller value was higher than the corresponding whole-plant value for each cultivar. There were marked differences in trends in translocation efficiency between certain cultivars as the soil nitrogen availability increased. A reasonably close positive correlation (r = + 0.74, P < 0.01) existed between the within-tiller and whole-plant values for translocation efficiency over the four nitrogen levels. It is suggested that wheat breeders use within-main-tiller translocation efficiency of nitrogen, in parental or crossbred selection to increase grain nitrogen yield in wheat. Because nitrogen translocation efficiency varied with soil nitrogen level, such selection would need to be conducted under soil nitrogen levels appropriate to field conditions. The relationship between total plant dry matter and total grain nitrogen across cultivars and nitrogen levels was not close (r = +0.41, P < 0.01), which suggests that a good potential exists for selecting for increased total grain nitrogen levels in wheat at existing levels of total dry matter production. The implications of these findings for further genetic and biochemical study of nitrogen metabolism in wheat, are outlined.
Ontogeny of spring wheat and barley infected with cereal cyst nematode (Heterodera avenae)
Authors: O'Brien PC , Fisher JM
Published: November 2004

A study of the effects of density (0, 150,300 or 450 juveniles) and time of inoculation (0, 7 or 14 days after sowing) with Heterodeva avenae on the growth of single plants of the susceptible wheat, Halberd, showed that only inoculation at sowing consistently affected growth and there was little difference between densities. Development of seminal, seminal laterals and nodal roots was delayed and the length of laminae of each of the first three leaves was shortened. Regular inoculations, until 25 days after sowing, of susceptible Halberd and resistant AUS 10894 wheat and susceptible Clipper and resistant Morocco barley resulted in reduced leaf area, delayed appearance of the earlier leaves and reduced numbers of spikelets per ear on Halberd, AUS 10894 and Clipper, but not Morocco. Following inoculation Halberd and Clipper had fewer leaves, and their time of ear emergence was later. These effects of H. avenae were attributed to induced nutrient and moisture stresses affecting cell division and development of the shoot apex. The maximum yield potential of cereals was therefore reduced.
A comparison of the root growth, root morphology and root response to defoliation of Aristida ramosa R.Br. and Danthonia linkii Kunth
Authors: Harradine AR , Whalley RDB
Published: November 2004

Establishing plants of Aristida ramosa R.Br. and Danthonia linkii Kunth grown in root observation tubes differed markedly in their root growth and root morphology. Radicle extension of A. ramosa proceeded far more rapidly than that of D. linkii, and root branching occurred earlier and to a much greater extent in D. linkii. From 2 months after germination onwards, the maximum rooting depth of A. vamosa was greater than that of D. linkii, although total root dry weights for the two species were not significantly different. At 25 weeks from germination, 48 % of the root dry weight of D. linkii was present in the 0-10 cm level of the soil profile, while the corresponding figure for A. ramosa was 33 %. Root weight and rooting depth of both species were severely reduced by foliage clipping at weekly or monthly intervals, with roots being more sensitive to clipping than shoots. Clipping led to a concentration of root mass in the 0-10 cm level. The rapidly establishing seedling root system of A. vamosa would give it a competitive advantage over D. linkii in the environment of the north-western slopes of New South Wales. The results of the clipping trial suggest that grazing management may be manipulated to alter the relative abundance of A. ramosa and D. linkii in native pastures.
Infectivity and effectiveness of five endomycorrhizal fungi: competition with indigenous fungi in field soils
Authors: Abbott LK , Robson AD
Published: November 2004

Five species of endomycorrhizal fungi differed in their ability to stimulate phosphorus uptake and growth of subterranean clover when inoculated into two untreated field soils which were phosphate deficient. Each soil contained a different indigenous endomycorrhizal fungus. The amount of roots converted to mycorrhizas by each indigenous and inoculant fungus was estimated by using differences in the morphology of the infection within the roots and a line-intercept method. Effectiveness of the inoculant fungi in increasing plant growth was related to the infectivity of the fungi from the inocula used. The fungi indigenous to the two soils used did not appear to affect the extent to which mycorrhizas were formed by any of the inoculant fungi.
Establishment of buffel grass, green panic and Siratro from seed broadcast into a speargrass pasture in Southern Queensland
Authors: Cook SJ , Dolby GR
Published: November 2004

The establishment and survival of seedlings from pasture seed oversown into a native speargrass (Hetevopogon contortus) pasture were studied in southern Queensland. Lime pelleted and unpelleted seed of buffel grass (Cenchrus ciliaris), green panic (Panicum maximum var, trichoglume) and Siratro (Macroptilium atvopuvpureum) were either sown into a cultivated seedbed or broadcast into native pasture pretreated as follows: untreated control; mown to 3 cm; or killed with herbicide. Buffel grass was sown both as fascicles and as caryopses. Establishment was similar in all oversown seedbeds with seedling numbers accounting for 37 % of the germinable seed sown, compared to 49% in the cultivated seedbed. Pelleting increased establishment where competition was present, the effect being greatest for Siratro and least for buffel grass fascicles. Establishment of buffel grass caryopses was markedly inferior to that of fascicles. Seedling survival rather than seed germination was the main factor influencing the success of the pasture sowing. Less than 1 % of the grass seedlings survived in the mown and control plots, but 38 % survived where competition was controlled by herbicides. Siratro survived equally as well as the grasses in the herbicide-treated plots, but survived markedly better when in competition with native grasses. Surface broadcasting into native pasture is therefore considered a satisfactory, though risky method of establishment for legumes such as Siratro, but not for grasses, unless competition is controlled.