bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation between and within species of rapeseed (Brassica campestris and B. napus) in response to drought stress III. Physiological and physicochemical characters
Authors: Richards RA
Published: November 2004

Genotypic variation in physiological and physicochemical parameters associated with drought resistance was observed between cultivars in Brassica napus and B. campestris. Significant variation in proline accumulation, chlorophyll stability, germination rate and percentage, relative turgidity, growth rates and water use efficiency were found in plants grown under simulated drought conditions in a glasshouse. No variation was detected between cultivars for leaf diffusive resistance or heat tolerance. A yield index for each cultivar was derived from yield performances in nine different field environments. Chlorophyll stability and proline accumulation in leaf tissue and germination percentage in solution equivalent to –17.5 bars osmotic potential was clearly related to this yield index in B. napus and to a lesser extent in B. campestris. The winter cultivars of B. napus also possessed drought resistance characteristics, and they may be a valuable resource for the development of cultivars for droughted environments. Parameters were measured in a glasshouse, prior to anthesis, and therefore offer potential as ancillary selection criteria for drought resistance in oilseed rape growing in Western Australia.
The effect of fallowing on the yield of wheat. I. The effect on soil water storage and nitrate supply
Authors: French RJ
Published: November 2004

The effect of fallowing before a wheat crop was studied in South Australia in an environment with suboptimal rainfall in the growing season. A 9–10 month pre-sowing fallow increased mean water storage (0–120 cm depth) at sowing by 28 mm, compared with a non-fallow soil preparation (2 month period of cultivation). Variation in additional storage ranged from nil to 125 mm. These amounts depended on soil type and season: in coarse-textured soils, fallowing conserved little additional water, but in fine-textured soils much additional water could be stored. Storage was not related to the summer rainfall (November-March) before sowing but was related to rainfall during July and August in the previous winter—just before or at the start of the fallow period. A combination of these two factors, fine-textured soil and good July–August rainfall, gave considerable storage. Fallowing also increased the nitrate nitrogen content in the surface 60 cm at sowing; the mean additional nitrogen amounted to 19 kg/ha in the coarse-textured soils and 30 kg/ha in the fine-textured soils. The largest increases due to fallowing were recorded in soils following medic leys and with ample rains on the fallow in spring. Comparison is made between these findings and those obtained with fallowing in other parts of Australia.
The effect of fallowing on the yield of wheat. II. The effect on grain yield
Authors: French RJ
Published: November 2004

The effect of fallowing on wheat yields is reported for a South Australian environment where 62% of the variation in yield is ascribed to water supply and where water use efficiency in grain production ranges from 1 to 11 kg/ha/mm. The mean yield response from a fallow (initial tillage 9 months before sowing) compared with a non-fallow (tillage 2 months before sowing) in 28 seasonal, site and fertility situations was 335 kg/ha and the maximum 875 kg/ha. Each additional millimetre of water stored through fallowing gave on average 8 kg grain per ha. Only fine-textured soils stored considerable water through fallowing. The additional nitrate in fallow gave yield responses when the non-fallow soil contained less than 70 kg nitrate nitrogen per ha, but only when water use by the crop exceeded 230 mm. The results are related to responses to fallowing obtained in other wheat-growing districts in Australia.
Distribution of physiologically inactive zinc in maize growing on a black earth soil
Authors: Leece DR
Published: November 2004

Physiologically inactive zinc occurred in the roots and leaves but not the stems of maize seedlings when grown for 30 days in pots on a black earth soil. Expanded leaves had very high zinc concentrations (60–200 µg/g), yet expressed symptoms of zinc deficiency, which indicated that most of the zinc in these tissues was inactive. By contrast, stem tissue, which was 36% leaf sheaths and 64% new leaves and meristems, contained low levels of zinc (17 µg/g) when unfertilized and normal levels (27 µg/g) when fertilized with 10 µg/g zinc. Stem growth indicated that this zinc was active. Fertilizer phosphorus (200 µg/g) induced phosphorus/zinc imbalance and inactivated zinc further in roots, certain expanded leaves, and the stem. Zinc and phosphorus deficiencies and zinc inactivation were prevented by fertilization with both zinc (10 µg/g) and phosphorus (200 µg/g). This system is proposed as a model for the study of chemical and biochemical forms of active and inactive zinc in maize.
Apical chlorosis and leaf spot of Tagetes spp. caused by Pseudomonas tagetis Hellmers
Authors: Trimboli D , Fahy PC , Baker KF
Published: November 2004

An undescribed apical chlorosis caused severe losses in seedlings of Tagetes erecta and T. patula types in Sydney, Brisbane and Melbourne in 1976. Bacterial leaf spots without chlorotic haloes invariably accompanied the disease. The same bacterium was isolated from leaf lesions and chlorotic tissue and produced leaf spots and chlorosis on marigold, zinnia and sunflower with spray inoculation. Leaf spots did not develop on T. signata. Apical chlorosis developed on a diverse range of plants following wound inoculation. The pathogen was shown to be seed-borne. The pathogen was identified as Pseudomonas tagetis, cultural and biochemical characteristics described, and a neotype culture proposed. An exotoxin was produced in vitro which caused apical chlorosis in Zinnia elegans and T. patula.
The influence of ornithine cycle enzyme activity on the plasma urea concentration in sheep
Authors: Thornton RF , Re VM
Published: November 2004

The influence of plane of nutrition and protein content of the diet on the in vitro hepatic activity of the rate-limiting enzyme of the ornithine cycle, arginine synthetase, and the relationship between arginine synthetase activity and plasma urea concentration were studied in lambs and mature sheep. Arginine synthetase activity was positively related to the protein content of the diet, and was reduced when food and thus protein intake was restricted. These findings indicated that in sheep arginine synthetase activity was influenced by the daily protein intake. The plasma urea concentration was positively related to arginine synthetase activity irrespective of the base used to express enzyme activity. There were differences between experiments in the regression equations describing the relationships between plasma urea concentration and arginine synthetase activity, which suggest that the relationships may not have broad application. The implications of these findings are discussed in relation to the control of plasma urea concentration in sheep.
Effectiveness of intravenous and abomasal doses of mimosine for defleecing sheep and effects on subsequent wool growth
Authors: Reis PJ
Published: November 2004

Four Merino sheep were given intravenous infusions of mimosine for 2 days at a rate of 110–120 mg/kg/day. Wool fibre growth stopped by about 1 day after the start of the infusions, and the sheep were subsequently manually defleeced. It was estimated that, on average, fibre growth stopped for about 12 days. Wool growth rates were above the pre-infusion rates in the early regrowth (3–5 weeks after dosing), and the mean fibre diameter was still about 2 µm above pre-infusion values at 11 weeks after dosing. Groups of Merino sheep were given intravenous infusions of mimosine for 2 days at rates ranging over 40–320 mg/kg/day. The minimal rate of infusion required to produce consistent defleecing was 80 mg/kg/day; infusions at a rate of 60 mg/kg/day were sometimes effective for defleecing, but at 40 mg/kg/day produced no discernible effects on the strength of wool fibres. No adverse effects were observed at a mimosine infusion rate of 80 mg/kg/day, but one out of four sheep died when dosed at a rate of 160 mg/kg/day, and higher rates (240 and 320 mg/kg/day) were lethal. The concentration of mimosine in plasma was related to the rate of infusion of mimosine. Consistent defleecing was associated with a concentration of mimosine in plasma approaching 100 µmoles/l; lethal doses resulted in plasma mimosine concentrations above 300 µmoles/l. Abomasal infusions of mimosine at a rate of 80 mg/kg/day were equivalent to intravenous infusions. Single injections of mimosine into the abomasum did not influence the strength of wool fibres; pIasma concentrations foIlowing injections indicated rapid absorption of mimosine and rapid removal from the body.
The influence of polypeepers and feather cover on starvation heat production in the laying hen
Authors: Johnson RJ , Cumming RB , Farrell DJ
Published: November 2004

Starvation heat production (SHP) of three groups, each of four crossbred hens previously held in multiple bird cages, was measured in respiration chambers at 8, 20 and 32°C, following a period of acclimation of 6 days. Group 1 hens, with polypeepers, had an average feather cover after 15 months of lay. The two other groups, without polypeepers, had either a slightly above-average (group 2) or average (group 3) feather cover after 15 months of lay. Polypeepers per se had no influence on SHP at any of the temperatures studied. The poorly feathered hens in group 3 had, on average, a 17% higher SHP at 8 and 20°C than those in group 2. Polypeepers would therefore indirectly reduce food requirement in this temperature range.
Effect of partial delignification on the in vitro digestibility of cell wall polysaccharides in Digitaria decumbens (pangola grass)
Authors: Ford CW
Published: November 2004

Leaf and stem fractions of Digitaria decumbens (pangola grass) cut at two stages of regrowth (47 and 89 days), were extracted with ether, ethanol and water (100°C) before being partially delignified with sodium chlorite in acetic acid. Delignification reduced the lignin concentrations by 52 and 72% in the 47-day-old leaf and stem, and by 69 and 87% in the 87-day-old leaf and stem. In vitro dry matter digestibility was correspondingly increased, by 17–20% (47-day material) and 28–31% (89-day material). Hemicelluloses were digested to a greater degree than cellulose in the delignified material. The reverse was found in the material prior to delignification. In the hemicelluloses arabinose was always digested to a greater extent than xylose. Polysaccharides from delignified 89-day regrowth leaf and stem tissue were still digested to a lesser extent than those from the 47-day regrowth. Maximum digestibilities estimated for zero lignin content were 96.6, 88.1 and 82.8% for young leaf, young stem-told leaf, and old stem respectively. Thus, while lignin has been shown to be the major factor limiting total digestion of the plant material, other minor factors could not be excluded, particularly in the older tissues.
Response to partial selection on clean fleece weight in South Australian strong-wool Merino sheep. IV.* Genetic parameters
Authors: Hancock TW , Mayo O , Brady RE
Published: November 2004

Estimates of heritabilities and of genetic, phenotypic and environmental correlations are presented for the South Australian strong-wool Merino sheep. Separate estimates are calculated for the male and female progeny for each of the two flocks selected by different methods in the Roseworthy clean fleece weight selection experiment. Inspection of these estimates demonstrates that differences have ' arisen between the two flocks.

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* Part III, Aust. J. Biol. Sci., 31: 667 (1978).
Protein and fat composition and some manufacturing properties of milk from dairy cows fed on hay and concentrate in various ratios
Authors: Bartsch BD , Graham ERB , McLean DM
Published: November 2004

Seven Friesian cows in each of four treatment groups consumed hay and a rolled barley concentrate in the ratios of 100:0, 80:20, 60:40 and 37:63 respectively. Cows fed on only hay consumed less dry matter than cows fed on barley and hay and produced less milk, fat, solids not fat, protein and casein. Solids not fat, protein, casein, β-lactoglobulin and α-lactalbumin percentages were generally higher when the ration contained a higher proportion of concentrate, although milk fat percentages were similar for all treatments. Casein, β-lactoglobulin and α-lactalbumin concentrations relative to the concentration of total protein were similar for all treatments. Milk fat from cows fed on hay only was generally lower in C10, C12, C18:2 fatty acids and higher in C18:1 and C18:3 fatty acids than milk fat from cows fed on hay and concentrate. The rennet curd firmness of the milk increased as the proportion of concentrate in the diet increased. The mean maximum heat stability of the skimmed milk from individual cows generally decreased as the proportion of concentrate in the diet increased.
The use of stable strontium as a chemical tracer for root penetration
Authors: Pinkerton A , Simpson JR
Published: November 2004

Stable strontium was used successfully, in the glasshouse and the field, as a tracer for root penetration and activity in some crop plants. Changes in strontium concentration in shoots were detected within a few days of roots coming into contact with soil enriched with strontium chloride, either mixed throughout a horizon as a powder or place at a particular depth as pellets. In glasshouse experiments there was a close correlation between dry weight of roots in the enriched zone and strontium accumulated in the shoots. Of various sizes of pellets used, 100 mg pellets were effective in raising the strontium content of shoots, while diffusing through only a limited volume of surrounding soil. Movement of strontium from larger pellets was excessive for accurate monitoring of root penetration and soil strontium concentrations were undesirably high, while smaller pellets, or a narrow band of enrichment, were ineffective. In the field, a technique of placing 100 mg pellets at 10 cm intervals in soil successfully monitored root penetration when wheat was grown under two systems of cultivation. Differences in shoot strontium concentration were greatest at early harvests and gradually disappeared. Hence it was essential to take frequent harvests in order to record root penetration with accuracy.
The effect of temperature on development of soybean rust (Phakopsora pachyrhizi)
Authors: Kochman JK
Published: November 2004

Uredospore survival and the development of soybean rust were examined across a range of temperatures. To determine the effect of temperature on uredospore survival, samples of dry uredospores were exposed to each of a series of eight temperatures for 8 h prior to a germination test on water agar at 21°C for 4 or 16 h. Germination was significantly reduced when uredospores had been exposed to temperatures of 28.5–42.5°C. Development of rust in soybeans was examined under four temperature regimes. Following inoculation with uredospores, plant foliage was sprayed with water and kept under conditions of dew at 21°C for 16 h. Plants were then placed in a selected regime. The 17–27°C regime provided the best conditions for rust development. These findings may partially explain some of the observations on rust occurrence in the field.
Selection in Lupinus albus L. for lower seed manganese concentration
Authors: Oram RN , David DJ , Green AG , Read BJ
Published: November 2004

Seeds of 49 Mediterranean white lupin accessions and of 36 F5 families derived from 13 of them were analysed for manganese concentration. High concentrations in the range 1770–4640 µg g-1 dry matter were found in material grown near Canberra and lower ones (1060-2750 µg g-l) at Wagga Wagga, N.S.W. A small number of L. angustifolius L. lines grown under comparable conditions at both sites had 7- to 70-fold lower concentrations of manganese in their seeds than L. albus. The means for accessions and families of L. albus varied widely and continuously about the site means. High alkaloid lines had approximately two-thirds the manganese concentration of low alkaloid lines. Seeds from primary inflorescences had 6% lower manganese concentrations than those from higher order inflorescences. About one-quarter of the variation within the low alkaloid class was associated with seed yield variation, there being a negative correlation between these traits. There was no line x site interaction. Broad sense heritabilities at Canberra and Wagga Wagga were moderately high, so that selection for lower concentrations should be effective. The results suggest that selection for higher yield could be almost as effective as direct selection in reducing seed manganese concentration. The reduction should be sufficient to enable white lupin seeds, grown on soils no higher in available manganese than those used in this study at Canberra, to be safely used as a high protein supplement in pig and poultry rations. Selection for lower seed manganese should not affect seed calcium, phosphorus or protein concentrations, but would tend to increase seed yield and plant height at maturity.
Survival of potato strain (race 3) of Pseudomonas solanacearum in the deeper soil layers
Authors: Graham J , Lloyd AB
Published: November 2004

In two naturally infested potato fields, Pseudomonas solanacearum E.F.Sm, race 3 was detected at all soil levels between 15 and 75 cm with the use of indicator plants. In artificially infested soils, recovery of the bacterium, by plating on a selective medium, was greater in soil sampled from the 55–65 cm layer than from the 10–15 cm layer. These results suggest that, in certain soils, the bacterium can survive for extended periods of time in the deeper soil layers.
Studies of weaned lambs before, during and after a period of weight loss. II Body composition
Authors: Searle TW , Graham NMcC , Smith E
Published: November 2004

Lambs at pasture were weaned when nearly 15 kg, brought indoors and given a balanced diet. They were studied during growth from 15 to 25 kg, then underfed for 21 weeks, which caused their weight to return to 17 kg, and finally allowed to regain weight on ad libitum feeding. The recovery phase was not commenced until some sheep were no longer able to stand and feed. At about 15, 20 and 25 kg in each phase of the experiment, tritiated water (TOH) space was measured on all sheep, and some were slaughtered and the chemical composition of the body determined. Body composition estimated from TOH space agreed closely with that measured post mortem. Allowing for variation with weight, the composition of the empty body was affected slightly by under-nutrition and by compensatory growth, but there was no net effect of the whole cycle of events. The only clear effect of weight change on body composition was a reduction in the protein content (with corresponding increase in fat) during the later stage of weight loss.
Infection of cherry trees and production of a toxin that causes foliar silvering by different isolates of Chondrostereum purpureum
Authors: Bishop GC
Published: November 2004

The susceptibility of pruned sapwood of cherry trees to invasion by basidiospores of Chondrostereum purpureum from several different sources was investigated. The results showed that spores from sources other than cherry are just as effective as spores from cherry in inducing silver leaf disease in cherry trees. The isolates did, however, differ in the amount of silvering of the foliage that they caused. Toxin production by the isolates was compared, and it was found that the isolate from broom (Teline monspessulana) which gave no foliar symptoms produced significantly less toxin than the other isolates of C. purpureum that were tested.
Undernutrition of the Merino sheep and its sequelae. V.* The influence of severe growth restriction during early post-natal life on reproduction and growth in later life
Authors: Allden WG
Published: November 2004

The growth of two groups of Merino lambs was severely restricted at different stages of early post-natal life so that at 420 days of age they weighed only 12 kg. When their normally grown sibs born 1 year later attained a similar weight at 53 days all groups were combined and moved to sown pastures, where they grazed together for 6½ years. During this period the ewe reproduction, growth and wool production of the experimental animals were compared. Nutritional deprivation in early life did not affect the reproduction performance of the ewes, or the birth weights and weaning weights of their progeny. The restricted lambs resumed normal growth for the first two years of the recovery period, but their growth potential was not sustained, and consequently the severe growth restrictions imposed in early life had as its sequel a smaller adult. Wool production, and the number of wool fibres per sheep, were both significantly reduced by growth restrictions in early life.

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*Part IV, Aust. J. Agric. Res., , 19: 997 (1968).
A multivariate procedure for classifying environments according to their interaction with genotypes
Authors: Seif E , Evans JC , Balaam LN
Published: November 2004

Canonical variates analysis was adapted to the problem of classifying environments according to their interactions with wheat genotypes, and was used to subdivide the Central West of New South Wales into uniform sub-regions. The method takes into account any fluctuations from year to year in the genotype x location interaction effects, and has several other advantages over the procedures previously used. Most of the variability among locations was represented by one canonical variate and was related to an east-westerly trend. It is suggested that the Central West be divided into two sub-regions, the eastern slopes and the western plains, for the purpose of varietal evaluations and recommendations.
The influence of radiant heat load on reproduction in the Merino ewe. II. The relative effects of heating before and after insemination
Authors: Sawyer GJ
Published: November 2004

The effect of radiant heat load imposed both before and after artificial insemination (AI) on the reproductive performance of Merino ewes was tested in two experiments. In the first experiment ewes were allocated to four groups: controls (group 1); hot-room conditions for 5.5 days prior to AI (day 0) (groups 2 and 4); hot-room conditions for days 1–9 after AI (groups 3 and 4). Ewes in the second experiment were allocated to three groups: controls (group 1); hot-room conditions for 5.5 days prior to AI then for days 1–4 after AI and days 5–8 after AI (groups 2 and 3 respectively). Hot-room conditions for both experiments ranged over 41–43°C and 2.07–3.08 kPa vapour pressure, and control room conditions over 22–27°C and 1.19–2.10 kPa. When subjected to hot-room conditions the rectal temperatures and respiration rates for all heated ewes were significantly higher than those of controls by c. 1.0°C and 120 respirations/min. In both experiments the number of ewes exhibiting oestrus was significantly reduced by about one-third following heating. Despite this most ewes ovulated. Heated ewes which showed oestrus in experiment 2 had significantly longer oestrous cycles than control ewes (17.9 days v. 16.9 days, P < 0.01). In this experiment lack of cyclical oestrous activity was the main cause of reduced fertility in heated ewes. The number of ewes lambing was depressed in heated ewes in both experiments, but was affected most severely in experiment 1. In this experiment the poorest lambing performance of 21.5% compared with 70.6% in controls resulted from heating both before and after insemination. Interference with cyclical oestrous activity by exposure to a high radiant heat load at the time of insemination (either natural or artificial) may contribute significantly to reproductive wastage associated with ewes which mate, apparently conceive, but fail to lamb.
The epidemiology of yellow spot of wheat in southern Queensland
Authors: Rees RG , Platz GJ
Published: November 2004

Aspects of the epidemiology of yellow spot of wheat, caused by Pyrenophovu tritici-repentis, have been examined in southern Queensland. Ascospores of the fungus were detected In the air above wheat stubble between March and October, but numbers at any one time were small. Small numbers of conidia trapped between late February and May apparently originated on the stubble. Large numbers of conidia in late October-November were produced predominantly on old lesions and dead tissues in a wheat crop planted through the stubble During late spring, numbers of air-borne conidia increased markedly the day after rain or irrigation. The results suggest that epidemics of yellow spot in southern Queensland are mainly initiated by ascospores and possibly conidia produced on stubble from the preceding diseased wheat crop. Large numbers of conidia produced on a diseased crop result in rapid development of the epidemic under favourable conditions and permit spread of the pathogen to other crops or localities.
Acid phosphatase activity of intact roots and phosphorus nutrition in plants. 2. Variations among wheat roots
Authors: McLachlan KD
Published: November 2004

Variation in phosphatase activity (E.C. 3.1.3.41) in some cultivated wheats and wild progenitors was examined and a comparison made. The limits likely to occur in wheat were estimated, and the usefulness of phosphatase activity as an indicator of plant potential for exploiting low phosphorus status situations was explored. Under the test conditions, within the cultivated wheats, the phosphatase activity varied in optical density from 4.6 to 9.3 per g fresh weight (P < 0.001), and selections among wheats on this basis could be made. Phosphorus uptake and total dry matter yield were negatively related to phosphatase activity (r = - 0.80 and - 0.82 respectively, each P < 0.00l), providing further supportive evidence of the proposition that plants with lower phosphatase activities may gain and use phosphorus more readily than plants with higher ones. The phosphatase activity of wild and cultivated progenitors of modern wheats ranged in optical density from 15.5 to 45.4 per g fresh weight. All the cultivated species had low phosphatase activities which, on the basis of the proposition, suggests that some unconscious selection for ability to use low fertility situations may have occurred with the domestication of wheat. On the other hand, there was no apparent grouping according to geographic origin of earlier cultivars used in Australia with respect to phosphatase activity to suggest any conscious selection for ability to grow well on low phosphorus status soils.
Emergence, growth and dominance in drilled and square-planted barley crops
Authors: Soeton o , Donald CM
Published: November 2004

A barley crop (cv. Clipper) was grown at three densities and in two plant arrangements, square-planted and drilled. Studies were made of the emergence and growth of individual plants within permanent quadrats. Later-emerging seedlings gave rise to smaller plants at stem elongation and at the early grain stage, and they produced fewer grains than plants which had emerged earlier. On drilled plots, at the normal commercial sowing rate (the medium density treatment), the regression of grain number per plant on day of emergence was - 14.4% of the mean number of grains per plant, so that a delay of 3 days in emergence caused a reduction of 43 % in the number of grains formed. The regression of grain number on day of emergence in the medium density square-planted plots was - 8.3 %. It is suggested that the difference in the regression coefficients within the drilled and square-planted plots respectively was due to the different incidence of intra-plant and interplant competition in the two situations. Plants were regrouped into decile groups at stem elongation (day 70). Thereafter, larger plants achieved not only greater absolute increases in weight, but also greater relative growth rates; the large plants thereby further increased their percentage contribution to the crop. For all plant sizes within both planting arrangements and within each of the three densities, the number of grains per plant was linear on the weight of the plants. The ear number per plant was the principal feature of difference between large and small plants, followed by spikelets per ear. The significance of these phenomena in plant breeding and agronomy is discussed. Appendix 1 reports two methods for the non-destructive estimation of the yield of individual plants in a cereal crop.
Prediction of oil quality of sunflower from temperature probabilities in eastern Australia
Authors: Harris HC , McWilliam JR , Bofinger VJ
Published: November 2004

The probability of the occurrence of temperatures suited to the production of high quality sunflower oil has been examined for 37 locations in eastern Australia. The results indicate that temperatures suited to development of oil with =62% linoleic acid occur throughout the potential cropping season with a probability =0.6 in Tasmania, south-western Victoria, south-eastern South Australia and the highlands of New South Wales. In most established cropping regions probabilities of this level are reached only in the later third or half of the sunflower growing season. The probability of temperature suited to production of oil with = 72 % linoleic acid is less than 0.6 in all regions for much of the season, and in any environment only very late-sown crops can be expected to yield oil of this quality. The results are discussed in the light of factors controlling the distribution of sunflower production, and it is concluded that, with existing genotypes, adequate supplies of high quality oil to meet market requirements will not be reliably available from the Australian crop.
The role of night temperature in the bulbing of onion (Allium cepa L.)
Authors: Steer BT
Published: November 2004

Onion (Allium cepa L.) cultivars Creamgold and Gladalan Brown were grown at three day lengths (13, 14 and 15 h) and three day temperatures (22, 26 and 30�C) in the Canberra phytotron. In each case bulbing was slower whcn the night temperature was 15' below day temperature than at 5� below day temperature. The cultivar Gladalan Brown, growing at 13 h day length and 26�C day temperature, bulbed faster when the first half of the 11 h night was at 21� and the second half at 11� than in a 11� then 21� night. The number of days from sowing to the start of bulbing decreased with increasing night temperature. The rate of bulbing after initiation increased with increasing night temperature.
Yield effects of herbicides on competition between crop and weed communities
Authors: Hawton D
Published: November 2004

A literature review showed that the relationship between crop and weed top dry matter yields at harvest time is often linear. It is suggested that by including monocultures of both crop and weeds and a series of partial weeding treatments in any herbicide screening experiment, the true effect of a herbicide can be determined with the separation of any effect due to interspecific competition. To do this, confidence limits are constructed for a linear regression fitted to the crop by weed yield coordinates for the non-herbicide treatments. Points produced by yield coordinates from herbicide-treated plots which lie outside these confidence limits indicate either depression or stimulation of both yield components. From the relationships between these points and the regression line, weed competition and herbicide phytotoxicity esects can be estimated separately. Evidence supporting this theory was obtained in a field experiment with a crop of Desmodium intortum and a natural weed community.
Effects of energy and protein intake on ovulation rate associated with the feeding of lupin grain to Merino ewes
Authors: Fletcher IC
Published: November 2004

Five rations formulated from varying amounts of pasture hay and oat, lupin and pea grains were fed to South Australian Merino ewes at different controlled levels of digestible energy and crude protein intakes. Ovulation was recorded by laparoscopy or laparotomy 17 days and 34 days after the commencement of the experiment, An increase in protein intake supplied by lupin grain increased the ovulation rate through an increased incidence of multiple ovulation only when the initial level of feeding supplied low protein and energy intakes, and not when the initial level of feeding provided moderate intakes of protein and energy. The response in ovulation rate was evident within the first 17 days after protein intake was increased, and did not change further during the second 17-day period. Particularly in November/ December, when a proportion of ewes failed to ovulate, the mean ovulation rate of ewes fed at low protein and energy intakes was increased more by additional protein and energy together than by additional protein alone. It is suggested that increased protein intake per se stimulates the ovulation rate only when the initial intake is close to the maintenance requirement, and that energy, either by itself or together with protein, subsequently becomes the limiting factor.
Barley yellow dwarf virus infectivity of cereal aphids trapped at two sites in Victoria
Authors: Smith PR , Plumb RT
Published: November 2004

Alate cereal aphids, Rhopalosiphum padi, R, maidis and Macrosiphum miscanthi avenae, caught in suction traps at Horsham and Burnley for two successive years (1977-78), were tested individually for infectivity with barley yellow dwarf virus (BYDV). R. padi was most numerous, making up 73.1-98.7 % of the total number of cereal aphids trapped at either site in either year. 22.6-61.3 % of R. padi caught were infective, with a larger proportion infective at Horsham than at Burnley in both years. 9.4.43-5 % of M. miscanthi avenae were infective, but there was little difference in the proportion infective between sites. R. maidis were trapped only at Burnley, and only in 1978 were they infective, when 7.8 % transmitted BYDV to test plants. Seasonal variation in the catches of R. padi differed at the two sites. At Horsham most aphids were trapped from August to October, whereas at Burnley most were caught from March to November.
Effects of subsoil acidity on the shoot and root growth of some tropical and temperate forage legumes
Authors: Pinkerton A , Simpson JR
Published: November 2004

The root and shoot growth of four tropical and two temperate summer-growing legumes were assessed when plants were grown in deep profiles of an acidic soil modified by additions of calcium carbonate. Species tested over three harvests were Desmodium intortum, Glycine wightii, Stylosanthes humilis (Townsville stylo), Macvoptilium atvopuvpureum (Siratro), Trifolium repens and Medicago sativa (lucerne). There were large and more immediate effects on root growth, particularly on fine root length, than on shoot growth. The species differed in their root responses to lime, the tropical species in general being more tolerant of subsoil acidity than the temperate species. There were marked differences between species in their responses when expressed as the ratio of fine root length to total shoot weight. The ratio of root weight to shoot weight showed much less variation with lime rate, and it is suggested that the ratio of fine root length to shoot weight is the better indicator of tolerance to subsoil acidity. S. humilis showed little response to lime at any time, and was notable for its length of fine root. Siratro grew well at first but later there was little increase in shoot weight or in length of fine root, although tap root weight increased greatly. Roots of D. intorturn, T. repens and lucerne were slow to penetrate beyond 55 cm depth. At later harvests the root lengths of these species and of G. wightii were highly responsive to lime. Agronomic implications of the results are discussed.
Tolerance of commercial cultivars and breeders' lines of wheat to Heterodera avenae Woll
Authors: Fisher JM , Rathjen AJ , Dube AJ
Published: November 2004

Many commercial cultivars and breeders' lines of wheat were ranked for tolerance to cereal eelworm by comparing their yield of grain on a site heavily infested with Heterodeva avenae with their average yield on five other areas of South Australia. Different methods for assessing tolerance were examined. A range from tolerance to intolerance was obtained, but most commercial cultivars were intolerant. Many breeders' lines were highly tolerant. A visual system for rating early growth was strongly correlated with final yield. Resistance and tolerance were not related.
Relationships between sites used in the interstate wheat variety trials
Authors: Fox PN , Rathjen AJ
Published: November 2004

A combination of statistical techniques was used to present useful information for breeders concerning the 197.5 Interstate Wheat Variety Trial. Grouping of sites was similar for all techniques, but was shown most clearly by the principal component analysis. Within three of the four groups of sites there was strong similarity between members. Some groups included widely geographically separated sites, which suggests that in the final stages of varietal testing, it might be possible to use widely separated sites as an alternative to testing over several years within a region. One group dominated the overall mean yields of the trial because it included more sites and because these sites were more uniform than sites within other groups. This domination, illustrated by regression and ranking techniques, may reduce the value to industry of the Interstate Wheat Variety Trials if these sites are not representative of extensive areas of wheat production. The differences in relative performances of varieties between sites could not be related either to differences in the mean yields at these sites or to edaphic or climatic variables. The need for such analysis of each year's data from the Interstate Wheat Variety Trials is stressed.
The influence of watering regimen on soil pH and zince nutrition of soyabean cv. Wills grown in soil pot culture
Authors: Hunter MN , Edwards DG
Published: November 2004

The changes over time in soil pH, plant growth and zinc uptake by soybean (Glycine max (L.) Merr.) cv. Wills grown in a zinc-deficient black earth under two watering regimens, viz. watering to weight (WTW) and constant water table (CWT), were determined in a pot experiment. In the absence of applied zinc, CWT plants achieved twice the dry matter yield of WTW plants. Interveinal chlorosis was observed on CWT plants at 20 days after sowing, but not on WTW plants at any time during the experiment. Leaf lamina zinc concentrations at a number of nodes were less than 10 �g g-1 in plants grown for 25 days under both watering regimens. Fertilization with zinc at 30 kg zinc ha-1 significantly increased the dry matter yield of CWT plants and, particularly, the size of laminae at node 5 and above. Plants grown in the absence of applied zinc recovered from zinc deficiency over the period from 25 to 35 days after sowing. Rates of dry matter and zinc accumulation over this period increased, while zinc concentrations in the plant and particularly in the younger leaves increased markedly. This recovery coincided with a substantial decline in soil pH. The recovery from zinc stress is attributed to the greatly increased availability of zinc to the plant roots which may have resulted from the drop in soil pH.
Maize sterile stunt — a delphacid transmitted rhabdovirus disease affecting some maize genotypes in Australia
Authors: Greber RS
Published: November 2004

A rhabdovirus disease causes severe stunting and sterility of a few susceptible maize (Zea mays L.) genotypes in eastern Australia. Maize sterile stunt virus (MSSV) also infected Aegilops variabilis Eig, barley (Hordeum vulgare L.), barnyard grass (Echinochloa colona (L.) Link.), triticale (x Triticosecale Wittmack), wheat (Triticum aestivum L.), T, aethiopicum Jakubz., T, monococcum L, and T. turgidum L. MSSV was transmitted with low efficiency by the maize planthopper Peregrinus maidis (Ashm.) and by Sogatella kolophon (Kirk.), but the chief natural vector was Sogatella longifurcifera Esaki and Ishihara, a delphacid found commonly on affected maize and on E. colona. The incubation period of MSSV in P, maidis was 10-14 days after acquisition on infected plants or 9-12 days after injection of infective sap. Transmission was demonstrated during a period of up to 23 days or until the insects died. Field incidence in the maize lines B37 and H84 often exceeded 90 %, but most maize lines were resistant and resistance was highly dominant. Temperate cereals were severely affected only during summer and triticale was the most susceptible. Particle dimensions were 230 by 50 nm in negative stain and 255 by 45 nm in thin section, with accumulations of particles found only in cytoplasmic vesicles. MSSV particles occurred mainly in companion cells, phloem parenchyma and bundle sheath cells in maize. Virus-like particles were also found in the brain and salivary glands of infective P. maidis.
Volatilization of ammonia from urine patches in a subtropical pasture
Authors: Vallis I , Harper LA , Catchpoole VR , Weier KL
Published: November 2004

Ammonia volatilization from artificially applied cattle urine was measured in a fertilized (374 kg nitrogen ha-1 year-1) and grazed (4 beef steers ha-1) pasture of Nandi setaria (Setaria sphacelata var. sericea) in south-eastern Queensland. Microplots (0.5 by 0.5 m) of pasture were treated with 1.4 1. of urine (= 37-48 g nitrogen m-2) and evolved ammonia measured with a flow-through chamber system that maintained near ambient temperatures and air flows. Calculated volatilization over a 14-day period was 18.8 % of the applied urine nitrogen in June, 14.4 % in November-December and 28.4 % in February-March. More than half of the volatilization occurred within 48 h of applying the urine. Measurements of soil mineral nitrogen in February-March showed that more than 80% of the urinary urea was hydrolysed within 2 h and only traces remained unhydrolysed after 24 h. Soil ammonium declined from 700 to 1000 �g nitrogen cm-3 in the surface 2.5 cm on the first day to near-background levels on the 14th day. Accumulation of nitrate was rapid after the 2nd day, and accounted for one-third of the applied nitrogen by the 14th day. Nitrite reached a maximum of 2.3 % of the applied nitrogen on the 7th day and had virtually disappeared by the 14th day. Only traces of nitrite were detected below 2.5 cm depth.
The effect of short-term waterlogging during furrow irrigation of cotton in a cracking grey clay
Authors: Hodgson AS , Chan KY
Published: November 2004

A crop of cotton cv. Deltapine 61 was waterlogged in the field by running water in furrows for 4, 8, 12 or 16 h at each of three crop irrigations in a cracking grey clay soil at Narrabri, N.S.W. The season was hot and dry, and rainfall did not influence waterlogging treatment. Increasing the inundation period from 4 to 16 h reduced lint yields by 15.9 g m-2 or 8%. Waterlogging treatment had little effect on leaf area, plant height, dry matter and boll size. Lint yield loss from waterlogging was largely associated with reduced boll number m-2. Soil aeration results showed that treatment affected the rate of recovery from waterlogging, and that recovery rate was also a function of soil depth. On taking an air-filled porosity of 0.10 cm3 cm-3 as limiting for growth of roots in soil, the surface 0-10 cm layer was always adequately aerated. However, increasing the inundation from 4 to 16 h delayed soil recovery at 10-20 cm from 0.85 to 1.54 days, and at 20-30 cm from 3.83 to 4.20 days. Multiple regression analysis showed that 77 % of the variation in lint yield could be accounted for by the lengths of time taken for the 10-20 cm and 20-30 cm layers to recover from waterlogging. However, associated yield losses were 2.5 times greater for the 10-20 cm layer than for the 20-30 cm layer for each day of waterlogging in the two layers. The results indicated that lint yield is likely to increase if cotton crops are irrigated and drained faster to reduce contact time. The farmer may achieve this by using larger siphons, more siphons per furrow, shorter furrows or steeper furrows.
A relation between wool production per animal and annual pasture dry matter production per animal
Authors: Rowe BA
Published: November 2004

A simple relation between the annual wool production per animal (y) and the amount of pasture dry matter produced per animal (x) was derived and tested using the results from a grazing experiment in which the effects of superphosphate and stocking rate on wool and pasture dry matter production were measured from pastures which were continuously grazed by Merino wethers for 3 years. The linear relation, y = a + b/x, accounted for 63% of the variance in wool production per animal in the first year, 82 % in the second and 97 % in the third. Exclusion of an outlier from the first year results increased the variance accounted for to 85 %. This model is simpler and more precise than some others that have been published. It is also consistent with the curvilinear relation between production per animal (y) and pasture production per animal (x).
Effects of yellow spot on wheat: comparison of epidemics at different stages of crop development
Authors: Rees RG , Platz GJ
Published: November 2004

Effects of yellow spot (Pyrenophoua tuitici-repentis) on two cultivars (Banks and Olympic) of wheat have been examined in a field experiment where distinctly different epidemics were produced in various treatments. Severe yellow spot before jointing reduced production of both tillers and dry matter, and substantially lowered leaf area index at jointing. Severe disease after jointing reduced leaf area index at flowering, dry weight of plants at maturity and harvest index. Crop phenology was also modified, with flowering being delayed by early disease and crop maturity hastened by late disease. Where yellow spot was severe throughout, the grain-filling period was greatly reduced. Grain yield of Banks was reduced by c. 13 % by early disease, c. 35 % by late disease, and c. 48 % by disease throughout the crop season. Most of the loss was in reduced grain size. Although yield loss in Olympic was less than in Banks, the resistance of Olympic was shown to be inadequate.
Thiaminase activity in the gut of cobalt-deficient sheep
Authors: Mann SO , Wilson AB , Barr M , Lawson WJ , Duncan L , Smith A , Fell BF , Walker HF , Macdonald DC
Published: November 2004

In an attempt to clarify the reported relationship between cobalt deficiency and the incidence of cerebrocortical necrosis (CCN), sheep were fed on a diet deficient in cobalt. High levels of thiaminase activity were found regularly in rumen and faeces samples from cobalt-deficient animals, and also from controls supplemented with cobalt or vitamin B12. There was a poor correlation between thiaminase activity and viable counts of the thiaminase-producing organisms Clostvidium spovogenes and Bacillus spp. Urinary excretion of thiamine appeared normal. When the sheep were killed, normal concentrations of thiamine were found in the liver. The sheep were deficient in vitamin B12, as judged by the concentrations in serum and liver, by urinary excretion of methylmalonic acid, and by clinical condition. Twitching and weakness were observed, but clinical signs of CCN did not develop.