bluuebunny/crossref_metadata_2025 huggingface dataset:
Some aspects of virus Y resistance in the potato (Salanum tuberosum)
Authors: Hutton EM
Published: November 2004

When the leaves of potato hybrids resistant to virus Y were inoculated, virus development was restricted and within 14 days the virus was inactivated in most instances. There was no evidence to suggest that resistance was due to hypersensitivity. Virus concentration increased gradually in susceptible varieties after inoculation. Four treatments of virus Y inocula were tried; that made with phosphate buffer of pH 7 produced the most lesions on the resistant potato hybrid 11-84. A marked reduction in lesion numbers occurred on 11-84 when sap from virus-free D. stramonium plants or X-infected N. glutinosa plants was added to inoculum of virus Y. Crossbred progenies were developed from two of the resistant hybrids and one of the varieties used to study virus development after inoculation. One progeny contained 68.3 per cent. phenotypes resistant to virus Y and the other had 29.4 per cent. In both progenies there was a strong association between resistance to virus Y and the immune reaction to virus X. The results indicate that immunity and high resistance to virus Y are governed by the nulliplex and simplex conditions of a major gene, while the quadruplex condition controls susceptibility.
A survey of the natural pastures of the Trangie District, New South Wales, with particular reference to the grazing factor.
Authors: Biddiscombe EF
Published: November 2004

The Trangie district has a rainfall of 1,750 points with a slight summer maximum, a high relative variability of rainfall, and high summer temperatures. Disclimax pasture communities produced by a range of sheep grazing intensities operative during the past 20-30 years are described. On light soils ungrazed pasture comprises a wide range of perennial grasses. Light grazing (1 sheep per 2 acres) gives increased dominance by Stipa fulcata. With successive increases in grazing pressure Chloris acicdaris and Stipa setacea become conspicuous in turn, only to be virtually replaced by Chloris trumata as grazing intensity reaches 1 sheep per 0.5 acre. On heavy soils Stipa aristiglumis is dominant under light grazing. With increased rate of stocking, first Sporobolus caroli and then Stipa setacea gain dominance. At the highest stocking rates all these species are largely replaced by Chloris truncata. Throughout the sere the number of species is far more restricted than on the light soils. The striking feature of these results is that though botanical composition of the perennial grass component on light and heavy soils respectively is vastly different under light grazing, it becomes similar under heavy grazing and almost identical under severe grazing. Degenerative changes common to pastures of both soil groups under increasing grazing pressure are the decline in density and basal area of the perennial grass component, the greater population of winter and summer annuals, and the declining contribution of perennial grasses to green forage production in the spring. The basis of these findings is firstly the measurement of basal area, density and yield of perennial grasses, and density and yield of annual species in pastures of varying stocking history, and secondly, the measurement of pasture composition in relation to increasing distance from watering points.
Studies in pedogenesis in NSW. 5. The Euchrozems.
Authors: Hallsworth EG , Colwell JD , Gibbons FR
Published: November 2004

A study has been made of certain red soils overlying basalt around Inverell, N.S.W., that are distributed in a complex manner amongst the black soils of chernozemic character considered to be the climax soils from basalt under the present climate. The red soils are sufficiently distinct from related soils to merit separation as a new soil group — the euchrozems. The euchrozems are shown to be affected by residual leached soils of a previous wetter climate, but are not merely relics. Laterite residuals, which are relics of a former period, are found in perched positions as a capping on most of the euchrozem catenas. The euchrozems are considered to be derived partly from basalt weathering under present-day conditions and partly from the relics of the former soils, the latter distributing sesquioxide by movement down the catena. Evidence for the conversion of euchrozems to chernozemic soils is shown, and the term "reversion" applied to this process, since it constitutes a reversal of the weathering sequence. A series of stages from the euchrozem catena to the chocolate/chernozem catena is described, which together with the occurrence of two distinct basalt flows, the upper overlying laterite on both basalt and other rocks, affords an adequate explanation of the complex distribution of the soils.
The effect on cattle of long-continued cutaneous applications of DDT.
Authors: Roulston WJ , Hitchcock LF , Turner AW , Campbell RD
Published: November 2004

An experiment was carried out near Brisbane and another near Melbourne to determine the hazard of long-continued cutaneous applications of DDT to cattle. In Queensland, steers were used. They were treated weekly for three years with 22.5 g DDT in peanut oil, and some were autopsied at the end of each year. In Victoria the experiment was commenced with heifers, and the same dosage of DDT in peanut or substitute oils was applied. They bore up to three calves, which they suckled for 5-6 months, and were autopsied 3½ years after the commencement of the experiment. Signs of toxicosis were never observed in adults or calves and except for a brief period during the second year of the Queensland experiment, there was no significant difference between the growth rates of treated and untreated animals. At autopsy UDT was found in tissues, particularly fatty tissues, in amounts up to 425 parts per million, and lower concentrations were found in similar tissues of untreated animals pashred with those treated. In no case was histological evidence of toxic effects upon tissues found. Milk samples taken during the first lactation of the Victorian heifers 20 months after treatment began contained 3-4 parts per million DDT. Since the intensity of application exceeded that of any treatment conceivable under field conditions, it is concluded that any likely rate of dipping in aqueous suspensions of 0.5 per cent. pp'-DDT for tick control would be quite harmless to cattle.
Reactions and field resistance of some potato varieties and hybrids to the leaf-roll virus.
Authors: Hutton EM , Brock RD
Published: November 2004

The leaf-roll reactions of a number of potato hybrids and varieties have been defined by external symptoms and the extent of phloem necrosis present in stem sections. There is no constant correlation between the leaf-roll reaction and field resistance of varieties and hybrids. The variety Bismark had the highest leaf-roll resistance of any of the types tested so it should prove a useful parent for this character. The resistance of Bismark and some hybrids is apparently dependent upon a virus-inactivating mechanism, which not only reduces field infection but prevents the transmission of leaf roll to a proportion of the tubers of infected plants. The initial selection of resistant hybrids could be made by sprout inoculating them and keeping those in which a proportion of the tuber progeny was free from leaf roll.
The influence of the introduction of rams on the incidence of oestrus in Merino ewes.
Authors: Riches JH , Watson RH
Published: November 2004

Two series of observations were carried out on the effect of the presence of the ram on the incidence of oestrus in ewes. In each series a group of Merino ewes was run continuously with vasectomized rams (the continuous group) and another group (the changing group), the ewes of which had been held separate from rams, was joined with the rams for a period of one month only, fresh ewes having been introduced each month. Each series of observations occupied a period of 12-15 months. In all except the spring months most of the ewes of both the continuous group and the changing group exhibited oestrus. During the spring months of one year, 1942, most of the ewes of the changing group exhibited oestrus but many of those in the continuous group failed to do so. During the spring months of the other year, 1943, most of the ewes of the changing group failed to exhibit oestrus as well as most of those of the continuous group, but whereas the proportion which exhibited oestrus did not fall below 30 per cent. in the changing group, it fell as low as 5 per cent. in the continuous group. The differences between the continuous group and the changing group in the proportion of ewes which exhibited oestrus during September and October 1942, and October 1943, are significant at the 1 per cent. level of probability, and that during August 1942 is significant at the 5 per cent. level. These significant differences in the behaviour of the ewes must be attributed to the difference in their previous association with rams.
Studies in soil fertility with special reference to organic manures. II. Plant growth and nutrition in the field.
Authors: Williams RF
Published: November 2004

This paper reports a study in crop physiology in which an analysis of plant growth response and nutrient intake under irrigation in the field is used to interpret the effects of rice hulls as an organic manure. An exploratory experiment showed that relatively speaking the main effects of treatment took place quite early in the growth of the crop. For this reason the main experiment was virtually restricted to these early growth stages. The test plant in both experiments was the tomato. It was found that rice hulls can influence the growth of the crop in at least three ways. Seedling emergence may be delayed, early growth may be retarded by temporary shortage of available nitrogen, and growth may be stimulated by increase in available phosphorus. All three effects are modified by the addition of sulphate of ammonia, but in all cases the result is an increase in yield with rice-hull treatment. Mean seedling emergence for the six experimental treatments had a range of 2.8 days, and it is shown that the mean weights of 18-day-old seedlings could have been accounted for by these differences alone. The pattern of response at 18 days remains for at least five weeks and is not without its effect on the final yields. In spite of their low nitrogen content, rice hulls alone had only a transitory adverse effect on the nitrogen status of the soil. It is suggested that this may not have had any direct effect on the rate of dry-matter production, but that there was a temporary deflection of assimilates to favour root growth at the expense of shoot growth. Such an effect would, of course, have an adverse effect on fruit yield. Plant analyses suggest very considerable increases in available soil phosphorus due to rice-hull treatment. Much of this phosphorus appears to have been fixed during the course of the experiment, but Truog values obtained after the experiment indicated that significant effects of treatment were still present. The increases in Available phosphorus were less when sulphate of ammonia was added with the rice hulls.
Studies on the assimilation and storage of copper in crossbred sheep.
Authors: Dick AT
Published: November 2004

Experiments reported in this paper show that increased copper intake of sheep is reflected by increased copper content of the liver. The magnitude of the rise in liver copper depends upon a number of factors, but under the described conditions, the amount of copper accumulated by the animal is proportional to the copper intake within the range 3-20 mg per day; the amount stored in the liver over a 6 months1 period was found to be 4.5-5 per cent. of the intake. Some of the conditions which may modify the retention of copper were examined. It was found that the addition of ferrous sulphide to the diet, which presumably converts added copper to the insoluble sulphide, lowered the expected copper accumulation in the liver by 75 per cent. Conditions which may modify this effect of ferrous sulphide have been examined and described. Other possible sources of sulphur for the formation of copper sulphide in the animal (elemental sulphur, sodium thiosulphate) were found not to be effective. The effects of some other metals (zinc, nickel, iron, and molybdenum) on copper accumulation in the liver were examined. Molybdenum was found to have a severely limiting effect, but this effect was only observed when the diet also contained a sufficient quantity of inorganic sulphate. For a given intake of molybdenum the limitation of copper storage was found to be proportional to the sulphate content of the diet. The possible bearing of these experimental findings on conflicting field observations relating to copper metabolism of sheep is discussed.
Varietal reactions of Trifolium subterraneum L. to Phaseolus virus 2 Pierce.
Authors: Hutton EM , Peak JW
Published: November 2004

A number of varieties of subterranean clover (Trifolium subterraneum L.) were tested with a severe strain of Phaseolus virus 2 Pierce. Northam First Early, Dwalganup, and Pink Flowered gave lethal necrotic reactions while the rest developed mottles and chlorosis of different degrees of intensity. Reductions in the mean fresh weights of plants of five subterranean clover varieties ranged from 26.1 to 76.7 per cent. Epidermal cells of mottled leaves contained irregular aggregates of viroplasts stained by treatment with phloxine-trypan blue. Viroplasts in young tip leaves did not stain if the plants were held at temperatures below 44.6°F while those in mature basal leaves were not so affected. The lethal-reactors Northam First Early, Dwalganup, and Pink Flowered were resistant in the field to Phaseolus virus 2. With hand inoculation in the glass-house an average of 10 per cent. of plants of these varieties remained free from systemic infection, whereas all the plants of mottle-reacting varieties became systemically infected. The virus had a discontinous distribution in plants of lethal-reactors, compared with a continuous distribution in those of mottle-reactors such as Mount Barker. The lethal reaction is heritable in a dominant fashion in most crosses, so that the development of desirable new virus- resistant varieties is possible.
Heterozygosity in subterranean clover (Trifolium subterraneum L.)
Authors: Symon DE
Published: November 2004

The examination of seedlings in a naturalized stand of subterranean clover (Trifolium subterraneum L.) showed that chlorophyll aberrations were quite common and that about one plant in 360 (0.28 per cent.) could be expected to be heterozygous for some chlorophyll defect.
A study of the virus diseases "Big bud" of tomato and "Yellow Dwarf" of tobacco.
Authors: Hill AV , Mandryk M
Published: November 2004

The two virus diseases "big bud" of tomato and "yellow dwarf" of tobacco are transmitted by the same insect vector. Both were transmitted by grafting but not by sap inoculation. Big bud but not yellow dwarf was transmitted by dodder. Nicotiana glauca Graham was a symptomless carrier of both viruses. Potato was infected by big bud but not by yellow dwarf. Evidence from experiments and field observations indicates that big-bud transmission occurs during summer whereas yellow-dwarf infection can occur throughout the year. From this and other evidence (anatomical, lack of cross protective power, symptoms) it is concluded that the two diseases are caused by different viruses.
Fertility of anoestrous ewes following injection of progesterone and Pregnant Mare Serum (PMS).
Authors: Robinson TJ
Published: November 2004

Experiments are described in which progesterone was used alone and in combination with pregnant mare serum (PMS) in breeding Suffolk, Suffolk crossbred, and Romney Marsh ewes in anoestrus. While oestrus, presumably with ovulation, was induced in a high proportion of ewes treated with the two hormones in combination, lambing percentages were low. Of 20 Romneys treated, 18 were served, but only 5 held to this service. Comparable figures for Suffolks were: 20 treated, 18 served, 7 lambed. The crossbreds gave better results; of 6 ewes treated all were served and 5 lambed. There was some evidence that the conception rate was higher following a complete ovarian cycle. Factors which may be involved in this phenomenon are discussed.
The hair follicle and apocrine gland population of cattle skin.
Authors: Carter HB , Dowling DF
Published: November 2004

Skin biopsy specimens were collected at a standard midside position from 321 individual cattle (Bos taurus L.) of known age or in defined age groups on pastoral properties in New South Wales and Queensland. Beef cattle were represented by samples from the breeds: Aberdeen Angus, Devon, Hereford, and Shorthorn. Dairy cattle were represented by samples from the breeds: Australian Illawarra Shorthorn, Holstein-Friesian, Jersey, and Red Poll. Data were also obtained on 30 beef Shorthorns repeatedly sampled from birth to the age of 2-1/2 years under severe drought conditions in north Queensland. In all specimens each hair follicle was associated with an apocrine gland as well as a sebaceous gland and an arrector pili muscle. Thus, all hair follicles were homologous with the primary follicles of sheep; no secondary follicles were at any time observed; hence, there was no follicle group comparable in its complexity to that in the sheep and many other mammalian species. Further and more systematic observations by the biopsy and histological methods used in this work are necessary to examine the true nature of breed differences in the follicle and apocrine gland population density of the skin. The Jersey appears to have a denser coat. The data presented in this paper emphasize the dual importance of age and nutritional status of the animal on the hair follicle population density.
Flower initiation in pasture legumes. III. Flower initiation in Medicago tribuloides Desr. and other annual medics.
Authors: Aitken Y
Published: November 2004

Observations on barrel medic (Medicago tribuloides Desr., commercial variety) sown throughout the year in the field showed that the flower initiation of the winter sowings was the most rapid and that of the late summer sowings the most delayed. This delay was due to the absence of sufficiently low temperature following germination. Low temperature and long photoperiod accelerate flower initiation in barrel medic as in subterranean clover. Five types of annual medic that persist under Mallee conditions are similar in their flower initiation character to that of the "second-early" varieties of subterranean clover.
Studies on the fertility of seddon soil (Kangaroo Island, South Australia). 1. The response of subterranean clover to various phosphatic fertilizers.
Authors: Tyson AG
Published: November 2004

Seddon gravelly sandy loam from Kangaroo Island has proved to be grossly deficient in both total and available native phosphorus. Growth of subterranean clover (Trifolium subterraneum L.) in this soil is virtually nil unless phosphatic fertilizers are applied to it. Experiments with eight different phosphatic fertilizers showed that thermal phosphates of the Rhenania type were slightly superior to monocalcic phosphate as a source of plant phosphorus on Seddon soil. Both types of phosphate were equally efficient in the contrasting Urrbrae loam. Rock phosphate proved to be an extremely poor source of plant phosphorus. In the first year the availability of monocalcic phosphate applied to the Seddon soil was 20 per cent. or half that of material applied to the Urrbrae loam. The comparative residual value in the second year of applied phosphate was greater, however, in the Seddon soil than in the Urrbrae loam. Yields and phosphate availability were influenced by seasonal variation, but the phosphorus content of the plant material was nearly constant in different years for any particular yield from the same soil. The requirement for phosphorus at yields below the maximum was greater, however, in plants growing on Urrbrae loam than on Seddon soil. At maximum yields the ratio N/P205 was constant for plants from the two soils, but this did not hold where phosphorus was in minimum supply. The availability of residual phosphate from Seddon soil to which small annual additions of fertilizer had been made over 12 years was markedly lower than that from virgin soil to which phosphate had been added 12 months previously. The lower availability from the partially developed soil has been tentatively ascribed to the concurrent accumulation of organic matter. Results support the practice of making small annual applications of superphosphate to Urrbrae loam but it would appear that greater overall production could be obtained from Seddon soil by heavier initial applications. Amounts of P205 as low as 0.17-0.20 per cent. were found in the dry matter of subterranean clover growing on Seddon soil. Values below 0.3 per cent. are considered to be indicative of phosphate deficiency.
Observations on survival and growth to weaning of lambs from ewes with defective udders.
Authors: Hayman RH , Turner HN , Turton E
Published: November 2004

Although work has been published showing relationships between milk production of the ewe and growth of the lamb, little has been done to investigate the effects of physical impairment or deficiency in mammary function in the ewe on the survival and growth of the lamb. This point has been studied by examining data for survival, birth weight, daily gain in weight to weaning age, and weaning weight from 621 Merino lambs born in the F. D. McMaster Field Station, C.S.I.R.O., flock from 1946 to 1949. When the performance of lambs from ewes having impaired or imperfect udder function was compared with that of lambs whose dams had normal function it was found that the lambs from ewes having defective function had a lower survival rate, a lower daily gain in weight to weaning age, and lower weight at weaning. The differences were statistically significant. Examination of the dry ewe flock in 1946 revealed that approximately 6 per cent. of all ewes aged from 1 to 7 years had damaged or imperfect udders. There was an association between age and incidence of defective udders, the incidence being highest among the oldest ewes. Culling of affected ewes from the flock was found to have very little effect in increasing the overall percentage of lambs raised to weaning age, or increasing their weaning weight. It is doubtful if culling for this fault would be beneficial in the average commercial Merino flock.
Sources of variation in residual milk and fat in dairy cows : their relation to secretion rates and persistency of lactation.
Authors: Turner HG
Published: November 2004

Duplicate determinations of residual milk and fat were made at milkings following intervals of 10, 14, and 24 hr at two stages of lactation in 12 cows. The data obtained thus represented 144 milkings. The amount of residual milk was correlated with total yield whether differences in total yield arose from differences between cows, stages of lactation, milking intervals, or error variation. The effect of changes in total yield was greater in early lactation than later, but within either stage of lactation the same relationship persisted approximately over most of the variables examined. However, between different milking intervals, change in total yield produced somewhat less effect on residual milk than when total yield varied from other causes. There were also differences between cows in the degree to which residual milk was affected by variation in total yield. For early and late lactation, and for milkings at 10 and 14-hr intervals, the mean relative amount of residual milk was constant at 17.8 per cent. of total yield. For 24-hr milkings it was 13.9 per cent. Independently of differences in yield, cows differed significantly in amount of residual milk. These differences were highly correlated with differences in persistency of lactation, low persistency being associated with high proportion of residual milk. Seventy-five per cent. of variation in persistency was accounted for by differences in residual milk. Fat percentages of residual milk differed between cows, between stages of lactation, and between milking intervals. The data were used to calculate rates of secretion of milk and fat, and fat percentage of milk secreted, during intervals of 10, 14, and 24 hr. With cows normally milked at intervals of 10 and 14 hr, secretion rate was not significantly less during the longer interval, and any difference which may exist must be extremely small. Fat percentage of milk secreted increased when the milking interval was lengthened. Imposition of a single 24-hr interval on cows normally milked twice daily reduced milk secretion rate by only 15 per cent., but there was also an aftereffect of the long interval upon immediately subsequent secretion rate.
Experimental induction of flower formation in Kikuyu grass (Pennisetum clandestinum Hochst. Ex Chiov.
Authors: Carr DJ , Eng Kok Ng
Published: November 2004

The literature on the flowering of kikuyu grass (Pennisetum clandestinum Hochst. ex Chiov.) is summarized. It is shown to be probable that some very vigorous strains are genetically male-sterile. An experiment is described in which flower initiation was caused by repeated defoliation and decapitation of shoots. The control of flowering in kikuyu grass is compared with that in other plants in which removal of apical dominance allows the initiation of flower primordia on lateral branches. The importance of the utilization of the genetic potential of both hermaphrodite and male-sterile strains in any kikuyu grass breeding programme is stressed.
Air-tight storage of grain; its effects on insect pests. II. Calandra oryzae (small strain)
Authors: Bailey SW
Published: November 2004

The independent and joint effects of lowered oxygen tensions and increased carbon dioxide tensions on the adult and immature stages of Calandra oryzae L. (small strain) have been examined. The concentrations of the two gases that occurred among infested grain stored in air-tight containers have been measured. It is concluded that the death of the insects was due to the depletion of oxygen and that the associated accumulation of carbon dioxide played only a minor role. The young immature stages were the most susceptible to the changing concentrations of oxygen and carbon dioxide.
The aetiology of Phalaris staggers in sheep. II. The toxicity to sheep of three types of pasture containing Phalaris tuberosa
Authors: Lee HJ , Kuchel RE , Trowbridge RF
Published: November 2004

The seasonal occurrence of phalaris staggers In sheep on three types of pasture containing Phalaris tuberosa L., during periods of 3 years, 2 years, and 1 year respectively, is described. A relatively pure stand of phalaris proved toxic to sheep for almost 6 consecutive months of its growing period. The consumption of appreciable quantities of lucerne, subterranean clover, or other plants, along with the phalaris, reduced the hazard very considerably. Neither the dormant tubers nor the standing straw of phalaris proved to be toxic. The widespread occurrence of phalaris staggers on a diversity of sol1 types is reported and the possibilities that the toxicity of phalaris may fluctuate according to climate and terrain are discussed. The view is advanced that actively growing phalaris is potentially toxic to sheep under most, if not all, circumstances.
Fat lamb studies in Victoria. I. An assessment of the relative value of various external measurements for differentiating between various grades of export lamb carcasses
Authors: Robinson TJ , Binet FE , Doig AG
Published: November 2004

Sixteen measurements were made on 240 intact export lamb carcasses, representing 12 weight-grade classifications of 20 each, with the object of determining measurements likely to be of value for the assessment of conformation. Six were immediately discarded as being of little value. The remaining 10, which included three probe measurements, were subjected to statistical analysis to determine linear combinations of measurements most convenient for discriminating between grades in each of three weight categories, namely, light (27-28 lb), medium (35-36 lb), and heavy (43-44 lb). The 10 measurements were length of leg ( F ) , depth of thorax (Th), thickness of loin (BC), thickness of flank (P), length of carcass (K), thickness of shoulder (Sh), width of shoulder ( W) , width of flank (E) , width of gigots (G), and twist (Z), with discriminating capacity roughly in that order. BC, P, and Sh were all estimates of muscle and fat obtained by using a probe, and results obtained compared favourably with overseas measurements made on the cut carcass. E, G, and Z had little or no discriminating capacity. Optimum discriminations between grades were given within each weight category by the following combinations of measurements: light — F, K, BC, Sh, P; medium — F, Th; heavy — F, K, W, P; overall — F, Th, BC, P. The groups of carcasses separated into clear weight and grade zones, and several trends were noticeable. The most important of these were: (i) grading of light-weight carcasses was highly subjective between all grades, as both conformation and fat cover were considered; (ii) grading of the top grades in heavier carcasses was more clear-cut and depended primarily on conformation; (iii) there was a tendency for heavier carcasses to be up-graded relative to light carcasses, owing to their heavier fat cover. In view of the fairly clear pattern that emerged from the statistical model used, it is suggested that a rounded form of a discriminant function, namely,

Y' = 0.057F + 0.050Th – 0.097BC – 0.17P, might be a useful index of conformation for fat lamb carcasses of all weights particularly if used in the form:

Conformation score = 250 – 10Y'.
Flowering time in subterranean clover
Authors: Morley FHW , Davern CI
Published: November 2004

Genotype-environment interactions have been observed in the flowering times of a number of varieties of subterranean clover (Trifolium subterraneum L.) grown in different locations. These interactions are interpreted in terms of the effects of photoperiod and temperature on flowering. Sensitivity to photoperiod may be independent of sensitivity to temperature. Flowering times of some strains, although simultaneous in one environment, may differ in another environment. This is due to variation in the relative importance of different components of the environment in controlling flowering time. These strain differences in flowering-time physiology are shown to be related to the climate of the strain's natural habitat. The importance of a knowledge of flowering physiology, and the recognition of the existence of genotype - environment interactions, are discussed in relation to plant breeding and introduction.
Definition of potato virus X strains present in New Zealand potato varieties
Authors: Thomson AD
Published: November 2004

Thirteen different isolates of virus X were made from the main New Zealand potato varieties. Twelve of these proved to be constant strains and the reactions of a number of plant species to them have been studied. All strains gave precipitin reactions with an antiserum prepared against one of them. Inoculation of Datura stramonium L. plants with an avirulent strain prevented their infection with the other strains. The relative severity of the strains on a number of test plants was similar. Nicotiana glutinosa L. was found to be satisfactory for the isolation and differentiation of most strains. Gomphrena globosa L. reacted with local lesions to all the strains. The symptom pictures of the strains have remained constant for 2 years except for one strain (XI), which showed a marked change in symptoms after 3 months in a deep-freeze unit. One isolate, AST1, contained both mild and severe components. Its passage through Cyphomandra betacea Sendt. resulted in the selection of a severe type. The same isolate contained a component which systemically invaded Chenopodium album L. No other strain produced systemic symptoms on this plant.
Parna in the riverine plain of south-eastern Australia and the soils thereon
Authors: Butler BE , Hutton JT
Published: November 2004

This study of Widgelli parna, aeolian material derived from soils during a previous arid period, shows that there is a relationship between particle size and the distance leeward from the dune zones. Within 1 or 2 miles of the dunes the modal size of the non-clay fraction is 150 to 200 µ, and this value changes to 40 µ at a distance of 150 miles leeward. The clay content varies inversely, being about 36 per cent. near the dunes and 70 per cent. 150 miles leeward. The non-clay fraction is highly graded. Within the dune zones, and particularly in the dune itself, the parna is mixed with coarser sand. The size and clay-content relationships for the parna sheet also hold in the dune zones with the modal size at the crest about 400 µ. The landscapes and soils to be related to the parna include the riverine plains, the adjoining hills, and the dune landscape of the Mallee. Highly differentiated soils occur on the parna layer, and these include brown solonized soils in the dune zones, red-brown earths on the hills, and red-brown earths and grey and brown soils of heavy texture on the riverine plains. Soil differentiation is largely caused by drainage differences.
The inheritance of flowering time in Trifolium subterraneum L
Authors: Davern CI , Peak JW , Morley FHW
Published: November 2004

The inheritance of flowering time in subterranean clover, using a number of strains and hybrids among them, was investigated on autumn-sown material at Canberra. Heterosis and dominance were not found, and genetic variation was polygenic. An F1 diallel analysis and F2 two-way analysis showed that approximately 90 per cent. of the total variance was attributable to additive genetic effects. An estimate of the repeatability of strain performance over two seasons showed that small but significant strain-year interactions were occurring. Strain repeatability, as measured by intraclass correlation, was 86 per cent. A breeding test involving F2 selections and their progeny gave a mean parent-offspring regression of 0.86 over the six crosses studied, which is well in accord with expectations of breeding behaviour based on the above analyses. The results are discussed in relation to other studies on flowering time, especially with reference to the problem of interpreting results based on the threshold expression of a character dependent on the value of a continuously variable factor.
The movement of cobalt and zinc in soils as indicated by radioactive isotopes
Authors: Jones GH , Riceman DS , McKenzie JO
Published: November 2004

A method has been developed whereby labelled cobalt and zinc were applied to the surface of columns of soil in order to study the movement of these cations under the influence of rainfall and various fertilizer treatments. The results of the investigation demonstrate that in soils of moderate exchange capacity, whether this is provided by clay or by organic matter, the cobalt and zinc remain close to the surface of the soil even after the application of water equivalent to several years' rainfall and dressings of copper sulphate, superphosphate, aqueous extract of lucerne, and water saturated with carbon dioxide. With very light soils of low exchange capacity a year's rainfall alone did not leach the cobalt or zinc downwards, but rainfall which followed treatments with the same dressings induced a considerable downward movement of both cobalt and zinc.
The distribution of trace elements in some South Australian red-brown earths
Authors: McKenzie RM
Published: November 2004

The maximum, minimum, and mean values for six trace elements in four soil horizons are reported for 14 profiles of red-brown earths from South Australia, and the pattern of variation and distribution of these elements discussed. The elements studied could be arranged in a series of decreasing mobility in the soil, the order being cobalt > copper > gallium > vanadium > molybdenum > manganese. The most mobile elements had greater variations within profiles and, except for manganese, greater variations between profiles. Gallium, vanadium, and molybdenum contents were correlated with the amount of clay present in all surface soils, as well as in individual profiles, whereas cobalt and copper contents were correlated with clay only in individual profiles.
The physical factors involved in the drying of sultana grapes
Authors: Martin RJL , Stott GL
Published: November 2004

The various physical factors involved in the drying of sultana grapes have been determined from measurements of drying rate under definite conditions of temperature, humidity, and air flow, in a specially constructed oven. Ninety-five per cent. of weight lost is water, 2 per cent. is carbon dioxide produced at an almost constant rate during drying, and 3 per cent. unassigned loss. Drying occurs in three distinct stages: (1) the grape retains its regular ellipsoidal shape by an elastic contraction of the skin; (2) the skin commences to wrinkle in the range of 20-50 per cent, loss in original weight; (3) the drying rate decreases markedly, beginning when approximately 95 per cent. of total loss of weight has occurred and when probably all the free water has been removed from the system. For each of these stages there is a linear relation between time and log [c / (c – w) 1, where c is the total loss in weight on complete drying (approximately initial water content), and w is the loss in weight at time t. A drying constant has been calculated from this logarithmic function for the initial stage of drying, and has been used for determining the mechanism of drying. Water movements through the parenchymal cells are fast compared with those through the skin. Since various dipping treatments give different drying rates there is no rate-controlling diffusion through the stationary air layer a t the grape surface. The drying rate is controlled by the diffusion of water through the waxy cuticle, and is inversely proportional to the amount of cuticle present as determined by extraction with chloroform. The elastic contraction of the skin causes an increase in the thickness of the cuticle which reduces the permeability. The heat required for the evaporation of water and for heating the grape to the equilibrium drying temperature is transferred from the surroundings to the grape. The rate of drying increases rapidly with rise in temperature owing to the vapour pressure of water and the permeability of the cuticle increasing with the temperature.
The aetiology of phalaris straggers in sheep. IV. The site of preventive action and its specificity to cobalt
Authors: Lee HJ , Kuchel RE , Good BF , Trowbridge RF
Published: November 2004

The preventive activity of cobalt against phalaris staggers in the sheep is very probably restricted to the rumen. In this disease cobalt does not act within the tissue cells nor within the intestines; cobalt injected intravenously is without effect. The destruction of the toxic substance present in the phalaris does not depend on the production of vitamin B12 by the rumen flora. The probability that cobalt acts by ensuring the proliferation of microorganisms in the rumen which accomplish this detoxication is discussed. The preventive action is specific to cobalt administered orally; frequent doses of a supplement that provide the daily equivalent of 10 mg each of boron, copper, iron, magnesium, manganese, molybdenum, nickel, titanium, and zinc fail to prevent the malady.
The effect of aggregate disruption on the activity of microorganisms in the soil
Authors: Rovira AD , Greacen EL
Published: November 2004

Laboratory tillage of soils causes an increase in the oxygen uptake of soil microorganisms. The effect is closely related to the extent of aggregate disruption caused by the tillage treatment and is attributed largely to exposure of organic matter that was previously inaccessible. In some soils drying and rewetting after tillage causes a further increase in microbial activity, but this is not accounted for by disaggregation. As drying and rewetting commonly follow tillage in the field the resultant higher microbial activity could contribute to the faster mineralization of organic matter in arable land.
Sperm transport in the fowl
Authors: Allen TE , Grigg GW
Published: November 2004

(1) The distributions of living and dead sperm in the oviducts of hens a t various time intervals after artificial insemination were determined by using sperm labelled with 32P and assaying the radioactivity of serial sections of the oviduct. Appropriate. tests of the method showed it to be valid and reasonably accurate for short-term experiments. (2) The number of sperm reaching the site of fertilization at the upper end of the oviduct (the infundibulum) was dependent primarily on where in the lower genital tract the sperm were deposited. Following intravaginal insemination with 2 X 108 sperm, from 7 X 103 to 70 X 103 sperm were detected in the infundibula of different hens up to 1 hr after insemination. After intra-uterine insemination with a like number, from 137 X 103 to 2642 X 10103 sperm were detected. (3) The junction of the vagina and uterus (or shell gland) proved to be a barrier to sperm progress, as was shown by the greater efficiency of sperm utilization above the junction than below it. (4) Dead sperm inseminated intravaginally did not pass into the uterus but those inseminated into the uterus reached the infundibulum in as great numbers as a similar sample of living sperm. This suggested that the mechanism of sperm transport differs on either side of the uterovaginal junction. (5) From the speed of transport of sperm and the passage up the oviduct of sperm-free fluid injected into the uterus, it is suggested that the spasmodic contraction of muscle investing the wall of the upper vagina and lower uterus induced as a response to tactile stimuli is mainly responsible for sperm movement from the uterovaginal junction to the infundibulum. (6) Motility of sperm is necessary only to traverse the vagina and perhaps to penetrate the vitelline membrane of the egg during the process of fertilization. At other stages of movement between the vagina and the egg, sperm play a passive role in their own transport.
Methionine supplements in chicken diets. III. The biochemical difference in sulphur-amino acid metabolism between White Leghorns and Australorps
Authors: McDonald MW
Published: November 2004

The ability of White Leghorn and Australorp chickens to use supplements of methionine or cystine for growth has been studied. While chickens of both breeds responded to a cystine supplement, White Leghorns showed an increase in growth rate when methionine was added to the basal diet but Australorps showed a growth depression. The effect of intraperitoneal injection of DL-methionine on the liver cysteine content of chickens of both breeds was also studied. Injections of 10 or 20 mg DLmethionine produced significant (P < 0.05) and highly significant (P < 0.01) rises in the liver cysteine contents of White Leghorn chickens, but produced only small, non-significant rises in the liver cysteine contents of Australorp chickens. Providing methionine by either intraperitoneal injection or crop drenching did not alter the breed difference in response of liver cysteine content. This indicates no difference between breeds in ability to absorb methionine from the alimentary canal. When all data on the effect of an Injection of 20 mg DL-methionine were examined, there was a significant breed x methionine interaction. These results are interpreted as due to a blockage in the synthesis of cysteine from methionine in Australorps. Attention is drawn to the linkage of the gene (or genes) limiting this process in Australorps with a gene producing slow feathering and thus possibly conserving cysteine. Possible advantages of this linkage are discussed, and a model derived to show that genetic drift would be unlikely to separate the possible genotypes containing the balanced alleles of these genes provided the disadvantage of the unbalanced genotypes was sufficiently great.
Survival of cattle ticks in central Queensland pastures
Authors: Wilkinson PR , Wilson JT
Published: November 2004

Observations on the gradual distension and shrinkage of cattle tick larvae (Boophilus microplus (Canestrini)) confirmed that they can take up water from, or lose water to, the atmosphere under suitable conditions. Further evidence was obtained that partially desiccated larvae can drink when in contact with free water. Consideration of the relative humidities recorded over sward adjoining a creek, during a drought, suggested that larvae would be able to absorb moisture during the 9-hr period before dawn. Dew m-as also available to the larvae in drought time, and on most mornings when observations were made. In the laboratory, larvae in cultures supplied with water droplets lived longer than those in similar cultures not supplied with water. Larval clusters on artificial supports out of doors lived longer if protected by fabric shades. At intervals over 2 years, female ticks were placed in grassland near Rockhampton and at Yeppoon, Qld., under simulated natural conditions. The times of hatching and periods of survival of the larvae were observed. In contrast with the marked decrease in tick fertility which occurs in the winter in south Queensland, ticks put out throughout the winter at Rockhampton laid large numbers of fertile eggs. Very few larval progeny of ticks put out in summer survived 3 months after the date of placement of the parent female. Progeny of ticks put out in the winter persisted up to 54 months after the date of placement of the parent. A graph of the 'pre-hatch' (pre-oviposition plus developmental) periods against screen temperatures followed the trend expected from laboratory data, but the difference between actual and computed hatching dates was large in some cases. Actual hatching date was usually later than computed hatching date, both for ticks in the soil and for ticks in humidified containers in a meteorological screen. The comparatively short survival periods of larvae in the central Queensland summer indicated the practicability of controlling the cattle tick by temporarily destocking pastures.
Extracellular fluid distribution in tropical merino sheep
Authors: Macfarlane WV , Morris RJH , Haward B , Budtz-Olsen OE
Published: November 2004

Merino ewes and wethers maturing from 12 to 53 months of age were studied for 3 1/2 years in the field at Julia Creek (lat. 2° S.) during summer and winter. Measureinents were made of plasma volume and extracellular volume, plasma proteins, haemoglobin, haematocrit, and plasma electrolytes. The range of normal in apparently healthy sheep was found to be very wide. Large changes took place in the fluid volumes during the period of investigation; the changes appeared to be independent of seasons but to a great extent determined by nutrition. Poorly nourished sheep as a whole had increased extracellular fluid space, and the space shrank again on improved pasture. Age and sex did not influence the fluid volumes. Lactation was associated with an increase in fluid spaces, and yard feeding with a decrease. Non-tropical sheep introduced from lat. 30° S. during winter had similar fluid volumes to the tropical sheep when investigated 2 months after their arrival. Tropical Merinos at any age or season had larger plasma volumes than sheep kept in laboratory pens in Brisbane or in Melbourne.