Variation in branchlet delta13C in relation to branchlet nitrogen concentration and growth in 8-year-old hoop pine families (Araucaria cunninghamii) in subtropical Australia     

Prasolova NV  Xu ZH  Farquhar GD  Saffigna PG  Dieters MJ 《Tree physiology》2000,20(15):1049-1055

Carbon isotope composition (delta13C) of branchlet tissue at nine canopy positions, and nitrogen concentration (N(mass)) at four canopy positions, were assessed in 8-year-old hoop pine (Araucaria cunninghamii Ait. ex D. Don) trees from 23 half-sib families, grown in six blocks of a progeny test in southeastern Queensland, Australia. There was considerable variation among sampling positions, families and blocks in both delta13C and N(mass). The delta13C was positively related to N(mass) only for samples from the upper outer crown (P < 0.005). Phenotypic correlations existed between tree growth and canopy delta13C. Branchlet delta13C of the inner and lower outer crown was positively related (P < 0.037) to tree height, but delta13C in branchlets of the upper outer crown was not related to tree height, or was related negatively (P < 0.045). There were significant differences in delta13C between hoop pine families for six canopy positions (upper canopy positions as well as lower canopy positions on the northern side), with heritabilities greater than 0.40. The significance of these findings is discussed in relation to water and light competition within the tree canopy of hoop pine.  相似文献   

Inheritance of Carbon Isotope Discrimination in Bread Wheat (Triticum Aestivum L.)     

G. J. Rebetzke  R. A. Richards  A. G. Condon  G. D. Farquhar 《Euphytica》2006,150(1-2):97-106

Summary Reliable selection of families with increased grain yield is difficult in breeding programs targeting water-limited environments. Carbon isotope discrimination (Δ) is negatively correlated with transpiration efficiency, and low Δ is being used for indirect selection of high wheat yield in rainfed environments. Yet little is known of genetic control and opportunities for improving selection efficiency of Δ in wheat. Half-diallel and generation means mating designs were undertaken to provide estimates of the size and nature of gene action for Δ in a range of wheat genotypes varying for this trait. Significant (P < 0.01) differences were observed for leaf tissue Δ among parents (19.3 to 20.7‰) and F₁ progeny (19.4 to 20.9‰) in the half-diallel. General (GCA) and specific combining ability (SCA) effects were significant (P < 0.05), while Baker's GCA/SCA variance ratio of 0.89 was close to unity, indicating largely additive gene effects. GCA effects varied from −0.38 to + 0.34‰ for low and high Δ genotypes `Quarrion' and `Gutha', respectively. GCA effects and parental means were strongly correlated (r = 0.95, P < 0.01) while directional dominance and epistasis contributed to small, non-additive gene action for Δ. Smaller Δ in F₁ progeny was associated with accumulation of recessive alleles from the low Δ parent. Narrow-sense heritability was high (0.86) on a single-plant basis. Generation means analysis was undertaken on crosses between low Δ genotype Quarrion and two higher Δ genotypes `Genaro M81' and `Hartog'. The F₁, F₂ and midparent means were not statistically (P > 0.05) different, whereas backcrossing significantly changed Δ toward the mean of the recurrent parent. Gene action was largely additive with evidence for additive × additive epistasis in one cross. Narrow-sense heritabilities were moderate in size (0.29 to 0.43) on a single-plant basis. Genetic gain for Δ in wheat should be readily achieved in selection among inbred or partially inbred families during the later stages of population development.  相似文献   

An examination of temporal/spatial variations in landfill-generated methane gas     

E. A. McBean  G. J. Farquhar 《Water, air, and soil pollution》1980,13(2):157-172

The experimental findings of a data-intensive in situ landfill monitoring study are described. Particular attention is given to the methodology employed in collecting the data, analyses of the spatial/ temporal variability of the gas percentages, by volume and the extent to which the variability in collected results is explained by variations in exogenous independent variables. Measurable gas flow rates from the soil could not be detected through the probe system employed in the field study.  相似文献   

Superphosphate and its effect on bone fluoride concentrations in sheep     

RW MASON  RND REID †  PG BROWN 《Australian veterinary journal》1989,66(4):120-121

  相似文献   

An automated in-line clinical mastitis detection system using measurement of conductivity from foremilk of individual udder quarters     

RW Claycomb  PT Johnstone  GA Mein  RA Sherlock 《New Zealand veterinary journal》2013,61(4):208-214

AIM: To assess a novel method for automatic in-line detection of clinical mastitis.

METHODS: For a brief period at the start of milking for each cow, electrical conductivity of foremilk was measured for each quarter in turn, using a single sensor installed in the long milk tube (LMT) about 1.5 m downstream from the milking-machine claw. Sequential separation of flow between udder quarters was achieved by control of pulsation to individual teatcups within a conventional cluster. The ratio of conductivity values between quarters was used as an indicator of mastitis status. The concept was evaluated initially in a pilot trial in a 200-cow herd milked in a 23-stall swing-over herringbone milking parlour. It was then tested rigorously in a field trial in a 640-cow herd milked in a 50-stall rotary milking parlour. Both trials were conducted in the Waikato region of New Zealand. In the latter trial, sensor results were compared with visual inspection of a commercial in-line mastitis filter fitted to each milking unit. These filters were inspected for clots immediately after every cow's milking, for 3 weeks. The dataset of approximately 27,000 individual milkings was tested against several published or potential alter- native ‘gold standards’ for diagnosing clinical mastitis.

RESULTS: In the pilot trial, 12–14 clinical events were detected out of 19 true clinical quarters, with a false-alert rate of between three and five false electrical-conductivity alerts per 1,000 individual milkings. In the more rigorous field trial, sensitivity ranged from 68 to 88%, and the false-alert rate (false-alert episodes per 1,000 individual milkings) ranged from 2.3 to 7.0.

CONCLUSION: The novel clinical mastitis detection system, based on separation of the flow and measurement of electrical conductivity from foremilk of individual udder quarters, has the potential to provide a new tool for helping farmers to monitor clinical mastitis in herds milked with conventional clusters.  相似文献   

Water cycle varies over land and sea   总被引：1，自引：0，他引：1  

Roderick ML  Sun F  Farquhar GD 《Science (New York, N.Y.)》2012,336(6086):1230-1231

  相似文献   

Human psittacosis associated with commercial processing of turkeys.     

P T Durfee  M M Pullen  I I Currier RW  R L Parker 《Journal of the American Veterinary Medical Association》1975,167(9):804-808

Between May 1 and Aug 1, 1974, 114 of approximately 1,000 employees in 7 turkey processing plants in Texas (5), Missouri (1), and Nebraska (1) had an illness compatible with psittacosis. The illness was characterized by fever, severe headache, and pneumonia. Treatment with tetracycline was effective in most cases. Psittacosis was confirmed in 41 (36%) of the cases by a fourfold change in complement-fixation titer to the Chlamydia group antigen. Investigations implicated several turkey flocks from Texas as the source of the disease. Control measured, including screening turkey flocks before slaughter and assuring treatment of infected birds, were instituted by a special task force of state and federal veterinarians.  相似文献   

First record of Ornithonyssus bacoti from a domestic pet in the United Kingdom     

Fox MT  Baker AS  Farquhar R  Eve E 《The Veterinary record》2004,154(14):437-438

  相似文献   

Immunodetection of a disease specific PrP fraction in scrapie-affected sheep and BSE-affected cattle.     

S Mohri  C F Farquhar  R A Somerville  M Jeffrey  J Foster  J Hope 《The Veterinary record》1992,131(23):537-539

  相似文献   

Abstract of Current Literature     

Shaw JHF  Wolfe RW 《Veterinary surgery : VS》1985,14(2):159-159

  相似文献