Glyphosate resistance in annual ryegrass (Lolium rigidum Gaud.) with multiple resistance mechanisms.

Glyphosate (N-(phosphonomethyl)glycine) is a post-emergent, systemic and non-selective herbicide for the control of annual and perennial weeds. This herbicide has very low toxicity to the mammals. The target enzyme for glyphosate in plants is 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Glyphosate inhibits the biosynthesis of the aromatic amino acids phenylalanine, tyrosine and tryptophan in the plant. The first case of glyphosate resistance was reported in Lolium rigidum in Australia after 15 years of persistence use of this herbicide and the number weeds reported resistant to glyphosate has increased around the world. So far, two mechanisms known to be involved in resistance to glyphosate are target-site mutation and reduced herbicide translocation. Recently, two populations of L. rigidum from Australia have been discovered with very high levels of resistance to glyphosate. This project aims to determine the levels of glyphosate resistance in these populations, investigate glyphosate resistance mechanisms in the populations and finally assess the mode of inheritance of resistance. In this project, four resistant (NLR70, SLR77, SLR80 and SLR88) and one susceptible (VLR1) L. rigidum populations were evaluated for their response to glyphosate. From the dose response experiments, the susceptible population of VLR1 was completely controlled with the recommended rate of glyphosate (450 g a.e ha⁻ ¹). In contrast, the resistant populations were not fully controlled by this herbicide rate. There was considerable variation between the populations in their resistance to glyphosate. In comparison to the susceptible population VLR1, SLR77 was 2.2 to 3.5 fold resistant to glyphosate, NLR70 was 3.7 to 8.4 fold resistant to glyphosate, SLR88 was 5.6 to 11.4 fold resistant to glyphosate and SLR80 was 8.2 to 76.7 fold resistant to glyphosate. The mechanism of glyphosate resistance in the populations was investigated. ¹⁴ C-glyphosate was used to determine the absorption and translocation of glyphosate among the populations. There was no significant difference on the absorption of ¹⁴ C-glyphosate 48 hours after treatment in the population. However, the accumulation of ¹⁴ C-glyphosate in the stem region was higher in the susceptible VLR1 population (25.9%) and in resistant SLR77 (25%) than the other three populations. The resistant populations NLR70, SLR88 and SLR80 had about half the amount of glyphosate accumulating in the stem region. These three resistant populations appear to be resistant to glyphosate as a result of reduced translocation of glyphosate to the shoot meristem. Part of the EPSP synthase gene of the susceptible and four resistant populations was amplified and sequenced to identify any changes in the nucleotide sequence. The predicted amino acid sequence from the susceptible population VLR1 was the same as the consensus sequence from other plant species in the conserved region sequenced. However, the resistant populations of NLR70, SLR77, SLR80 and SLR88 showed polymorphisms within the nucleotide sequence in this region. Single nucleotide substitutions of A for C at codon 106 were observed in the resistant populations SLR77 and SLR80. This nucleotide change is predicted to substitute threonine for proline at position 106. In the resistant population SLR88, a nucleotide substitution of T for C was observed at the same codon. This nucleotide substitution is predicted to change the amino acid from proline 106 to serine. Therefore, these three populations appear to be resistant to glyphosate as a result of a target-site mutation. An inheritance study was conducted by cross pollinating the susceptible VLR1 and resistant SLR88 population. From the dose response, the parent susceptible was completely killed with the recommended rate of glyphosate and higher rates of glyphosate were required to control parental resistant and both F₁ progenies (maternal susceptible and resistant). Both F₁ progenies showed an intermediate response to glyphosate compared with the parental populations. This indicated that the resistance to glyphosate in population SLR88 is inherited by nuclear gene(s) through the transfer of pollen during the cross pollination. It is suggested that SLR88 and SLR80 population contain both glyphosate resistant mechanisms due to the cross pollination between individuals with different resistant mechanisms. Having two resistant mechanisms results in populations being highly resistant to glyphosate compared to those with one resistance mechanism. The higher level of glyphosate resistance in these multiple glyphosate resistance populations will likely make them harder to manage.Thesis (M.Ag.Sc.) -- University of Adelaide, School of Agriculture, Food and Wine, 201

Pollution Control, Competitiveness, and Border Tax Adjustment

This paper explores in a general equilibrium framework the welfare and sectoral implications of an optimally designed system of border tax adjustments (BTA) on the imports of energy-intensive industries. Recently, several propositions have been made by policy makers and researchers to use BTA as a restrictive trade policy instrument to address the loss of competitiveness induced by unilateral stringent domestic pollution control policies. In this paper, we define the loss of competitiveness not as a loss of output by domestic energy-intensive producers, but instead as a loss of their market shares. We argue and we show using the Canadian economy as illustration that the most often proposed BTA, which is based on the carbon embodiment of the import good, may under- or over-achieve the objective of addressing the competitive disadvantage of domestic energy-intensive industries. In some cases, the proposed BTA may over protect the domestic energy-intensive industries by providing implicit subsidies as they might even increase their production in the presence of carbon taxes. Similarly, the proposed BTA may fail to fully restore the competitiveness of domestic producers, vis-à-vis their foreign peers. We determine the optimal BTAs on imports that fully restore the competitiveness of domestic firms following unilateral stringent pollution control policies. The ‘optimal’ BTAs take into consideration the general equilibrium effects of the carbon tax and of the import charges on the prices of domestic goods. In most cases, the impact their impact on import prices is higher than in the previous case. As a consequence, they entail higher distortions on resource allocation in the economy and hence higher welfare cost to households.Border tax adjustment, competitiveness, energy-intensive industries, general equilibrium, Canada.

Hadronisation corrections for jets in the k_t algorithm

It has recently been established that hadronisation corrections to QCD jets vary as $1/R$, at small $R$, for jets of radius $R$. Here we demonstrate, using jets in the $k_t$ algorithm, that the magnitude of these $1/R$ corrections are unambiguously linked to the magnitude of $1/Q$ corrections to commonly studied event shapes in $e^{+}e^{-}$ annihilation.Comment: Presented at DIS 2009, Madrid, Spai

Konsumen dan Produsen Jasa: antara Persepsi dan Ekspektasi

Muncul dan disepakatinya Deklarasi Bogor telah semakin mempertegas sosok ekonomi kita sejak dekade awal tahun 2000 an. Pergeseran tulang punggung ekonomi kita bukan saja hanya telah dan akan terjadi dari sekotor pertanian ke industri, tetapi juga dari ketergantungan akan minyak menjadi menggantungkan diri pada sektor industri dan jasa

Non-global logarithms at finite Nc beyond leading order

We analytically compute non-global logarithms at finite Nc fully up to 4 loops and partially at 5 loops, for the hemisphere mass distribution in e+e- to di-jets to leading logarithmic accuracy. Our method of calculation relies solely on integrating the eikonal squared-amplitudes for the emission of soft energy-ordered real-virtual gluons over the appropriate phase space. We show that the series of non-global logarithms in the said distribution exhibits a pattern of exponentiation thus confirming - by means of brute force - previous findings. In the large-Nc limit, our results coincide with those recently reported in literature. A comparison of our proposed exponential form with all-orders numerical solutions is performed and the phenomenological impact of the finite-Nc corrections is discussed.Comment: 31 pages, 5 figure, uses jheppub.sty, minor corrections to previous version and added some reference

Energy Substitutability in Canadian Manufacturing: Econometric Estimation with Bootstrap Confidence Intervals

This study provides estimates of the price and Morishima substitution elasticities between energy and non-energy inputs in two Canadian energy-intensive manufacturing industries: Primary Metal and Cement. The elasticities are estimated using annual industry-level KLEM data (1961- 2003) and relying on two flexible functional forms: the Translog and the Symmetric Generalized McFadden (SGM) cost functions. In addition to the point estimates, the confidence intervals of the elasticities are computed using single- and double-bootstrap resampling techniques. For both industries, the estimation results suggest that capital, labour, material and energy are pairwise substitutes and that energy is the most substitutable input. However, the low magnitudes of the estimated elasticities do not seem to offer great flexibility to these industries to adapt to high increases in energy prices.Energy; Elasticity of substitution; Translog cost function; Symmetric Generalized McFadden (SGM) Cost Function; Single Bootstrap; Double Bootstrap.