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Showing papers by "Agriculture and Agri-Food Canada published in 2008"


Journal ArticleDOI
TL;DR: In this paper, a variety of nutritional management strategies that reduce enteric methane (CH4) production are discussed, such as increasing the level of grain in the diet, inclusion of lipids and supplementation with ionophores (>24ppm) are most likely to be implemented by farmers.
Abstract: A variety of nutritional management strategies that reduce enteric methane (CH4) production are discussed. Strategies such as increasing the level of grain in the diet, inclusion of lipids and supplementation with ionophores (>24 ppm) are most likely to be implemented by farmers because there is a high probability that they reduce CH4 emissions in addition to improving production efficiency. Improved pasture management, replacing grass silage with maize silage and using legumes hold some promise for CH4 mitigation but as yet their impact is not sufficiently documented. Several new strategies including dietary supplementation with saponins and tannins, selection of yeast cultures and use of fibre-digesting enzymes may mitigate CH4, but these still require extensive research. Most of the studies on reductions in CH4 from ruminants due to diet management are short-term and focussed only on changes in enteric emissions. Future research must examine long-term sustainability of reductions in CH4 production and impacts on the entire farm greenhouse gas budget.

984 citations


Journal ArticleDOI
TL;DR: In this article, the biochemical bases for color and firmness changes in fruit and vegetable tissues are described, since appearance and texture are two of the most fundamental factors affecting the quality of fresh-cut products.

765 citations


Journal ArticleDOI
TL;DR: In this article, the structural characteristics and separation of lignin in the straws of corn, wheat, rice and flax are discussed, and the first attempt to generalize the information about the structure and processes for the separation of Lignin from hemicellulose and cellulose in lignocellulosic crop residues is made.

692 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a synthesis of rotational and continuous grazing on rangelands and conclude that rotational grazing is superior to continuous grazing in terms of ecological effectiveness.

591 citations


Journal ArticleDOI
TL;DR: A novel approach based on a much shorter barcode sequence is established and demonstrated its effectiveness in archival specimens, which will significantly broaden the application of DNA barcoding in biodiversity studies.
Abstract: The goal of DNA barcoding is to develop a species-specific sequence library for all eukaryotes. A 650 bp fragment of the cytochrome c oxidase 1 (CO1) gene has been used successfully for species-level identification in several animal groups. It may be difficult in practice, however, to retrieve a 650 bp fragment from archival specimens, (because of DNA degradation) or from environmental samples (where universal primers are needed). We used a bioinformatics analysis using all CO1 barcode sequences from GenBank and calculated the probability of having species-specific barcodes for varied size fragments. This analysis established the potential of much smaller fragments, mini-barcodes, for identifying unknown specimens. We then developed a universal primer set for the amplification of mini-barcodes. We further successfully tested the utility of this primer set on a comprehensive set of taxa from all major eukaryotic groups as well as archival specimens. In this study we address the important issue of minimum amount of sequence information required for identifying species in DNA barcoding. We establish a novel approach based on a much shorter barcode sequence and demonstrate its effectiveness in archival specimens. This approach will significantly broaden the application of DNA barcoding in biodiversity studies.

586 citations


Journal ArticleDOI
TL;DR: Results from in vitro batch culture studies provide evidence that EO and their components have the potential to improve N and/or energy utilization in ruminants and identification of EO that favorably alter fermentation without resulting in broad overall inhibition of rumen fermentation, continues to be a major challenge for researchers.

472 citations


Journal ArticleDOI
TL;DR: Results indicate that selection is driving the rapid spread of an introduced pathogen population that is more toxigenic and potentially more vigorous and has significant implications for food safety and cereal production in North America.

433 citations


Journal ArticleDOI
TL;DR: Inclusion of soil animals will improve the predictive capabilities of region- or biome-scale decomposition models, soil animal influences on decomposition are important at the regional scale when attempting to predict global change scenarios, and the statistical relationship between decomposition rates and climate, at the global scale, is robust against changes in soil faunal abundance and diversity.
Abstract: Climate and litter quality are primary drivers of terrestrial decomposition and, based on evidence from multisite experiments at regional and global scales, are universally factored into global decomposition models. In contrast, soil animals are considered key regulators of decomposition at local scales but their role at larger scales is unresolved. Soil animals are consequently excluded from global models of organic mineralization processes. Incomplete assessment of the roles of soil animals stems from the difficulties of manipulating invertebrate animals experimentally across large geographic gradients. This is compounded by deficient or inconsistent taxonomy. We report a global decomposition experiment to assess the importance of soil animals in C mineralization, in which a common grass litter substrate was exposed to natural decomposition in either control or reduced animal treatments across 30 sites distributed from 43°S to 68°N on six continents. Animals in the mesofaunal size range were recovered from the litter by Tullgren extraction and identified to common specifications, mostly at the ordinal level. The design of the trials enabled faunal contribution to be evaluated against abiotic parameters between sites. Soil animals increase decomposition rates in temperate and wet tropical climates, but have neutral effects where temperature or moisture constrain biological activity. Our findings highlight that faunal influences on decomposition are dependent on prevailing climatic conditions. We conclude that (1) inclusion of soil animals will improve the predictive capabilities of region- or biome-scale decomposition models, (2) soil animal influences on decomposition are important at the regional scale when attempting to predict global change scenarios, and (3) the statistical relationship between decomposition rates and climate, at the global scale, is robust against changes in soil faunal abundance and diversity.

425 citations


Journal ArticleDOI
TL;DR: In vitro and in vivo studies suggest that the use of antioxidants and other protective compounds in mastitis control programs is worth investigating, because they may aid in alleviating damage to secretory cells and thus reduce subsequent milk loss.
Abstract: Mastitis, an inflammatory reaction of the mammary gland that is usually caused by a microbial infection, is recognized as the most costly disease in dairy cattle. Decreased milk production accounts for approximately 70% of the total cost of mastitis. Mammary tissue damage reduces the number and activity of epithelial cells and consequently contributes to decreased milk production. Mammary tissue damage has been shown to be induced by either apoptosis or necrosis. These 2 distinct types of cell death can be distinguished by morphological, biochemical, and molecular changes in dying cells. Both bacterial factors and host immune reactions contribute to epithelial tissue damage. During infection of the mammary glands, the tissue damage can initially be caused by bacteria and their products. Certain bacteria produce toxins that destroy cell membranes and damage milk-producing tissue, whereas other bacteria are able to invade and multiply within the bovine mammary epithelial cells before causing cell death. In addition, mastitis is characterized by an influx of somatic cells, primarily polymorphonuclear neutrophils, into the mammary gland. With more immune cells migrating into the mammary gland and the breakdown of the blood-milk barrier, damage to the mammary epithelium worsens. It is well known that breakdown of the extracellular matrix can lead to death of the epithelial cells. Meanwhile, polymorphonuclear neutrophils can harm the mammary tissue by releasing reactive oxygen intermediates and proteolytic enzymes. In vitro and in vivo studies suggest that the use of antioxidants and other protective compounds in mastitis control programs is worth investigating, because they may aid in alleviating damage to secretory cells and thus reduce subsequent milk loss.

416 citations


Journal ArticleDOI
TL;DR: McAllister et al. as discussed by the authors proposed to redirect rumen fermentation to reduce methanogenesis in order to reduce the methanogenicity of rumen and achieved a promising result.
Abstract: McAllister, T. A., Newbold, C. J. (2008). Redirecting rumen fermentation to reduce methanogenesis. Australian Journal of Experimental Agriculture, 48, (1-2), 7-13.

413 citations


Journal ArticleDOI
TL;DR: The North American stem rust nomenclature system is proposed to be revised by the addition of four genes (Sr24, Sr31, Sr38, and SrMcN) as the fifth set and differentiates isolates within race TTKS into two separate races: TTKSK and TTKST, with avirulence and virulence on Sr24, respectively.
Abstract: The stem rust resistance gene Sr24 is effective against most races of Puccinia graminis f. sp. tritici, including race TTKS (syn. Ug99), and is used widely in commercial wheat cultivars worldwide. In 2006, susceptible infection responses were observed on wheat lines and cultivars carrying Sr24 in a field stem rust screening nursery at Njoro, Kenya. We derived 28 single-pustule isolates from stem rust samples collected from the 2006 Njoro nursery. The isolates were evaluated for virulence on 16 North American stem rust differential lines; on wheat lines carrying Sr24, Sr31, Sr38, and SrMcN; and on a wheat cultivar with a combination of Sr24 and Sr31. All isolates were identified as race TTKS with additional virulence on Sr31 and Sr38. These isolates were divided into two groups: group A (seven isolates and the two control isolates), producing a low infection type, and group B (21 isolates), producing a high infection type on Sr24, respectively. Isolates of group B represented a new variant of race TTKS with virulence to Sr24. Eighteen simple sequence repeat (SSR) markers were used to examine the genetic relationship between these two groups of isolates in race TTKS and five North American races (MCCF, QCCQ, RCRS, RTHS, and TPMK) that are representative of distinct lineage groups. All isolates of race TTKS shared an identical SSR genotype and were clearly different from North American races. The virulence and SSR data indicated that the new variant of race TTKS with Sr24 virulence likely has arisen via mutation within the TTKS genetic lineage. We propose to revise the North American stem rust nomenclature system by the addition of four genes (Sr24, Sr31, Sr38, and SrMcN) as the fifth set. This revision recognizes the virulence on Sr31 and differentiates isolates within race TTKS into two separate races: TTKSK and TTKST, with avirulence and virulence on Sr24, respectively. The occurrence of race TTKST with combined virulence on Sr24 and Sr31 has substantially increased the vulnerability of wheat to stem rust worldwide.

Journal ArticleDOI
24 Jan 2008-Lipids
TL;DR: The present method takes advantage of differences in the relative elution times between different types of FAs to determine most of the geometric and positional isomers of 16:1, 18:2 and 18:3 without a prior silver-ion separation in total milk fat.
Abstract: Milk fat is a complex mixture of geometric and positional isomers of monounsaturated and polyunsaturated, including short-, long- and branch-chain fatty acids (FAs). There has been partial success to resolve this mixture of FAs using different GC temperature programs, or a combination of GC isothermal and temperature programs. To overcome the problem associated with overlapping isomers prior silver-ion separation was recommended. However, this procedure is time consuming and not practical for routine analysis. In addition, previous methods focused mainly on the trans and cis isomers of 18:1. The present method takes advantage of differences in the relative elution times between different types of FAs. The method involved analyzing each milk fat using the same highly polar 100-m capillary column and GC instrument, and conducting two separations using temperature programs that plateau at 175 and 150 °C. The relative shift among the geometric and positional isomers at these two temperature settings was enough to permit identification of most of the trans and cis 16:1, 18:1 and 20:1, the c/t-18:2 and the c/c/t-18:3 isomers found in milk fat. The identity of these FAs was confirmed by prior separation of the total fatty acid methyl esters (FAMEs) of milk fat using Ag+-SPE columns, and comparing the fractions to the total milk fat. The Ag+-SPE technique was modified to obtain pure saturated, trans- and cis-monounsaturated and diunsaturated FAMEs. By combining the results from these two separate GC analyses, knowing the elution order, it was possible to determine most of the geometric and positional isomers of 16:1, 18:1, 20:1, 18:2 and 18:3 without a prior silver-ion separation. Only few minor FAs could not be resolved, notable the conjugated linoleic acid isomers that still required the complimentary Ag+-HPLC separation. The two GC temperature programs have been successfully used to routinely analyze most FA isomers in total milk and beef fats in about 200 min without the use of prior silver-ion separations.

Journal ArticleDOI
TL;DR: The purpose of this paper is to review the recent literature of the main factors that can improve the nutritional quality of tomato and consequently their beneficial role in human diet and identify several prospects for future research such as modelling and genetic engineering of the nutritional value of tomato.
Abstract: It is widely accepted that a healthy diet is an important factor in preventing chronic diseases, and in improving energy balance and weight management. Studies have shown strong inverse correlations between tomato consumption and the risk of certain types of cancer, cardiovascular diseases and age-related macular degeneration. Because tomato is the second-most important vegetable in the world after potato, this horticultural crop constitutes an excellent source of health-promoting compounds due to the balanced mixture of minerals and antioxidants including vitamins C and E, lycopene, β-carotene, lutein and flavonoids such as quercetin. Improvement in phytonutrients in tomatoes can be achieved by cultivar selection, environmental factors, agronomic practices, stage of ripeness at harvest, and appropriate handling and conditioning all the way from the field to the consumer. The purpose of this paper is to review the recent literature of the main factors that can improve the nutritional quality of tomato and consequently their beneficial role in human diet. The importance of genotype selection and the optimization of environmental conditions (light, temperature, humidity, atmospheric CO2 and air pollutants) for high nutritional value is outlined first, followed by the optimization of agricultural practices (soil properties, water quality, mineral nutrition, salinity, grafting, pruning, growing systems, growth promoters, maturity, and mechanical and pest injuries). The review concludes by identifying several prospects for future research such as modelling and genetic engineering of the nutritional value of tomato.

Journal ArticleDOI
TL;DR: It was found that basic peptides had greater capacity to scavenge hydroxyl radical than acidic or neutral peptides and that hydrophobic peptides contributed more to the antioxidant activities of hydrolysates than the hydrophilic peptides.

Journal ArticleDOI
TL;DR: Li et al. as mentioned in this paper investigated the quality parameters, total carotenoid, phenolic compounds (total phenolics, flavanone glycosides (FGs), and phenolic acids), and antioxidant capacity (ferric reducing antioxidant power (FRAP) assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay).

Journal ArticleDOI
TL;DR: The comprehensive application of green chemistry principles were demonstrated in the preparation of CASN and CASN/GPS composites and it was revealed that CASN was dispersed evenly in the GPS matrix.

Journal ArticleDOI
TL;DR: Plant growth promoting microorganisms and biological control agents are shown to possess secondary beneficial effects that would increase their usefulness as bio-inoculants, regardless of the need for their primary function.
Abstract: Plant growth promoting microorganisms (PGPM) and biological control agents (BCA) are shown to possess secondary beneficial effects that would increase their usefulness as bio-inoculants, regardless of the need for their primary function. Indeed, PGPM, such as Rhizobium and Glomus spp., can promote plant growth and productivity (primary effect) but have now been shown to also play a role in reducing disease (secondary effect). Conversely, BCA, such as Trichoderma and Pseudomonas spp., can control disease (primary effect) but have recently demonstrated stimulation of plant growth (secondary effect) in the absence of a pathogen. Further work shedding light onto the precise mode of action and ecophysiology of these microorganisms would assist with their timely and appropriate use and potentially unleash their full promise as beneficial rhizosphere bio-inoculants for improved growth and health of plants. The potential increased use of these microorganisms afforded by their multifaceted beneficial effects may further help in reducing problems associated with the use of synthetic chemicals in agriculture.

Journal ArticleDOI
TL;DR: The results suggest that anthocyanins can accumulate in tissues, including tissues beyond the blood-brain barrier, and may confer benefits in brain function, including vision.
Abstract: Dietary intervention with anthocyanins may confer benefits in brain function, including vision. Research to date indicates that animals have only a limited capacity to absorb anthocyanins, compared to other types of flavonoids. Pigs, which are a suitable model for human digestive absorption, were used to examine the deposition of anthocyanins in tissues including the liver, eye, and brain tissue. Pigs were fed diets supplemented with 0, 1, 2, or 4% w/w blueberries ( Vaccinium corymbosum L. 'Jersey') for 4 weeks. Prior to euthanasia, pigs were fasted for 18-21 h. Although no anthocyanins were detected in the plasma or urine of the fasted animals, intact anthocyanins were detected in all tissues where they were sought. LC-MS/MS results are presented for the relative concentration of 11 intact anthocyanins in the liver, eye, cortex, and cerebellum. The results suggest that anthocyanins can accumulate in tissues, including tissues beyond the blood-brain barrier.

Journal ArticleDOI
TL;DR: In this paper, the influence of simple (glucose) and complex (red clover and barley residue) carbon sources on the amount of denitrification, N2O molar ratio, and abundance of soil total bacterial and denitrifier communities was investigated using repacked soil cores.
Abstract: Bacterial denitrification plays an important role in the global nitrogen cycle and is a principal contributor of nitrous oxide (N2O) to the atmosphere. The influence of simple (glucose) and complex (red clover and barley residue) carbon (C) sources on the amount of denitrification, N2O molar ratio (N2O:(N2 + N2O)), and abundance of soil total bacterial and denitrifier communities was investigated using repacked soil cores. Quantitative PCR was used to determine the abundance of the total bacterial community (16S rRNA gene) and components of the denitrifier community, cnorBP (Pseudomonas mandelii and related species), cnorBB (Bosea/Bradyrhizobium/Ensifer spp.) and nosZ gene bearing communities. The relationship between the supply of, and demand for, terminal electron acceptors (TEAs), as determined by the relative availability of C and nitrate (NO3−), influenced the amount of denitrification and the N2O molar ratio for both simple and complex C sources. Addition of glucose and red clover to the soil increased microbial activity, leading to NO3− depletion and an increased consumption of N2O, whereas in soil amended with barley straw, there was not sufficient stimulation of microbial activity to create sufficient TEA demand to cause a measurable increase in emissions. This resulted in a higher N2O molar ratio at the end of the incubation for the barley straw amended soil. A significant relationship (R2 = 0.83) was found between respiration and cumulative denitrification, suggesting that the available C increased microbial activity and O2 consumption, which led to conditions favorable for denitrification. The source of C did not significantly affect the total bacterial community or the nosZ copy numbers with an average of 4.9 × 107 16S rRNA gene copies g−1 dry soil and 4.6 × 106 nosZ gene copies g−1 dry soil, respectively. The addition of red clover plus NO3− significantly increased the cnorBP denitrifier community in comparison with the unamended control while the density of the cnorBP denitrifier community increased from 3.9 × 104 copies g−1 dry soil to a maximum of 8.7 × 105 copies g−1 dry soil following addition of glucose plus NO3− to soil. No significant correlations were found between the denitrifier community densities and cumulative denitrification or N2O emissions, suggesting that the denitrification activity was decoupled from the denitrifier community abundance.

Journal ArticleDOI
TL;DR: In this article, a total of 25 field studies presenting direct comparisons between conventional tillage and no-till (approximately 45 site-years of data) were reviewed and grouped according to soil aeration status estimated using drainage class and precipitation during the growing season.
Abstract: Denitrification rates are often greater in no-till than in tilled soils and net soil-surface greenhouse gas emissions could be increased by enhanced soil N 2 O emissions following adoption of no-till. The objective of this study was to summarize published experimental results to assess whether the response of soil N 2 O fluxes to the adoption of no-till is influenced by soil aeration. A total of 25 field studies presenting direct comparisons between conventional tillage and no-till (approximately 45 site-years of data) were reviewed and grouped according to soil aeration status estimated using drainage class and precipitation during the growing season. The summary showed that no-till generally increased N 2 O emissions in poorly-aerated soils but was neutral in soils with good and medium aeration. On average, soil N 2 O emissions under no-till were 0.06 kg N ha −1 lower, 0.12 kg N ha −1 higher and 2.00 kg N ha −1 higher than under tilled soils with good, medium and poor aeration, respectively. Our results therefore suggest that the impact of no-till on N 2 O emissions is small in well-aerated soils but most often positive in soils where aeration is reduced by conditions or properties restricting drainage. Considering typical soil C gains following adoption of no-till, we conclude that increased N 2 O losses may result in a negative greenhouse gas balance for many poorly-drained fine-textured agricultural soils under no-till located in regions with a humid climate.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the thermal effects of vegetation and snow on the heat and water fluxes within patterned ground systems in all five Arctic bioclimate subzones along an 1800 km trans-Arctic temperature gradient in northern Alaska and northwestern Canada.
Abstract: Arctic landscapes have visually striking patterns of small polygons, circles, and hummocks. The linkages between the geophysical and biological components of these systems and their responses to climate changes are not well understood. The "Biocomplexity of Patterned Ground Ecosystems" project examined patterned-ground features (PGFs) in all five Arctic bioclimate subzones along an 1800-km trans-Arctic temperature gradient in northern Alaska and northwestern Canada. This paper provides an overview of the transect to illustrate the trends in climate, PGFs, vegetation, n-factors, soils, active-layer depth, and frost heave along the climate gradient. We emphasize the thermal effects of the vegetation and snow on the heat and water fluxes within patterned-ground systems. Four new modeling approaches build on the theme that vegetation controls microscale soil temperature differences between the centers and margins of the PGFs, and these in turn drive the movement of water, affect the formation of aggradation ice, promote differential soil heave, and regulate a host of system propel-ties that affect the ability of plants to colonize the centers of these features. We conclude with an examination of the possible effects of a climate wan-ning on patterned-ground ecosystems.

Journal ArticleDOI
TL;DR: In this paper, two series of films were prepared by blending poly(vinyl alcohol) (PVA) with NPS and PSN, respectively, and the results revealed that PSN had much smaller sizes and dispersed more homogeneously in PVA matrix, resulting in stronger interactions with PVA.

Journal ArticleDOI
TL;DR: In this article, the phenolic composition, concentration and total antioxidant capacity (TAC) were determined in the flesh and peel of eight advanced cider apple breeding lines and cultivars to be used for cider production in Canada.

Journal ArticleDOI
TL;DR: Observations confirm the persistence of the HR trait over time, which occurred over a 6‐year period, in the absence of herbicide selection pressure, and in spite of the fitness cost associated with hybridization.
Abstract: The existence of transgenic hybrids resulting from transgene escape from genetically modified (GM) crops to wild or weedy relatives is well documented but the fate of the transgene over time in recipient wild species populations is still relatively unknown. This is the first report of the persistence and apparent introgression, i.e. stable incorporation of genes from one differentiated gene pool into another, of an herbicide resistance transgene from Brassica napus into the gene pool of its weedy relative, Brassica rapa, monitored under natural commercial field conditions. Hybridization between glyphosate-resistant [herbicide resistance (HR)] B. napus and B. rapa was first observed at two Quebec sites, Ste Agathe and St Henri, in 2001. B. rapa populations at these two locations were monitored in 2002, 2003 and 2005 for the presence of hybrids and transgene persistence. Hybrid numbers decreased over the 3-year period, from 85 out of ~200 plants surveyed in 2002 to only five out of 200 plants in 2005 (St Henri site). Most hybrids had the HR trait, reduced male fertility, intermediate genome structure, and presence of both species-specific amplified fragment length polymorphism markers. Both F1 and backcross hybrid generations were detected. One introgressed individual, i.e. with the HR trait and diploid ploidy level of B. rapa, was observed in 2005. The latter had reduced pollen viability but produced ~480 seeds. Forty-eight of the 50 progeny grown from this plant were diploid with high pollen viability and 22 had the transgene (1:1 segregation). These observations confirm the persistence of the HR trait over time. Persistence occurred over a 6-year period, in the absence of herbicide selection pressure (with the exception of possible exposure to glyphosate in 2002), and in spite of the fitness cost associated with hybridization.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a minimum set of criteria for reliable soil N 2 O flux measurements using non-flow-through non-steady-state (NFT-NSS) chambers.
Abstract: The vast majority of soil N 2 O flux data reported in the literature was obtained using non-flow-through non-steady-state (NFT-NSS) chambers. Considerable variation in chamber methodology may influence N 2 O flux measurements, however, raising concerns about the reliability and accuracy of these measurements. The objectives of this study were to determine criteria for assessing the quality of soil N 2 O flux measurements made using NFT-NSS chambers, to evaluate NFT-NSS chamber methodologies used in the scientific literature, and to propose a minimum set of criteria for NFT-NSS chamber design and deployment methodology. We identified 16 characteristics of chamber methodology and developed four factors contributing to the quality of N 2 O flux measurements made using NFT-NSS chambers. We compiled a data set of 356 studies and evaluated the quality of each study against the set of characteristics and factors to determine the confidence in the reported N 2 O flux. Confidence in the absolute flux values reported in about 60% of the studies was estimated to be very low or low due to poor methodologies or incomplete reporting. The confidence in flux measurements improved with time; however, there were still about 50% of recent studies (2005-2007) with low or very low confidence levels. This study has shown that the quality of soil N 2 O flux measurements reported in the literature is often poor. While the flux data obtained may be valid for comparisons between situations (e.g., treatments) within a given study, they are often biased estimates of actual fluxes. We propose a minimum set of criteria for reliable soil N 2 O flux measurements using NFT-NSS chambers.

Journal ArticleDOI
TL;DR: Field spectral measurements collected over corn and wheat canopies in different intensive field campaigns organized during the growing seasons of 2004 and 2005 were used to test and evaluate several combined indices for chlorophyll determination using hyperspectral imagery (Compact Airborne Spectrographic Imager).
Abstract: This paper examines the use of simulated and measured canopy reflectance for chlorophyll estimation over crop canopies. Field spectral measurements were collected over corn and wheat canopies in different intensive field campaigns organized during the growing seasons of 2004 and 2005. They were used to test and evaluate several combined indices for chlorophyll determination using hyperspectral imagery (Compact Airborne Spectrographic Imager). Several index combinations were investigated using both PROSPECT-SAILH canopy simulated spectra and field-measured reflectances. The relationships between leaf chlorophyll content and combined optical indices have shown similar trends for both PROSPECT-SAILH simulated data and ground-measured data sets, which indicates that both spectral measurements and radiative transfer models hold comparable potential for the quantitative retrieval of crop foliar pigments. The data set used has shown that crop type had a clear influence on the establishment of predictive equations as well as on their validation. In addition to generating different predictive equations, corn and wheat data yielded contrasting agreement between estimated and measured chlorophyll contents even for the same predictive algorithm. Among the set of indices tested in this paper, index combinations like modified chlorophyll absorption ratio index/optimized soil-adjusted vegetation index (OSAVI), triangular chlorophyll index/OSAVI, moderate resolution imaging spectrometer terrestrial chlorophyll index/improved soil-adjusted vegetation index (MSAVI), and red-edge model/MSAVI seem to be relatively consistent and more stable as estimators of crop chlorophyll content.

Journal ArticleDOI
TL;DR: This discussion paper proposes that any newly found isolates of PVY should be described within the context of the original strain groups based on the original methods of distinguishing strains, and sequence characterization of the complete genomes of isolates is highly recommended.
Abstract: Potato virus Y (PVY) strain groups are based on host response and resistance gene interactions. The strain groups PVYO, PVYC and PVYN are well established for the isolates infecting potato in the field. A switch in the emphasis from host response to nucleotide sequence differences in the virus genomes, detection of isolates recombining sequences of different strains, and the need to recognize isolates that cause necrotic symptoms in potato tubers have led to the assignment of new acronyms, especially to isolates of the PVYN strain group. This discussion paper proposes that any newly found isolates should be described within the context of the original strain groups based on the original methods of distinguishing strains (i.e., tobacco and potato assays involving use of ‘differential’ potato cultivars). Additionally, sequence characterization of the complete genomes of isolates is highly recommended. However, it is acceptable to amend the names of PVY isolates with additional, specific codes to show that the isolate differs at the molecular, serological or phenotypic level from the typical strains within a strain group. The new isolates should preferably not be named using geographical, cultivar, or place-association designations. Since many new variants of PVY are being discovered, any new static classification system will be meaningless for the time being. A more systematic investigation and characterization of PVY from potato at the biological and molecular levels should eventually result in a biologically meaningful genetic strain concept.

Journal ArticleDOI
TL;DR: In this paper, a comparison of the scavenging capacity (antioxidant activity) of the combinations of antioxidants to the arithmetic sum of scavenging capacities of the individual antioxidants was used to calculate the synergistic effects (SEs) between the antioxidants.
Abstract: The biological activity of lycopene can be enhanced by the presence of these other active antioxidants such as β-carotene, vitamin E, and vitamin C. Since many of these natural antioxidants are consumed together in foods, the potential for synergistic interactions is high in the human diet. The aim of this study was to determine what concentrations and combinations of antioxidants among lycopene, vitamin E, vitamin C, and β-carotene are capable of producing synergistic antioxidant effects, based on tomato-based food products. Solutions of the scavenging capacities of lycopene, vitamin E, vitamin C, and β-carotene, alone and in different combinations were measured using the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Three different levels of each antioxidant were used. A comparison of the scavenging capacity (antioxidant activity) of the combinations of antioxidants to the arithmetic sum of the scavenging capacities of the individual antioxidants was used to calculate the synergistic effects (SEs) between the antioxidants. The results showed that the mixture that had the highest SEs (P<0.01) was the solution combining lycopene (15 μmol/L), vitamin E (5.0 μmol/L), vitamin C (0.16 μmol/L), and β-carotene (10.83 μmol/L). The results suggest that the antioxidant property of this combination was substantially superior to the sum of the individual antioxidant effects, and these interactions can enhance the antioxidant effectiveness of natural antioxidants. The results could guide in the formulation and development of functional food products that have high antioxidant potential.

Journal ArticleDOI
TL;DR: In this paper, the effects of CMC and MC contents on the morphology, thermal stability, dynamic mechanical thermal analysis (DMTA), mechanical properties, as well as water vapor permeability (WVP) were investigated.

Journal ArticleDOI
TL;DR: In this paper, the authors applied the Box-Behnken design to evaluate the effects of three independent variables (ultrasonic power, time and temperature) on the recovery and 1,1′-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of longan fruit pericarp (PLFP).