Effects of flaxseed supplementation on milk production,milk fatty acid composition and nutrient utilization by lactating dairy cows

Twelve multiparous Holstein cows at 72 ± 20 days in milk were used in a switch-back design with 14-d periods to determine the effect of replacing barley grain into a dairy total mixed ration with micronized or raw flaxseed on nutrient digestibility, milk yield, milk composition. Total mixed diets were (DM basis) 50% barley silage, 50% concentrate mix mainly rolled barley grain and canola meal. Diets were supplemented with 1 kg raw (RF) or micronized (MF) flaxseed to substitute 1 kg of rolled barley grain (C). Neutral detergent fibre, ADF and CP digestibility of the diets were not significantly affected by supplementation; however, calcium digestibility was reduced by 62% and 46% when raw and micronized flax were fed, respectively. Milk yield (38.3, 39.6, and 38.4 kg/d for diets C, RF and MF, respectively) was similar for all diets. Milk fat (3.50, 3.48, and 3.52%) and protein (3.31, 3.34, and 3.31%) for diets C, RF and MF, respectively, were not affected by treatment diets. Concentrations of c9, t11 conjugated linoleic acid (CLA; 0.51, 0.72 and 0.76 g/100 g fatty acids) in milk fat increased (P < 0.05) similarly among the two flaxseed supplemented diets. The RF and MF diets significantly increased the C18:1, C18:1 trans-11, C18:2 cis-9, cis-12 and C18:3 in milk fat however, C12:0, C14:0 and C16:0 were significantly reduced compared with control. Replacing barley grain with flaxseed in the diet of lactating cows increased the beneficial fatty acids in milk without depressing nutrient digestibility. Micronization of flaxseed did not reveal any advantage over raw flaxseed.     

Total area of C-heterochromatin in nuclei and chromosomes as a measure of cultivated flax genome variability

Comparative statistical analysis of total C-heterochromatin content (total area of darkly stained C-bands) in prophase nuclei and metaphase chromosomes of eight flax (Linum usitatissimum L.) varieties, viz., three oil flax varieties (Shafir, Oliver, Linotte), three modern (Orshansky-2, Belinka, Baltuchai) and two ancient fiber flax varieties (Zaretsky Kryazh, K-37) has been carried out. Karyotypes of flax varieties selected for different agronomical traits differed from one another in C-heterochromatin content. The total C-band area of oil flax varieties exceeded that of fiber flax varieties. Genomic polymorphism in C-heterochromatin markers is a testimony of different breeding directions. A simple test for determining total C-heterochromatin content in prophase nuclei is recommended as a useful tool for screening specimens with predetermined characteristics during selection of new varieties.     

Variation within flax (Linum usitatissimum) and barley (Hordeum vulgare) in response to allelopathic chemicals

Summary A possible method of manipulating allelopathy would be to develop crop varieties showing an increased tolerance to allelopathic chemicals. We therefore examined four flax (Linum usitatissimum) varieties and two wild Linum species in the presence of p-coumaric acid and four barley (Hordeum vulgare) varieties in the presence of p-coumaric acid, scopoletin and wild oat (Avena fatua) extract. Analysis of variance indicates significant interaction between variety and treatment for shoot and root growth for seedling flax, shoot growth for older flax, and root growth for seedling barley. These differences in tolerance between varieties could be exploited to develop-varieties with greater tolerances to the allelochemicals produced by weeds or in crop residues and therefore potentially more tolerant of the presence of weeds.     

Identification of Canadian durum wheat varieties using a single PCR

Accurate and reliable means of variety identification are necessary to assess purity of seed supplies, to support claims relating to plant breeders rights and, in Canada, to provide quality assurances in the grain handling system. A single, multiplexed set of seven simple-sequence-repeat (SSR) markers was found to uniquely identify all 18 durum wheat varieties that have been developed in Canada and are currently, or were formerly, registered for commercial production. Significant features of this multiplexed set include an allele that is specific, within Canadian durum varieties, to those having high gluten strength, and redundancy that was included in an effort to increase the capacity to accommodate future varieties. In combination with a reasonably rapid individual-kernel DNA extraction protocol and automated allele calling, this marker system offers a higher resolution alternative to complement established protein-based variety identification methods.Communicated by P. Langridge     

QTL mapping reveals genetic architectures of malting quality between Australian and Canadian malting barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.)

Australia and Canada are major exporters of malting barley (Hordeum vulgare L.), with Baudin from Australia and AC Metcalfe from Canada being the benchmark varieties for premium malting quality in the past 10 years. We used the barley doubled haploid population derived from a cross of Baudin and AC Metcalfe to map quantitative trait loci (QTLs) for malting quality. The results revealed different genetic architectures controlling malting quality for the two cultivars. Sixteen QTLs were identified and located on chromosomes 1H, 2H, 5H and 7H. The Australian barley Baudin mainly contributed to the malting quality QTL traits of high diastatic power and high β-glucanase on chromosome 1H, while Canadian barley AC Metcalfe mainly contributed to the QTL traits of high hot water extract, high free amino nitrogen, high α-amylase and low malt yield in chromosome 5HL telomere region. This study demonstrated the potential to breed new barley varieties with superior malting quality by integrating genes from Australian and Canadian malting barley varieties. This paper also provides methods to anchor traditional molecular markers without sequence information, such as amplified fragment length polymorphism markers, into the physical map of barley cv. ‘Morex’.     

The effect of rate and Cd concentration of repeated phosphate fertilizer applications on seed Cd concentration varies with crop type and environment

Background and aims

Limited information is available on how cadmium (Cd) applied in phosphate fertilizer interacts with soil and environmental conditions over time to affect crop Cd concentrations.

Methods

Field studies from 2002 to 2009 at seven locations evaluated the cumulative effects of P fertilizer rate and Cd concentration on seed Cd concentration of durum wheat (Triticum turgidum L.) and flax (Linum usitatissiumum L.).

Results

Soil characteristics and environment affected Cd availability. Durum wheat grain Cd increased with P fertilizer rate but effect on flaxseed Cd concentration was smaller. Cadmium concentration in fertilizer had a greater effect on flaxseed than durum wheat Cd concentration. Seed Cd concentration of both crops was greatest with the highest rate P fertilizer containing the highest Cd concentration. There was not a strong cumulative effect of fertilization over the 8 years of the study, indicating attenuation of Cd availability over time.

Conclusions

Cadmium in phosphate fertilizer increases Cd available for crop uptake, but crop Cd concentration is also affected by soil characteristics and annual environmental conditions. Type of crop produced and soil and environmental characteristics that affect phytoavailability must be taken into account when assessing the Cd risk from P fertilization.     

The assessment of field trials in GMO research around the world and their possible integration in field trials for variety registration

Most regulations worldwide stipulate that a new genetically modified (GM) crop event has to be compared to its closest non-GM counterpart as a corner stone of the pre-market risk assessment. To this end the GM crop and its comparator should be grown in field trials for a phenotypic comparison as well as for subsequent detailed analysis of the composition of the two crop varieties. A more in-depth globally harmonised approach for the conduct of these field trials is lacking. Only a few countries have formulated detailed protocols for the set-up of GM field trials. In some countries, commercial non-GM reference varieties need to be included in a field study to compile reliable data that indicate the range of natural variation for the compounds tested at the specific location. Detailed analysis of pre-market assessment reports have so far not shown the added value of including these reference varieties in the field trials. In all cases where specific values were found to be outside of the range of the reference varieties, it proved possible to draw conclusions on the part of the pre-market risk assessment that relates to the compositional analysis, on the basis of already available compositional data. With the increasing quality of several databases on compositional data of a growing number of crop species, it seems unlikely that reference varieties will become more important on future occasions. It was furthermore investigated whether this part of the risk assessment can be related to field trial requirements for variety registration with the explicit intention of reducing the data burden on producers of new GM plant varieties. Field trials for variety registration so far include an assessment of phenotypic characteristics that do not cover safety aspects, with the exception of establishment of the glycoalkaloid content in potatoes in the Netherlands and Sweden. It may, however, under certain conditions be relatively easy to exchange data from compositional measurements between variety registration and GM testing procedures, thus laying a foundation for testing the feasibility of combining both pre-market assessment procedures in a single pre-market evaluation path.     

Preceding crop and phosphorus fertilization affect cadmium and zinc concentration of flaxseed under conventional and reduced tillage

Field studies were conducted over 4 years at two locations in Manitoba, Canada to evaluate effects of preceding crop, tillage and phosphorus (P) fertilization on Cd and Zn concentration in oilseed flax (linseed—Linum usitatissimum L.). Canola (Brassica napus L.) and spring wheat (Triticum aestivum L.) were grown under conventional and reduced tillage with three rates of monoammonium phosphate. Flax was seeded the year following the spring wheat or canola, with or without P fertilizer, and Cd and Zn concentration and accumulation were determined in the flax tissue at 5 weeks and in the mature seed. Flax following canola had lower Zn concentration and accumulation and higher Cd concentration and Cd:Zn ratio in the tissue and seed relative to flax following wheat. Phosphorus fertilization tended to increase Cd concentration and Cd:Zn ratio and decrease Zn concentration in the tissue and seed. Effects of tillage and interactions among tillage, preceding crop, and P fertilization were inconsistent. Changes in flax Cd and Zn concentration may be due to changes in mycorrhizal colonization or by the high concentration of Cd in the decomposing canola residue. Crop sequence and P management can be used to improve flaxseed food quality, by increasing Zn and decreasing Cd concentration.     

Monitoring the occurrence of genetically modified soybean and maize around cultivated fields and at a grain receiving port in Korea

Increased imports of genetically modified (CM) soybean and maize might cause genetic contamination of those crops that are conventionally bred, as well as wild soybeans within Korea. Leaves of maize and both cultivated and wild soybeans were sampled in and near rural fields to detect the presence of transgenes. Roadsides around a major grain port in Incheon were also surveyed to monitor the occurrence of incoming CM soybean and maize. The amplificability of DNA extracted from the collected samples was determined by PCR using soybean- or maize-specific primers: lectin and zein genes, respectively. The presence or absence of transgenes was detected by primer sets for the 35S and nos genes. Transgenes were not found in the cultivated or wild soybean or in the maize collected from cultivated fields. However, we obtained one GM maize plant among seven along the roadsides around Incheon Port. Although the effect of a single GM maize plant would be negligible and would not pose any threat to natural environments, an increase in the import of GM plants might lead to future, unapproved cultivation of GM crops. Therefore, appropriate monitoring is necessary to detect the occurrence of GM plants in areas around grain receiving ports and within agroecosystems.     

Detection of aster yellows phytoplasma in false flax based on PCR and RFLP

False flax (Camelina sativa L.) plants were found to be infected with a yellows-type disease caused by a phytoplasma in experimental plots at the Edmonton Research station. Alberta, Canada. Typical phytoplasmas were detected in the phloem cells in ultrathin sections from leaf midrib tissues examined by electron microscopy. These observations were supported by polymerase chain reaction (PCR) using two primer pairs, R16 F2n/R2 and R16(1)F1/R1, derived from phytoplasma rDNA sequences. Aster yellows (AY) and potato witches'-broom (PWB) phytoplasma DNA samples served as controls and were used to study group relatedness. In a direct PCR assay, DNA amplification with universal primer pair R16F2n/R2 gave the expected PCR products of 1.2 kb. Based on a nested-PCR assay using the latter PCR products as templates, and a specific primer pair, R16(1)F1/R1, designed on the basis of AY phytoplasma rDNA sequences, a PCR product of 1.1 kb was obtained from each phytoplasma-infected false flax and AY sample, but not from PWB phytoplasma and healthy controls. DNA amplification with specific primer pair R16(1)F1/R1 and restriction fragment length polymorphism indicated the presence of AY phytoplasma in the infected false flax sample. This is the first reported characterization of AY phytoplasma in false flax.     

Changes in the Ribonuclease Activity of Flax Cotyledons following Inoculation with Flax Rust

There was a significant increase in the ribonuclease activity of both resistant (Bombay) and susceptible (Bison) varieties of flax (Linum usitatissimum L.) 3 to 4 days after inoculation with flax rust (Melampsora lini [Pers.] Lev., race No. 3). A second and much greater increase in the activity of this enzyme occurred only in the susceptible host at later stages of disease development. While a similar increase in ribonuclease level was also caused by mechanical injury, evidence is presented showing qualitative differences between the enzyme from parasitized tissue and that from the mechanically injured cotyledons. Comparison of the enzyme from healthy and inoculated cotyledons and from flax rust revealed the presence of a relatively unstable component and some unique catalytic properties in the enzyme from inoculated cotyledons.     

Genetic polymorphism of flax Linum usitatissimum based on the use of molecular cytogenetic markers

Using a set of approaches based on the use of molecular cytogenetic markers (DAPI/C-banding, estimation of the total area of DAPI-positive regions in prophase nuclei, FISH with 26S and 5S rDNA probes) and the microsatellite (SSR-PCR) assay, we studied genomic polymorphism in 15 flax (Linum usitatissimum L.) varieties from different geographic regions belonging to three directions of selection (oil, fiber, and intermediate flax) and in the k-37 × Viking hybrid. All individual chromosomes have been identified in the karyotypes of these varieties on the basis of the patterns of differential DAPI/C-banding and the distribution of 26S and 5S rDNA, and idiograms of the chromosomes have been generated. Unlike the oil flax varieties, the chromosomes in the karyotypes of the fiber flax varieties have, as a rule, pericentromeric and telomeric DAPI-positive bands of smaller size, but contain larger intercalary regions. Two chromosome rearrangements (chromosome 3 inversions) were detected in the variety Luna and in the k-37 × Viking hybrid. In both these forms, no colocalization of 26S rDNA and 5S rDNA on the satellite chromosome was detected. The SSR assay with the use of 20 polymorphic pairs of primers revealed 22 polymorphic loci. Based on the SSR data, we analyzed genetic similarity of the flax forms studied and constructed a genetic similarity dendrogram. The genotypes studied here form three clusters. The oil varieties comprise an independent cluster. The genetically related fiber flax varieties Vita and Luna, as well as the landrace Lipinska XIII belonging to the intermediate type, proved to be closer to the oil varieties than the remaining fiber flax varieties. The results of the molecular chromosome analysis in the fiber and oil flax confirm their very close genetic similarity. In spite of this, the combined use of the chromosome and molecular markers has opened up unique possibilities for describing the genotypes of flax varieties and creating their genetic passports.     

Determinants of resistant starch accumulation in wheat endosperm

A part of the big three cereal crops in the world, wheat has become a major constituent of the everyday food chain and is grown at a massive scale to meet global demands. This makes it an important crop from an economic as well as food security perspective. Selection of high-quality cultivars and consistent trait enhancement for such cultivars is crucial, and in light of new challenges from climate change, this has become an absolute necessity of time. In this regard, we conducted a detailed qualitative and quantitative trait analysis for multiple commercially viable varieties of wheat, and corresponding results were subjected to a series of critical statistical analyses. Final results have shown that five cultivars including Uqaab-2000, Faisalabad- 85, Anmol-19, NARC-2009, and Pirsabak-2004 depicts higher levels of various essential qualitative and quantitative traits (including Starch content, grain weight, RS content, Protein content, etc.) and are most viable varieties for further growth and trait enhancements to meet regional and global food challenges.     

Genetic diversity among varieties and wild species accessions of pea (Pisum sativum L.) based on molecular markers, and morphological and physiological characters.

Random amplified polymorphic DNA, simple sequence repeat, and inter-simple sequence repeat markers were used to estimate the genetic relations among 65 pea varieties (Pisum sativum L.) and 21 accessions from wild Pisum subspecies (subsp.) abyssinicum, asiaticum, elatius, transcaucasicum, and var. arvense. Fifty-one of these varieties are currently available for growers in western Canada. Nei and Li's genetic similarity (GS) estimates calculated using the marker data showed that pair-wise comparison values among the 65 varieties ranged from 0.34 to 1.00. GS analysis on varieties grouped according to their originating breeding programs demonstrated that different levels of diversity were maintained at different breeding programs. Unweighted pair-group method arithmetic average cluster analysis and principal coordinate analysis on the marker-based GS grouped the cultivated varieties separately from the wild accessions. The majority of the food and feed varieties were grouped separately from the silage and specialty varieties, regardless of the originating breeding programs. The analysis also revealed some genetically distinct varieties such as Croma, CDC Handel, 1096M-8, and CDC Acer. The relations among the cultivated varieties, as revealed by molecular-marker-based GS, were not significantly correlated with those based on the agronomic characters, suggesting that the 2 systems give different estimates of genetic relations among the varieties. However, on a smaller scale, a consistent subcluster of genotypes was identified on the basis of agronomic characters and their marker-based GS. Furthermore, a number of variety-specific markers were identified in the current study, which could be useful for variety identification. Breeding strategies to maintain or enhance the genetic diversity of future varieties are proposed.     

Molecular characterization of vernalization response genes in Canadian spring wheat.

Vernalization response (Vrn) genes play a major role in determining the flowering/maturity times of spring-sown wheat. We characterized a representative set of 40 western Canadian adapted spring wheat cultivars/lines for 3 Vrn loci. The 40 genotypes were screened, along with 4 genotypes of known Vrn genes, using previously published genome-specific polymerase chain reaction primers designed for detecting the presence or absence of dominant or recessive alleles of the major Vrn loci: Vrn-A1, Vrn-B1, and Vrn-D1. The dominant promoter duplication allele Vrn-A1a was present in 34 of 40 cultivars/lines, whereas the promoter deletion allele Vrn-A1b was present in only 1 of the western Canadian cultivars (Triticum aestivum L. 'Rescue') and 2 of its derivative chromosomal substitution lines. The intron deletion allele Vrn-A1c was not present in any line tested. Only 4 of the western Canadian spring wheat cultivars tested here carry the recessive vrn-A1 allele. The dominant allele of Vrn-B1 was detected in 20 cultivars/lines. Fourteen cultivars/lines had dominant alleles of Vrn-A1a and Vrn-B1 in combination. All cultivars/lines carried the recessive allele for Vrn-D1. The predominance of the dominant allele Vrn-A1a in Canadian spring wheat appears to be due to the allele's vernalization insensitivity, which confers earliness under nonvernalizing growing conditions. Wheat breeders in western Canada have incorporated the Vrn-A1a allele into spring wheats mainly by selecting for early genotypes for a short growing season, thereby avoiding early and late season frosts. For the development of early maturing cultivars with high yield potential, different combinations of Vrn alleles may be incorporated into spring wheat breeding programs in western Canada.     

Comparison of transgenic <Emphasis Type="Italic">Gerbera hybrida</Emphasis> lines and traditional varieties shows no differences in cytotoxicity or metabolic fingerprints

Genetic modification using gene transfer (GM) is still controversial when applied to plant breeding at least in Europe. One major concern is how GM affects other genes and thus the metabolism of the plant. In this study, 225 genetically modified lines of the ornamental plant Gerbera hybrida and 42 non-GM gerbera varieties were used to investigate changes in secondary metabolism. The cytotoxicity of GM and non-GM gerbera extracts was evaluated on human cell lines derived from lung, liver, and intestinal tissues. The results indicate that the safety profile for GM gerbera lines is similar to the viability pattern for non-GM varieties-none of the extracts were toxic. In addition, metabolic fingerprints of gerbera extracts were identified using thin-layer chromatography and analysed by principal component analysis (PCA), the nearest neighbour classifier, and Fligner-Killeen test. No new compounds unique to GM lines were observed. With PCA, no separation between GM gerbera lines and varieties could be demonstrated. In the nearest neighbour classifier, 54% of the samples found the expected neighbour based on the gene constructs used for transformation. With Fligner-Killeen test, we studied if the amounts of compounds vary more in GM gerberas than in varieties. In most cases, there were no statistically significant differences between the varieties and GM lines or there was more variation among the non-GM varieties than in the GM lines. The variance of a single compound was significantly larger in transgenic gerbera lines than in varieties and of three compounds in non-GM varieties.     

Ecology,evolution and genetics join together on Canada's east coast

The 4th regular meeting of the Canadian Society of Ecology and Evolution was held in conjunction with the 52nd Annual Conference of the Genetics Society of Canada at Dalhousie University, Halifax, from 14 to 17 May 2009.     

Genetic polymorphism of flax Linum usitatissimum based on use of molecular cytogenetic markers

Using a set of approaches based on the use of molecular cytogenetic markers (DAPI/C-banding, estimation of the total area of DAPI-positive regions in prophase nuclei, FISH with 26S and 5S rDNA probes) and the microsatellite (SSR-PCR) assay, we studied genomic polymorphism in 15 flax (Linum usitatissimum L.) varieties from different geographic regions belonging to three directions of selection (oil, fiber, and intermediate flaxes) and in the k-37 x Viking hybrid. All individual chromosomes have been identified in the karyotypes of these varieties on the basis of the patterns of differential DAPI/C-banding and the distribution of 26S and 5S rDNA, and idiograms of the chromosomes have been generated. Unlike the oil flax varieties, the chromosomes in the karyotypes of the fiber flax varieties have, as a rule, pericentromeric and telomeric DAPI-positive bands of smaller size, but contain larger intercalary regions. Two chromosomal rearrangements (chromosome 3 inversions) were discovered in the variety Luna and in the k-37 x Viking hybrid. In both these forms, no colocalization of 26S rDNA and 5S rDNA on the satellite chromosome was detected. The SSR assay with the use of 20 polymorphic pairs of primers revealed 22 polymorphic loci. Based on the SSR data, we analyzed genetic similarity of the flax forms studied and constructed a genetic similarity dendrogram. The genotypes studied here form three clusters. The oil varieties comprise an independent cluster. The genetically related fiber flax varieties Vita and Luna, as well as the landrace Lipinska XIII belonging to the intermediate type, proved to be closer to the oil varieties than the remaining fiber flax varieties. The results of the molecular chromosomal analysis in the fiber and oil flaxes confirm their very close genetic similarity. In spite of this, the combined use of the chromosomal and molecular markers has opened up unique possibilities for describing the genotypes of flax varieties and creating their genetic passports.     

玉米遗传转化与商业化转基因玉米开发*

玉米是世界上种植面积最大的粮食作物,为了提高玉米产量和满足人类需求,转基因育种已经成为改良玉米性状的有效手段。自1996年美国种植商业化转基因玉米以来,利用玉米遗传转化技术开发商业化转基因玉米已取得巨大成功。综述了玉米遗传转化体系优化的重要步骤,系统总结了已开发的商业化转基因玉米的种类,并对玉米遗传转化未来发展方向进行了展望。