Acids In Rapeseed Research Articles

A novel type of sprout food development: Effects of germination on phytic acid, glucosinolates, and lipid profiles in rapeseed

Germination, a new processing technology, is widely used to improve the nutritional value of plant seeds. Cereals and legumes sprouts are widely popular around the world. In this study, a novel form of sprouts-based rapeseed was produced. Germination promoted the degradation of phytic acid and glucosinolates (GLs) in rapeseed. On the fourth day of germination, the degradation rate of phytic acid in rapeseed was nearly 80%, and the degradation rate of GLs reached more than 90%. The changes in lipid species and content by sprouting were assessed. The crude fat content was significantly reduced during rapeseed germination. Using non-targeted lipidomics, three hundred eighty-nine lipid molecules in 4 categories and 17 subclasses were identified in rapeseed/rapeseed sprouts. Glycerides were most abundant, followed by fatty acids, glycerophospholipids, and sphingolipids. Germination affected not only the lipid content but also its composition. Some functional lipids (such as FAHFAs) were generated and enriched during germination. The content of monounsaturated fatty acids first raised and then decreased during germination. The finding will serve as a theoretical reference for developing novel sprouts based on rapeseed, furnish primary data concerning the nutritional content of rapeseed sprouts, and provide fresh ideas for rapeseed resource exploitation.

Effect of Sulphur Nutrition on the Production Potential of Brassica spp.: A Review

This paper examines the effect of sulphur on yield and quality of oilseed Brassica spp. Sulphur is a crucial nutrient for rapeseed since it is linked to productivity and a number of quality characteristics. It is necessary for the production of protein along with nitrogen and contains considerably higher sulfur-containing amino acids in rapeseed than in other crop plants. Brassicas also need sulphur in order to produce the sulfur-containing chemicals called glucosinolates. Rapeseed has a higher sulphur requirement than other crops, with 20-30 kg S ha-1 removed in the seed, whereas cereals remove only 5-15 kg ha-1. As a result, oilseed rape is especially vulnerable to sulphur shortages. Sulphur is required for the production of chlorophyll within the plant, and deficiency symptoms begin with a slight paling of the leaves and progress to interveinal chlorosis.

Safety evaluation of FAD2 RNAi transgenic Brassica napus L. based on microbial diversity and metabonomic analysis.

Oleic acid desaturase (FAD2) is the key enzyme that produces polyunsaturated fatty acids in rapeseed (Brassica napus L), which is one of the main oil crops. RNA interference (RNAi) is an emerging technique that provides new opportunities for the generation of new traits in plants. To increase oleic acid content and reduce linoleic and linolenic acid content in rapeseed, we constructed an ihpRNA plant expression vector of the FAD2 gene and obtained transgenic plants for multiple generations by stable inheritance. In this study, third-generation transgenic plants (T3), seventh-generation transgenic plants (T7), and wild-type plants (WT) were used. The differences in microbial community diversity between transgenic plants and wild-type plants and the up- and downregulation of rhizosphere metabolite contents were investigated. In conclusion, the results showed that the soil microbial community structure was stable, the general microbial community structure was not changed by the transgenic rhizosphere exudates, and no significant harmful root exudate of transgenic rapeseed on the environment was found through the microbial community and metabolomics analysis. This work may provide an understanding of the impact of RNAi on plant metabolites and a safety evaluation method for transgenic plants and a reference for rapeseed breeding.

Promising Novel Method of Acetylation Modification for Regulating Fatty Acid Metabolism in Brassica napus L.

Simple SummaryThe quality of rapeseed (Brassica napus) oil depends mainly on the degree of hydrocarbon chain saturation of fatty acids. In previous studies, seeds of the B. napus near-isogenic lines were used as raw materials by iTRAQ analysis at 20–35 days after pollination, and three differential proteins related to oleic acid metabolisms were found to be related to acetylation modification. Thus, we analyzed lysine acetylation using the same raw materials. The function of the corresponding genes of fatty acid metabolisms-related differential proteins was verified by identifying the overexpression of BnACP363K, BnACP363R, and BnACP363 in Arabidopsis thaliana. The results show that the acetylation modification of BnaACP3 may have a selective effect on oleic acid and slow down the conversion of oleic acid to linoleic acid. This is the first report of oleic acid synthesis regulation by acetylation. In this study, lysine acetylation analysis was conducted using two Brassica napus near-isogenic lines, HOCR and LOCR, containing high and low oleic acid contents, respectively, to explore this relationship. Proteins showing differences in quantitative information between the B. napus lines were identified in lysine acetylation analysis, and KEGG pathways were analyzed, yielding 45 enriched proteins, most of which are involved in carbon fixation in photosynthetic organisms, photosynthesis, ascorbate and aldarate metabolism, and glycolysis. Potential key genes related to fatty acid metabolisms were determined. To further explore the effect of acetylation modification on fatty acid metabolisms, the acyl-ACP3 related gene BnaACP363K was cloned, and a base mutation at No.63 was changed via overlapping primer PCR method. This study is the first to demonstrate that acetylation modification can regulate oleic acid metabolisms, which provides a promising approach for the study of the molecular mechanism of oleic acid in rapeseed.

Stability comparison of four lipases and catalytic mechanism during the synthesis of 1,3-di-oleic-2-medium chain triacylglycerols in a trace water-in-oil system: Experimental analyses and computational simulations.

In the present study, a kind of structured lipids, namely 1,3-di-oleic-2-medium chain (OMO) triacylglycerols, were synthesized through lipase-catalyzed reactions using coconut oil and rapeseed acid as materials in a trace water-in-oil system. Experimental analysis and computational simulations were undertaken to compare the stability of four lipases including Lipozyme RMIM, Lipozyme TLIM, Novozym 435, and Aspergillus oryzae immobilized lipase (AOIM), and illustrate catalytic mechanism of Novozym 435 during the synthesis of OMO. Fourier transform infrared and molecular dynamics simulation results demonstrated that a decrease in ordered structure (α-helix and β-sheet) led to a reduction in enzyme activity. Compared with Lipozyme RMIM and Novozym 435, Lipozyme TLIM and AOIM exhibited better stability due to a short-chain lid in TLIM, which covers activity sites, and hydrogen bonds formed between activity center of AOIM and water. Among four lipases, AOIM exhibited best catalytic performance: a OMO yield of 30.7% at 3hr and a good stability of long term (48hr). Density functional theory results demonstrated that specifically, during the synthesis of OMO triacylglycerol, the addition of Novozym 435 (derived from Candida antarctica lipase B, CALB) substantially lowered reaction barriers (64.4KJ/mol with CALB vs. 332.7KJ/mol with no lipase), aiding in the generation of OMO because of the formations of transitional tetrahedral intermediates. A trace water-in-oil system was a green and efficient alternative for lipase-catalyzed production of OMO, and this study provided crucial insights into the stability/instability and catalytic mechanisms of lipase in the synthesis of structured lipids. PRACTICAL APPLICATIONS: We compared the stability of Lipozyme RMIM, Lipozyme 435, Lipozyme TLIM, and AOIM during the synthesis of the OMO triacylglycerols in a trace water-in-oil system, where exhibited a high catalytic activity of lipase in water-oil interface. AOIM had the highest stability and showed the best catalytic performance due to the formation of hydrogen bonds. Besides, for the first time, the transition tetrahedral structure was revealed in the enzymatic synthesis of medium- and long-chain triacylglycerols. This study provides a rational approach to compare lipase stability and a possible hint to choose appropriate enzyme in a specific catalytic condition.

New Interspecific Brassica Hybrids with High Levels of Heterosis for Fatty Acids Composition

Winter oilseed rape (Brassica napus L.) is the most important oil crop in Europe. Optimizing the profile and quantity of fatty acids in rapeseed is critical for maximizing the value of edible oil. Although the utilization of crop heterosis for hybrid breeding in rapeseed is limited by the relatively narrow genetic basis of adapted germplasm, an up-to-date significant effort has been made to broaden the rapeseed gene pool using different strategies. The present study was aimed to estimate heterosis for oil quality of the newly developed Brassica interspecific hybrids, using selected parental lines. For this purpose, five parental genotypes and twenty-two interspecific cross-derived Brassica lines were evaluated in a randomized complete block design with three replications in the Greater Poland region during 2009, 2010 and 2011. Generally, the variation among genotypes was evident for most of the tested fatty acids mean values, but the differences between genotypes were not always statistically significant when based on individual fatty acids (FAs). However, the highest number of significant heterosis effects was observed for behenic and lignoceric acids and for Brassica hybrid line H1. Based on obtained results it was possible to select one genotype—the hybrid line H5, which is recommended for further inclusion in the breeding programs.

Biolubricants from Rapeseed and Castor Oil Transesterification by Using Titanium Isopropoxide as a Catalyst: Production and Characterization

The transesterification of rapeseed and castor oil methyl esters with different alcohols (2-ethyl-1-hexanol, 1-heptanol and 4-methyl-2-pentanol) and titanium isopropoxide as a catalyst, to produce biolubricants, was carried out. Parameters such as temperature, alcohol/methyl ester molar ratio, and catalyst concentration were studied to optimize the process. The reaction evolution was monitored with the decrease in FAME concentration by gas chromatography. In general, the reaction was almost complete in two hours, obtaining over 93% conversions. All the variables studied influenced on the reaction yields. Once the optimum conditions for the maximum conversion and minimum costs were selected, a characterization of the biolubricants obtained, along with the study of the influence of the kind of alcohol used, was carried out. The biolubricants had some properties that were better than mineral lubricants (flash points between 222 and 271 °C), needing the use of additives when they do not comply with the standards (low viscosity for rapeseed biolubricant, for instance). There was a clear influence of fatty acids of raw materials (oleic and ricinoleic acids as majority fatty acids in rapeseed and castor oil, respectively) and the structure of the alcohol used on the final features of the biolubricants.

Mapping loci controlling fatty acid profiles, oil and protein content by genome-wide association study in Brassica napus

Optimizing the profile and quantity of fatty acids in rapeseed (Brassica napus L.) is critical for maximizing the value of edible oil and biodiesel. However, selection of these complex seed quality traits is difficult before haplotypes controlling their contents are identified. To efficiently identify genetic loci influencing these traits and underlying candidate genes and networks, we performed a genome-wide association study (GWAS) of eight seed quality traits (oil and protein content, palmitic, stearic, oleic, linoleic, eicosenoic and erucic acids content). The GWAS population comprised 370 diverse accessions, which were phenotyped in five environments and genotyped using 60K SNP arrays. The results indicated that oil and protein contents generally showed negative correlations, while fatty acid contents showed positive or negative correlations, with palmitic and erucic acid contents directly affecting oil content. Seven SNPs on five chromosomes were associated with both seed oil and protein content, and five genes orthologous to genes in Arabidopsis thaliana were predicted as candidates. From resequencing data, besides known haplotypes in BnaA.FAE1.a and BnaC.FAE1.a, three accessions harboring a new haplotype conferring moderate erucic acid content were identified. Interestingly, in a haplotype block, one haplotype was associated with high palmitic acid content and low oil content, while the others showed the reverse effects. This finding was consistent with a negative correlation between palmitic acid and oil contents, suggesting historical selection for high oil content. The identification by this study of genetic variation and complex correlations of eight seed quality traits may be beneficial for crop selection strategies.

Up to 21 Different Sulfur‐Heterocyclic Fatty Acids in Rapeseed and Mustard Oil

AbstractThree sulfur‐heterocyclic fatty acids (SHFA) had been tentatively identified in rapeseed oil in the late 1980s. In this study we aimed to enrich and verify the presence of potential SHFA in one sample of native rapeseed oil, refined rapeseed oil and mustard seed oil. Fifty‐gram samples of the three oils were individually saponified and converted into methyl esters. The resulting samples were hydrogenated and subjected three times to urea complexation. The resulting extracts of native rapeseed oil and mustard oil contained 21 different SHFA with 18, 20, 22 or 24 carbons. The refined rapeseed oil contained only nine C18‐SHFA. Structure investigation of the SHFA was performed by gas chromatography with mass spectrometry (GC/MS) using methyl esters and also 3‐pyridylcarbinol esters. A direct screening of non‐enriched samples by GC/MS in the selected ion monitoring mode and by GC with flame photometric detector (sulfur‐selective) verified that the SHFA were native compounds of the oils and no artefacts of the sample preparation. Similar abundances of the four isomer groups of SHFA with monoenoic fatty acids of the same carbon number in these and five further rapeseed and mustard samples indicated that these could be the precursors of the SHFA.

Synthesis of environment friendly biosurfactants and characterization of interfacial properties for cosmetic and household products formulations

In this study, 2 types of zwitterionic phospholipid biosurfactants LP(A) and LP(O) were prepared using 2 different raw materials such as rapeseed oil and rapeseed acid respectively. The structure of the resulting products was elucidated by FT-IR, 1H NMR, and 13C NMR spectroscopies and the interfacial properties of LP(A) and LP(O) have been examined such as CMC, static and dynamic surface tensions, interfacial tension, wetting property, emulsion stability, and foam property. Detergency test evaluated by using a Terg-o-tometer showed moderately good detergency compared with conventional nonionic and anionic surfactants used in detergent formulations. Biodegradability, acute oral toxicity, acute dermal irritation and acute eye irritation tests revealed that LP(O) surfactant possesses excellent mildness and superior environmental compatibility, indicating the potential applicability in cosmetic and household products formulations.

Allelic Variation of BnaC.TT2.a and Its Association with Seed Coat Color and Fatty Acids in Rapeseed (Brassica napus L.).

Efficient molecular markers for the selection of rapeseed genetic materials with high seed oil content and ideal fatty acid (FA) composition are preferred by rapeseed breeders. Recently, we reported the molecular mechanism of TRANSPARENT TESTA 2 (TT2) in inhibiting seed FA biosynthesis in Arabidopsis. However, evidence showing the association of rapeseed TT2 homologs and seed FA production are still insufficient. In this study, we collected 83 rapeseed (Brassica napus L.) landraces from different geographical backgrounds to conduct association mapping of BnaC.TT2.a in relation to seed coat color and FA biosynthesis. Population background was corrected by 84 pairs of SSR markers that were uniformly distributed among the linkage groups of the Tapidor-Ningyou-7 DH population. A single copy of BnaC.TT2.a for single nucleotide polymorphism (SNP) assay was cloned by a pair of previously reported specific primers. From the analysis of BnaC.TT2.a allelic variations using GLM+Q model, four SNPs on intron 1 of BnaC.TT2.a that were associated with seed FA were discovered. Moreover, an InDel at position 738 on exon 3 of BnaC.TT2.a indicated a change of protein function that was significantly associated with seed coat color, linoleic acid (C18:2), and total FA content. These findings revealed the role of BnaC.TT2.a in regulating the seed color formation and seed FA biosynthesis in rapeseed, thereby suggesting effective molecular markers for rapeseed breeding.

QTL mapping based on the embryo and maternal genetic systems for non-essential amino acids in rapeseed (Brassica napus L.) meal.

Non-essential amino acids are a good source of nitrogen and also very important contributors to the metabolic process. Analysis of quantitative trait locus (QTL) simultaneously located on the amphidiploid embryo and maternal plant nuclear genomes for non-essential amino acid contents in rapeseed meal across different environments was conducive to further clarify the genetic mechanism of seed quality traits. Twenty-eight QTLs associated with arginine (five QTLs), histidine (four QTLs), glutamic acid (three QTLs), glycine (three QTLs), proline (three QTLs), alanine (four QTLs) and aspartic acid (six QTLs) contents were identified in present study. All of these QTLs had significant additive main effects from embryo and maternal plant nuclear genomes with eight of them showing significant embryo dominance main effects and 12 showing notable QTL × environment interaction effects. Among them, 12 QTLs were major QTLs which could explain 13.27-35.71% of the phenotypic variation. Specially, five QTL clusters associated with several QTLs related to multiple traits were distributed on chromosomes A1, A4, A5, A7 and C2. Non-essential amino acids in rapeseed meal could be simultaneously controlled by the genetic effects from the QTLs which were located on the chromosomes both in the embryo and maternal plant genetic systems.

Winter Oilseed Rape Productivity and Nutritional Quality Responses to Zinc Fertilization

Soil Zn is always potentially deficient in Yangtze River Basin (YRB) of China, due to widespread alkaline soils, high soil P, and large Zn removal of high‐yielding oilseed rape (Brassica napus L.) and rice (Oryza sativa L.) cultivars. However, Zn fertilizer response of winter oilseed rape in YRB is not clear. Therefore, on‐farm experiments were conducted at six locations to investigate the effects of experimental sites and Zn rates (0 and 6.8 kg Zn ha−1) on plant growth, seed yield and quality, and Zn uptake of oilseed rape (Huashuang no. 5 cultivar). Across all the sites, Zn application increased seed yield by 5.0 to 16.0%, oil yield by 6.2 to 19.5%, and protein yield by 2.3 to 17.7%. Application of Zn fertilizer increased the concentrations of total oil, oleic acid, and linoleic acid in rapeseed, but reduced stearic acid concentration. No differences were observed on protein and linolenic acid concentrations between Zn rates. Total Zn uptake in plants increased by 13.5 to 62.3% with Zn fertilizer applied, while Zn harvest index reduced by 3.4 to 18.5%. Oilseed rape performance varied among sites. The extensive significant Zn × site interactions indicated that Zn response was dependent on the environments we studied. Thus, Zn fertilizer management will probably need to be adjusted at different sites. Our results suggested to apply Zn fertilizer to improve oilseed rape productivity, nutritional quality, and Zn uptake. This study also increased the understanding of the positive effects of Zn on rapeseed oil content and fatty acids composition.

EMS-induced Mutagenesis for C18 Unsaturated Fatty Acids in Rapeseed (Brassica napus L.)

Rapeseed (Brassica napus L.) oil with high oleic acid content is of great interest for both food and non-food uses. The 'Tamla' variety, characterized by oleic acid content of approximately 69%, was treated with 1% ethyl methane sulfonate (EMS) to induce mutations in the fatty acid biosynthesis pathway. <TEX>$M_1$</TEX> plants were selfed and subsequent generations (<TEX>$M_2$</TEX>, <TEX>$M_3$</TEX>, and <TEX>$M_4$</TEX> mutants) were analyzed to identify mutants having increased levels of oleic acid. <TEX>$M_2$</TEX> mutants showed oleic acid content ranging from 13.5% to 76.9% with some mutants (TR-458 and TR-544) having up to 74.7% and 76.9% oleic acid, which was an increase of nearly 5% and 7%, respectively, compared to untreated cv 'Tamla'. We selected two <TEX>$M_3$</TEX> mutants with >75% oleic acid content. One mutant (TR-458-2) had increased oleic acid (75.9%) and decreased linoleic acid (12.5%) and linolenic acid (4.4%) contents. The other (TR-544-1) showed increased oleic acid content (75.7%) and decreased linoleic acid (13.5%) and linolenic acid (3.3%) contents. The accumulation or reduction of oleic acid content in the selected <TEX>$M_4$</TEX> mutants was also accompanied by a simultaneous decrease or increase in linoleic and linolenic acid contents. The high-oleic lines could be utilized further in breeding programs for improvement of rapeseed oil quality.

Green Ester Lubricants Based on Rapeseed Acid and their Lubricity

Several complex esters were synthesized from phthalic anhydride, neopentyl glycol and rapeseed acid. Their rheological properties, biodegradability and tribological properties were measured. It was found that the complex esters have a wide viscosity range of 126~325mm2/s at 40°C with viscosity indices about 127~143, and solidifying points lower than-38°C. The maximum non seizure load of a complex ester with degree of polymerization 1.42 is as high as 735 N, with a wear scar diameter of 0.41mm, superior to mineral oil. The biodegradation rates are higher than 73%, and the thermal stability is good. So these complex esters are a class of green synthetic ester oils with excellent properties.

Mapping of QTLs controlling content of fatty acid composition in rapeseed (Brassica napus)

The improvement of fatty acid composition is one of the major goals of breeding in rapeseed (Brassica napus). The aim of this study was to provide more information on the genetic determination of fatty acid composition by investigating quantitative trait loci (QTLs). The study was based on two-year of field trials (in 2006 and 2007) with a population of recombinant inbred lines (RILs), which originated from a cross between GH06 and P174. The level of erucic acid (C22:1) was significantly negatively correlated with those of palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2), linolenic acid (C18:3), and eicosenoic acid (C20:1) in both years. A total of 40 QTLs for six fatty acids were detected and most of them were clustered on linkage groups N8, N9, and N13. These results suggested strongly that there were significant correlations between the levels of fatty acid components and would be useful for the future improvement of breeding programs focused on fatty acids in rapeseed.

Effect of sowing time on grain yield, oil content, and fatty acids in rapeseed (Brassica napus subsp. oleifera)

Sowing time is an important factor affecting crop yield and quality, especially in arid and semi-arid regions. The aim of this research was to investigate the effects of sowing time on the growth, yield, and quality of rapeseed genotypes and to determine genotype × sowing time interactions for grain yield and its related traits. The study was carried out using 8 winter rapeseed genotypes (H604049, H604038, H604041, Viking, Elan, Titan, Lorenz, and Trabant) and 4 sowing times (10 October, 20 October, 30 October and 10 November) during the 2005-2006 and 2006-2007 growing seasons. An NIRS system was used to determine oil, protein, glucosinolate and sinapic acid esters. Fatty acid analyses were done by the capillary gas chromatography method. Significant differences were found between sowing times for most of the traits measured. The lowest average seed yield (1027.40 kg ha^{-1}) was obtained from the latest sowing time, whereas the highest average seed yield (2437.50 kg ha^{-1}) was obtained from the earliest sowing time. The genotype H604038 produced the highest seed yield (1988.4 kg ha^{-1}), and it was followed by Trabant (1980.8 kg ha^{-1}) and Titan (1963.8 kg ha^{-1}). The highest oil content, at 42.0%, was obtained from genotype Lorenz at the first sowing time and from genotype Trabant at the second sowing time. No interaction was found between genotype and sowing time for oil content, but significant interactions were found for seed yield and glucosinolates. Seed yield significantly decreased as sowing time was delayed. The effects of sowing time on fatty acid composition were also significant. As a result, it was found that sowing time is an important factor for seed yield and quality in rapeseed.

Production of unusual fatty acids in rapeseed

Vegetable-derived oils are of interest for industrial applications partly because of the chemical similarity of plant oils to mineral oils but also because of the economic need to reduce overproduction of seed oils for nutritional use. Complex oils can be produced in seeds as a low cost agricultural product based on renewable solar energy that requires less refining and is biodegradable and thus produces less adverse effects on the environment. In addition, biotechnologies have accelerated selection programmes and increased the genetic diversity available for the development of new varieties of oilseeds with specific fatty acid compositions. In the developing oilseed, energy and carbon are stored as lipid under the form of triacylglycerol, that is, a glycerol molecule to which three fatty acids are esterified. Fatty acids comprise a linear chain of carbon atoms, the first of which carries an organic acid group. The chain length and the presence of double bonds determine the properties of the fatty acid which in turn determine the physical and chemical properties of the oil of storage lipids and hence their economic value. In addition to the common C16- and C18-saturated and unsaturated fatty acids of membrane lipids, the seed storage lipids of many plant species contain unusual fatty acids (UFAs) which can vary in chain length, in the degree of unsaturation, possess double bonds in unusual positions, or can contain additional functional groups such as hydroxy, epoxy, cyclic and acetylenic groups [1]. These unusual fatty acids are of value as industrial feedstocks and their uses include the production of fuels and lubricants, soap and detergents, paints and varnishes, adhesives and plastics (Figure 1).

Beneficial effects of Rhizopus oligosporus fermentation on reduction of glucosinolates, fibre and phytic acid in rapeseed ( Brassica napus) meal

Solid state fermentation was employed using Rhizopus oligosporus to develop a fermented product from rapeseed meal (RSM). The contents of glucosinolates, thiooxazolidones, phytic acid and crude fibre declined by 43.1%, 34%, 42.4% and 25.5%, respectively, following inoculation with R. oligosporus. Fermentation also increased nitrogen and protein contents of the meal. This study may open a new prospective for a simple and cost effective technique for reduction of toxicants in RSM.

SCAR and RAPD markers associated with 18‐carbon fatty acids in rapeseed, Brassica napus

AbstractBreeding rapeseed for enhanced oil quality includes the development of varieties with low linolenic acid content. The breeder also aims to develop varieties with a high linoleic acid content because of its nutritional value. Restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) markers have been developed for linolenic acid content, but they are not best suited for a direct application in marker‐assisted selection. The RFLP technique is too complex and time‐consuming and RAPD markers lack codominance, precluding the distinction of homozygous from heterozygous individuals. In this report the conversion of a RAPD marker to a codominant sequence characterized amplified region (SCAR) marker named L1L9 is described. One of the alleles consisting of an 899 bp fragment (allele A), is associated with low linolenic acid content. The other allele consists of an 641 bp fragment (allele B) and is associated with high linolenic acid content. This marker explains approximately 25% of the genetic variation for this trait. Linkage analysis in the mapping population indicates that the SCAR marker probably tags an ω‐3 desaturase gene in B. napus. Two RAPD markers were found to be associated with oleic/linoleic acid content. Markers M14‐350 and I06‐650 explained approximately 10% and 7% of the genetic variation for linoleic acid content, respectively. These two markers were found linked at 12.3cM in the segregating B. napus F2 progeny used for mapping. All the markers reported in this paper should be useful in breeding programmes for developing high linoleic and low linolenic acid rapeseed varieties.